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JW: Principles of Anesthesia I > Exam 1- Clinical Monitoring (6/8/23) > Flashcards

Exam 1- Clinical Monitoring (6/8/23) Flashcards

1
Q

AANA Monitoring Standards for Oxygenation

A
  • Clinical Observation (watch your patient)
  • Continuous Pulse Oximetry
  • ABG’s as indicated
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2
Q

AANA Monitoring Standards for Ventilation

A
  • Auscultation
  • Chest excursion (rise/fall of chest)
  • ETCO2 documentation
  • Pressure monitors as indicated
  • Monitor RR q 5 mins
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3
Q

AANA Monitoring Standards for Cardiovascular System

A
  • Electrocardiogram
  • Auscultation as needed
  • BP and HR documentation q 5 mins
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4
Q

AANA Monitoring Standards for Thermoregulation

A
  • When clinically significant changes in body temp are anticipated or suspected
  • Continuous monitor of temperature in cases longer than 20 minutes, pediatric cases, or elderly patients.
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5
Q

AANA Monitoring Standards for Neuromuscular System

A
  • When neuromuscular blocking agents are administered.
  • TOF are charted q 15 mins
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6
Q

Name factors that will cause the Hb dissociation curve to shift right.

Name factors that will cause the Hb dissociation curve to shift left

A

Remember:
Right shift = ↓ Hb affinity to O2.
Left shift = ↑ Hb affinity to O2

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7
Q

How low can a healthy normal adult patient’s PaO2 decrease before their O2 saturation drops below 90%?

A

PaO2 can decrease to 60 mmHg before O2 saturation drops below 90%.

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8
Q

Upon what law of physics is pulse oximetry based?

A
  • Beer-Lambert Law
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9
Q

Explain how concentration of a solute affects light absorption in pulse oximetry.

A
  • Amount of light absorbed is proportional to the concentration of the light absorbing substance (Beer’s Law)
  • Higher Hb concentration, more light absorption
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10
Q

Explain how distance affect light absorption in pulse oximetry.

A
  • Amount of light absorbed is proportional to the length of the path that the light has to travel in the absorbing substance (Lambert’s Law)
  • Wider arteries, more light absorption
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11
Q

What were the four species of Hb in adult blood discussed in lecture?

A
  • Oxyhemoglobin (O2Hb)
  • Deoxyhemoglobin (deO2Hb)
  • Methemoglobin (metHb)
  • Carboxyhemoglobin (COHb)
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12
Q

What is considered the gold standard for SaO2 measurements and is relied on when pulse oximetry readings are inaccurate or unobtainable?

A
  • CO-oximetry
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13
Q

The wavelength of red light

A
  • 660 nm
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14
Q

The wavelength of infrared light

A
  • 940 nm
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15
Q

__________ absorbs more infrared light.

___________ absorbs more red light.

A

SeXy DARLing:
SiX hundred wavelength, DeoxyHb Absorbs Red Light.

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16
Q

How does the amount of oxyhemoglobin and deoxyhemoglobin in the blood affect oxygen saturation?

A
  • As the amount of oxy Hb and deoxy Hb changes, the light ratio comparing red and infrared light also changes.
  • The pulse oximeter uses the ratio to work out the oxygen saturation.
  • More DeoxyHb present, ↑ Red Light: Infrared Light Absorption Ratio, ↓ O2 sat
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17
Q

Which Hb species absorbs as much light in the 660 nm range as OxyHb?

A
  • Carboxyhemoglobin

The absorption of light at 660 nm by COHb is similar to that of O2Hb. At 940 nm, COHb absorbs virtually no light. Thus, in a patient with carbon monoxide poisoning, the SpO2 will be falsely elevated.

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18
Q

Each 1% increase in COHb will increase SpO2 by _____%.

A
  • 1%
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19
Q

Many smokers have > ______% of COHb.

A
  • 6%
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20
Q

Schematic of the Pulse Principle.

A
  • Light absorption through tissue is characterized by a pulsatile component (AC) and a non-pulsatile component (DC).
  • The pulsatile component of absorption is due to arterial blood. The non-pulsatile component is due to venous blood and the remainder of the tissues.
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21
Q

What factors cause signal artifacts in pulse oximetry?

A
  • Ambient light
  • Low perfusion
  • Venous blood pulsations
  • Additional light absorbers (methylene blue)
  • Additional forms of Hb
  • Nail polish
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22
Q

How accurate is pulse oximetry when measured against ABGs as long as the patient’s O2 saturation is >70%?

A
  • Pulse oximetry’s accuracy is within 2% of an ABG.
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23
Q

List advantages of pulse oximetry. (Long list, common sense)

A
  • Accurate/ Convenient
  • Not affected by anesthetic vapors
  • Noninvasive
  • Continuous
  • May indicate decreased cardiac output
  • Tone modulation
  • Probe variety (Ear probe)
  • Battery-operated/ Cheap
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24
Q

List disadvantages of pulse oximetry. (Long list, common sense)

A
  • Poor function with poor perfusion
  • Delayed hypoxic event detection
  • Erratic performance with dysrhythmias
  • Inaccuracy with different hemoglobin (COHb)
  • Inaccuracy with dyes
  • Optical interference
  • Nail polish and coverings
  • Motion artifact
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25
Q

Fingers are relatively sensitive to ________

A
  • vasoconstriction
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26
Q

What kind of nails inhibit pulse oximeter transmission?

A
  • Dark polish or synthetic nails
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27
Q

True/False: Pulse Oximetry detection of desaturation and resaturation from the periphery is slow.

A
  • True
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28
Q

Why shouldn’t the pulse oximeter be placed on the index finger?

A
  • ↑ risk of corneal abrasion
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29
Q

Where will you place a pulse oximeter for the most accurate reading during an epidural block?

A
  • Toes

Toes will be more dilated than fingers with an epidural block.

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30
Q

What three parts of the body are least affected by vasoconstriction and will reflect desaturation quickly?

A
  • Tongue
  • Cheek
  • Forehead
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31
Q

Most indirect methods of blood pressure measurement utilize a sphygmomanometer. What is the series of audible frequencies produced by turbulent flow beyond the partially occluded cuff called?

A
  • Korotkoff sounds
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32
Q

Describe the phases of the Korotkoff sounds.

During what phase will you hear SBP and DBP?

A
  • Phase I: the most turbulent/audible (SBP)
  • Phase II: softer and longer sounds
  • Phase III: crisper and louder sounds
  • Phase IV: softer and muffled sounds
  • Phase V: sounds disappear (DBP)
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33
Q

Give the formula to calculate MAP

A
  • MAP = DBP + 1/3 (SBP - DBP)
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34
Q

What factors will limit BP auscultation?

A
  • Decrease peripheral flow (shock/vasoconstriction)
  • Changes in vessel compliance (atherosclerosis)
  • Incorrect cuff size
  • Obesity
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35
Q

What is the best way to measure BP in pediatric patients?

A
  • Use the automatic NIBP
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36
Q

Blood pressure cuff bladder should should be ____% of arm circumference and _____ % of length of upper arm.

A
  • Blood pressure cuff bladder should should be 40% of arm circumference and 80% of length of upper arm.
37
Q

What method is used by many automatic NIBP devices to measure blood pressure non-invasively.

A
  • Oscillometry

Automatic NIBP correlates well with invasive BP in healthy pts.

38
Q

What factors will cause errors in automatic NIBP resulting in low SBP and high DBP?

A
  • Atherosclerosis
  • Edema
  • Obesity
  • Chronic HTN
39
Q

What will be the result of a BP reading if the patient’s BP cuff is too large?

A
  • falsely low BP
40
Q

What will be the result of a BP reading if the patient’s BP cuff is too small?

A
  • falsely high BP
41
Q

For standards of automatic NIBP they must be within how many mmHg?

A
  • +/- 5 mmHg

Deviations up to 20 mmHg are acceptable

42
Q

What part of the arm is preferable in obese patient when measuring their BP?

A
  • Forearm
43
Q

What are advantages of automatic NIBP?

A
  • Eliminate clinician subjectivity
  • Improved quality and accuracy
  • Automaticity
  • Noninvasive
44
Q

What are disadvantages of automatic NIBP?

A
  • Unsuitable in rapidly changing situations
  • Patient discomfort
  • Complications (Compartment syndrome, Pain, Limb edema, etc)
45
Q

Caution use of automatic NIBP in:

A
  • Severe coagulopathies
  • Peripheral neuropathies
  • Arterial/venous insufficiency
  • Recent thrombolytic therapy
46
Q

List indication for an arterial line.

A
  • Continuous, real-time
  • Planned pharmacologic manipulation
  • Repeated blood sampling
  • Determination of volume responsiveness
  • Timing of balloon pump counterpulsation
47
Q

Monitoring sites with arterial line.

A
  • Radial (most common, easy to access)
  • Ulnar
  • Brachial
  • Axillary
  • Femoral
  • Posterior tibial
  • Dorsalis pedis
48
Q

What test is used to assess collateral blood flow to the hands before radial arterial line placement.

A
  • Allen’s Test
  • Good circulation: Color returns <5 seconds
  • > 10 seconds indicate severely reduced collateral flow

Predictive value of this test is poor

49
Q

Describe the Seldinger technique for arterial placement.

A
50
Q

Describe the Transfixion technique for arterial placement.

A
  • Front and back walls are punctured intentionally
  • Needle removed
  • Catheter withdrawn until pulsatile blood flow appears and then advanced
51
Q

When placing an arterial line, the needle should enter at a _______ degree angle (range) to the skin directly over the point at which the pulse is palpated.

A
  • 30 to 45 degrees
52
Q

What is used to prevent thrombus formation in an arterial line?

A
  • 1-3 ml/hr automatic NS flush (pressure bag)
53
Q

What does zeroing an arterial line do?

A
  • The measuring system must also be zeroed to obtain accurate data.
  • Zeroing the system provides a reference point of pressure.
  • Most commonly, this is atmospheric pressure.
54
Q

Where is the arterial line leveled?

A
  • Aortic root (mid axillary chest)
55
Q

How can the waveform of an arterial line be maximized?

A
  • Limit stopcocks
  • Limit tube length
  • Use non-distensible tubing (hard tubing)
56
Q

Label parts 1-6 of the arterial waveform.

A
  • 1: systolic upstroke
  • 2: systolic peak pressure
  • 3: systolic decline
  • 4: dicrotic notch (closing of the aortic valve)
  • 5: diastolic runoff
  • 6: end-diastolic pressure

SBP is measured at 2 and the DBP is measured at 6.

57
Q

As the pressure wave moves to the periphery, what happens to the:

Arterial upstroke
Systolic Peak
Dicrotic notch
End Diastolic pressure

A
  • Arterial upstroke will be steeper
  • Systolic Peak will be higher
  • Dicrotic notch will appear later
  • End Diastolic pressure will be lower
58
Q

What causes the difference in morphologies of arterial pressures measured at different sites?

A
  • Impedance and harmonic resonance along the vascular tree
59
Q

What two waves make up a typical pressure wave (summation wave)?

A
  • Fundamental wave
  • Harmonic wave
60
Q

What is the square wave test?

A
  • The arterial line can measure BP inaccurately unless properly calibrated.
  • Rapidly flushing the line generates a square wave.
  • Counting oscillations after the square wave indicates that the arterial line works properly.
  • There should be no more than two oscillations after the fast flush
61
Q

Describe an under-dampened arterial waveform.

A
  • Systolic pressure is falsely high
  • > 2 oscillations
  • Multiple dicrotic notches
62
Q

Describe an over-dampened arterial waveform

A
  • Systolic pressure is falsely low
  • No oscillations
  • Absence of dicrotic notch
  • Loss of detail
  • Falsely narrowed pulse pressure, but accurate MAP
63
Q

What factors affect pressure gradient changes in arterial waveforms?

A
  • Age: lack of distensibility
  • Atherosclerosis
  • Peripheral vascular resistance changes
  • Septic shock
  • Hypothermia
64
Q

Compare the arterial waveforms between a normal young person and an elderly person.

A
  • The elderly patient will have an ↑ SBP
  • The elderly patient will be a widened Pulse Pressure
  • This is due to the decrease in distensibility in the elderly patient
65
Q

Pathologic changes in peripheral vascular resistance may also produce generalized arterial pressure gradients that can affect the site choice for arterial pressure monitoring. In patients receiving vasopressor infusions for septic shock, the femoral arterial pressure may exceed the radial pressure by greater than ______ mm Hg.

A
  • 50 mmHg

Miller pg. 1164

66
Q

Compare the pressure gradient changes during hypothermia and rewarming.

A
  • During hypothermia, vasoconstriction causes systolic pressure in the radial artery to exceed that in the femoral artery.
  • During rewarming, vasodilation reverses the gradient.

Miller pg. 1164

67
Q

List arterial line complications.

A
  • Distal ischemia or pseudoaneurysm
  • Hemorrhage, hematoma (hold pressure longer)
  • Arterial embolization (Art line staying in too long)
  • Local infection
  • Peripheral neuropathy
68
Q

Cyclic arterial BP variations d/t respiratory-induced changes in intra-thoracic pressure are related to what two factors?

A
  • Positive pressure ventilation
  • Lung volume changes
69
Q

During the EARLY inspiratory phase of PPV, the increase in intrathoracic pressure simultaneously _______ LV afterload while _________ total lung volume, which displaces blood from the pulmonary venous reservoir forward into the left side of the heart and _________ LV preload.

A

During EARLY the inspiratory phase of PPV, the increase in intrathoracic pressure simultaneously decreases LV afterload while increasing total lung volume, which displaces blood from the pulmonary venous reservoir forward into the left side of the heart and increases LV preload.

Miller pg. 1167

70
Q

During the EARLY inspiratory phase of PPV, the increase in LV preload and decrease in afterload produce an increase in what three variables?

A
  • ↑ LV SV
  • ↑ CO
  • ↑ Systemic arterial pressure

Miller pg. 1167

71
Q

Rising intrathoracic pressure impairs systemic venous return and RV preload; this will ________ RV afterload by slightly increasing pulmonary vascular resistance. These effects combine to reduce RV ejection during the early phase of inspiration.

A

Rising intrathoracic pressure impairs systemic venous return and RV preload; this will increase RV afterload by slightly increasing pulmonary vascular resistance. These effects combine to reduce RV ejection during the early phase of inspiration.

Miller pg. 1167

72
Q

What happens to RV stroke volume during the early phase of inspiration?

A
  • RV SV drops
73
Q

What is the overall effect of increasing intrathoracic pressure on cardiac output?

A
  • ↑ Intrathoracic Pressure = ↓ CO
    Memorize the flowchart
74
Q

During the expiratory phase, the decreased stroke volume ejected from the RV during inspiration travels through the pulmonary vascular bed and enters the left heart, reducing what three variables?

A
  • ↓ LV filing
  • ↓ LV SV
  • ↓ Systemic arterial pressure
75
Q

The cycle of increasing and decreasing stroke volume and systemic arterial blood pressure in response to inspiration and expiration is known as _________________.

A
  • Systolic pressure variation (SPV).
76
Q

In mechanically ventilated patients, normal SPV is __________ mmHg (range).

A
  • 7-10 mmHg
77
Q

What is a normal Δ up SPV?

A
  • 2-4 mmHg
78
Q

What is a normal Δ down SPV?

A
  • 5-6 mmHg
79
Q

What does an increased SPV indicate?

A
  • Patient may be volume responsive
  • Patient may have residual preload reserve
  • Possible early indicator of hypovolemia
  • Critically ill patients will have an increased SPV with a drastic Δ down component.
80
Q

This variable is used as a dynamic indicator of preload reserve by utilizing the max and min pulse pressure over the entire respiratory cycle.

A
  • Pulse Pressure Variation
81
Q

What is considered a normal pulse pressure variation?

A
  • < 13-17%

PPV >13-17% will indicate a positive response to volume expansion

82
Q

PPV formula

A

[Maximum difference in arterial pulse pressure] / [ Average of Max and Min pulse pressure]

83
Q

The changes in stroke volume between the inspiratory and expiratory phases of positive pressure ventilation.

A
  • Stroke Volume Variation
84
Q

How do you calculate SSV?

A

(SV max - SV min) / SV mean

85
Q

What is normal SVV?

A
  • Less than 10-13%

SVV >10-13% indicates a positive response to volume expansion.

86
Q

SVV uses computer analysis of arterial pulse pressure waveforms and correlates resistance and compliance based on what two factors?

A
  • age
  • gender
87
Q

Mechanical ventilation should have a tidal volume of ______ (range).

A
  • 8-10 mL/kg
88
Q

To predict accurate results of residual preload reserve through SPV, PPV, and SVV, what factors need to be met in mechanically vented patients?

A
  • Tidal volume of 8 to 10 mL/kg
  • Positive end-expiratory pressure ≥ 5 mm Hg
  • Regular cardiac rhythm
  • Normal intra-abdominal pressure
  • A closed chest

Miller pg. 1168

89
Q

What is the importance of the Frank-Starling Law?

A
  • Left ventricular filling determines the left ventricular end-diastolic volume (LVEDV), which is generally directly proportional to left ventricular preload and CO.
  • The Frank–Starling Law describes the relationship between LVEDV and CO.
  • According to the Starling Law, CO increases with increasing left ventricular preload.

JW: Principles of Anesthesia I (61 decks)

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