Exam 1 Clinical Monitoring Part 1 [6/6/24] Flashcards
1
Q
AANA Monitoring Standards for Oxygenation
A
- Clinical Observation (watch your patient for chest rise and fall)
- Continuous Pulse Oximetry
- ABG’s as indicated
S2
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 [in practice q3min]
CEAP’M Ventilated
S2
3
Q
AANA Monitoring Standards for Cardiovascular System
A
- Electrocardiogram [its okay to have just the pulse OX as long as its showing the HR continuously]
- Auscultation as needed
- BP and HR documentation q 5 mins
S2
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.
- in children, we set the OR to be warm bc they lose body heat very rapidly compared to adults
S2
5
Q
AANA Monitoring Standards for Neuromuscular System
A
- When neuromuscular blocking agents are administered.
- TOF are charted q 15 mins
S2
6
Q
Additional means of monitoring depends on the needs of ?
A
- patient, surgical technique, or procedure
S3
7
Q
If not charting monitoring standards, what must be done?
A
- Omission with reason must be charted
S3
8
Q
Name factors that will cause the Hb dissociation curve to shift left
A
Left:
* Alkalosis
* Hypocarbia
* Hypothermia
* Decreased 2,3 DPG
* COHb
* Fetal Hb
Right shift = ↓ Hb affinity to O2.
Left shift = ↑ Hb affinity to O2*
S5
9
Q
Name factors that will cause the Hb dissociation curve to shift right.
A
Right
* acidosis
* hypercarbia
* hyperthermia
* Increased 2,3 DPG
Right shift = ↓ Hb affinity to O2.
Left shift = ↑ Hb affinity to O2
S5
10
Q
How low can a healthy normal adult patient’s PaO2 decrease before:
* their O2 saturation drops below 90%?
* their O2 saturation drops below 75%?
* their O2 saturation drops below 50%?
A
- PaO2 can decrease to 60 mmHg before O2 saturation drops below 90%.
- PaO2 can decrease to 40 mmHg before O2 saturation drops below 75%
- PaO2 can decrease to 27 mmHg before O2 saturation drops below 50%
S5
11
Q
Light through matter
is ______, ______, or _____.
A
Transmitted, absorbed, or reflected
S6
12
Q
Upon what law of physics is pulse oximetry based?
A
- Beer-Lambert Law
S6
13
Q
What is the beer-lambert law?
A
- Law of absorption
- Relates the transmission of light through a solution to the concentration of the solute in the solution
- Light absorption must be measured at wavelengths that are proportional to the number of solutes
S6
14
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
S7
15
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
S7
16
Q
What were the four species of Hb in adult blood discussed in lecture?
A
- Oxyhemoglobin (O2Hb)
- Deoxyhemoglobin (deO2Hb)
- Methemoglobin (metHb)
- Carboxyhemoglobin (COHb)
S8
17
Q
What is sulfahemoglobin?
A
- Sulfahemoglobin is not normally present in the body.
- Made from oxidation of iron in the body usually from drugs.
S8
Most common etiology of sulfhemoglobinemia is the use/misuse of sulfur-containing medications such as AZO
18
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
- instead of looking at 2 wavelengths like a pulse ox it looks at 4 wave lengths.
S8
pulse ox is inaccurate with COhb [will show higher than normaly] so this is the gold standard.
19
Q
All types of hemoglobin are read at 940 nm except?
A
- Carboxyhemglobin
S8
20
Q
The wavelength of red light
A
- 660 nm
S9
21
Q
The wavelength of infrared light
A
- 940 nm
S9
22
Q
__________ absorbs more infrared light.
___________ absorbs more red light.
A
- Oxyhemoglobin (O2Hb) absorbs more infrared light than deoxyhemoglobin
- Deoxyhemoglobin (deO2Hb) absorbs more red light than oxyhemoglobin
- SeXy DARLing:
SiX hundred wavelength, DeoxyHb Absorbs Red Light.
S9
23
Q
Pulsatility of arterial blood flow estimates _____
A
- SaO2
S10
24
Q
Light is transmitted through
A
- Skin
- Soft tissue
- Venous blood
- Arterial blood
- Capillary blood
S10
25
# Ratio of AC and DC light absorption
* Pulsatile expansion of the artery ____ length of light path which _____ absorbency
* Pulsatile component divided by?
* Pulsatile expansion of the artery **increases** length of light path which **Increases** absorbency
* Pulsatile component divided by **non-pulsatile component for each wavelength**
| S10
## Footnote
AC= alternating current = pulsatile
DC=direct current = non-pulsatile
26
Schematic of the Pulse Principle.
* 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.
27
____ absorbs as much light in the 660 nm range as oxyhemoglobin does. What is the clinical relevance?
* Carboxyhemoglobin
* Falsely elevates SpO2
| S11
28
What patients are we concered about with in regards to carboxyhemoglobin?
* Pts who have been in fires
* Carbon monoxide poisoning.
| S11
29
Each 1% increase in COHb will increase SpO2 by _____%.
* 1%
| S11
30
Many smokers have > ______% of COHb.
* 6%
| S11
31
What factors cause signal artifacts in pulse oximetry?
* **Ambient light**: Usually solved by alternating red/infrared
* **Low perfusion**: Signal amplitude reduced
* **Venous blood pulsations**: Detection of venous O2Hb sat, results in reduction of presumed arterial SpO2
* **Additional light absorbers** (methylene blue/IV dyes)
* **Additional forms of Hb**
* **Nail polish**
NAAALV
| S12
32
# Advantage of Pulse Ox
How accurate is pulse oximetry when measured against ABGs as long as the patient's O2 saturation is >70%?
* Pulse oximetry's accuracy is within 2% of an ABG.
| S13
33
List advantages of pulse oximetry. (Long list, common sense)
* Accurate/ Convenient
* Not affected by anesthetic vapors
* Noninvasive
* Continuous
* May indicate decreased cardiac output
* Tone modulation
* Probe variety (Ear probe)
* Battery-operated
* Economical
| S13
34
List disadvantages of pulse oximetry. (Long list, common sense)
* 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
| S14
35
# Useful Tips
Fingers are relatively sensitive to ________
* vasoconstriction
| S15
36
# Useful Tips
Useful tips to take into consideration about SPO2:
* Fingers are relatively sensitive to ____
* Dark polish or synthetic nails ____ transmission
* Detection of desaturation and resaturation is ____ peripherally
* Should not be placed on ____ _____.
* ____ may be more reliable with epidural blocks
* _____, _____, _____ less affected by vasoconstriction, reflects desaturation quicker
* Fingers are relatively sensitive to **vasoconstriction**
* Dark polish or synthetic nails **inhibit transmission**
* Detection of desaturation and resaturation is **slower** peripherally
* Should not be placed on **index finger**
* **Toes** may be more reliable with epidural blocks
* **Tongue, Cheek, Forehead** less affected by vasoconstriction, reflects desaturation quicker
| S15
37
# Useful Tips
Why shouldn't the pulse oximeter be placed on the index finger?
* ↑ risk of corneal abrasion
38
Where will you place a pulse oximeter for the most accurate reading during an epidural block?
* Toes
*Toes will be more dilated than fingers with an epidural block.*
| S15
39
What three parts of the body are least affected by vasoconstriction and will reflect desaturation quickly?
* Tongue
* Cheek
* Forehead
| S15
40
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?
* Korotkoff sounds
| S17
41
Describe the phases of the Korotkoff sounds.
During what phase will you hear SBP and DBP?
* **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)**
2-cheese pull, 3 lays chip, 4 brownie
| S17
42
Give the formula to calculate MAP
* MAP = DBP + 1/3 (SBP - DBP)
| s17
43
What factors will limit BP auscultation?
* Decrease peripheral flow (shock/vasoconstriction)
* Changes in vessel compliance (atherosclerosis, severe edema)
* Incorrect cuff size
* Obesity
44
What is the best way to measure BP in pediatric patients?
* Use the automatic NIBP
| S18
45
Blood pressure cuff bladder should should be ____% of arm circumference and _____ % of length of upper arm.
* Blood pressure cuff bladder should should be **40%** of arm circumference and **80%** of length of upper arm.
| S18
46
What method is used by many automatic NIBP devices to measure blood pressure non-invasively.
**Oscillometry**
* The maximal amplitude of oscillations = MAP
* SBP and DBP calculated from algorithm
* SBP – the least agreement with invasive BP
*Automatic NIBP correlates well with invasive BP in healthy pts.*
| S19
47
What factors will cause errors in automatic NIBP resulting in low SBP and high DBP?
* Atherosclerosis
* Edema
* Obesity
* Chronic HTN
| S19
48
* What will be the result of a BP reading if the patient's BP cuff is too large?
* What will be the result of a BP reading if the patient's BP cuff is too small?
* Large cuff = falsely low BP
* Small cuff = falsely high BP
| S19
49
For standards of automatic NIBP they must be within how many mmHg?
* +/- 5 mmHg
*Deviations up to 20 mmHg are acceptable*
| S20
50
What part of the arm is preferable in obese patient when measuring their BP? What should the clinician be aware of in this pt?
* Forearm
* Overestimating SBP; underestimating DBP
| S20
51
What are the problems with estimations for automatic NIBP?
* Underestimate MAP during hypertension
* Overestimate MAP during hypotension
* Underestimating SBP; overestimating DBP
*Averaging/trending is necessary for measurements to be reliable*
| S20
52
What are advantages of automatic NIBP?
* Eliminate clinician subjectivity
* Improved quality and accuracy
* Automaticity [helps reduce white coat syndrome]
* Noninvasive
| S21
53
What are disadvantages of automatic NIBP?
* Unsuitable in rapidly changing situations
* Patient discomfort
* Complications
| S22
54
What complications can arise from automatic NIBP?
* Compartment syndrome
* Pain
* Petechiae and ecchymoses
* Limb edema
* Venous stasis and thrombophlebitis
* Peripheral neuropathy
PPP.com Very Late
| S22
55
Caution use of automatic NIBP in:
* Severe coagulopathies
* Peripheral neuropathies
* Arterial/venous insufficiency
* Recent thrombolytic therapy
| S22
56
List indication for invasive BP monitoring [arterial line]
* Continuous, real-time
* Planned pharmacologic manipulation
* Repeated blood sampling
* Determination of volume responsiveness
* Timing of balloon pump counterpulsation
| S23
57
Arterial monitoring sites
* Radial [Most common site, Easy to access, Complications uncommon]
* Ulnar
* Brachial
* Axillary
* Femoral
* Posterior tibial
* Dorsalis pedis
| S24
58
What test is used to assess collateral blood flow to the hands before radial arterial line placement.
If there is good circulation, how long before color returns?
> how many seconds indicates severely reduced collateral flow?
* Allen's Test
* Good circulation: Color returns <5 seconds
* > 10 seconds indicate severely reduced collateral flow
*Predictive value of this test is poor*
| S25
59
Describe the Seldinger technique for arterial placement.
1. insert the needle
2. pass guidewire through needle
3. Remove needle
4. Insert catheter
| S27
60
Describe the Transfixion technique for arterial placement.
* Front and back walls are punctured intentionally
* Needle removed
* Catheter withdrawn until pulsatile blood flow appears and then advanced
61
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.
* 30 to 45 degrees
| S26
62
What is used to prevent thrombus formation in an arterial line?
Fluid lacks ____ or ____
* 1-3 ml/hr automatic NS flush (pressure bag)
* dextrose or heparin
| S29
63
What does zeroing an arterial line do?
* The measuring system must also be zeroed to obtain accurate data.
* References pressure against atmospheric air
| S29
64
Where is the arterial line leveled?
* Aortic root (mid axillary chest)
| S29
65
How can the waveform of an arterial line be maximized?
* Limit stopcocks
* Limit tube length
* Use non-distensible tubing (hard tubing)
Short hard cocks
| S29
66
Label parts 1-6 of the arterial waveform.
* 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.*
| S30
67
As the pressure wave moves to the periphery, what happens to the:
* Arterial upstroke
* Systolic Peak
* Dicrotic notch
* End Diastolic pressure
* Arterial upstroke will be steeper
* Systolic Peak will be higher
* Dicrotic notch will appear later
* End Diastolic pressure will be lower
| S31
68
What causes the difference in morphologies of arterial pressures measured at different sites?
* Impedance and harmonic resonance along the vascular tree
| S31
69
What two waves make up a typical pressure wave (summation wave)?
* Fundamental wave
* Harmonic wave
| S32
70
What is the square wave test?
* The arterial line can measure BP inaccurately unless properly calibrated.
* Rapidly flushing the line generates a square wave.
* Counting 2 or less oscillations after the square wave indicates that the arterial line works properly.
* The amplitude of each oscillation should be no greater than 1/3rd of the previous osscilation
| S32
71
Describe an under-dampened arterial waveform.
* Systolic pressure is falsely high
* diastole pressure is underestimated.
* MAP is accurate.
* >2 oscillations
* Multiple dicrotic notches/ artifacts
| S34
72
Describe an over-dampened arterial waveform
* Systolic pressure is falsely low
* Absence of dicrotic notch
* Loss of detail
* Falsely narrowed pulse pressure, but accurate MAP
* Fails to oscillate normally
| S34
73
What factors affect pressure gradient changes in arterial waveforms?
* Age: lack of distensibility
* Atherosclerosis
* Peripheral vascular resistance changes
* Septic shock
* Hypothermia
| S35
74
Compare the arterial waveforms between a normal young person and an elderly person.
* The elderly patient will have an ↑ SBP & decreased DBP
* The elderly patient will be a widened Pulse Pressure
* This is due to the decrease in distensibility in the elderly patient
| S35
75
List arterial line complications.
* Distal ischemia or pseudoaneurysm
* Hemorrhage, hematoma (hold pressure longer)
* Arterial embolization (Art line staying in too long)
* Local infection
* Peripheral neuropathy
| S36
76
Cyclic arterial BP variations d/t respiratory-induced changes in intra-thoracic pressure are related to what two factors?
* Positive pressure ventilation
* Lung volume changes
| S37
77
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.
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*
| S38
78
During the EARLY inspiratory phase of PPV, the increase in LV preload and decrease in afterload produce an increase in what three variables?
* ↑ LV SV
* ↑ CO
* ↑ Systemic arterial pressure
*Miller pg. 1167*
| S38
79
Rising intrathoracic pressure impairs systemic venous return and RV preload; this will ____ RV afterload by slightly ____ pulmonary vascular resistance. These effects combine to reduce RV ejection during the early phase of inspiration.
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*
| S38
80
What happens to RV stroke volume during the early phase of inspiration?
* RV SV drops
| S38
81
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?
* ↓ LV filling
* ↓ LV SV
* ↓ Systemic arterial pressure
| S40
82
The cycle of increasing and decreasing stroke volume and systemic arterial blood pressure in response to inspiration and expiration is known as _________________.
* Systolic pressure variation (SPV).
| S40
83
In mechanically ventilated patients, normal SPV is __________ mmHg (range).
* 7-10 mmHg
| S41
84
What is a normal Δ up SPV?
* 2-4 mmHg
| S41
85
What is a normal Δ down SPV?
* 5-6 mmHg
| S41
86
What does an increased SPV indicate?
* Patient may be volume responsive or have residual preload reserve
* Possible early indicator of hypovolemia
* Critically ill patients will have an increased SPV with a drastic Δ down component.
| S41
87
This variable is used as a dynamic indicator of preload reserve by utilizing the max and min pulse pressure over the entire respiratory cycle.
* Pulse Pressure Variation
| S42
88
What is considered a normal pulse pressure variation?
A PPV > than this indicates what?
* < 13 -17%
* PPV >13 - 17% will indicate a positive response to volume expansion*
| S42
89
PPV formula
[difference in arterial pulse pressure] / [ Average of Max and Min pulse pressure]
| S42
90
The changes in stroke volume between the inspiratory and expiratory phases of positive pressure ventilation.
* Stroke Volume Variation
| S43
91
How do you calculate SVV?
(SV max - SV min) / SV mean
| S43
92
What is normal SVV?
* 10-13%
*SVV >10-13% indicates a positive response to volume expansion.*
| S43
93
SVV uses computer analysis of arterial pulse pressure waveforms and correlates resistance and compliance based on what two factors?
* age
* gender
| S43
94
Mechanical ventilation should have a tidal volume of ______ (range).
* 8-10 mL/kg
| S44
95
To predict accurate results of residual preload reserve through SPV, PPV, and SVV, what factors need to be met in mechanically vented patients?
* 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
* can also be altered by pt position: L lat or trendelenburg not accurate
*Miller pg. 1168*
| S44
96
What is the importance of the Frank-Starling Law?
* 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.
| S45
97
Which artierial line monitoring site is the most common site and easy to access with complications being uncommon?
what kind of complication is most common with arterial lines?
What are the 6 other sites?
Radial artery
hematoma
ulnar, brachial, axillary, femoral, posterior tibial, and dorsalis pedis
| S24
98
Describe the process of performing an Allen's test
Patient makes a tight fist (which exsanguinates the palm)
patient opens hand
examiner releases ulnar artery and observes the return of color
| S25
99
Allen's test is only ____ % accurate for color change at ____ seconds.
T/F
Pulse oximetry and ultrasound improve the accuracy.
80%
5 seconds
False! doesnt improve accuracy
| S25
100
T/F
The transfixion technique is associated with more frequent complications
False, it is not associated with more frequent complications
| S28
101
____ to ____ harmonics are required for most arterial pressure waveforms.
6-10
| S32
102
____ ____ is the analysis of the summation of multiple sine waves
Fourier Analysis
| S32
103
In order to calculate accurate results for SVV, PPV, and SPV, the patient must be ____ ____
Mechanically ventilated
| S44
