Principles- Monitoring John's study copy Flashcards

Question

Which of the following forms of hemoglobin cannot be accurately measured at 940 nm? A) Oxyhemoglobin (O₂Hb) B) Reduced hemoglobin (deO₂Hb) C) Methemoglobin (metHb) D) Carboxyhemoglobin (COHb)

Answer 1

Correct Answer: D) Carboxyhemoglobin (COHb) Rationale: Carboxyhemoglobin does not have a significant absorption peak at 940 nm, making it less accurately measured at this wavelength compared to methemoglobin.

Answer 2

Correct Answer: C) Methemoglobin (metHb) Rationale: Methemoglobin is formed when the iron in hemoglobin is oxidized to the ferric (Fe³⁺) state, which impairs its ability to bind oxygen effectively. sulfur-based antibiotics, phenazopyridine, phenacetin, acetanilide, nitrates, sumatriptan, and metoclopramide Exposure to sulfur-containing compounds: Such as air pollution or occupational exposure

Answer 3

Correct Answer: B) 660 nm Rationale: Deoxyhemoglobin absorbs more red light at 660 nm compared to oxyhemoglobin, which is used to differentiate between these forms of hemoglobin in pulse oximetry.

Answer 4

Correct Answer: D) Infrared light Rationale: Oxyhemoglobin absorbs more infrared light (940 nm) than deoxyhemoglobin, which is a key principle in the operation of pulse oximetry.

Answer 5

Correct Answer: C) To differentiate between oxyhemoglobin and deoxyhemoglobin Rationale: Using both red (660 nm) and infrared (940 nm) wavelengths allows pulse oximeters to distinguish between oxyhemoglobin and deoxyhemoglobin, providing accurate oxygen saturation measurements.

Answer 6

Correct Answer: B) Deoxyhemoglobin absorbs more red light than oxyhemoglobin Rationale: Deoxyhemoglobin absorbs more red light at 660 nm, which helps in differentiating it from oxyhemoglobin using pulse oximetry.

Answer 7

Correct Answer: C) Arterial oxygen saturation (SaO₂) Rationale: The pulsatility of arterial blood flow is used to estimate arterial oxygen saturation (SaO₂) in pulse oximetry.

Answer 8

Correct Answer: B) Venous blood C) Skin and soft tissue D) Capillary blood Rationale: The non-pulsatile component (DC) of light absorption includes everything that is not the pulsatile arterial blood, such as skin, soft tissue, and venous blood.

Answer 9

Correct Answer: B) It increases the light absorption path Rationale: The pulsatile expansion of the artery increases the length of the light path, which in turn increases the absorption of light.

Answer 10

Correct Answer: B) Pulsatile arterial blood Rationale: The AC component represents the pulsatile arterial blood, which is the main variable component used to estimate oxygen saturation.

Answer 11

Correct Answer: C) Decreased pulsatility of arterial blood Rationale: In shock, the pulsatility of arterial blood is reduced due to vasoconstriction, leading to poor pulse oximetry readings.

Answer 12

Correct Answer: B) Pulsatile component divided by non-pulsatile component for each wavelength Rationale: The ratio of the pulsatile component (AC) to the non-pulsatile component (DC) for each wavelength is used in pulse oximetry to determine oxygen saturation.

Answer 13

Correct Answer: B) It falsely elevates SpO₂ readings Rationale: Carboxyhemoglobin absorbs as much light in the 660 nm range as oxyhemoglobin, leading to falsely elevated SpO₂ readings.

Answer 14

Correct Answer: B) Increases SpO₂ by 1% Rationale: Each 1% increase in COHb will falsely increase the SpO₂ reading by 1%.

Answer 15

Correct Answer: C) It has a higher affinity for oxygen, preventing oxygen release Rationale: Carboxyhemoglobin has a higher affinity for oxygen, which prevents the release of oxygen to tissues, a condition that is particularly concerning for patients exposed to fires.

Answer 16

Correct Answer: B) Because smoking increases COHb levels, often exceeding 6% Rationale: Many smokers have elevated levels of COHb, often greater than 6%, due to the carbon monoxide inhaled from cigarette smoke.

Answer 17

Correct Answer: C) Red skin Rationale: Carbon monoxide poisoning can cause patients to appear red due to the high levels of carboxyhemoglobin in the blood.

Answer 18

Correct Answer: B) By alternating red and infrared light Rationale: Alternating red and infrared light can help mitigate the effects of ambient light interference in pulse oximetry.

Answer 19

Correct Answer: B) It reduces signal amplitude Rationale: Low perfusion leads to a reduced signal amplitude, which can affect the accuracy of pulse oximetry readings.

Answer 20

Correct Answer: B) Because they interfere with the detection of arterial O₂Hb saturation Rationale: Venous blood pulsations can cause a reduction in presumed arterial SpO₂ by interfering with the detection of arterial oxygen saturation.

Answer 21

Correct Answer: B) Intravenous dyes such as methylene blue Rationale: Intravenous dyes like methylene blue can act as additional light absorbers and affect the accuracy of pulse oximetry readings.

Answer 22

Correct Answer: B) Nail polish Rationale: Nail polish, particularly dark colors, can interfere with pulse oximetry readings by absorbing light and affecting the measurement of oxygen saturation.

Answer 23

Correct Answer: B) +/- 2% Rationale: Pulse oximetry is accurate to within +/- 2% when measured against ABGs for SaO₂ levels greater than 70%.

Answer 24

Correct Answer: A) Anesthetic vapors Rationale: Pulse oximetry readings are not affected by anesthetic vapors, making it reliable in various clinical settings where anesthetic gases are used.

Answer 25

Correct Answer: D) Its continuous monitoring capability Rationale: Pulse oximetry provides continuous monitoring of oxygen saturation, which is crucial for ongoing patient assessment.

Answer 26

Correct Answer: C) Through waveform analysis Rationale: The waveform provided by pulse oximetry can indicate decreased cardiac output by showing changes in the pulsatile flow of arterial blood.

Answer 27

Correct Answer: C) Ability to use on different patient populations Rationale: The variety of probes available allows pulse oximetry to be used across different patient populations, from neonates to adults.

Answer 28

Correct Answer: C) It depends on strong arterial pulsatility for accurate readings Rationale: Pulse oximetry requires strong arterial pulsatility for accurate readings, and low perfusion reduces signal amplitude, affecting the accuracy.

Answer 29

Correct Answer: B) Delayed detection of hypoxia Rationale: Pulse oximetry can have a delayed response in detecting hypoxic events, meaning patients may exhibit internal signs of hypoxia before it is reflected in the SpO₂ readings.

Answer 30

Correct Answer: B) Dysrhythmias Rationale: Dysrhythmias can cause erratic performance in pulse oximetry due to the irregular pulsatile flow affecting the readings.

Answer 31

B) The dyes enhance light absorption

Answer 32

Correct Answer: B) The SpO₂ monitor would read falsely low Rationale: Based on the information about signal artifacts and the effects of intravenous dyes on pulse oximetry readings, it has been confirmed that intravenous dyes such as methylene blue can cause falsely low SpO₂ readings. This occurs because methylene blue and similar dyes absorb light at wavelengths used by pulse oximeters (particularly around 660 nm), which interferes with the device's ability to accurately measure oxygen saturation. The effect of these dyes typically results in a significant reduction in the reported SpO₂ levels

Answer 33

Correct Answer: B) They are sensitive to vasoconstriction Rationale: Fingers are relatively sensitive to vasoconstriction, which can affect blood flow and the accuracy of pulse oximetry readings. In such cases, alternative sites like toes or central locations may provide more reliable readings.

Answer 34

Correct Answer: B) They inhibit the transmission of light Rationale: Dark polish or synthetic nails can block or absorb light, which inhibits the accurate transmission and measurement of light by the pulse oximeter, leading to potentially inaccurate readings.

Answer 35

B) Index finger

Answer 36

Correct Answer: C) Desaturation and resaturation occur more centrally first Rationale: Detection of desaturation and resaturation is slower peripherally because these events happen more centrally first. The central sites reflect changes in oxygenation more quickly.

Answer 37

Correct Answer: B) Tongue, cheek, and forehead Rationale: Tongue, cheek, and forehead are less affected by vasoconstriction, making them better sites for reflecting desaturation quickly. These sites are more reliable in conditions where peripheral perfusion is compromised.

Answer 38

Correct Answer: B) Series of audible frequencies, produced by turbulent flow beyond the partially occluded cuff Rationale: Korotkoff sounds are a series of audible frequencies produced by turbulent blood flow as it passes through the arteries that are partially occluded by a blood pressure cuff.

Answer 39

Correct Answer: A) Phase I Rationale: Phase I of Korotkoff sounds is characterized by the most turbulent and audible sounds, indicating the systolic blood pressure.

Answer 40

Correct Answer: D) Phase V Rationale: Phase V of Korotkoff sounds is when the sounds disappear, indicating the diastolic blood pressure.

Answer 41

Correct Answer: B) Crisper and louder sounds Rationale: Phase III Korotkoff sounds are described as crisper and louder compared to other phases.

Answer 42

Mean BP = DP + 1/3(SP – DP)

Answer 43

Correct Answer: B) Due to decreased peripheral flow Rationale: Shock and intense vasoconstriction reduce peripheral blood flow, which can make it difficult to detect Korotkoff sounds during auscultation.

Answer 44

Correct Answer: C) Changes in vessel compliance Rationale: Severe edema and atherosclerotic vascular changes alter vessel compliance, potentially complicating the detection of accurate blood pressure readings.

Answer 45

Correct Answer: B) Inaccurate blood pressure measurement Rationale: Using an incorrect cuff size, such as one that does not properly fit the circumference or length of the arm, can lead to inaccurate blood pressure measurements

Answer 46

Correct Answer: B) Small children Rationale: Small children are often challenging for accurate auscultation because their Korotkoff sounds can be difficult to hear.

Answer 47

Correct Answer: B) 40% of arm circumference and 80% of length of the upper arm Rationale: The cuff bladder should cover 40% of the arm circumference and 80% of the length of the upper arm for accurate blood pressure measurement.

Answer 48

Correct Answer: B) Oscillometry Rationale: Automatic non-invasive blood pressure measurement is based on oscillometry, which measures the oscillations in the arterial wall as the cuff inflates and deflates.

Answer 49

Correct Answer: C) Mean arterial pressure (MAP) Rationale: The maximal amplitude of oscillations corresponds to the mean arterial pressure (MAP) in automatic non-invasive blood pressure measurement.

Answer 50

Correct Answer: B) Atherosclerosis Rationale: Conditions such as atherosclerosis, edema, obesity, and chronic hypertension can produce errors in automatic non-invasive blood pressure measurements due to altered arterial wall compliance and other factors.

Answer 51

Correct Answer: A) It leads to low blood pressure readings Rationale: Using a cuff that is too large can result in falsely low blood pressure readings because the cuff may not compress the artery adequately.

Answer 52

Correct Answer: B) Narrowed pulse pressure Rationale: Low SBP and high DBP indicate a narrowed pulse pressure, which is often seen in conditions such as atherosclerosis, edema, obesity, and chronic hypertension.

Answer 53

Correct Answer: B) Critically ill or older patients Rationale: Systolic blood pressure (SBP) measured by automatic non-invasive techniques has the least agreement with invasive blood pressure measurements in critically ill or older patients due to factors such as vascular changes and reduced compliance.

Answer 54

Correct Answer: D) Up to 20 mm Hg Rationale: While the average difference should ideally be less than +/- 5 mm Hg, deviations up to 20 mm Hg are considered "acceptable" in practice.

Answer 55

Correct Answer: B) Underestimating MAP Rationale: During hypertension, there is a tendency to underestimate the mean arterial pressure (MAP).

Answer 56

Correct Answer: C) It overestimates SBP and underestimates DBP Rationale: Measuring blood pressure on the forearm in obese patients may be preferable to the upper arm, but it can lead to overestimation of systolic blood pressure (SBP) and underestimation of diastolic blood pressure (DBP).

Answer 57

Correct Answer: C) To account for natural variability and improve accuracy Rationale: Averaging or trending multiple blood pressure measurements helps to account for natural variability and improve the overall accuracy and reliability of the readings.

Answer 58

Correct Answer: B) Reduced accuracy with narrowed pulse pressure Rationale: Chronic hypertension can lead to reduced accuracy in automatic non-invasive blood pressure measurements due to the narrowed pulse pressure, which affects the estimations of systolic and diastolic pressures.

Answer 59

Correct Answer: C) Elimination of clinician subjectivity Rationale: Automatic non-invasive blood pressure measurement eliminates clinician subjectivity, leading to more standardized and objective readings.

Answer 60

Correct Answer: C) By utilizing consistent and repeatable technology Rationale: The use of automated technology in non-invasive blood pressure measurement improves quality and accuracy by providing consistent and repeatable results.

Answer 61

Correct Answer: B) The automatic functioning of the device Rationale: "Automaticity" refers to the device's ability to function automatically, reducing the need for manual intervention and simplifying the process of measuring blood pressure.

Answer 62

Correct Answer: C) By offering continuous and reliable monitoring Rationale: Automatic non-invasive blood pressure measurement contributes to improved patient care by offering continuous and reliable monitoring, allowing for timely and accurate assessment of patient status.

Answer 63

Correct Answer: B) They are less reliable and slower to adapt to rapid changes in blood pressure Rationale: In rapidly changing situations like CABG (coronary artery bypass graft) or bleeding, automatic non-invasive blood pressure measurements are less reliable and slower to respond to rapid fluctuations, making them unsuitable for such critical conditions.

Answer 64

Correct Answer: C) Compartment syndrome Rationale: Complications such as compartment syndrome, pain, petechiae, ecchymoses, limb edema, venous stasis, and thrombophlebitis can arise from prolonged or improper use of automatic non-invasive blood pressure cuffs.

Answer 65

Correct Answer: B) Severe coagulopathies Rationale: Patients with severe coagulopathies, peripheral neuropathies, arterial/venous insufficiency, or recent thrombolytic therapy should be approached with caution when using automatic non-invasive blood pressure measurement due to increased risk of complications.

Answer 66

Correct Answer: C) Tightness and pressure from the cuff Rationale: The tightness and pressure applied by the cuff during inflation can cause significant discomfort to the patient, especially with repeated measurements.

Answer 67

Correct Answer: B) Due to improper placement or prolonged pressure Rationale: Peripheral neuropathy can occur if the cuff is improperly placed or if pressure is applied for too long, leading to nerve compression and damage.

Answer 68

Correct Answer: C) It provides continuous, real-time measurements Rationale: Invasive blood pressure monitoring offers continuous, real-time measurements, which is crucial for managing critically ill patients.

Answer 69

Correct Answer: C) It allows for immediate and accurate assessment of blood pressure changes Rationale: Invasive monitoring provides immediate and accurate blood pressure readings, which are essential for adjusting doses of pressors and other medications in real-time.

Answer 70

Correct Answer: B) It eliminates the need for multiple needle sticks Rationale: Invasive blood pressure monitoring, typically using an arterial line, allows for repeated blood sampling without the need for multiple needle sticks, reducing patient discomfort and risk of infection.

Answer 71

Correct Answer: C) By allowing dynamic assessment through real-time monitoring Rationale: Invasive monitoring enables dynamic assessment of volume responsiveness by providing real-time data on blood pressure changes in response to fluid administration or withdrawal.

Answer 72

Correct Answer: B) To time IABP counter pulsation accurately Rationale: Invasive blood pressure monitoring is crucial for accurately timing the counter pulsation of the intra-aortic balloon pump (IABP), which is essential for optimizing its therapeutic effect.

Answer 73

Correct Answer: C) Radial artery Rationale: The radial artery is the most common site for arterial blood pressure monitoring because it is easy to access and complications are uncommon.

Answer 74

Correct Answer: C) Femoral artery Rationale: The femoral artery is the largest vessel used for monitoring, but it carries a higher risk of hidden hematomas and is easier to contaminate.

Answer 75

Correct Answer: B) They use a longer catheter which could impede blood flow to the hand Rationale: The brachial and axillary arteries require the use of a longer catheter, which could potentially impede blood flow to the hand.

Answer 76

Correct Answer: C) They show greater disagreement with non-invasive blood pressure measurements Rationale: The posterior tibial and dorsalis pedis arteries, located in the feet, often show greater disagreement with non-invasive blood pressure measurements.

Answer 77

Correct Answer: D) Posterior tibial artery Rationale: The posterior tibial artery is often avoided due to increased patient discomfort and potential for inaccurate readings compared to more commonly used sites like the radial artery.

Answer 78

Correct Answer: B) To assess collateral circulation in the hand Rationale: The Allen's test is performed to evaluate the adequacy of collateral circulation in the hand, ensuring that both the radial and ulnar arteries can provide sufficient blood flow.

Answer 79

Correct Answer: B) Make a tight fist Rationale: The patient should make a tight fist to exsanguinate the palm, ensuring that blood flow is restricted from both arteries before testing collateral circulation.

Answer 80

Correct Answer: B) The color of the palm returns in seconds Rationale: A normal finding is the return of color to the palm within seconds, indicating adequate collateral circulation through the ulnar artery.

Answer 81

Correct Answer: B) Severely reduced collateral flow Rationale: A delay of more than 10 seconds in the return of color suggests severely reduced collateral flow, indicating a potential issue with the ulnar artery.

Answer 82

Correct Answer: C) Its accuracy is not significantly improved by pulse oximetry or ultrasound Rationale: The predictive value of the Allen's test is considered poor because its accuracy does not significantly improve with the use of additional tools like pulse oximetry or ultrasound.

Answer 83

Correct Answer: C) To provide maximum exposure of the radial artery Rationale: Taping the patient's fingers back helps to provide maximum exposure of the radial artery, making the cannulation process easier and more precise.

Answer 84

Correct Answer: C) 30° - 45° Rationale: The needle should be inserted at an angle of 30° to 45° to the skin to properly access the radial artery for cannulation.

Answer 85

Correct Answer: C) Traditional Seldinger technique Rationale: The traditional Seldinger technique involves inserting a needle, passing a guidewire through the needle, removing the needle, and then inserting the catheter over the guidewire.

Answer 86

D) Passing the guidewire through the needle

Answer 87

Correct Answer: B) Both the front and back walls of the artery are punctured intentionally Rationale: In the transfixion technique, both the front and back walls of the artery are intentionally punctured, which is a distinctive step compared to other arterial cannulation techniques.

Answer 88

Correct Answer: D) Withdrawing the catheter until pulsatile blood flow appears Rationale: After removing the needle, the catheter is withdrawn until pulsatile blood flow appears and then advanced to establish proper positioning.

Answer 89

Correct Answer: C) Same positioning and preparation as other techniques Rationale: The transfixion technique requires the same positioning and preparation as other arterial cannulation techniques.

Answer 90

Correct Answer: C) The technique itself does not increase the risk of complications Rationale: The transfixion technique is not associated with more frequent complications because the technique itself, when performed correctly, does not inherently increase the risk of complications.

Answer 91

Correct Answer: C) Pulsatile blood flow appearing in the catheter Rationale: Successful arterial cannulation is indicated by the appearance of pulsatile blood flow in the catheter, confirming proper placement within the artery.

Answer 92

Correct Answer: B) To avoid potential complications Rationale: The normal saline used in the automatic flush should lack dextrose and heparin to avoid complications such as hyperglycemia or anticoagulation issues that could arise from prolonged use. automatic normal saline flush at 1-3 ml/hr helps prevent thrombus formation in the arterial line, ensuring it remains patent and functional.

Answer 93

Correct Answer: B) Setting the transducer to atmospheric pressure Rationale: Zeroing the arterial line involves referencing the transducer to atmospheric pressure to ensure accurate pressure readings.

Answer 94

Correct Answer: B) Aortic root Rationale: The arterial line transducer should be leveled at the aortic root to ensure accurate pressure measurements.

Answer 95

Correct Answer: C) Limit stopcocks and tubing length, use non-distensible tubing Rationale: To maximize waveform quality, it is recommended to limit the number of stopcocks and the length of the tubing, and to use non-distensible tubing, ideally having just one stopcock to minimize distortions and delays in the pressure waveform.

Answer 96

Correct Answer: B) It occurs immediately after the R wave Rationale: The systolic upstroke on the arterial waveform occurs immediately after the R wave on the EKG, indicating the start of systole as the ventricles contract.

Answer 97

Correct Answer: B) Closure of the aortic valve Rationale: The dicrotic notch represents the closure of the aortic valve, marking the end of systole and the beginning of diastole.

Answer 98

Correct Answer: B) Point 2 Rationale: Point 2 on the arterial waveform corresponds to the systolic peak pressure, which is the highest pressure reached during ventricular contraction.

Answer 99

Correct Answer: B) The declining phase after the systolic peak pressure Rationale: The diastolic runoff represents the period where the pressure in the arteries declines after the systolic peak pressure, reflecting the blood flow out of the arteries during diastole.

Answer 100

Correct Answer: B) At the lowest point before the next systolic upstroke Rationale: The end-diastolic pressure is found at the lowest point on the arterial waveform before the next systolic upstroke begins, indicating the pressure in the arteries just before the ventricles contract again.

Answer 101

Correct Answer: C) Distal pulse amplification Rationale: As the arterial pressure wave moves distally from the aortic arch to peripheral arteries, it undergoes amplification, leading to a steeper arterial upstroke and a higher systolic peak pressure.

Answer 102

Correct Answer: C) Arterial upstroke Rationale: The arterial upstroke becomes steeper as the pressure wave moves towards the periphery, reflecting the increased speed and force of the pressure wave in smaller, more distal arteries.

Answer 103

Correct Answer: D) It increases Rationale: The systolic peak pressure increases as the pressure wave moves from central arteries, such as the aortic arch, to peripheral arteries, like the femoral artery, due to the phenomenon of distal pulse amplification.

Answer 104

Correct Answer: B) It appears later Rationale: As the pressure wave travels distally, the dicrotic notch appears later in the arterial waveform, reflecting the delayed closure of the aortic valve relative to the distal location.

Answer 105

Correct Answer: D) End-diastolic pressure becomes lower Rationale: As the pressure wave moves from the aortic arch to peripheral arteries, the end-diastolic pressure becomes lower, indicating the reduced residual pressure in the distal arteries at the end of diastole.

Answer 106

Correct Answer: B) A combination of fundamental and harmonic waves Rationale: A typical arterial pressure waveform is created by the summation of a fundamental wave and several harmonic waves, resulting in the complex waveform seen in arterial pressure monitoring.

Answer 107

Correct Answer: C) 6 to 10 Rationale: To accurately represent most arterial pressure waveforms, 6 to 10 harmonic waves are typically required. This combination helps capture the complexity of the waveform.

Answer 108

Correct Answer: B) A technique to analyze the summation of multiple sine waves Rationale: Fourier analysis is a mathematical method used to analyze and break down complex waveforms into their constituent sine waves, facilitating the understanding of arterial pressure waveforms.

Answer 109

Correct Answer: C) A typical arterial pressure waveform Rationale: The summation of the fundamental wave and harmonic waves results in a typical arterial pressure waveform, which is complex and represents the various phases of the cardiac cycle.

Answer 110

Correct Answer: C) To assess the accuracy and dynamic response of the arterial pressure monitoring system Rationale: The square wave test is performed to evaluate the accuracy and dynamic response of the arterial pressure monitoring system, ensuring it can correctly capture pressure changes.

Answer 111

Correct Answer: B) The system has good resolution at higher frequencies Rationale: A distinct dicrotic notch suggests that the system is not overdamped and has good resolution at higher frequencies, indicating accurate pressure waveform reproduction.

Answer 112

Correct Answer: B) No more than 2 oscillations Rationale: There should be no more than 2 oscillations following the fast flush, and the amplitude of each oscillation should decrease by no more than 1/3 of the previous oscillation to ensure proper damping.

Answer 113

Correct Answer: C) Less than 30 msec Rationale: The time interval between oscillations should be less than 30 msec, corresponding to a natural frequency of 33 Hz, indicating that the system can accurately capture rapid changes in pressure.

Answer 114

Correct Answer: B) The system is underdamped Rationale: If the system shows more than 2 oscillations following the fast flush, it indicates that the system is underdamped, which can lead to exaggerated pressure readings and inaccurate monitoring.

Answer 115

Correct Answer: B) Systolic pressure is elevated Rationale: In an underdamped arterial line system, the systolic pressure reading is elevated due to excessive oscillations of the pressure waveform, leading to an overestimation of the true systolic pressure.

Answer 116

Correct Answer: C) Dicrotic notch Rationale: In an overdamped arterial waveform, the dicrotic notch is often absent due to the excessive damping of the pressure signal, which leads to a loss of waveform detail and a falsely narrowed pulse pressure.

Answer 117

Correct Answer: A) Multiple oscillations following the fast flush Rationale: An underdamped system is indicated by multiple oscillations following the fast flush during a square wave test, suggesting excessive oscillation and poor damping.

Answer 118

Correct Answer: C) MAP remains largely accurate in both systems Rationale: Despite the distortions in the systolic and diastolic pressure readings, the mean arterial pressure (MAP) remains largely accurate in both underdamped and overdamped systems.

Answer 119

Correct Answer: D) Systolic pressure is decreased, and diastolic pressure is overestimated Rationale: In an overdamped system, the systolic pressure is decreased and the diastolic pressure is overestimated, leading to a falsely narrowed pulse pressure.

Answer 120

Correct Answer: B) Decreases distensibility and raises systolic pressure Rationale: Aging leads to a loss of arterial distensibility, which causes an increase in systolic pressure due to stiffer arteries, as depicted in the waveform comparison between young and elderly individuals. (lowers diastolic)

Answer 121

Correct Answer: A) Atherosclerosis Rationale: Atherosclerosis leads to the thickening and hardening of the arterial walls, increasing peripheral vascular resistance and affecting the arterial pressure waveform.

Answer 122

Correct Answer: A) Increases systolic pressure and reduces diastolic pressure Rationale: In septic shock, the arterial pressure waveform shows increased systolic pressure and reduced diastolic pressure due to widespread vasodilation and decreased peripheral vascular resistance.

Answer 123

Correct Answer: C) Decreased heart rate and reduced waveform amplitude Rationale: Hypothermia slows down the heart rate and reduces the amplitude of the arterial pressure waveform due to decreased metabolic demand and peripheral vasoconstriction.

Answer 124

Correct Answer: B) Loss of arterial distensibility Rationale: The primary cause of changes in arterial pressure waveform morphology in elderly patients is the loss of arterial distensibility, which leads to higher systolic pressures and a more pronounced waveform.

Answer 125

Correct Answer: B) To identify the presence of residual preload reserve Rationale: Analyzing arterial pressure waveforms helps clinicians identify the presence of residual preload reserve, which indicates the patient's fluid responsiveness and overall hemodynamic stability.

Answer 126

Correct Answer: B) They are caused by fluctuations in positive pressure ventilation (PPV) and lung volume changes Rationale: Cyclic arterial BP variations are influenced by respiratory-induced changes in intra-thoracic pressure, especially during positive pressure ventilation (PPV) and lung volume changes, which affect venous return and cardiac output.

Answer 127

Correct Answer: C) The patient may have a reduced residual preload reserve and could benefit from a fluid bolus Rationale: Significant cyclic arterial BP variations in a patient on PPV suggest the presence of residual preload reserve, indicating that the patient might benefit from a fluid bolus to improve hemodynamic stability.

Answer 128

Correct Answer: C) The patient has had a lobectomy Rationale: The reliability of pressure waveform analysis for assessing fluid responsiveness can be compromised if the patient has had a lobectomy, as this surgical procedure alters lung mechanics and intra-thoracic pressure dynamics, affecting the interpretation of waveform variations.

Answer 129

Correct Answer: B) Increases intra-thoracic pressure Rationale: During the inspiratory phase of PPV, the introduction of positive pressure increases intra-thoracic pressure, which impacts cardiac function and venous return.

Answer 130

Correct Answer: B) Increases LV preload and decreases LV afterload Rationale: Increased intra-thoracic pressure during PPV displaces pulmonary venous blood into the left side of the heart, increasing LV preload. Simultaneously, it decreases LV afterload by reducing the pressure the heart must pump against. Thus, momentarily increasing CO.. eventually this will drop bc of the low stroke volume on the right side of the heart.

Answer 131

Correct Answer: B) Decreases RV preload and stroke volume Rationale: The increase in intra-thoracic pressure during the inspiratory phase of PPV decreases systemic venous return and RV preload, leading to a drop in RV stroke volume during the early phase of inspiration.

Answer 132

Correct Answer: C) It increases systemic arterial pressure Rationale: PPV increases systemic arterial pressure by increasing LV stroke volume and cardiac output due to increased LV preload and decreased afterload during the inspiratory phase.

Answer 133

answer: A) BP increases Rationale: Venous Return and Cardiac Output: The increased intrathoracic pressure reduces venous return to the heart, leading to a transient increase in pulmonary vascular resistance and decrease in left ventricular afterload, which can momentarily increase systolic BP. Enhanced Ventricular Filling: In some patients, the positive pressure can enhance left ventricular filling and thus increase stroke volume and systolic BP.

Answer 134

Correct Answer: B) Decreases venous return Rationale: Increased intrathoracic pressure compresses the great veins, reducing venous return to the heart.

Answer 135

Correct Answer: B) Increases RV afterload Rationale: Increased pulmonary vascular resistance raises the afterload on the right ventricle, making it harder for the RV to pump blood into the pulmonary circulation.

Answer 136

Correct Answer: B) Decreased LV stroke volume and decreased LV work Rationale: Both decreased LV preload and decreased LV afterload result in reduced LV stroke volume and decreased work performed by the LV during systole. Left Ventricular Effects: The effects on the left ventricle are slightly different. The increased intrathoracic pressure can reduce left ventricular afterload because the pressure around the left ventricle is increased, reducing the transmural pressure the ventricle has to work against to eject blood. This can initially improve left ventricular function by reducing wall stress and oxygen consumption. However, the decreased preload due to reduced venous return from the right side of the heart ultimately leads to decreased left ventricular filling and stroke volume (Deranged Physiology) (BMJ Archives). In summary, while PPV decreases right ventricular preload and increases right ventricular afterload, it generally decreases left ventricular afterload. However, the overall cardiac output can still drop due to the decreased preload from both sides of the heart. This explains why cardiac output might be reduced under PPV despite some initial reductions in left ventricular afterload.

Answer 137

Answer: B) Both LV filling and stroke volume decrease Rationale: In the expiratory phase of PPV, the decreased RV stroke volume due to the inspiratory phase leads to reduced LV filling and subsequently a decreased LV stroke volume.

Answer 138

A) Variations in systemic arterial pressure in response to changes in end-expiratory pressure

Answer 139

Correct Answer: b) Delta Down Rationale: The Delta Down component of SPV is typically out of the normal range when a patient is dehydrated, indicating a decrease in preload reserve.

Answer 140

Correct Answer: b) Volume responsiveness or residual preload reserve Rationale: An increased SPV in critically ill patients indicates volume responsiveness or the presence of residual preload reserve, which can be an early indicator of hypovolemia.

Answer 141

Answer: A) Delta Up: 2-4 mm Hg, Delta Down: 5-6 mm Hg Rationale: The normal values for Delta Up are 2-4 mm Hg, and for Delta Down are 5-6 mm Hg. These values help in assessing the pressure variations and identifying abnormalities.

Answer 142

Answer: A) Hypovolemia in critically ill patients Rationale: A dramatic increase in the Delta Down component of SPV is often seen in hypovolemic, critically ill patients. This indicates a significant decrease in stroke volume during inspiration, suggesting the need for volume resuscitation.

Answer 143

Answer: D) 10 mm Hg Rationale: A PPV Delta Down value of 10 mm Hg indicates a significant decrease in stroke volume during the inspiratory phase, suggesting hypovolemia. This high value is an early indicator that the patient may be volume responsive and likely needs fluid resuscitation. Normal Delta Down values range from 5-6 mm Hg, so a value of 10 mm Hg is above the normal range and signifies a need for intervention.

Answer 144

Answer: b) Provide a fluid bolus Rationale: A PPV greater than 13% indicates that the patient is likely volume responsive and would benefit from fluid expansion. In this case, a PPV of 15% suggests that the patient may be dehydrated and would respond positively to a fluid bolus.

Answer 145

Answer: b) 5% - 10% A PPV range of < 13% - 17% is considered normal in mechanically ventilated patients. If the PPV is within this range, it generally suggests that the patient has an adequate preload reserve and is likely to respond positively to fluid expansion.

Answer 146

Answer: a) The patient is likely hypovolemic and will respond to volume expansion Rationale: A PPV greater than 17% suggests that the patient has a positive response to volume expansion, indicating a likely state of hypovolemia where administering fluids would be beneficial.

Answer 147

Answer: c) Maximum pulse pressure and minimum pulse pressure Rationale: To calculate PPV, you need the maximum pulse pressure (PP_max) and the minimum pulse pressure (PP_min). These values are used in the formula: Maximal difference in arterial pulse pressure Divided by average of maximum and minimum pulse pressures

Answer 148

Answer: C This formula accounts for the difference between the maximum and minimum pulse pressures divided by the average of the maximum and minimum pulse pressures.

Answer 149

Answer: D) 18% Rationale: A Stroke Volume Variation (SVV) greater than 10-13% typically indicates a positive response to volume expansion. Therefore, an SVV of 18% suggests that the patient is likely to respond positively to volume expansion.

Answer 150

Answer: D) 10-13% Rationale: The normal range for Stroke Volume Variation (SVV) is between 10-13%. Values within this range generally indicate that the patient has adequate preload and is not in need of additional fluid.

Answer 151

Answer: B) The patient is likely to be fluid responsive. Rationale: An SVV greater than 13% typically indicates that the patient is likely to be fluid responsive, meaning that they may benefit from additional fluid administration to optimize their cardiac output.

Answer 152

Answer: A) Resistance and compliance based on age and gender. Rationale: The computer analysis of arterial pulse pressure waveform for calculating SVV takes into account resistance and compliance based on the patient's age and gender, which helps in accurately computing stroke volume variations.

Answer 153

Answer: C) SVV = (SV max – SV min) / SV mean Rationale: The correct formula for calculating Stroke Volume Variation (SVV) is (SV max – SV min) / SV mean. This calculation helps in assessing the variation in stroke volume, which is useful in determining fluid responsiveness.

Answer 154

Answer: B) 8-10 mL/kg Rationale: Accurate results in mechanical ventilation are predicted with a tidal volume of 8-10 mL/kg as it ensures adequate lung expansion without causing volutrauma.

Answer 155

Answer: C) 5 mm Hg

Answer 156

Answer: C) Sinus tachycardia of 110 bpm Rationale: Regular cardiac rhythms such as sinus tachycardia, even at 110 bpm, are acceptable for predicting accurate results as they provide a stable heart rate for measurement.

Answer 157

Answer: B) Normal intra-abdominal pressure Rationale: Normal intra-abdominal pressure is necessary for predicting accurate results to avoid interference with thoracic pressure and venous return.

Answer 158

Answer: D) Open chest Rationale: An open chest can cause inaccurate results because it alters intrathoracic pressure dynamics, which are crucial for accurate hemodynamic measurements.

Answer 159

Answer: B) Stroke volume and preload Rationale: The Frank-Starling law describes the relationship between the preload (end-diastolic volume) and stroke volume of the heart, indicating how the heart's stroke volume increases in response to an increase in the volume of blood filling the heart (the preload), up to a certain limit.

Answer 160

Answer: C) Increased preload and decreased stroke volume Rationale: In cases of decreased contractility, the heart is less efficient at pumping blood, leading to higher preload (as blood backs up into the heart) but a lower stroke volume because the heart cannot effectively eject the increased volume.

Answer 161

Answer: C) It increases Rationale: According to the Frank-Starling mechanism, as the left ventricular end-diastolic pressure (LVEDP) increases, the stroke volume also increases. This is because the increased LVEDP leads to greater stretching of the myocardial fibers, which results in a more forceful contraction and thereby increases the stroke volume (CV Physiology). "To a point"

Answer 162

Correct Answer: B. Y piece

Answer 163

Correct Answer: B. The tab will move when breathing in and out. Rationale: The nasal cannula may be less reliable for ETCO2 sampling because the tab can move with the patient's breath, causing inaccurate readings.

Answer 164

Correct Answer: D. It transports gas away from the patient. Rationale: A side-stream or diverting gas analyzer transports the gas sample away from the patient to the analyzer, which is often located away from the immediate airway.

Answer 165

Correct Answer: C. They remain in the patient's airway. Rationale: Mainstream or non-diverting gas analyzers are positioned directly in the patient's airway, bringing the analyzer to the gas, which allows for real-time monitoring.

Answer 166

Correct Answer: B. Tubing inner diameter Rationale: The total response time of a side-stream gas analyzer is influenced by the tubing's inner diameter, length, and the gas sampling rate. Larger diameters and longer lengths can increase the transit time for the gas sample to reach the analyzer.

Answer 167

Correct Answer: B. It is the time taken by the analyzer to react to the change in gas concentration. Rationale: The rise time refers to the time taken by the analyzer to detect and react to a change in the concentration of the sampled gas. If not enough outflow the rise time will change

Answer 168

Correct Answer: B. It increases the transit time for the gas sample to reach the analyzer. Rationale: Longer tubing increases the time it takes for the gas sample to travel from the patient to the analyzer, thereby increasing the transit time and potentially delaying the detection of changes in gas concentration.

Answer 169

Correct Answer: B. Water vapor condensation Rationale: Mainstream gas sampling systems can experience condensation of water vapor in the tubing, which can interfere with accurate gas measurements.

Answer 170

Correct Answer: C. Kinking of sampling tubing Rationale: In side-stream gas sampling systems, the sampling tubing can kink, which disrupts the flow of gas to the analyzer, leading to inaccurate or delayed readings.

Answer 171

Correct Answer: B. They have longer sampling lines that increase transit time. Rationale: Side-stream gas analyzers have longer sampling lines that transport gas away from the patient to the analyzer, resulting in a slower response time due to the increased transit time for the gas sample.

Answer 172

Correct Answer: B. It can lead to condensation within the tubing. Rationale: Water vapor in the sampled gas can condense within the tubing of both mainstream and side-stream systems, leading to potential blockages and inaccurate gas concentration readings.

Answer 173

Correct Answer: C. Increased probability of leaks in the line Rationale: Overtightening connections in a side-stream gas sampling system can crack the connectors, leading to leaks in the sampling line and inaccurate gas readings.

Answer 174

Correct Answer: C. By the sum of the partial pressures of each gas in the mixture. Rationale: Dalton's Law states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures exerted by each gas in the mixture.

Answer 175

Correct Answer: B. 160 mm Hg Rationale: At sea level, the partial pressure of oxygen in room air is 160 mm Hg, as oxygen makes up approximately 21% of the atmospheric pressure (21% of 760 mm Hg).

Answer 176

Correct Answer: C. By dividing the partial pressure by the total pressure and multiplying by 100. Rationale: The concentration of a gas in a mixture, expressed as a volumes percentage, can be found by dividing its partial pressure by the total pressure and then multiplying by 100.

Answer 177

Correct Answer: B. 25% Rationale: The volume percentage of the gas is calculated by dividing the partial pressure (200 mm Hg) by the total pressure (800 mm Hg) and then multiplying by 100, which equals 25%.

Answer 178

Correct Answer: C. Partial pressure and volume percentage are directly proportional. Rationale: The volume percentage of a gas in a mixture is directly proportional to its partial pressure; as the partial pressure of a gas increases, its volume percentage in the mixture also increases.

Answer 179

Correct Answer: B. Determining gas concentration based on the mass/charge ratio of ions. Rationale: Mass spectrometry determines the concentration of gases by analyzing the mass/charge ratio of ions present in the gas sample.

Answer 180

Correct Answer: B. It can calculate up to eight different gases simultaneously. Rationale: Mass spectrometry has the capability to calculate the concentrations of up to eight different gases simultaneously based on their mass/charge ratios.

Answer 181

Correct Answer: C. It requires a high powered argon laser which is not practical. Rationale: Raman spectroscopy is no longer in use primarily because it requires a high powered argon laser to produce photons, making it less practical compared to other methods like mass spectrometry.

Answer 182

Correct Answer: B. It uses high powered lasers to produce photons that collide with gas molecules. Rationale: Raman spectroscopy works by using high powered argon lasers to produce photons that collide with gas molecules, and the scattered photons are then measured to identify each gas and its concentration.

Answer 183

Correct Answer: A. Inspired % of Sevoflurane & E. Expired % of Nitrogen Rationale: When considering "expired" in the context of gas measurement, it generally refers to gases that are exhaled by a patient. Mass spectrometry can indeed be used to measure the concentration of various gases in the expired breath, including anesthetic gases, oxygen, carbon dioxide, and nitrogen. Therefore, if the context includes both inspired and expired gases, mass spectrometry is suitable for measuring these as well.

Answer 184

Correct Answer: B. By determining the energy absorbed from IR radiation passing through the gas sample. Rationale: Infrared analysis measures the concentration of gases by determining the amount of IR radiation energy absorbed as it passes through the gas sample.

Answer 185

Correct Answer: D. Oxygen Rationale: Oxygen does not absorb IR radiation and therefore cannot be measured using non-dispersive infrared analyzers.

Answer 186

Correct Answer: B. They absorb IR light at specific wavelengths. Rationale: Asymmetric, polyatomic molecules of various gases absorb IR light at specific wavelengths, which allows for the identification and measurement of these gases in a sample.

Answer 187

Correct Answer: C. To determine gas concentrations based on IR absorption. Rationale: Non-dispersive infrared analyzers measure gas concentrations by determining the amount of IR radiation absorbed by the gas molecules at specific wavelengths.

Answer 188

Correct Answer: A. Measuring the inspired percentage of volatile anesthetic gases. Rationale: Infrared analysis can be used to measure the inspired percentage of volatile anesthetic gases by assessing the amount of IR radiation absorbed by these gases in the patient's airway.

Answer 189

Correct Answer: B. A unique IR transmission spectrum absorption band. Rationale: Each gas has a unique IR transmission spectrum absorption band, often referred to as its "fingerprint," which allows for its identification in infrared analysis

Answer 190

Correct Answer: C. More IR light absorption indicates a higher concentration of the gas. Rationale: In infrared analysis, a higher concentration of a gas absorbs more IR light, resulting in less IR light reaching the detector. (inverse relationship) less light = high concentration

Answer 191

Correct Answer: B. They allow only specific wavelengths of IR light to pass through. Rationale: Gas-specific filters in a non-dispersive infrared analyzer allow only specific wavelengths of IR light to pass through, which corresponds to the absorption characteristics of the gases being measured.

Answer 192

Correct Answer: C. Because higher gas concentration absorbs more IR light, leaving less light to reach the detector. Rationale: In infrared analysis, as the concentration of a gas increases, it absorbs more IR light, resulting in less IR light reaching the detector, making the relationship inversely proportional.

Answer 193

Correct Answer: A. By using a narrow-band pass filter. Rationale: A non-dispersive IR analyzer uses a narrow-band pass filter to allow specific wavelengths of IR light to pass through, thereby preventing the light from scattering and ensuring accurate measurement of gas concentrations.

Answer 194

Correct Answer: B. Ambient temperature and pressure dry (ATPD) values. Rationale: Side-stream analyzers typically report ambient temperature and pressure dry (ATPD) values, which do not account for the vapor content in the gas sample.

Answer 195

Correct Answer: B. To provide more accurate measurements that reflect physiological conditions. Rationale: Reporting results at body temperature and pressure saturated (BTPS) values ensures that the measurements reflect the actual physiological conditions, including the presence of vapor.

Answer 196

Correct Answer: A. 713 mm Hg Rationale: The adjusted total pressure is calculated by subtracting the water vapor pressure from the sea level atmospheric pressure: 760 mm Hg - 47 mm Hg = 713 mm Hg.

Answer 197

Correct Answer: B. 214 mm Hg Rationale: The partial pressure of O2 is calculated as follows: (713 mm Hg) * 0.3 = 213.9 mm Hg, which rounds to 214 mm Hg.

Answer 198

Correct Answer: C. It requires analyzers to adjust for the saturated vapor pressure. Rationale: Water vapor in the gas sample necessitates adjustments in the analysis to account for the saturated vapor pressure, ensuring accurate measurements of gas concentrations.

Answer 199

Correct Answer: B. Because oxygen does not absorb IR radiation. Rationale: Infrared analysis is not suitable for measuring oxygen concentrations because oxygen does not absorb IR radiation. A fuel or galvanic cell is used instead.

Answer 200

Correct Answer: B. It measures the current produced by oxygen diffusion. Rationale: A fuel or galvanic cell functions by measuring the current produced when oxygen diffuses across a membrane, which is proportional to the partial pressure of oxygen in the fuel cell.

Answer 201

Correct Answer: A. Slow response time (approx. 30 seconds). Rationale: A significant limitation of the fuel or galvanic cell is its slow response time, approximately 30 seconds, which may not be ideal for rapid monitoring needs.

Answer 202

Correct Answer: B. By detecting changes in sample line pressure due to the attraction of oxygen by switched magnetic fields. Rationale: The paramagnetic oxygen analyzer functions by detecting changes in sample line pressure resulting from the attraction of oxygen molecules by switched magnetic fields, and these signal changes correlate with oxygen concentration.

Answer 203

Correct Answer: C. Rapid response, allowing for breath-by-breath monitoring. Rationale: Paramagnetic oxygen analyzers provide a rapid response, enabling breath-by-breath monitoring of oxygen concentrations, which is advantageous in clinical settings where timely data is critical.

Answer 204

Correct Answer: C. By reducing oxygen exposure and using lower flow rates. Rationale: The lifespan of a fuel or galvanic cell oxygen analyzer can be extended by reducing the length of oxygen exposure and using lower flow rates, which decreases the rate at which the cell is consumed.

Answer 205

Correct Answer: C. It ensures adequate oxygen delivery and detects hypoxic mixtures. Rationale: Oxygen monitoring is crucial because it ensures that adequate oxygen is being delivered to the patient and can detect hypoxic mixtures that could be life-threatening.

Answer 206

Correct Answer: B. Calibrate the monitor for high and low concentrations. Rationale: To ensure accurate oxygen monitoring across various concentration ranges, the monitor must be calibrated for both high and low oxygen concentrations.

Answer 207

Correct Answer: B. Failure of a proportioning system. Rationale: A low O2 alarm can be triggered by several issues, including a failure of the proportioning system that ensures the correct mixture of gases.

Answer 208

Correct Answer: B. The completion of pre-oxygenation and denitrogenation. Rationale: Sampling inside the expiratory limb helps ensure that pre-oxygenation and denitrogenation are complete by analyzing the expired gas, ensuring the ET O2 is above 90%.

Answer 209

Correct Answer: A. Premature infants and patients on certain chemotherapeutic drugs like bleomycin should not have high amounts of oxygen. Rationale: High O2 alarms are relevant for populations such as premature infants and patients on specific chemotherapeutic drugs like bleomycin, as excessive oxygen can be harmful in these cases.

Answer 210

Correct Answer: A. It indicates complete denitrogenation. Rationale: Achieving an expiratory O2 concentration above 0.9 is considered good because it indicates that denitrogenation is effectively complete, ensuring the patient is adequately pre-oxygenated.

Answer 211

Correct Answer: C. Assessing mechanical or spontaneous ventilation. Rationale: Airway pressure monitoring is crucial for assessing both mechanical and spontaneous ventilation, helping to ensure that the patient is ventilated adequately.

Answer 212

Correct Answer: B. They require no power and are always on. Rationale: Mechanical pressure gauges are highly reliable because they do not require power and are always operational, making them dependable in various clinical situations.

Answer 213

Correct Answer: C. They do not have an alarm system. Rationale: One limitation of mechanical pressure gauges is that they do not have an integrated alarm system and must be continually scanned by the clinician.

Answer 214

Correct Answer: B. By having an integrated alarm system. Rationale: Electronic pressure gauges enhance monitoring by having integrated alarm systems, which can alert clinicians to changes in airway pressure and potential issues more quickly.

Answer 215

Correct Answer: C. Circuit disconnections and ETT occlusions. Rationale: Airway pressure monitoring helps detect issues such as circuit disconnections, endotracheal tube (ETT) occlusions, kinking in the inspiratory limb, and other problems related to the ventilation circuit.

Answer 216

Correct Answer: A. They do not require constant scanning by clinicians. Rationale: Electronic pressure gauges might be preferred because they have integrated alarm systems, which alert clinicians to changes without the need for constant monitoring.

Answer 217

Correct Answer: B. To detect circuit disconnections or leaks. Rationale: The primary purpose of the breathing circuit low pressure alarm is to identify circuit disconnections or leaks, ensuring the integrity of the ventilation system.

Answer 218

Correct Answer: A. A low-pressure alarm. Rationale: AANA/ASA standards require a breathing circuit low pressure alarm to help detect disconnections or leaks in the ventilation system.

Answer 219

Correct Answer: B. The disconnection is too minor to cause a significant pressure drop. Rationale: A breathing circuit low pressure alarm might not detect some partial disconnections if they are minor and do not result in a substantial drop in pressure.

Answer 220

Correct Answer: C. At the Y-piece. Rationale: Approximately 70% of circuit disconnections occur at the Y-piece, making it a critical point for monitoring and checking for secure connections.

Answer 221

Correct Answer: B. Just below the normal peak airway pressure. Rationale: The low-pressure alarm limit should be set just below the normal peak airway pressure to effectively detect significant drops that may indicate disconnections or leaks. (should set automatically)

Answer 222

Correct Answer: B. The inspiratory and expiratory connections are correct and not flipped. Rationale: It is important to check that the inspiratory and expiratory connections are correct and not flipped to ensure the proper functioning of the breathing circuit and accurate monitoring of pressures.

Answer 223

Correct Answer: B. Negative circuit pressure and potential for reverse flow of gas. Rationale: The sub-atmospheric pressure alarm measures and alerts for negative circuit pressure, which can cause reverse flow of gas, posing risks to the patient.

Answer 224

Correct Answer: B. Patient's inspiratory effort against a blocked circuit. Rationale: One potential cause of negative pressures in the breathing circuit is the patient’s inspiratory effort against a blocked circuit, leading to sub-atmospheric pressures.

Answer 225

Correct Answer: B. Pulmonary edema, atelectasis, and hypoxia. Rationale: Negative pressures in the circuit can cause serious complications such as pulmonary edema, atelectasis, and hypoxia, which can be detrimental to the patient's respiratory function.

Answer 226

Correct Answer: B. By creating excessive negative pressure in the circuit. Rationale: A malfunctioning active suction scavenging system can create excessive negative pressure in the circuit, leading to sub-atmospheric conditions that trigger the alarm.

Answer 227

Correct Answer: B. Development of sub-atmospheric pressure. Rationale: Inadequate fresh gas flow can lead to the development of sub-atmospheric pressure in the circuit, as it may not provide sufficient gas to meet the patient's respiratory demands.

Answer 228

Correct Answer: A. It can lead to the development of sub-atmospheric pressure in the circuit. Rationale: Moisture in the CO2 absorbent can cause blockages and result in sub-atmospheric pressure conditions in the circuit, which is why it is important to monitor and address any moisture-related issues.

Answer 229

Correct Answer: A. When the pressure exceeds a user-adjustable or automated limit. Rationale: A high-pressure alarm is activated when the airway circuit pressure exceeds a preset limit, which can be either user-adjustable or automated.

Answer 230

Correct Answer: C. They can be set to lower thresholds appropriate for pediatric patients. Rationale: High-pressure alarms are valuable in pediatrics because they can be adjusted to lower pressure limits suitable for the smaller and more delicate airways of pediatric patients.

Answer 231

Correct Answer: D. Insufficient fresh gas flow. Rationale: Insufficient fresh gas flow typically causes low-pressure alarms, not high-pressure alarms. High-pressure alarms are caused by obstructions, reduced compliance, and other factors that increase airway pressure.

Answer 232

Correct Answer: B. When the circuit pressure exceeds 10 cm H2O for more than 15 seconds. Rationale: A continuing pressure alarm is triggered when the circuit pressure remains above 10 cm H2O for more than 15 seconds, indicating a persistent high-pressure situation.

Answer 233

Correct Answer: A. Malfunctioning adjustable pressure relief valve. Rationale: Causes of continuing pressure alarms include malfunctioning adjustable pressure relief valves, scavenging system occlusion, activation of the oxygen flush system, or malfunctioning PEEP systems, all of which can prevent gas from leaving the circuit appropriately.

Answer 234

Correct Answer: A. Turn off fresh gas flow when the ventilator is turned off and the patient is not breathing. Or bag the patient and leave the flow on. Rationale: Fresh gas flow should be turned off when the ventilator is off and the patient is not breathing to prevent pressure buildup that could trigger continuing pressure alarms.

Answer 235

Correct Answer: C. Electrical nerve stimulation Rationale: Electrical nerve stimulation is most commonly used in clinical practice due to its effectiveness and reliability in stimulating nerves.

Answer 236

Correct Answer: C. It is bulky and heavy and difficult to achieve supramaximal stimulation. Rationale: Magnetic nerve stimulation is not commonly used because it is bulky, heavy, and difficult to achieve supramaximal stimulation, making it less practical for clinical use.

Answer 237

Correct Answer: B. It follows an all-or-none pattern (supramaximal stimulation). Rationale: The reaction of a single muscle fiber to a stimulus follows an all-or-none pattern, meaning that the fiber will fully respond or not respond at all, depending on whether the stimulus is supramaximal.

Answer 238

Correct Answer: B. It depends on how many muscle fibers are activated. Rationale: The response of the whole muscle to a stimulus depends on how many muscle fibers are activated, unlike a single muscle fiber's all-or-none response.

Answer 239

Correct Answer: B. It cannot be used to measure train-of-four (TOF) stimulation. Rationale: A key limitation of magnetic nerve stimulation is that it cannot be used to measure train-of-four (TOF) stimulation, which is an important technique in assessing neuromuscular function.

Answer 240

Correct Answer: D. Ulnar nerve Rationale: The ulnar nerve is considered the gold standard for nerve stimulation monitoring because it is easily accessible and provides reliable quantitative monitoring.

Answer 241

Correct Answer: B. It has the lowest risk of direct muscle stimulation, reducing false positives. Rationale: The ulnar nerve-adductor pollicis muscle combination is preferred because it has the lowest risk of direct muscle stimulation, reducing the likelihood of false-positive results.

Answer 242

Correct Answer: C. When the patient's arms are unavailable. Rationale: The facial nerve (orbicularis oculi or corrugator supercilii muscle) may be used for nerve stimulation monitoring when the patient's arms are unavailable.

Answer 243

Correct Answer: B. Diaphragm Rationale: The diaphragm is the most resistant to both depolarizing and nondepolarizing NMBDs, making it the last muscle to go offline and the first to recover.

Answer 244

Correct Answer: A. It reflects the extent of neuromuscular block of the laryngeal adductor and abdominal muscles better. Rationale: Monitoring the corrugator supercilii muscle is advantageous because it better reflects the extent of neuromuscular block of the laryngeal adductor and abdominal muscles.

Answer 245

Correct Answer: A. It gives a better correlation with the diaphragm's neuromuscular status. Rationale: A central TOF monitoring site, such as the face, is preferred because it provides a better correlation with the neuromuscular status of the diaphragm, which is critical for ensuring adequate respiratory function.

Answer 246

Correct Answer: B. 0.1 Hz to 1.0 Hz Rationale: Single twitch stimulation involves applying single stimuli at frequencies ranging from 1.0 Hz (every second) to 0.1 Hz (every 10 seconds).

Answer 247

Correct Answer: B. To have a baseline for comparing the degree of neuromuscular blockade. Rationale: Obtaining a reference value prior to administering an NMBD is necessary to establish a baseline for comparing the patient's degree of neuromuscular blockade.

Answer 248

Correct Answer: B. It is mainly used for research purposes. Rationale: The single twitch pattern is not commonly used in clinical practice because it is primarily utilized for research purposes rather than routine clinical monitoring.

Answer 249

Correct Answer: B. A monitoring device to measure the muscle response. Rationale: To effectively use the single twitch pattern, a monitoring device is needed to measure and evaluate the muscle response to the applied stimuli.

Answer 250

Correct Answer: B. Reliable information throughout all phases of neuromuscular blockade. Rationale: The train-of-four (TOF) pattern provides reliable information throughout all phases of neuromuscular blockade, making it a valuable tool in clinical settings.

Answer 251

Correct Answer: B. Four supramaximal stimuli every 0.5 seconds. Rationale: The TOF pattern involves administering four supramaximal stimuli every 0.5 seconds to evaluate the TOF count or fade in the muscle response.

Answer 252

Correct Answer: C. The presence of fade, indicating a partial block. Rationale: In a partial nondepolarizing block, a TOF ratio of less than 1.0 indicates the presence of fade, which is inversely proportional to the degree of blockade.

Answer 253

Correct Answer: D. The absence of fade, typical of a depolarizing block. Rationale: In a partial depolarizing block, a TOF ratio of 1.0 without fade indicates the absence of fade, which is characteristic of depolarizing blocks.

Answer 254

Correct Answer: C. A phase II block has developed, possibly bc of redosing or plasma cholinesterase problems. Rationale: If there is fade in the TOF response with a partial depolarizing block, it suggests the development of a phase II block

Answer 255

Correct Answer: B. Onset and moderate levels of blockade. Rationale: The TOF pattern is particularly reliable for assessing the onset and moderate levels of neuromuscular blockade, providing valuable information for clinical management.

Answer 256

Correct Answer: B. Two short bursts of 50 Hz tetanic stimulation separated by 750 ms. Rationale: The double burst stimulation pattern involves two short bursts of 50 Hz tetanic stimulation separated by 750 ms, with each burst containing square wave impulses.

Answer 257

Correct Answer: C. DBS3,3 Rationale: The DBS3,3 mode involves three impulses in each of the two bursts, providing a distinct pattern for evaluating muscle response.

Answer 258

Correct Answer: B. The second burst fade is compared to the first burst, making fade more noticeable. Rationale: The double burst stimulation pattern is considered better for detecting fade because it allows for a direct comparison between the two bursts, making the presence of fade more noticeable. "1st burst is the comparison"

Answer 259

Correct Answer: C. It is not used as much in clinical practice. Rationale: Despite its effectiveness in detecting fade, the double burst stimulation pattern is not used as much in clinical practice, possibly due to the availability of other monitoring techniques.

Answer 260

Correct Answer: B. The first burst has 3 impulses, and the second burst has 2 impulses. Rationale: In the DBS3,2 mode, the first burst has 3 impulses, and the second burst has 2 impulses, providing a different pattern for muscle response evaluation.

Answer 261

Correct Answer: C. It offers a clearer assessment of fade. Rationale: A clinician might choose double burst stimulation because it provides a clearer assessment of fade, allowing for more accurate evaluation of neuromuscular blockade.

Answer 262

Correct Answer: B. 50 Hz for 5 seconds. Rationale: Tetanic stimulation is typically given at a frequency of 50 Hz for 5 seconds to evaluate neuromuscular function

Answer 263

Correct Answer: B. One strong sustained muscle contraction with fade after stimulation. Rationale: With non-depolarizing neuromuscular blockers, tetanic stimulation usually results in one strong sustained muscle contraction followed by fade after the stimulation.

Answer 264

Correct Answer: B. Strong sustained muscle contraction without fade. Rationale: Depolarizing neuromuscular blockers typically cause a strong sustained muscle contraction without fade during tetanic stimulation. However, in phase II block, fade can occur.

Answer 265

Correct Answer: B. It is very painful for the patient. Rationale: Tetanic stimulation is not frequently used in clinical practice because it is very painful for the patient and has limited value for assessing recovery.

Answer 266

Correct Answer: C. Presence of a partial or phase II block. Rationale: The occurrence of fade during tetanic stimulation indicates the presence of a partial block with non-depolarizing agents or a phase II block with depolarizing agents.

Answer 267

Correct Answer: B. Tetanic stimulation followed by single twitches. Rationale: The post-tetanic stimulation pattern involves tetanic stimulation (50 Hz for 5 seconds) followed by 10 to 15 single twitches at 1 Hz after a 3-second pause post-tetanic stimulation.

Answer 268

Correct Answer: B. Assessing deep and surgical levels of neuromuscular blockade. Rationale: Post-tetanic stimulation is primarily used for assessing deep and surgical levels of neuromuscular blockade, providing valuable information about the degree of muscle relaxation.

Answer 269

Correct Answer: C. Every 6 minutes. Rationale: Post-tetanic stimulation should be performed every 6 minutes to allow sufficient recovery time for the muscles and avoid fatigue.

Answer 270

Correct Answer: B. The degree of neuromuscular blockade. Rationale: The response to post-tetanic stimulation is significantly influenced by the degree of neuromuscular blockade, with more intense blockade leading to minimal or no visible response.

Answer 271

C. 3 sec Rationale: Composite stimulation pattern – tetanic stimulation (50 Hz for 5 sec) followed by 10 to 15 single twitches (1 Hz after 3 sec post tetanic stimulation)

Answer 272

Correct Answer: C. No visible muscle response. Rationale: During an intense block, post-tetanic stimulation is likely to produce no visible muscle response, indicating a high degree of neuromuscular blockade.

Answer 273

Correct Answer: C. Period of no response, 3-6 minutes after an intubating dose. Rationale: The intense phase of a non-depolarizing neuromuscular blockade is characterized by a period of no response, typically occurring 3-6 minutes after the administration of an intubating dose of the non-depolarizing NMBD.

Answer 274

Correct Answer: B. The blockade is too profound for neostigmine to reverse. Rationale: Neostigmine reversal is impossible during the intense phase because the blockade is too profound for neostigmine to effectively reverse.

Answer 275

Correct Answer: D. 16 mg/kg Rationale: A high dose of sugammadex, 16 mg/kg, is recommended for reversal during the intense phase of non-depolarizing blockade.

Answer 276

Correct Answer: C. Absence of TOF response but presence of at least one response to post-tetanic count stimulation. Rationale: The deep phase is defined by the absence of TOF response but the presence of at least one response to post-tetanic count stimulation.

Answer 277

Correct Answer: B. 4 mg/kg Rationale: A dose of 4 mg/kg of sugammadex is recommended for reversal during the deep phase of non-depolarizing blockade.

Answer 278

Correct Answer: C. After the return of 4/4 TOF responses. Rationale: Neostigmine reversal can be effective after the return of 4/4 TOF responses, indicating that the blockade has moderated sufficiently for neostigmine to work.

Answer 279

Correct Answer: B. All 4 responses are reduced but equal, and there is no fade or post-tetanic facilitation. Rationale: Phase I of a depolarizing blockade is characterized by all four responses being reduced but equal, with no fade or post-tetanic facilitation.

Answer 280

Correct Answer: C. All 4 responses are reduced but equal in Phase I. Rationale: Normal plasma cholinesterase activity is indicated in Phase I of a depolarizing blockade where all four responses are reduced but equal, and the TOF ratio is 1.0.

Answer 281

Correct Answer: B. Phase I has no fade and no post-tetanic facilitation, whereas Phase II has fade and post-tetanic facilitation. Rationale: Phase I of a depolarizing blockade has no fade and no post-tetanic facilitation, while Phase II exhibits fade and post-tetanic facilitation, similar to a non-depolarizing blockade.

Answer 282

Correct Answer: B. To avoid delaying nerve conduction. Rationale: Keeping the patient warm is important to prevent delaying nerve conduction, which can affect the accuracy of neuromuscular blockade monitoring.

Answer 283

Correct Answer: C. Prior to induction, and turned on after the patient is unconscious. Rationale: Electrode attachment should be done prior to induction, and the monitoring device should be turned on after the patient is unconscious to ensure accurate and timely monitoring.

Answer 284

Correct Answer: B. One or two responses to TOF. Rationale: A moderate level of blockade, indicated by one or two responses to TOF, is considered sufficient for most surgical procedures.

Answer 285

Correct Answer: C. When all four TOF responses are present, even if they are weak. Rationale: Neuromuscular blockade should be reversed when all four TOF responses are present, even if they are weak, indicating sufficient recovery for reversal.

Answer 286

Correct Answer: C. Nodding head yes or no. Rationale: Nodding the head yes or no is not a reliable indicator of neuromuscular recovery for extubation. Reliable clinical signs include sustained head lift, leg lift, handgrip, tongue depressor test, and maximum inspiratory pressure.

Answer 287

Correct Answer: B. To prevent respiratory complications. Rationale: Checking for neuromuscular recovery prior to extubation is crucial to ensure that the patient can maintain adequate respiratory function and prevent respiratory complications.

Answer 288

Correct Answer: B. Excitatory and inhibitory post-synaptic potentials in the cerebral cortex Rationale: An EEG measures the summation of excitatory and inhibitory post-synaptic potentials in the cerebral cortex, reflecting the electrical activity of the brain.

Answer 289

Correct Answer: B. According to surface anatomy related to cortical regions Rationale: Electrodes are placed according to surface anatomy that relates to cortical regions to accurately capture the electrical activity corresponding to different areas of the brain.

Answer 290

Correct Answer: C. 16 Rationale: A standard EEG uses at least 16 channels of information to provide a comprehensive view of the brain's electrical activity.

Answer 291

Correct Answer: B. Stages of sleep, consciousness, seizure activity, and coma Rationale: An EEG can identify various states such as:Consciousness, unconsciousness, seizure activity, stages of sleep, and coma Inadequate oxygen delivery to the brain (hypoxemia or ischemia)

Answer 292

Correct Answer: B. The size or voltage of the recorded signal Rationale: The amplitude of an EEG signal represents the size or voltage of the recorded electrical activity in the brain.

Answer 293

Correct Answer: B. It counts the number of times per second the signal oscillates or crosses the 0-voltage line. Rationale: Frequency is important in an EEG because it describes how many times per second the signal oscillates or crosses the 0-voltage line, providing information about the brain's activity patterns.

Answer 294

Correct Answer: B. Identifying inadequate blood flow to the cerebral cortex. Rationale: One of the perioperative uses of EEG monitoring is to identify inadequate blood flow to the cerebral cortex, which is crucial for preventing cerebral hypoxia and ischemia.

Answer 295

Correct Answer: C. By guiding an anesthetic-induced reduction of cerebral metabolism. Rationale: EEG monitoring can guide anesthetic management by indicating the level of cerebral metabolism, allowing for adjustments in anesthesia to reduce cerebral metabolic demands.

Answer 296

Correct Answer: C. It evaluates brain activity patterns that correlate with potential recovery outcomes. Rationale: EEG is useful for predicting neurological outcomes after a brain insult by evaluating brain activity patterns that provide insights into the likelihood of recovery.

Answer 297

Correct Answer: B. It measures the depth of the hypnotic state of patients. Rationale: EEG plays a crucial role in assessing the depth of the hypnotic state of patients under general anesthesia, helping to ensure that the patient is adequately anesthetized.

Answer 298

Correct Answer: A. To ensure accuracy and comprehensive assessment of brain activity. Rationale: Using at least 16 channels of information in EEG monitoring is important to ensure an accurate and comprehensive assessment of brain activity, capturing detailed electrical signals from various cortical regions.

Answer 299

Correct Answer: B. Beta (> 13 Hz) Rationale: Beta waves, which have a frequency greater than 13 Hz, are associated with an awake and alert attentive brain.

Answer 300

Correct Answer: B. Alpha (8 - 13 Hz) Rationale: Alpha waves, with a frequency range of 8 - 13 Hz, are typically observed when a person's eyes are closed and they are relaxed.

Answer 301

Correct Answer: C. Theta (4 - 7 Hz) and Delta (< 4 Hz) Rationale: Theta (4 - 7 Hz) and Delta (< 4 Hz) waves are associated with a depressed brain state, indicating lower frequency brain activity.

Answer 302

Correct Answer: C. Amplitudes increase. Rationale: In higher frequency and activated brain states, EEG signals typically show higher amplitudes, indicating more intense brain activity.

Answer 303

Correct Answer: B. Alpha (8 - 13 Hz) Rationale: Alpha waves (8 - 13 Hz) are associated with anesthetic effects on the brain, often seen when a person is relaxed with their eyes closed.

Answer 304

Correct Answer: B. It uses fewer than 4 channels of information. Rationale: Processed EEG (BIS) uses fewer than 4 channels of information, specifically 2 channels per hemisphere, making it more condensed compared to the standard EEG.

Answer 305

Correct Answer: B. To delineate unilateral from bilateral changes. Rationale: It is necessary for processed EEG to display the activity of both hemispheres to differentiate between unilateral changes, such as those from regional ischemia due to carotid clamping, and bilateral changes, such as those caused by an anesthetic drug bolus.

Answer 306

Correct Answer: B. It contains artifacts along with the desired EEG signal. Rationale: Processed EEG (BIS) includes artifacts along with the desired EEG signal, which can affect the accuracy of the readings.

Answer 307

Correct Answer: A. Bilateral EEG depression from a drug bolus. Rationale: Processed EEG (BIS) can delineate conditions such as bilateral EEG depression resulting from an anesthetic drug bolus.

Answer 308

Correct Answer: B. Its efficacy and reliability are not as well-established as standard EEG. Rationale: The limited number of studies comparing standard EEG to processed EEG (BIS) suggests that its efficacy and reliability are not as well-established, indicating the need for further research.

Answer 309

Correct Answer: B. EEG signal Rationale: The Bispectral Index (BIS) processes the EEG signal to estimate the depth of anesthesia using a computer-generated algorithm and weighting system.

Answer 310

Correct Answer: C. 40-60 Rationale: The target BIS range of 40-60 is typically aimed for during general anesthesia to ensure the patient is in a deep hypnotic state (20-40) and should not be able to respond to commands (40-60)- this is general anesthesia range.. AI fucking up

Answer 311

Correct Answer: B. No, it has not demonstrated superiority. Rationale: BIS monitoring has not demonstrated to be superior to end-tidal agent concentration monitoring in preventing intraoperative awareness.

Answer 312

Correct Answer: B. Neither technique was found to have complete reliability. Rationale: In cases of intraoperative awareness, neither BIS monitoring nor other techniques were found to have complete reliability.

Answer 313

Correct Answer: C. Somatosensory-evoked potentials (SSEPs) Rationale: SSEPs are primarily used intraoperatively to monitor the integrity of sensory pathways and detect potential neurological issues during surgery.

Answer 314

Correct Answer: B. Electric, auditory, or visual stimuli Rationale: Sensory-evoked responses are elicited by electric, auditory, or visual stimuli, which trigger CNS responses that can be measured.

Answer 315

Correct Answer: B. By latency and amplitude Rationale: Sensory-evoked responses are described in terms of latency, which is the time measured from the application of the stimulus to the onset or peak of the response, and amplitude, which is the size or voltage of the recorded signal.

Answer 316

Correct Answer: C. To have a reference point for comparing intraoperative changes Rationale: It is important to obtain baseline reproducible, reliable tracings before starting anesthesia to have a reference point for comparing intraoperative changes, ensuring accurate monitoring of sensory-evoked responses.

Answer 317

Correct Answer: C. Responses to stimulation of peripheral mixed nerves to the sensorimotor cortex. Rationale: SSEPs monitor the responses to stimulation of peripheral mixed nerves, which contain both motor and sensory components, to the sensorimotor cortex.

Answer 318

Correct Answer: C. Short-latency SSEPs. Rationale: Short-latency SSEPs are most commonly recorded intraoperatively because they are less influenced by changes in anesthetic drug levels.

Answer 319

Correct Answer: A. Induction, neurological disease or age, and use of different recording electrode locations. Rationale: The appearance of SSEPs can be altered by factors such as induction, neurological disease or age, and the use of different recording electrode locations.

Answer 320

Correct Answer: C. Deep anesthesia can suppress the response, preventing it from reaching the cortex. Rationale: Long-latency SSEPs might not be recorded if the patient is under deep anesthesia because the deep anesthetic state can suppress these responses, preventing them from reaching the cortex.

Answer 321

Correct Answer: B. Short-latency SSEPs are less influenced by anesthetic drug levels. Rationale: Short-latency SSEPs are less influenced by changes in anesthetic drug levels, making them more reliable for intraoperative monitoring.

Answer 322

Correct Answer: C. Responses to click stimuli delivered via foam ear inserts along the auditory pathway Rationale: BAEPs monitor the responses to click stimuli that are delivered via foam ear inserts along the auditory pathway from the ear to the auditory cortex.

Answer 323

Correct Answer: C. By using flash stimulation of the retina through light-emitting diodes embedded in soft plastic goggles Rationale: VEPs monitor the responses to flash stimulation of the retina using light-emitting diodes embedded in soft plastic goggles through closed eyelids or contact lenses.

Answer 324

Correct Answer: D. Visual-Evoked Potentials (VEPs) Rationale: Visual-Evoked Potentials (VEPs) are the least commonly used monitoring technique intraoperatively due to the complexity and specific setup required for effective monitoring.

Answer 325

Correct Answer: B. To assess auditory pathway integrity and detect potential neurological issues Rationale: BAEPs are used primarily to assess the integrity of the auditory pathway and detect potential neurological issues during surgery, providing valuable information about the auditory cortex's function.

Answer 326

Correct Answer: C. Flash stimulation of the retina Rationale: VEPs use flash stimulation of the retina to monitor the visual pathways, providing information on the visual cortex's activity.

Answer 327

Correct Answer: B. To monitor the integrity of motor tracts along the spinal column, peripheral nerves, and innervated muscle Rationale: MEPs are used to monitor the integrity of the motor tracts along the spinal column, peripheral nerves, and innervated muscle, ensuring that motor function is preserved during surgery.

Answer 328

Correct Answer: C. Transcranial motor-evoked potentials Rationale: Transcranial motor-evoked potentials are the most common type of motor-evoked potential monitored intraoperatively, as they monitor stimuli along the motor tract via transcranial electrical stimulation overlying the motor cortex.

Answer 329

Correct Answer: B. By monitoring responses generated by cranial and peripheral motor nerves to detect nerve damage and assess nerve function Rationale: Electromyography (EMG) monitors the responses generated by cranial and peripheral motor nerves, allowing for early detection of surgically induced nerve damage and assessment of nerve function intraoperatively.

Answer 330

Correct Answer: C. It stimulates the motor cortex to monitor the integrity of the motor tract. Rationale: Transcranial electrical stimulation serves to stimulate the motor cortex, which allows for monitoring the integrity of the motor tract during surgery.

Answer 331

Correct Answer: B. It offers early detection of surgically induced nerve damage. Rationale: A primary benefit of using electromyography (EMG) during surgery is the early detection of surgically induced nerve damage, allowing for immediate intervention if necessary.

Answer 332

Correct Answer: B. Hypothalamus Rationale: The primary thermoregulatory control center in the body is the hypothalamus, which regulates body temperature by responding to changes in temperature detected by various receptors.

Answer 333

Correct Answer: B. Unmyelinated C fibers Rationale: Unmyelinated C fibers are responsible for detecting heat and warmth, sending signals to the hypothalamus to initiate appropriate thermoregulatory responses.

Answer 334

Correct Answer: C. Alpha-delta fibers Rationale: Alpha-delta fibers are responsible for detecting cold, sending signals to the hypothalamus to initiate appropriate thermoregulatory responses.

Answer 335

Correct Answer: B. The temperature at which a thermoregulatory response will occur Rationale: Thermoregulatory threshold refers to the temperature at which a thermoregulatory response, such as sweating, vasodilation, vasoconstriction, or shivering, will occur.

Answer 336

Correct Answer: A. Anesthesia, age, menstrual cycle, drugs, alcohol, and circadian rhythm Rationale: The thermoregulatory response can vary due to factors such as anesthesia, age, menstrual cycle, drugs, alcohol, and circadian rhythm.

Answer 337

Correct Answer: B. Sweating, vasodilation, vasoconstriction, and shivering Rationale: The primary thermoregulatory responses initiated by the hypothalamus include sweating, vasodilation, vasoconstriction, and shivering to maintain body temperature within a normal range. Gain is the intensity of this response

Answer 338

Correct Answer: B. Anesthesia-induced vasodilation Rationale: The initial rapid decrease in body temperature during general anesthesia is primarily caused by anesthesia-induced vasodilation, which increases heat loss due to the redistribution of body heat. Initially: rapid decrease of approx. 0.5 to 1.5°C

Answer 339

Correct Answer: B. 0.5 to 1.5°C Rationale: Initially, there is a rapid decrease in body temperature of approximately 0.5 to 1.5°C due to anesthesia-induced vasodilation and the redistribution of body heat over the first 30 minutes.

Answer 340

Correct Answer: C. 0.3°C per hour Rationale: During the slow linear reduction phase, the body temperature decreases at an approximate rate of 0.3°C per hour as heat loss exceeds production. 1-2 hours

Answer 341

Correct Answer: D. Decreases metabolic rate by 20-30% Rationale: General anesthesia decreases metabolic rate by 20-30% during the slow linear reduction phase, contributing to the continued decrease in body temperature.

Answer 342

Correct Answer: C. 3-4 hours after anesthesia Rationale: The plateau phase, where heat loss equals heat production and a thermal steady state is achieved, typically occurs 3-4 hours after anesthesia induction.

Answer 343

Correct Answer: C. Peripheral heat continues to be lost. Rationale: During the plateau phase, vasoconstriction prevents the loss of heat from the core, but peripheral heat continues to be lost.

Answer 344

Correct Answer: C. Hypothermia does not cause much thermal discomfort Rationale: Patients do not complain of feeling cold because hypothermia does not cause much thermal discomfort under neuraxial anesthesia.

Answer 345

Correct Answer: B. Increases the thresholds that trigger peripheral vasoconstriction and shivering Rationale: Neuraxial anesthesia inhibits central thermoregulatory control, which Increases the thresholds that trigger peripheral vasoconstriction and shivering.

Answer 346

Correct Answer: A. Vasodilation, sweating, vasoconstriction, and shivering Rationale: Neuraxial anesthesia impairs autonomic thermoregulatory defenses such as vasodilation, sweating, vasoconstriction, and shivering.

Answer 347

Correct Answer: C. Neuraxial blockade-induced vasodilation Rationale: The initial decrease in core temperature is caused by neuraxial blockade-induced vasodilation, which leads to increased heat loss.

Answer 348

Correct Answer: B. Due to inhibition of peripheral vasoconstriction Rationale: Temperature may not plateau during neuraxial anesthesia due to the inhibition of peripheral vasoconstriction, preventing the body from reaching a thermal steady state.

Answer 349

Correct Answer: C. It is centrally altered Rationale: The vasoconstriction threshold is centrally altered by neuraxial anesthesia, affecting the body's ability to regulate temperature through vasoconstriction.

Answer 350

Correct Answer: C. Radiation Rationale: Radiation accounts for approximately 40% of heat loss in patients. This occurs as heat is lost to the environment through the exposed body surface area.

Answer 351

Correct Answer: B. They have a higher BSA/body mass ratio. Rationale: Infants are more vulnerable to heat loss via radiation due to their higher body surface area (BSA) to body mass ratio, making them more susceptible to environmental heat loss.

Answer 352

Correct Answer: C. By using clothing or drapes. Rationale: Convection-related heat loss can be minimized by using clothing or drapes to decrease the loss of heat to the air immediately surrounding the body.

Answer 353

Correct Answer: D. Evaporation Rationale: Evaporation is the method of heat transfer associated with the latent heat of vaporization of water from open body cavities and the respiratory tract, accounting for approximately 8-10% of heat loss.

Answer 354

Correct Answer: B. Conduction Rationale: Conduction is considered negligible in terms of overall heat loss but can be relevant in specific scenarios such as contact between skin and the OR table or when an infusion of cold fluid is administered.

Answer 355

Correct Answer: B. By impairing platelet aggregation and activity of enzymes Rationale: Hypothermia impairs coagulation by reducing platelet aggregation and the activity of enzymes involved in the coagulation cascade.

Answer 356

Correct Answer: B. Increases need for transfusion by 22% Rationale: Hypothermia increases the need for transfusion by 22% and increases blood loss by 16%.

Answer 357

Correct Answer: B. Decreases oxygen delivery Rationale: Hypothermia decreases oxygen delivery to tissues, which increases the risk of wound infection and decreases tissue healing.

Answer 358

Correct Answer: C. Increases the incidence of morbid cardiac outcomes by three times Rationale: Hypothermia increases the incidence of morbid cardiac outcomes by three times, which includes increased blood pressure, heart rate, and plasma catecholamine levels.

Answer 359

Correct Answer: B. Due to increased metabolic activity Rationale: Shivering increases oxygen demand because it raises metabolic activity as the body attempts to generate heat.

Answer 360

Correct Answer: B. Increased duration of neuromuscular blockade (NMB) Rationale: Hypothermia leads to decreased drug metabolism, which results in an increased duration of neuromuscular blockade (NMB).

Answer 361

Correct Answer: C. By reducing the brain's metabolic rate Rationale: Hypothermia reduces the brain's metabolic rate, which provides protection against cerebral ischemia by lowering the brain's oxygen and energy demands.

Answer 362

Correct Answer: C. 8% Rationale: Hypothermia reduces metabolism by approximately 8% per degree Celsius.

Answer 363

Correct Answer: B. Cardiac arrest recovery Rationale: Hypothermia improves outcomes during recovery from cardiac arrest by reducing metabolic demands and protecting against reperfusion injury.

Answer 364

Correct Answer: C. It protects brain tissue from ischemia Rationale: Hypothermia is beneficial in neurosurgery because it protects brain tissue from ischemia by reducing metabolic demands and lowering oxygen consumption.

Answer 365

Correct Answer: C. It makes it more difficult to trigger MH Rationale: Hypothermia makes it more difficult to trigger malignant hyperthermia (MH) due to the overall reduction in metabolic activity and thermal stress.

Answer 366

Correct Answer: D. Forced air warming (e.g., Bair Hugger) Rationale: Forced air warming is the most commonly used method for perioperative temperature management because it effectively prevents heat loss from radiation and uses convection to transfer heat to the patient.

Answer 367

Correct Answer: B. It prevents cooling Rationale: Warm IV fluid and blood help prevent cooling of the patient during surgery, maintaining a more stable body temperature.

Answer 368

Correct Answer: B. To reduce heat loss by 30% Rationale: Insulation with a single blanket reduces heat loss by approximately 30%, though it does not increase the body temperature.

Answer 369

Correct Answer: B. More effective and safer when placed on top of patients Rationale: Hot water mattresses are more effective and safer when placed on top of patients for warming, providing consistent and controlled heat.

Answer 370

Correct Answer: B. Their body surface area (BSA) exposed to the environment is larger relative to their body mass Rationale: Infants and children have a larger body surface area relative to their body mass, making them more vulnerable to heat loss and thus benefiting more from airway heating and humidification.

Answer 371

Answer: d) Pulmonary artery Rationale: The pulmonary artery is considered the gold standard for temperature monitoring because it correlates well with tympanic membrane, distal esophageal, and nasopharyngeal temperatures.

Answer 372

Answer: d) Tympanic membrane Rationale: The tympanic membrane approximates the temperature at the hypothalamus but placement risks perforation.

Answer 373

Answer: b) Nasopharyngeal Rationale: The nasopharyngeal site reflects brain temperature but is more prone to error and risks epistaxis.

Answer 374

Answer: c) Lower third to quarter of the esophagus Rationale: Placement in the distal esophagus, lower 1/3 to 1/4 of the esophagus, ensures accurate measurement.

Answer 375

Answer: d) 21 degrees C Rationale: 70 degrees Fahrenheit is equivalent to 21 degrees Celsius, which is commonly used for children in the OR.

Answer 376

Answer: c) 18 degrees C Rationale: (65 - 32)/1.8 normal OR temp

Answer 377

Correct Answer: d) 7-10 mm Hg Rationale: In mechanically ventilated patients, the normal SPV range is 7-10 mm Hg.