Week 4 Handout Flashcards
What does an Electrocardiogram (ECG) measure?
Electrical activity in the heart
Produces waveforms representing cardiac cycles
Why is ECG monitoring crucial during anesthesia?
Allows real-time assessment of cardiac function and enhances patient safety
What are the types of ECG systems mentioned?
- 3-Lead ECG System
- 5-Lead ECG System
- 12-Lead ECG System
What is the primary lead used for continuous monitoring in a 3-lead ECG?
Lead II
What does the P wave represent in an ECG waveform?
Atrial depolarization
What does the QRS complex reflect in an ECG waveform?
Ventricular depolarization
What does the T wave indicate in an ECG waveform?
Ventricular repolarization
What are common clinical indications for ECG monitoring?
- Procedures involving general anesthesia
- Patients with known cardiovascular conditions
What is the standard for rhythm analysis in ECG monitoring?
Lead II
What is the advantage of the 5-lead ECG system?
Provides earlier detection of cardiac issues for high-risk patients
What are common pitfalls in ECG monitoring?
- Patient movement
- Lead-wire displacement
- Electrocautery use
- 60-Hz interference
What is the significance of ST elevation in an ECG?
Suspicion of acute myocardial infarction (STEMI)
What does the J-point in an ECG indicate?
The point where the QRS complex ends and the ST segment begins
Fill in the blank: The 5-lead ECG system enhances detection of _______.
ischemic changes
What is Mean Arterial Pressure (MAP) calculated as?
MAP = DP + (SP - DP) / 3 or ((DP x 2) + SP) / 3
What are the methods for noninvasive blood pressure monitoring mentioned?
- Palpation
- Doppler probe
- Auscultation
- Oscillometry
- Tonometer/Finger Cuff method
What does oscillometry in blood pressure monitoring rely on?
Arterial pulsations causing oscillations within the blood pressure cuff
What is a potential limitation of arterial tonometry?
Frequent calibration requirements
True or False: Continuous intraoperative ECG monitoring has known contraindications.
False
What is the purpose of using conductive gel in ECG monitoring?
Enhances electrode-skin conductivity for optimal signal quality
What should be done to minimize 60-Hz interference in ECG monitoring?
Keep ECG away from interfering sources
What is the primary purpose of noninvasive blood pressure monitoring?
To obtain interval and accurate blood pressure measurements
What are the phases of Korotkoff sounds used in auscultation?
- Phase 1: Systolic measurement
- Phase 5: Diastolic measurement
What is the role of ECG in detecting electrolyte imbalances?
Helps monitor and detect abnormalities
What is arterial tonometry?
Measures arterial blood pressure by sensing the pressure required to partially occlude a superficial artery supported by a bony structure.
What are the benefits of arterial tonometry?
Offers continuous NIV blood pressure monitoring, along with waveform tracing.
What are the limitations of arterial tonometry?
Frequent calibration requirements and sensitivity to patient movement.
What does the Finger Cuff method facilitate?
NIV blood pressure monitoring via a small-volume cuff with an infrared light detector.
What does the ClearSight System do?
Aids in guiding fluid management for the anesthesia provider via NIV methods.
What parameters does the ClearSight System monitor?
- SV
- SVV
- SVR
- MAP
- CO
Why is correct cuff sizing and positioning important?
To achieve accurate blood pressure measurements.
Where are acceptable cuff positions if the upper arm is inaccessible?
- Forearm
- Wrist
- Ankle
What is the recommended cuff bladder encirclement for accurate measurement?
Should encircle ≥ 50% of the patient’s extremity.
What effect does a more distally positioned cuff have on blood pressure readings?
Will yield elevated SBP results, while DBP will be decreased.
What is the preferred site for blood pressure measurement in pediatric patients?
The upper extremity due to its closer correlation to cerebral perfusion.
True or False: Marked positional changes in cuff site can greatly affect measurement results.
True
If a patient’s blood pressure cuff is 12 in. below the heart, how much should the reading be adjusted?
24 mmHg less than the monitor reading.
What are some complications associated with blood pressure monitoring?
- Patient discomfort with repetitive use
- Increased tendency for errors in measurement
- Limb ischemia
- Neuropathies
- Compartment syndrome
- Bruising
- Petechiae
What are contraindications for blood pressure monitoring?
- Bone fractures
- Open injuries (burns)
- Arteriovenous fistulas
- Peripherally inserted central lines (PICC)
- Sites of previous lymph node dissection
What factors should be considered for advancing to invasive monitoring in anesthesia?
- Abrupt and extreme changes in blood pressure
- Present or anticipated inability to compensate for hemodynamic changes
- Surgical procedures that dispose the patient to large intra/extracellular volume shifts
- Patients with compromised respiratory function, oxygenation, or ventilation
What are the three most frequent methods of NIV blood pressure monitoring in anesthesia care?
- Oscillometry
- Tonometry
- Finger Cuff Methods
What is the purpose of the precordial stethoscope?
Used for auscultating heart and breath sounds.
How is the precordial stethoscope secured to the patient?
Double-sided adhesive keeps the weighted piece of metal secured to the patient’s chest.
What is the function of an esophageal stethoscope?
Provides high-quality heart and breath sounds by being placed in the esophagus after intubation.
What should be done before inserting an esophageal stethoscope?
Dip the ballooned tip in lubricant.
Why can esophageal stethoscopes only be used on ventilated patients?
To confirm unobstructed endotracheal intubation by auscultating movement in lungs.
What are the benefits of esophageal stethoscopes?
- Higher quality detection of turbulent breath sounds
- Confirmation of regularity and quality of heart sounds
- Identification of murmurs and muffling
What risks are associated with esophageal stethoscopes?
- Trauma and bleeding in patients with esophageal strictures or varices
- Misplacement into the trachea can create a cuff leak
- Compression of the posterior tongue decreasing lymphatic drainage
What is the primary reason for using esophageal stethoscopes?
For high-quality heart and lung auscultation that electronic monitoring cannot detect.
What are the limitations of esophageal stethoscopes?
Can cause trauma to the airway or decreased lymphatic drainage.
Are esophageal stethoscopes necessary alongside modern monitoring?
They are still depended on as reliable tools in the event of technology failure.
What are precordial and esophageal stethoscopes used for?
Reliable tools in the event of technology failure.
What is capnography?
The continuous monitoring of end tidal carbon dioxide (EtCO2).
What is the normal range for mean PaCO2 in adults?
35-45 mmHg.
What is the normal range for mean PaCO2 in newborns?
30-35 mmHg.
How does EtCO2 compare to PaCO2?
EtCO2 is approximately 2-5 torr lower than PaCO2.
What is the main byproduct of aerobic metabolism?
CO2.
What do central chemoreceptors detect?
H+ resulting from CO2 combining with water.
What condition results from failure to expel CO2?
Respiratory acidosis.
What is the difference between non-diverting and diverting capnography equipment?
Non-diverting measures CO2 directly at the circuit; diverting removes gas for monitoring.
What is a reason to use capnography in patient monitoring?
More sensitive detection of hypoventilation than oxygen saturation alone.
What can capnography confirm?
Endotracheal tube placement.
What are the clinical causes of altered EtCO2 in anesthesia?
- Increased CO2 delivery/production * Decreased CO2 delivery/production.
What are the three phases of capnography?
- Phase I - Dead Space * Phase II - Mixture of dead space and alveolar gas * Phase III - Alveolar gas plateau.
What is a common issue seen in patients with obstructive pulmonary disease in capnography?
No plateau is reached before the next inspiration.
What does a depression during phase III of EtCO2 indicate?
Spontaneous respiratory effort.
What is used to determine CO2 absorbent exhaustion?
Color change of the cannister.
What are early clinical signs of CO2 absorbent exhaustion?
- Elevated EtCO2 monitor readings * Respiratory acidosis * Hyperventilation.
What is the importance of capnography in anesthesia monitoring?
Provides improved monitoring of ventilation when combined with pulse oximetry.
What does pulse oximetry measure?
Pulse rate and the oxygen saturation of hemoglobin (SpO2).
What does pulse oximetry not measure?
The quantity of hemoglobin or the total oxygen content bound to hemoglobin.
What are the two types of pulse oximetry devices?
- Transmittance * Reflectance.
What is the accuracy range of modern pulse oximeters at 70%-100% saturation?
Within 2% to 3%.
What is the Beer-Lambert law related to in pulse oximetry?
The absorption of light is proportional to the concentration of the absorbing substance.
What is the significance of the oxyhemoglobin dissociation curve?
Describes the relationship between oxygen saturation and oxygen tension.
What is hypoxemia?
Low arterial oxygen levels (PaO2 < 60 mmHg).
What clinical signs are often masked during anesthesia?
Clinical signs of hypoxemia such as tachycardia and altered mental status.
What role does pulse oximetry play in CRNA practice?
Provides real-time monitoring of oxygenation to enhance patient safety.
Where should the pulse oximeter probe be placed in neonates?
On the right hand or earlobe.
What is the purpose of real-time monitoring of oxygenation?
To enhance patient safety and outcomes
What can early detection of hypoxemia and hypoventilation decrease?
Perioperative morbidity and mortality rates
Where should the pulse oximeter probe be placed on neonates?
On the right hand or earlobe
What can pulse oximetry be utilized in place of before radial artery cannulation?
Allen’s test
For which patients is pulse oximetry beneficial?
Patients with cardiac or pulmonary disorders/diseases
True or False: Pulse oximetry is a reliable indicator of adequate ventilation.
False
What may affect pulse oximetry readings during descending aorta aneurysms repairs?
Compromised perfusion to distal organs
What does pulse oximetry require for accurate readings?
Pulsatile flow
What can alter pulse oximetry readings?
Carboxyhemoglobin and methemoglobin
What can interfere with pulse oximetry if the photodetector senses radiofrequency emissions?
Electrocautery
What should be done in low perfusion states to improve pulse oximetry accuracy?
Move oximetry site centrally (nose, ear, forehead)
What technology may improve accuracy in pulse oximetry?
Multi-wavelength technology
What is a limitation of current pulse oximeters in low-perfusion states?
Inaccuracies in readings
What is the definition of hypothermia in terms of core body temperature?
Core body temperature of less than 36 degrees Celsius
What is the most common cause of hypothermia in the operating room?
General and regional anesthesia
What is hyperthermia defined as?
Core body temperature raises above 38 degrees Celsius
What genetic condition can lead to malignant hyperthermia?
Genetic hypermetabolic muscle disease
What can atropine do in relation to temperature regulation?
Inhibit sweating response and raise core body temperature
What is a critical aspect of core temperature monitoring during surgery?
Patient safety and standard of care
What are some consequences of hypothermia during surgery?
- Increased risk of surgical site infection
- Impaired coagulation/platelet dysfunction
- Cardiac arrhythmias
What is the recommended operating room temperature range?
Between 68 degrees Fahrenheit (20 degrees Celsius) and 75 degrees Fahrenheit (24 degrees Celsius)
What should be done to address limitations in pulse oximetry?
Secure placement and choose appropriate sites
Fill in the blank: Deoxyhemoglobin absorbs more _______ light.
red
Fill in the blank: Oxyhemoglobin absorbs more _______ light.
infrared
What can lead to tachycardia, vasodilation, and neurological injury?
Hypothermia
Butterworth et al., 2022, p. 126
What is the recommended operating room temperature range?
68 to 75 degrees Fahrenheit
Butterworth et al., 2022, p. 15
What technology is used for temporal noninvasive temperature monitoring?
Infrared technology
Elisha et al., 2023, p. 322
What are the advantages of axillary temperature monitoring?
- Safe
- Ease of placement
- Close to core temperature
Elisha et al., 2023, p. 322
What is a disadvantage of oral temperature monitoring?
Not an accurate reflection of core temperature
Elisha et al., 2023, p. 322
True or False: Tympanic temperature is considered core temperature if a contact probe is used.
True
Elisha et al., 2023, p. 322
What is the most ideal site for measuring temperature with an aural probe?
Tympanic site
Elisha et al., 2023, p. 322
What is a disadvantage of nasopharyngeal temperature monitoring?
- Not usable if trauma sustained to head or neck
- Possible bleeding if probe inserted
- Less useful in awake patients
Elisha et al., 2023, p. 322
What is an advantage of esophageal temperature monitoring?
Considered to reflect core temperature
Elisha et al., 2023, p. 322
Fill in the blank: Bladder temperature monitoring provides a _______ reflection of core temperature.
definite
Elisha et al., 2023, p. 322
What are the disadvantages of pulmonary artery temperature monitoring?
- Invasive
- Possible risk of infection
- Not reliable during open chest procedures
Elisha et al., 2023, p. 322
What is the purpose of preoperative prewarming?
To reduce phase one decline in core temperature
Butterworth et al., 2022, p. 1239
What can contribute to hypothermia or hyperthermia during surgery?
- Cool ambient temperature
- Prolonged exposure of large wound
- High flow of unhumidified gases
Butterworth et al., 2022, p. 1239
What is a treatment for postoperative shivering?
- IV dose of meperidine (12.5-25 mg)
- Warming blankets
- Forced-air warming device
Butterworth et al., 2022, p. 1239
What can occur in the PACU due to hypothermia?
Shivering
Butterworth et al., 2022, p. 1239
True or False: Shivering can cause hyperthermia and metabolic acidosis if sustained for long periods.
True
Butterworth et al., 2022
What should be considered for patients vulnerable to temperature fluctuations?
- Specific comorbidities (e.g., hypothyroidism, burns)
- Pediatric patients
Butterworth et al., 2022, p. 1239
