Clinical Monitoring Complete (Exam I) Flashcards
(119 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 are the normal changes in systolic pressure variation?
Up: 2-6mmHg
Down: 5-6mmHg
39
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.
40
How do you find the maximal difference in arterial pulse pressure?
(PPmax-PPmin)/(PPmax+PPmin)/2)
The difference/the average
41
What is normal Stroke Volume Variation (SVV) ?
10 - 13%
If greater, patient will likely respond to fluids.
42
Compare side-stream and main-stream gas analyzing
Main-stream: gas is not removed from the circuit
Side-Stream: Gas is removed from the circuit (monitored by another machine
43
What are the two types of gas sampling systems?
- Side-stream monitoring
- Mainstream monitoring
44
True or False: The further away the sampler is from the elbow, the less accurate the gas analyzing is.
True
45
What are challenges associated with mainstream CO₂ gas sampling?
- H₂O vapor
- Secretions
- Blood
- Disconnections
46
What are challenges associated with sidestream CO₂ gas sampling?
- Tubing kinking
- H₂O vapor
- leaks in line
- slower response time
47
What is the partial pressure of O₂ at sea level?
160 mmHg
48
Dalton's Law
The total pressure exerted by a mixture of gases is equal to the the sum of the partial pressures of each gas.
49
What is the Patm ?
760 mmHg
50
What is the percentage O₂ at sea level?
*exclude water vapor*
160 mmHg ÷ 760 mmHg = 21%
51
How are quantities of CO₂, N₂O, H₂O, and VAA's measured?
Infrared Analysis
*O₂ cannot be measured via IR analysis.*
52
What is atmospheric air pressure for ventilated patients?
713 mmHg (take account for humidification)
53
What is the difference between oxygen analyzers inside the inspiratory limb and on the expiatory side?
Inspiratory limb ensures oxygen delivery whereas on the expiatory side ensures complete pre-oxygenation
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
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 is more rapid and utilized with side-stream sampling analyzers? It also measure real time breath by breath
Paramagnetic
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
What two conditions would set off a high O₂ alarm?
- Premature infants
- Bleomycin (chemotherapy)
61
What can cause low O2 pressure alarms?
-Pipeline corssover
-Incorrectly filled tanks
- Failure of a proportioning system
62
What is the purpose of a proportioning system?
Allow us to turn up the O2 without nitrous being turned up, but ensure that O2 is turned up if the nitrous is turned up
63
What is normal peak airway pressure?
18 - 20 mmhg
64
What can cause low PIP alarms?
-Disconnects
-Apnea
-Vent failure
-Leaks in system
-OGT in lung on suction
65
What is the normal fixed high PIP alarm and what causes it to alarm?
50-80 cmH20
-Obstructions
-Reduced compliance
-Coughing/straining
66
True or False: High PIP alarms are functional in pressure controlled ventilation
False
67
What is sustained elevated pressure PIP?
Pressure that remains elevated during the respiratory cycle exceeding 10 cmH2O >15 sec
68
What can cause sustained elevated PIP?
-Improperly adjusted APL
-Activation of oxygen flush system
-Malfunctioning PEEP
-Scavenging system occlusion
69
What nerve is the gold standard for peripheral nerve stimulation monitoring?
ulnar nerve (adductor pollicis)
70
What is the most resistant place to neuromuscular blocking drugs?
Diaphragm (needs 2x as much drug for identical block as AP)
71
Most sensitive muscles to paralysis
-Orbiculari oculi
-Masseter
-Upper ariway
72
What muscle most closely reflect laryngeal adductor muscle?
Corrugator supercilli of facial nerve
73
What muscle(s) are better indicators (vs the adductor pollicis) of neuromuscular blockade at the laryngeal muscles and abdominal muscles?
- Orbicularis Oculi
- Corrugator supercilli
74
What muscle may chosen when the surgical procedure requires the HOB away from anesthesia?
Posterior tibial (flexor hallucis longus)
75
Single twitch stimulations occurs every...
1hz every second
76
TOF fade is noted with what drug class?
non-depolarizing NMBD's
77
Tetanic Stimulation
Stimulus at 50Hz for 5 seconds
Very painful
78
Post tetanic stimulation
Present prior to TOF returning
79
What is the case if fade has occurred with succinylcholine administration?
Phase II Blockade
80
What are the reversal drugs (and doses) use for intense/extreme blockade?
- Neostigmine N/A
- Suggamadex 16 mg/kg
81
Intense block
period of no response 3-6 minutes after intubating dose of NDNMB
82
Depp Block
Absence of TOF but presence of at least one response to post tetanic count stimulation
83
Moderate Block
Gradual return of the 4 responses to TOF stimulation appears
84
What are the reversal drugs (and doses) use for deep blockade?
- Neostigmine usually doesn't work
- Succinylcholine 4 mg/kg
85
What are the reversal drugs (and doses) used for moderate blockade?
- Neostigmine after TOF 4/4
- Succinylcholine 2 mg/kg
86
What is a phase I block?
No fade and no-post tetanic facilitation occurs and it represents normal plasma cholinesterase activity
87
What is a phase II block?
Fade present in response to TOF and occurrence of post-tetanic facillitation and represents abnormal plasma cholinesterase activity
88
What EEG signals are noted for an awake patient?
- Βeta (>13Hz) waves
89
What numbers are the left and right side of the hemisphere?
Left: Odd
Right: Even
90
What does an EEG measure?
Summation of excitatory and inhibitory PSPs that objectively identifies consciousness, seizure activity,, stages of sleep, and coma as well as ischemia
91
What EEG signals are noted for patients who are mildly anesthetized?
Αlpha (8 - 13Hz) waves
92
What is the bispectral index?
Processes EEG signal to monitor LOC
93
What BIS range do we want our patients in?
40-60
94
What should the suppression ratio be on the BIS monitor?
0
95
What are sensory evoked potentials?
CNS response from electric, auditory, or visual stimuli
96
What are the different sensory potentials?
SSEPS: peripheral nerves
BAEPs: clicks in auditory canal
VEP: flash stimulation of retina
97
Motor Evoked Potentials
Monitors integrity of the motor tracts
-must not have NMB on board
98
What EEG signals are noted for patients who are fully anesthetized?
Theta (4-7Hz)and Delta (<4Hz)waves
99
What causes the initial decrease of 0.5 - 1.5°C in anesthesia within the first 30 minutes?
Anesthesia induced vasodilation
100
What is temperature regulated by and what is it mediated by?
Hypothalamus
mediated by: dopamine, norepi, Ach, prostaglandins
101
What fibers signal cold and warm?
Cold: a-delta
Warm: c fibers
102
How much will body temp decrease for every hour of surgery?
0.3°C
103
What is the cause of heat loss during anesthesia?
- Anesthesia-induced vasodilation
- GA-induced decrease in metabolism
104
21°C = ____°F
70
105
18°C = ____°F
65
106
What type of heat transfer accounts for the most heat loss in surgical patients?
Radiation
107
What type of heat loss accounts for less than 10%?
Evaporation through sweating
108
What type of heat transfer is increased with rooms with laminar airflow in surgeries such as TKA?
Convection
109
When do the continual and plateau phases of hypothermia happen?
Continual: hours 1-2
Plateau: Hours 3-4
110
How is hypothermia affected in spinal anesthesia?
-Dec threshold that trigger vasoconstriction
-Induces vasodilation in the periphery
-Redistributes heat periphery
-Decreases shivering
111
What is the gold standard for temperature monitoring?
Pulmonary artery
112
What does the tympanic membrane measure the temperature of?
hypothalamus
113
What does the nasopharyngeal reflect the temperature of?
The brain
114
Name sites that are not "as good" for temperature monitoring?
Oral
Axillary
Rectal
Bladder
Skin
115
How does hypothermia increase incidence of morbid cardiac outcomes 3x?
Inc BP, HR, and catecholamine release
Inc O2 demand by shivering
116
How does hypothermia increase the incidence of wound infection by 3x?
decreases O2 delivery to tissues
117
Hypothermia Complications
Impairs platelet, PT, and PTT function
Inc blood loss 16% and need for transfusion by 20%
Inc NMB duration (cisatracurium and atracurium)
Patient discomfort
118
Benefits of hypothermia
Improved outcome from cardiac arrest
Protective against cerebral ischemia
More difficult trigger MH
Reduces metabolism
119
How much does hypothermia decrease metabolism by?
6-8% per degree C
