from beginning of induction of anesthesia to loss of consciousness
(stage of disorientation)
(stage of excitement or the stage of delirium)
from loss of consiousness to the onset of automatic breathing.
eyelash reflex disappear but other reflexes remain intact
intact: coughing, vomiting and struggling may occur; respiration can be irregular with breath holding
(stage of surgical anesthesia)
from onset of automatic respiration to respratory paralysis
plane I (III)
from onset of automatic respiration to cessation of eyeball movements.
eyelid is lost, swallowing is gone,
marked eyeball movement may occur but conjuntival refle is lost at the bottom of the plane
plane II (III)
cessation of eyeball movement to beginning of paralysis of intercostal muscles.
respiration is automatic and regular
from beginning to completion of intercostal muscle paralysis.
diaphargmatic respiraiton persists but there is progessive intercostal paralysis.
pupils dilate and light relex is gone!
laryngeal reflex is lost in plane II but can still be elicited by dilation of anus or cervix (coughing, gagging)
this is the desired plane for surgery when muscle relaxants are not used
plane IV (III)
from complete intercostal paralyst to diaphragmatic paralysis (apnea)
from stoppage of respiration to death.
this is anesthetic overdose causing medullary paralysis with resp. arrest and vasomotor collapse. pupils are widely dilated