8. Monitoring Anesthesia Flashcards
The big 5s
ECG, pulsox, capnograph, BP, temperature
main causes of complications of anesthetic death
respiratory and CV
50% in post-op period
which palpebral do you loose first?
lateral
Guedel’s classification
clinical assessment of CNS, eyes mostly, old school
BIS bispectral index
0-100 100 = awake
indicates level of consciousness
results controversial in dogs, used in humans
why monitor BP?
indicates tissue perfusion
hypotension
MAP <65mmHg
range of pressure where range of perfusion to organ is preserved, below 65 autoregulation is not preserved and adequate perfusion will not happen
measuring BP
Indirect v. Direct
*pulse does not indicate BP its just difference between systolic and diastolic
Oscillometic method
indirect, cuff inflates above systolic and deflates in stepwise fashion, when the P = systolic the vessell starts vibrating, when vibrating the most thats the MAP.
cuff width
40-60% circumference of extremity, between ELBOW AND CARPUS is best!
inaccurate BP because?
wrong size cuff!! (too big cuff -> lower BP, vice versa) And put cuff at level of the heart
Doppler method
emits US, signal becomes sound indicating blood flow. First audible sound = systolic AP.
- does NOT give diastolic or mean!!!!!!!
- **sortof inaccurate, portela doesn’t like it.
Direct monitoring
gold standard. continuous monitoring*
which artery for direct BP?
dorsopedal artery (dorsal metatarsal) most often (lingual, radial/carpal, coccygeal, femoral, auricular) *Flush regularly to avoid clotting
inaccuracies of direct bp monitoring?
- overdamping - air bubble, systolic lower than real
2. underdamping - systolic higher than real number
Fluid responsiveness
increase in volume causes inc. left ventricle, inc. preload, inc. stroke volume.
- doesn’t work if in FLUID OVERLOAD
Pulse pressure variation must be ____ for patient to be responsive to fluids
above 15%
what measures Tidal volume
wright respirometer
What is capnography
indirectly measures ventilation, espimates PaCO2
- differences between PaCO2 and end tidal CO2 due to dead space ventilation
- can indicate, problem in circuit, obstruction, cardiogenic shock
What happens when hypoventilating?
- if hypoventilating, theyre moving mostly deadspace, end tidal CO2 would be low
- if ET CO2 is low, give a big breath and see if it goes up (if it doesn’t they may be hyperventilating)
two types of capnography monitoring
- side stream:
- monitor is away from patient, sampling continuously, delayed response every time it aspirates
- in small animals doesn’t work
- sample is contaminated in nonrebreathing system - main stream:
- monitor in connector, in real time, more accurate, big awkward thing connected to tube
low ET CO2 indicates?
high ET CO2 indicates?
hyperventilation/deadspace
hypoventilation
Ventilating Deadspace indicates what on capnography??
Low end tidal CO2
** Know this, he kept saying it**
Check by giving big breath!!
Cardiac oscillations
normal, heart pushing on lung parynchyma
