chapter 3 monitoring Flashcards
What are indications for EKG in anesthetized patient (4)
1)diagnosis of dysrhythmias, 2)diagnosis of ischemia 3)diagnosis of conduction defects 4)diagnosis of electrolyte distrubances
What are best leads for determining an inferior MI
II, III, AVF
What are best leads for determining lateral MI
I, AVL
Which lead is preferable for cardiac surgical patients
V5-single best lead for diagnosis of myocardial ischemia
best when analyzed with lead II (90% of ischemic episodes)
What are limitations of using 3 lead system vs. 5 electrode system
3 lead-right arm, left arm, and left leg
limits areas of monitoring to anterior, lateral, and inferior walls
Advantages of 5 lead system
5 lead system is all limbs plus unipolar precordial lead(V5 position, or right precordium to monitor Right wall)
7 different leads can be monitored, all but posterior wall can be monitored for ischemia
name bipolar leads, unipolar leads augmented leads
Bipolar I, II, III (monitor + and- electrical potential b/t leads
unipolar augmented AVR, AVL, AVF (one is positive, determine absolute electrical potential between 3 leads)
what is esophageal lead sensitive for
with esophageal stethoscope, atrial dysrhythmias, posterior ischemia
what is tracheal ECG leads good for
pediatric patients for atrial dysrhythmias
what are epicardial electrodes used for
ventricular/atrial wires good for weaning off of CPB before sternal closure, recording of atrial or ventricular epicardial EKG, post operatively to diagnosis conduction issues/dysrhythmias
risks associated with ECG
minimal-microshock
Will non invasive blood pressure work during CPB?
no, must use invasive mechanisms, as pulsatile blood flow is absent in these patients
what are components of invasive BP monitoring
intravascular catheter, fluid filled tubing, transducer, electronic analyzer/display system
critically dampened art line, under dampened, over dampened art line correlate to what type of heart rates
critically dampened HR >150, under dampened, low HR and overestimation od systolic and underestimation of diastolic, and over dampened underestimate of systolic and overestimate of diastolic
describe most transducer systems in anesthesia
under dampened systems with low natural frequency
what effect does air have on invasive BP monitoring
leads to over dampening of system (underestimate of systolic, overestimate of diastolic
describe catheter whip
noticeable pressure swing in PA or LV catheters
describe radial arterial pressure in relation to aortic pressure
radial arterial pressure 20 to 50 mmHG higher than aortic pressure due to decreased peripheral arterial elastane and wave summation
aortic wave form vs. femoral vs.dorsals pedis waveform
aortic rounded, definite dicrotic notch
femoral-delay in pulse transmission (higher systolic pressure) and slurring
dorsals-loss of dicrotic notch, second wave due to arterial arteriolar impedance mismatch
where is reference position for transducer in hemodynamic monitoring
at the right atrium
what are indications for arterial pressure monitoring in cardiac patient
1)small changes in arterial perfusion pressure increase patient risk requiring beat to beat assessment 2)wide variation in BP or intravascular volume is anticipated, 3)frequent blood sampling, 4) assessment of BP can not be performed by other methods (CBP no pulsatile flow) dysrhythmia, or marked obesity)
what are advantages of using femoral artery for invasive BP
1)assessment of central venous pressure 2) access for intra aortic balloon pump
if difficult weaning from CPB is expected (depressed EF, severe wall motion abnormalities, or significant CAD)
*seldinger technique
other areas for arterial BP
radial, ulnar, femoral, axillary, brachial, dorsalis pedis, posterior tibial arteries can all be used
describe respiratory variation in waveforms in relation to hypovolemia
decrease in arterial systolic pressure with PPV (pulses paradox) with PPV impeding venous return to the heart and will seen in hypovolemia
other arterial artery assessments-contractility, SV, vascular resistance-describe
contractility(rate of rise during systole effected by preload, and after load and HR), SV(area under curve from onset of systole to dicrotic notch), vascular resistance(position of dicrotic notch with a notch appearing high on downslope of pressure tracing suggesting high resistance, low resistance causes a dicrotic notch that is low not diastolic portion of the pressure tracing)
what are 5 complications of arterial catheterization
ischemia, thrombosis, infection, bleeding and false lowering of radial artery pressure may be significantly lower than aortic pressure at completion of CPB with forearm vasodilation secondary to rewarming leading to AV shunting resulting in steal phenomenon