hemodynamics Flashcards
AANA Standard 9: monitoring and alarms
- monitoring device pitch and threshold alarms on and audible
- BP, HR, RR q 5 min
- continuously monitor
1. oxygenation (pulse ox)
2. ventilation (end tidal)3
3. CV; HR, BP, circulation (EKG)
4. thermoregulation (temp)
5. neuromuscular when applicable
precordial/ esophageal stethoscope
- continuous assessment of heart and breath sounds
- more commonly used in cases with high risk of air embolism
Electrocardiogram (ECG)
- detects arrhythmias
- monitor HR
- detects ischemia
- detects electrolyte changes
- monitor pacemaker function
3 Lead ECG
- electrodes on RA, LA, LL
- not for complex arrhythmia, ST segment elevation or ischemia
5 Lead ECG
- RA, LA, LL, RL, chest
- dysrhythmias/ ischemia seen during anesthesia can be detected by a combination of monitoring leads II and V5.
ST depression
ischemic changes
ST elevation
full thickness ischemia or infarct
ECG for Ischemic Detection
- ST segment change
depression (flat or downslope)elevation >1mm - peaked, flattened or inverted T wave
- Development of Q waves
- Arrhythmias
ST segment
- myocardial repolarization
- ST elevation: ischemia likely r/t acute coronary artery occlusion
- ST depression: ischemia
- CAD pts might have baseline ST segment. abnormalities
- set alarms 1 mm above and below the baseline ST-segment level in patients at high risk for ischemia.
ST segment changes unrelated to ischemia
- drugs (digitalis)
- temp change
- position change
- hyperventilation
Hides ST segment changes
- hypokalemia
- digitalis
- LBBB
- Wolf-parkinson white syndrome
- acute pericarditis
- LVH with strain
QT interval
- highly HR dependent
- if prolonged can be associated with ventricular arrhythmias
R sided leads
- aVR
- V1
L sided leads
- I
- aVl
- V5
- V6
QRS complex
- Left ventricular activity
- normal QRS complex less than 120msec
Systolic BP
ventricular contraction
-changes in SBP correlate with changes in myocardial 02 requirement
Diastolic
ventricular relaxation
-changes in DBP reflect coronary percussion pressure
Ohms Law
BP = CO x SVR
intra op hypotension
MAP between 55-60 mmHG
percussion pressure
systemic = MAP-CVP
pulmonary circulation = Mean pulmonary artery pressure - L atrial pressure (pulmonary artery wedge pressure; PAWP)
noninvasive BP
- palpation: only measures systolic and its underestimated (palpate return of arterial pulse)
- doppler: only reliably measures SBP (sound waves that reflect RBCs moving through artery)
- auscultation: permits estimation of SBP and DBP, BP cuff unreliable in HPTN pts- usually lower (korotkoff sound from blood flow through artery and cuff)
- oscillometry: senses fluctuation/ oscillations in cuff pressure produced by arterial pulsations while cuff deflates (1st oscillation SBP, oscillations end DBP)
Cuff size
Width: 40% of arms circumference
Length: encircle 80% of extremity
- *too large: false low BP
- *too small: false high BP
False High BP
- cuff to small
- cuff too loose
- extremity below heart level
- arterial stiffness (HTN, PVD)
False Low BP
- cuff too big
- extremity above heart
- poor tissue perfusion
- too quick deflation