Monitoring Depth of Anesthesia Flashcards
When monitoring anesthesia depth, both cortical and subcortical activities need to be assessed?
True
___ times more anesthetic is needed to inhibit movement than to inhibit consciousness
Three
T/F: immobility can be used to ensure unconsciousness
false
First part of CNS inhibited by anesthesia?
cortex
Stage 1 of Guedel’s system describes _____
from drug administration to loss of consciousness
What is likely to occur during stage 1?
excitement and violent struggle (maybe)
epinephrine release, tachycardia, pupillary dilation
irregular breathing, breath hold, coughing
salivation, urination, defecation
ataxia, recumbency
Stage 2 of Guedel’s system describes _________
from loss of consciousness until onset of regular breathing
What is likely to occur during stage 2?
state of delirium
struggling and exaggerated reaction to stimuli
epinephrine release, tachycardia, pupillary dilation
strong palpebral and eyelash reflexes
irregular breathing, breath holding, laryngeal spasm
vomiting, regurgitation, salivation
strong jaw tone, intubation not possible or difficult
Stage 3 of Guedel’s system describes ________
from onset of regular breathing until cessation of effective breathing
At what stage do you expect no movement in response to noxious stimuli?
Stage 3
Describe Stage 3 plane 1
light anesthesia nystagmus, lacrimation weakening palpebral and corneal reflexes no swallowing reflexes pupils constricted no involuntary movement simple procedures/exams may be possible
Describe Stage 3 plane 2
medium plane of anesthesia progressive intercostal paralysis stable respiration and pulse loss of laryngeal reflexes weak palpebral strong corneal reflexes adequate muscle relaxation for most surgical procedures
Describe Stage 3 plane 3
deep anesthesia diaphragmatic breathing pupils dilate, eyes central no palpebral/corneal reflexes some patients may have to be maintained at this stage, should ideally decrease to plane 2
Describe stage 4
overdose
resp failure, cardiac arrest, death
T/F: cardiovascular adverse effects are only possible if isoflurane is overdosed
false
T/F: a patient is only considered hypotensive if it is too deep
false, can even be hypotensive if anesthesia is light
What stage are most surgeries and intubation performed in?
Stage 3 plane 2-3
What drug can cause nystagmus, blinking, central eye position and dilated pupils even at moderate anesthetic depth?
Ketamine
3 goals for practicality
1) acceptable cardiovascular function
2) fully relaxed and immobile patient
3) least necessary anesthetic depth
rotated eyes likely indicate stage ______
stage 3 plane 2
is ideal but not mandatory
central eye and dilated pupils indicate:
either too light or too deep anesthesia
nystagmus likely indicates
too light anesthesia
____ may have slow nystagmus at light but appropriate anesthetic depth
horses
spontaneous blinking likely indicates
too light anesthesia
slow blinking may be seen in ______ and may be acceptable if everything else is okay
horses
lacrimation may be seen at
light but appropriate depth especially in horses
Should you perform corneal reflex?
no - may cause injury
_____ tone indicates overall muscle tone
jaw
The tongue should be _____
relaxed
If spontaneous respiratory rate is high (>20br/min), may indicate?
too light anesthesia or low lung volume
What can a changing RR and pattern in response to surgical stimulus be a sign of?
anesthesia may be too light or analgesia may be insufficient
Common causes of increased heart rate?
surgical stimulus (nociception)
life threatening stress (hypoxemia)
anemia, hypovolemia, shock, hyperthermia
common causes of decreased heart rate?
drugs or hypothermia
