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The Photomotor Reflex as an Indicator of Consciousness in the Immobilized Dog
Author(s) -
CROFT PHYLLIS G.
Publication year - 1961
Publication title -
journal of small animal practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 67
eISSN - 1748-5827
pISSN - 0022-4510
DOI - 10.1111/j.1748-5827.1961.tb04119.x
Subject(s) - barbiturate , reflex , medicine , anesthesia , atropine , premedication , unconsciousness , tracheal intubation , stimulus (psychology) , general anaesthesia , pupil , muscle relaxant , intubation , psychology , neuroscience , psychotherapist
— When a relaxant is used in conjunction with light general anaesthesia, it is not possible to distinguish between true unconsciousness, and consciousness masked by immobilization, by the usual reflexes involving voluntary muscle. Experiments are described which show that the photo‐motor reflex (contraction of the pupil of the eye with increase in intensity of light stimulus), unlike the other reflexes commonly used for testing anaesthesia, gave a reliable indication of returning consciousness in a dog immobilized by a relaxant. The reflex was not affected by premedication with atropine, provided that the dose of atropine did not exceed 0.032 mg./kg. body‐weight. The reflex is valid when anaesthesia is induced by barbiturate alone, or by a combination of barbiturate and ether.