Anesthetic Monitoring

Question 1

which ecg leads r most useful for intraoperative monitoring in the adult?

Answer 1

leads II, V4, V5 detect up to 96% of ischemic episodes (usually II and V5 up in OR)

Question 2

what is the oscillometric method of bp monitoring

Answer 2

• determines arterial bp - cuff unflated until oscillations on the bp gauge are no longer seen = systolic pressure
• cuff then deflated until point of maximum oscillations occur = mean bp
• diastolic isn’t measured with this technique

Question 3

clinically important diffs b/w use of pulse-wave doppler vs cont wave doppler in echo?

Answer 3

• pulsed-wave = slow b/c has one crystal for both emitting & returning…measures slow velocities but knows location of the tissue
• continuous wave = can measure higher velocities b/c has one crystal for emit & one for return. but can’t measure exactly which tissue rather takes an average of the velocities along the path of the ultrasound beam

Question 4

why do we monitor SSEP’s during spine surgery

Answer 4

monitor integrity of dorsal columns of the spinal cord which r supplied by posterior spinal arteries…therefore if you lose SSEP it tells you there is posterior spinal cord ischemia

Question 5

which special precautions need to be taken with SSEP?

Answer 5

don’t use inhaled anesthetics b/c cause decrease in SSEP amplitude and increase in latency. N2O also does this.
opioids and benzos may cause slight changes
mm relaxants don’t affect SSEP

Question 6

which are the most accurate body temp monitoring sights? the least accurate?

Answer 6

most - PA catheter, tympanic membrane (carotid artery), bladder fluid
worst: rectal, axillary, skin

esoph is +/- best to look at the trend vs abs #