The PioneersThe MilitaryReferences


Arthur E Guedel 1883-1956

Arthur Guedel is better known today for his design of the oropharyngeal airway.

Guedel is another of the Anaesthetists who cut his teeth during the great war. He put together his Guedel chart which explained the depth and signs of Ether anaesthesia. This was done so that the operaters during the war could recognise the stages the patient was in.

However, anaesthetist and assistants know Guedel for his classification or stages of anaesthesia, which is:





Stages of Anaesthesia

Stage I (Stage of Analgesia or the stage of Disorientation): from beginning of induction of anaesthesia to loss of consciousness.

Stage II (Stage of Excitement or the stage of Delirium): from loss of consciousness to onset of automatic breathing. Eyelash reflex disappear but other reflexes remain intact and coughing, vomiting and struggling may occur; respiration can be irregular with breath-holding.

Stage III (Stage of Surgical anaesthesia): from onset of automatic respiration to respiratory paralysis. It is divided into four planes:
"Plane I" - from onset of automatic respiration to cessation of eyeball movements. Eyelid reflex is lost, swallowing reflex disappears, marked eyeball movement may occur but conjunctival reflex is lost at the bottom of the plane
"Plane II" - from cessation of eyeball movements to beginning of paralysis of intercostal muscles. Laryngeal reflex is lost although inflammation of the upper respiratory tract increases reflex irritability, corneal reflex disappears, secretion of tears increases (a useful sign of light anaesthesia), respiration is automatic and regular, movement and deep breathing as a response to skin stimulation disappears.
"Plane III" (Surgical Anaesthesia) from beginning to completion of intercostal muscle paralysis. Diaphragmatic respiration persists but there is progressive intercostal paralysis, pupils dilated and light reflex is abolished. The laryngeal reflex lost in plane II can still be initiated by painful stimuli arising from the dilatation of anus or cervix. This was the desired plane for surgery when muscle relaxants were not used.
"Plane IV" - from complete intercostal paralysis to diaphragmatic paralysis (apnoea). 267

Stage IV: from stoppage of respiration till death. Anaesthetic overdose cause medullary paralysis with respiratory arrest and vasomotor collapse. Pupils are widely dilated and muscles are relaxed.