3. In administering an anesthesia
Signpost
Guides in determination of depth of anesthesia
Guedel describe depth of anaesthesia by dividing it
into stages and planes.
4. Guedel’s criteria based on :
Respiration
Eyeball movement
Presence or absence of various reflexes
Gillespie added other criteria
Secretion of tears
Response to skin incision
Evaluation of pharyngeal &
laryngeal reflexes
5. Stages were first described for ether anesthesia
Can be used with modification for all agents
Can be recognized during both induction & recovery
6.
7. Starts from beginning of anaesthetic inhalation and
lasts up to the loss of consciousness.
Pain is progressively abolished.
Patient remains conscious, can hear and see, and feels
a dream like state
8. Reflexes and respiration remain normal.
Some minor operations can be carried out during this
stage
But it is difficult to maintain
Therefore use is limited to short procedures
9. Stage starts from loss of consciousness upto gain of
rhythmical respiration
Respiration – Irregular and large in volume
Heart rate and BP raises
Pupils – Large and divergent
Muscle tone increased – jaw may be tight
Patient may shout or struggle
Involuntary micturation , or defecation
10.
11. Extends from onset of regular respiration to cessation of
spontaneous breathing.
This has been divided into 4 planes:
o Plane 1- Roving eyeballs.
o This plane ends when eyes become fixed.
o Plane 2- Loss of corneal and laryngeal reflexes.
o Plane 3- Pupil starts dilating and light reflex is lost.
o Plane 4- Intercostal paralysis
Shallow abdominal respiration
Dilated pupil.
12. As anaesthesia passes to deeper planes
Progressively-muscle tone decreases
BP falls
Heart Rate increases with weak pulse
Respiration decreases in depth and later in frequency
13. There is cessation of breathing leading to failure of
circulation and death.
Pupil is widely dilated
Muscles are totally flabby
Pulse is thready or imperceptible
BP is very low.
