L9: Monitoring during Anesthesia (Tenenbaum) Flashcards
(27 cards)
what systems are monitored at minimum?
CNS CVS Respiratory Renal (temp)
signs to look for when assessing whether patient is in good plane of anesthesia***
position of eye movement m. tone certain reflexes response to surgical stimulation nystagmus (esp. in horse) shivering eye reflexes present
signs of LIGHT plane of anesthesia
- central eye position
- cessation of limb movements
- m. tone remains
- response to sx stimulation
- nystagmus
- eye reflexes
- shivering
- moist cornea
signs of MEDIUM plane of anesthesia
- no spontaneous movement
- no reflex movement
- no change in hemodynamic or breathing during sx stim.
- mod. m. tone
- dec. in tidal volume
- no palpebral reflex
- no shivering
- ventromedial rotation of eye
- small pupil aperture
- moist corneas
signs of DEEP plane of anesthesia
- dec. in Vt
- abd. breathing
- eyes fixed centrally
- no reflexes
- bradycardia/hypotension and worsening of hemodynamic fx
- dilated pupil
- dry cornea
causes of white/pale mm
anemia
vasoconstriction
lack of circulating fluid
causes of cyanotic mm
lung disease
dec. in oxygen flow to the breathing circuit
endobronchial intubation
causes of red/bright pink mm
hypercapnia
common arrhythmias
sinus tachycardia
sinus bradycardia
2nd degree AV block
VPCs
ECG:
- good for detecting HR and rhythm but not in evaluating cardiac fx and heart disease
- each patient is different!**
- N dog: 70-140
- N cat: 110-140
- N horse: 30-45
mean BP should be maintained above:
60mmHg (70 in horses)
direct BP measurement
- arterial catheter connected to pressure transducer
- provides real time beat by beat pressure monitoring
- invasive
indirect BP measurement
- aka sphymomanometry
- use of pressure cuff, doppler shift pulse detectors
- if cuff to wide or tight, underestimate blood pressure
- systolic should be >80mmHg
oscillometric method
- cuff inflated to a pressure and pressure is slowly released as the monitor detects the oscillations in the cuff caused by the blood flow under the cuff
- MAP >60mmHg
how can CO be measured
invasive thermodilution
-not used routinely
how is pulse oximetry measured
light absorption of 2 different wavelengths at fast intervals during pulsations
- detects reduced Hb and oxyHb
- % of saturated Hb is calculated
- sensitive to movement, cold, vasoconstriction
- should be >95%
central venous pressure
- P within the thoracic vena cava
- balance b/w venous blood volume and contractility of the heart
- dec. CVP: hypovolemia
- inc. CVP: fluid overload
urine output depends on
CO
blood volume
renal function
normal tidal volume***
10-15mg/kg
blood gas analysis
- measures lvls of oxygen and CO2 in arterial blood
- provides acid-base status
- can also measure electrolytes/glucose/lactate
capnography**
-measures the end tidal CO2 and the inspired CO2 tension
-connected between the patient and the breathing system
-useful to measure:
hypoventilation
hyperventilation
apnea
disconnection
rebreathing
obstruction
embolism
-provides info on:
1) adequacy of ventilation
2) CV system
3) patient’s metabolism
phases of the capnogram: phase I***
Inspiratory baseline
- represents the inspiration of fresh gas with CO2
- should stay at the level that corresponds to zero concentration of CO2
phases of the capnogram: phase II***
Expiratory upstroke
- occurs shortly after inspiration ends
- caused by the rapid washing out of the fresh gas in the anatomic space and then replacement by CO2-rich alveolar gas
- should be steep
phases of the capnogram: phase III***
Expiratory plateau
- represents continuous exhalation
- horizontal line if no V/Q mismatch, but usually CO2 slowly increases as the gas from the lung areas with lower rate of ventilation to perfusion reaches the sampling site
