Effects of low-dose isoflurane on saccadic eye movement generation.
The effects of 0.15% quasi-steady-state end-tidal isoflurane on two saccadic eye-movement tests were examined in five volunteers using a newly devised computer-based recording system. The tests were saccadic latency and a countermanding task, the latter being an indicator of the highest levels of conscious performance. A moving light-emitting diode target was displayed on a screen and in the saccadic-latency task the latency of eye movement to the target was measured. In all five subjects the latency increased with anaesthetic by an amount which varied from 8 to 45 ms. This result was significantly different (p < 0.05) from subjects without anaesthetic. In the countermanding task, the subject had to voluntarily inhibit movement to the target. Again anaesthetic increased the latency of response, which varied from 6 to 33 ms. This result was significantly different (p < 0.05) from subjects without anaesthetic. In these studies it appeared that two tasks, one a simple latency test and the other, the countermanding task, requiring higher cortical processing were equally impaired at subanaesthetic concentrations of isoflurane.
Khan
O
O
University Department of Anaesthesia, Addenbrooke's Hospital, Cambridge, UK.
Taylor
S J
SJ
Jones
J G
JG
Swart
M
M
Hanes
D P
DP
Carpenter
R H
RH
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D011930:Reaction Time / Q000187:drug effects; D012438:Saccades / Q000187:drug effects*
D018685:Anesthetics, Inhalation; D007530:Isoflurane