Exam I Clinical Monitoring (6/06/24 & 6/10/24) Flashcards
(103 cards)
1
Q
What physics law deals with pulse oximetry and the laws governing absorption of light?
A
Beer Lambert
2
Q
A low concentration of hemoglobin results in a ____ light absorption rate.
A
lower
3
Q
What should be utilized if oximetry is determined to be inaccurate?
A
Co-oximetry
4
Q
What is co-oximetry?
A
Co-oximetry is the measurement of:
- O₂Hb
- DeO₂Hb
- MetHb
- CarboxyHb
all through differing wavelengths of light
5
Q
Red wavelengths of light measure at ______ nanometers.
A
660
6
Q
Infrared wavelengths of light measure at ______ nanometers.
A
940
7
Q
Deoxyhemoglobin preferentially absorbs more ________ than oxyhemoglobin.
A
red
8
Q
Oxyhemoglobin preferentially absorbs more ________ than deoxyhemoglobin.
A
Infrared
9
Q
What makes up the AC portion of the graph below?
A
Light absorption from pulsatile arterial blood.
10
Q
What makes up the DC portion of the graph below?
A
Light absorption from:
- Non-pulsatile arterial blood
- Venous and capillary blood
- Tissue
11
Q
What formula is used to determine the ratio of AC to DC light absorption? (and thus give our pulse oximetry)
A
12
Q
What will falsely elevate SpO₂ ?
A
Elevated carboxyhemoglobin
13
Q
Each __% of COHb (carboxyhemoglobin) will increase SpO₂ by __%.
A
1 : 1
14
Q
_______ will absorb as much 660nm light at oxyHb does.
A
COHb
15
Q
What percent carboxyhemoglobin will smokers have?
A
> 6% usually
16
Q
What are possible reasons for SpO₂ signal artifact and thus incorrect readings?
A
- Ambient light
- Low perfusion
- Venous blood pulsations
- Dyes (ex. Methylene blue)
- Nail polish
17
Q
Where can a pulse ox be placed if the fingers won’t work?
A
- Forehead
- Tongue (!)
- Cheek
18
Q
What are Korotkoff sounds related to?
A
Blood pressure (Through partial occlusion with the BP cuff)
19
Q
How is MAP calculated?
A
DP + ⅓(SP - DP)
20
Q
What Korotkoff phase is the loudest?
Quietest?
A
- Phase 1: loudest (SBP) due to turbulence
- Phase 6: Sounds disappear (DBP)
21
Q
How should a cuff fit on a person’s arm?
A
- 40% of arm circumference
- 80% of length of upper arm
- Centered over artery
22
Q
A BP cuff that is too large will read a blood pressure that is _______.
A
too low
23
Q
A BP cuff that is too small will read a blood pressure that is _______.
A
too high
24
Q
Where can a blood pressure be obtained from an obese patient if the upper arm won’t work?
A
forearm
25
What is the best site for invasive blood pressure monitoring?
Radial artery
26
How does the Transfixion technique for arterial catheter placement differ from the seldinger technique?
Transfixion involves puncturing through the back of the artery and withdrawing until the needle can be removed.
27
Label the various parts of the arterial waveform.
1. Systolic upstroke
2. Systolic peak pressure
3. Systolic decline
4. Dicrotic notch
5. Diastolic runoff
6. End-diastolic pressure
28
What occurs to an arterial waveform as it moves centrally (aorta) to the periphery (ex. femoral artery) ?
- Arterial upstroke steepens
- ↑ systolic peak
- Dicrotic notch occurs later
- Lower EDP
29
How are summation waves formed?
Through the combination of Fundamental and Harmonic waves.
30
How many oscillations should follow a square wave test?
No more than two
31
What would the systolic pressure read in an underdamped system?
↑ SBP
32
What would the characteristics of an overdampened arterial waveform be?
- ↓SBP
- Absent dicrotic notch
- Loss of detail
- Narrowed pulse pressure w/ accurate MAP
33
What occurs with RV and LV afterload during the inspiratory phase?
RV afterload increases
LV afterload decreases
34
What occurs with RV and LV preload during the inspiratory phase?
RV preload decreases
LV preload increases
35
RV stroke volume ____ during early phase of inspiration.
drops
36
How much systolic pressure variation is typical in mechanically ventilated patients?
7 - 10 mmHg
37
What would increases systolic pressure variation be indicative of?
Volume responsiveness (i.e. patient needs fluids)
38
What is the normal change in pulse pressure variation over an entire respiratory cycle?
13 - 17%
If greater than 13 - 17% you need to give volume.
39
What is normal Stroke Volume Variation (SVV) ?
10 - 13%
If greater, patient will likely respond to fluids.
40
What are the two types of gas sampling systems?
- Side-stream (Diverting) monitoring
- Mainstream monitoring
41
time lag for the gas sample to reach the analyzer
Transit Time
42
time taken by the analyzer to react to the change in gas concentration
Rise Time
43
dependent on sampling tubing inner diameter, length, and gas sampling rate
Side-Stream Responses
44
What are challenges associated with mainstream CO₂ gas sampling?
- H₂O vapor
- Secretions
- Blood
- Disconnections
45
What are challenges associated with sidestream CO₂ gas sampling?
- Tubing kinking
- H₂O vapor
- Failure of sampling pump
- leaks in line
- slower response time
46
What is the partial pressure of O₂ at sea level?
160 mmHg
47
What is the Patm ?
760 mmHg
48
What is the percentage O₂ at sea level?
*exclude water vapor*
160 mmHg ÷ 760 mmHg = 21%
49
Concentration determined according to mass/charge ratio
Mass Spectrometry
50
Mass Spectometry can calculate up to ___ different gases.
Eight
51
High powered argon laser produces photons that collide with gas molecules in a gas sample, no longer in use
Raman Spectroscopy
52
What does infrared analysis measure?
Concentrations of gases
53
How are quantities of CO₂, N₂O, H₂O, and VAA's measured?
Infrared Analysis
54
Which gas cannot be measured via infrared analysis?
O₂ cannot be measured via IR analysis.
55
The less IR light that reaches the sensor means that the gas has a ___ concentration.
higher
| Amount of IR light that reaches the detector is inversely related to the
56
What is the partial pressure of water vapor?
47 mmHg
57
O₂ is at 30%, what is the partial pressure?
*Be sure to take water vapor into account*.
(760 - 47) x 0.30 = 214 mmHg
58
Which type of oxygen analyzer has a more rapid response time and is utilized with side-stream sampling analyzers?
Paramagnetic
| Side-Stream is seen more often
59
Which type of oxygen analyzer has a slower response time and is best to monitor O₂ concentration in the inspiratory limb?
Fuel or Galvanic cell
60
While sampling inside the expiratory limb, we want to ensure ___.
How can we measure this?
Complete denitrogenation
ETO2 above 90% is adequate
61
If there is an oxygen tank that is incorrectly filled or there was a pipeline crossover, we may see ___.
A low O2 alarm
62
What two conditions would set off a high O₂ alarm?
- Premature infants
- Bleomycin (chemotherapy)
63
Describe important components of mechanical pressure gauges
* No recording of data
* No alarm system
*** Must be continually scanned!!**
64
What should the Low-pressure limit be set at?
Just below the normal peak airway pressure
65
What is normal peak airway pressure?
18 - 20 mmhg
66
Causes of a "Sub-Atmospheric" pressure alarm?
* Active (suction) scavenging system malfunctions
* Pt inspiratory effort against a blocked circuit
* Inadequate fresh gas flow
* Suction to misplaced NGT/OGT
* Moisture in CO2 absorbent
67
Which type of alarm, per lecture, is valuable in pediatrics?
High-Pressure Alarms
68
When is the continuing pressure alarm triggered?
Triggered when circuit pressure exceeds 10 cm H2O for >15 seconds
69
True or False:
Magnetic peripheral nerve stimulation is the most common type used, but is the more painful option.
False
Electrical is most common, Magnetic is less painful
70
What nerve is the gold standard for peripheral nerve stimulation monitoring?
ulnar nerve
71
What is the most resistant place to neuromuscular blocking drugs?
Diaphragm
72
What muscle is a better indicator (vs the adductor pollicis) of neuromuscular blockade at the laryngeal muscles and abdominal muscles?
**- Corrugator supercilli**
73
Single twitch stimulations occurs every...
1hz every second
74
TOF fade is noted with what drug class?
non-depolarizing NMBD's
75
What is the case if fade has occurred with succinylcholine administration?
Phase II Blockade
76
What are the reversal drugs (and doses) use for intense/extreme blockade?
- Neostigmine N/A
- Sugammadex 16 mg/kg
77
What are the reversal drugs (and doses) use for deep blockade?
- Neostigmine usually doesn't work
- Sugammadex 4 mg/kg
78
What are the reversal drugs (and doses) used for moderate blockade?
- Neostigmine after TOF 4/4
- Sugammadex 2 mg/kg
79
What EEG signals are noted for an awake patient?
- Βeta (>13Hz) waves
80
What EEG signals are noted for patients who are mildly anesthetized?
Αlpha (8 - 13Hz) waves
81
What EEG signals are noted for patients who are fully anesthetized?
Theta (4-7 hz) and Delta (< 4 hz) waves
82
Ideal BIS range for General Anesthesia
40-60
83
Most common type of evoked potentials monitored intra-op:
Sensory-Evoked Potentials
84
BAEPs or VEPs?
Monitors the responses to click stimuli
BAEPs
85
BAEPs or VEPs?
Monitors the responses to flash stimulation of the retina:
VEPs
86
These type of evoked potentials monitor the responses to stimulation of peripheral mixed nerves (contain motor and sensory nerves) to the sensorimotor cortex
Somatosensory-Evoked Potentials
87
Most common MEP
**Transcranial** motor-evoked potentials
88
Where is the primary thermoregulatory control center?
Hypothalamus
89
What causes the initial decrease of 0.5 - 1.5°C in anesthesia?
Anesthesia induced vasodilation
90
How much will body temp decrease for every hour of surgery?
0.3°C
91
What is the cause of heat loss during anesthesia?
- Anesthesia-induced vasodilation
- GA-induced decrease in metabolic rate by 20-30%
92
True or False:
Central thermoregulatory control is inhibited in neuraxial anesthesia?
TRUE
93
# Methods of Heat transfer:
heat loss to the environment, approx. 40% of heat loss in pt
Radiation
94
# Methods of Heat transfer:
loss of heat to air immediately surrounding the body, approx. 30%
Convection
95
# Methods of Heat transfer:
heat loss due to direct contact of body tissues or fluids with a colder material, negligible
Conduction
96
# Methods of Heat transfer:
latent heat of vaporization of water from open body cavities and respiratory tract, approx. 8-10%
Evaporation
97
Hypothermia Complications:
* Coagulopathy
* Transfusion needs increased (22%)
* Blood loss increased (16%)
* Decreased oxygen delivery to tissues
* Increased BP, HR, Catecholamine levels
* Shivering
* Decreased drug metabolism (Longer DOA of NMBD)
98
Hypothermia Benefits:
* Protective against cerebral ischemia
* Reduces metabolism… 8% per degree Celsius
* Improved outcome during recovery from cardiac arrest
* Neurosurgery when brain tissue ischemia is expected
* More difficult to trigger MH
99
Which types of patients may need an increased room temperature?
* Liver Transplants
* Major Trauma
* Pediatrics
100
Most commonly used peri-op temperature management method?
A. Cutaneous Warming
B. Forced Air Warming
C. Warm IV Fluids
D. Airway Heating
E. Hot Water Mattresses
B. Forced Air Warming
Most common, prevent heat loss from radiation
Uses convection to transfer heat to pt
101
Gold standard temperature monitoring site:
Pulmonary Artery
102
21°C = ____°F
70
103
18°C = ____°F
65
