Hemodynamics Flashcards
1
Q
What is your first duty as an anesthesia care provider
A
-vigilance
2
Q
Electrocardiogram
A
- monitors HR and rhythm
- detects arrhythmias, electrolyte disturbances, myocardial ischemia
- be mindful of many sources of interference in the OR
3
Q
3 lead ECG
A
- lead I, II, and III (RA, LA, LL) (black, white, red)
- lateral and inferior views
- detects HR and Vfib
4
Q
What leads are most sensitive to ischemia?
A
-precoridal leads
5
Q
5 lead ECG
A
- I, II, III, aVR, aVL, aVF, V (7 views)
- RA, LA, LL, RL, V
6
Q
What lead monitors for special arrhythmias
A
V1: distinguishes between RBBB and LBBB
7
Q
What leads are preferred for monitoring for ischemia
A
-V3 through V5
8
Q
What is the standard for monitoring patients who are at higher risk for perioperative ischemia detection?
A
-Lead II and V5
9
Q
Where does V5 lead get placed
A
-
10
Q
What should your gain and filtering capacity be set to?
A
Gain = 1mV
Filtering Capacity = diagnostic mode
11
Q
What are some indicators of ischemia
A
- ST segment elevation >1.0 mm
- T wave flattening or inversion
- presence of Q waves
- ST segment flattening or downslope of >1.0mm
- peak t-waves
- arrhythmias
12
Q
ST elevation vs ST depression
A
- ST elevation usually signals a poor supply (thrombus, block etc.)
- ST depression usually means ischemic demand.
- ST elevation specific to occluded artery;
- ST depression not specific to artery, just indicates demand ischemia
- ST elevation = transmural ischemia; coronary artery occlusion or arterial vasospasm; reciprocal ST depression contralateral leads = coronary thrombosis; subendocardial ST depression ischemia = stable angina occurs in tachycardia
13
Q
What does the ST segment mean?
A
-ventricular repolarization
14
Q
Baseline ST depression
A
- find baseline
- set alarms between 1/2mm elevation and depression
-antidysrythmics, prior ischemia
15
Q
Changes in II, III, AVF insinuate
A
- inferior wall ischemia
- Right Coronary Artery
16
Q
Changes in I, aVL, V5-V-6 insinuate:
A
- Lateral wall ischemia
- Left circumflex
17
Q
Changes in V3-V4
A
- Anterior Wall ischemia
- Left Coronary Artery
18
Q
Changes in Lead V1-V2
A
- Septal Ischemia
- Left Anterior Descending
19
Q
What leads are most sensitive for exercise induced ischemia?
A
-leads V4-V5
20
Q
What do you do in the OR if you suspect your patient is having a ischemic event
A
1) regulate supply/demand: lower HR, increase BP, lower catecholamine response
2) order TEE to check for RWMA
21
Q
Left axis deviation
A
,
22
Q
Right axis deviation
A
.
23
Q
Changes in SBP correlate with
A
-myocardial oxygen requirements
24
Q
Changes in DBP
A
-changes in coronary perfusion pressure
25
MAP
-time weighted average of blood pressure during cardiac cycle
26
Auscultation of blood pressure relies on
-Korotkoff sounds
27
Oscillatory method measures
- oscillations or pressure fluctuations that occur in response to arterial pulsation
- DBP mathematically calculated
- requires pulsatile flow; cannot be done with VAD or ECMO
- usually underestimates SBP and overestimates DBP
28
What issues will give you a falsely high BP
- too small cuff
- extremity below heart
- stiff blood vessels (atherosclerotic dx)
29
What issues will give you a false low BP
- cuff too big
- too quick deflation
- extremity level above heart
- poor tissue perfusion
- dysrythmias, tremors, shaking
30
Indications for arterial line
- continuous real time blood pressure monitoring
- planned pharmacological CV manipulation
- repeated blood sampling
- failure of indirect arterial blood pressure monitoring
- severe end organ disease
- anticipated or induced hypotension
31
When do you place an arterial line in relation to induction?
-can do pre or post induction; if you anticipate patient will have HD changes upon induction or high risk; place pre-induction
32
Where is the A-line transduced from?
- phlebostatis axis (RA)
| - Circle of Willis (tragus of ear)
33
What are the components of an arterial waveform? How does the morphology change as you change location?
- systolic uptake
- peak systolic pressure
- systolic decline
- dichroic notch
- diastolic runoff
-as you get more peripherally, the waveform becomes more exaggerated: higher peak, sleaper slope, wider pulse pressure, more prominent dichrotic notch
34
What is the interval between the R wave and systolic upstroke?
- 180 msec
- represents the delay between ventricular depolarization, isovolumetric ventricular contraction, aortic valve opening, blood pressure wave, and blood pressure that signals to the transducer
35
Dichroic notch
-closure of aortic valve
36
Overdamped
- when the a-line waveform is too severe a slope and difficult to discern dichroic notch
- kinks
- air bubbles
- vasospasm
- blood clot
37
Underdampened
- when the pulse pressure is narrowed and flattened, however the MAP will stay the same; no pulsatility
- hypothermia
- tachycardia/arrhythmia
- not enough fluid in the bag
38
Ways to troubleshoot different dampening
- ensure adequate pressure in pressure bag 300mmHg
- power flush
- reposition patient
- verify appropriate scale
39
Arterial waveform in Aortic Stenosis
- Pulses parvus (narrow pulse pressure)
| - Pulses tardus (delayed upstroke)
40
Arterial waveform in Aortic Regurgitation
- Bisferiens Pulse (two peaks)
| - wide pulse pressure
41
Arterial waveform in Hypertrophic Cardiomyopathy
-Spike and Dome
42
Arterial waveform in Systolic LV Failure
-Pulses Alternans
43
Arterial waveform in Cardiac Tamponade
Pulses Paradoxus
44
Beers Law
Absorption of a wavelength of light depends on the absorptivity of the material, the concentration, and the thickness of the material
-oxygenated hemoglobin and deoxygenated hemoglobin have different absorption spectra
45
What wavelengths do pulse oximeters measure at
-660 and 940 nm
46
How do pulse oximeters work?
- pulse oximeters measure the % of O2 bound to Hgb (HgbO2)
- they do this by measuring concentrations of HgbO2 in systole and diastole and find the difference to find concentration in arterial blood
47
Types of Hbg in blood
- oxygenated hgb
- deoxygenated hgb
- carboxy hgb
- met hbg
48
CarboxyHbg
- does not absorb any light
| - patient with carbon monoxide poisoning will have falsely elevated Spo2
49
Met Hbg
- absorbs light at 660
| - O2 sat well be 85% regardless of what the SaO2
50
Indications for CVC
- CVP/PAP monitoring
- administration of medications (vasoactive, chemo etc)
- intermittent dialysis
- temporary pacing of heart
51
Complications of CVC insertion
- cardiac tamponade
- pneumothorax
- hemothorax
- nerve injury
- infection
- arrhythmia
- thromboembolic event
52
CVP
- central venous pressure (2-8)
| - waveform: 3 peaks (a, c, v) 2 descents (x,y)
53
“A” wave
- atrial contraction
- follows p wave
- corresponds with atrial kick which actively fills RV
- occurs end diastole
54
“C” wave
- represents isovolumetric contraction of RV
- during this time TV is closed, so RV bulges into RA
- occurs at early systole
55
“X” descent
- corresponds with atrial relaxation
| - occurs mid systole
56
“V” wave
- refilling of atrium from ventricular ejection
- TV still closed
- occurs: late systole
- occurs: just after t-wave EKG
57
“Y” descent
- TV opens
- atrial empties
- occurs early diastole
58
CVP waveform in a fib
- loss of a-wave
| - prominent c-wave
59
CVP waveform in AV disassociation
-cannon a waves
60
CVP waveform in Tricuspid stenosis
-tall a and v waves
61
CVP waveform in TR
-Tall c-v waves
62
Indications for PAC
- cardiac surgery
- assess LV function, LV filling,
- cardiac ischemia
- valvular disease
- shock (septic, cardiogenic, distributive, hypovolemic)
- ARF
- pulm HTN, ARDS, severe pulm dysfunction
63
Complications of PAC
- arrhythmias (afib, VF, CHB)
- catheter knotting
- balloon rupture
- thromboembolic event
- pneumothorax
- PA rupture
- valvular damage
- contraindications: WPW, complete LBBB
64
Distance of PAC in skin
- RA = 25cm
- PA = 35-45
- wedge = 40-50
65
PCWP “a” wave
- left atrial contraction
| - pronounced in mitral stenosis
66
PCWP “c” wave
-bulging on mitral valve back into left atrium as left ventricle contracts
67
PCWP “v” wave
- Passive filling of left atrium
| - prominent v wave indicative of mitral vale insuffienciency
68
Normal cardiac output
-5L/min
69
Normal stroke volume
-75mL
70
Normal SVR
- 800-1600
| - normal ~1200
71
Normal PVR
- 40-180
| - Normal ~80
72
Mixed Venous O2Sat
-70-80
73
TEE measures:
1) ventricular wall (regional wall motion abnormalities)
2) valve structure/function
3) EF
4) CO
5) blood flow
6) intracardiac air
7) intracardiac masses
74
Reasons for TEE in OR
- tamponade
- PE
- MI
- dissection
- hypotension
- valvular disease
- valvular function
- wall motion
75
Complications
- hoarseness
- sore throat
- arrhythmias
- esophageal trauma
