The effect of anesthetics on neurologic outcome during the recovery period of spinal cord injury in rats.
We evaluated the effects of anesthetics on neurologic outcome in a model of recoverable experimental spinal cord injury (SCI). Adult rats were implanted with various sizes of hygroscopic plastic material at the T12 spinal level to determine the dimensions that would produce a progressive neurologic deficit from which recovery could occur. Neurologic evaluation was conducted on an inclined plane, noting the maximum angle at which an animal was able to maintain orientation perpendicular to the longitudinal midline. Scores were statistically modeled for each group to develop profiles of neurologic deficits. Rats were subjected to a 4-h exposure to isoflurane, fentanyl/nitrous oxide, or ketamine 7 or 8 days postimplantation. Neurologic outcomes were compared to a SCI reference group which received no postimplant anesthesia. An animal weight/desiccated implant volume (Wa/Vi) ratio of 53 to 73 g/mm3 produced postimplant neurologic deficits which deteriorated to near maximum within 3 days, followed by a gradual improvement beginning at Day 8 and returning to near normal between 21 and 25 days. Final outcome was based on modeled ramp scores for each group and reported in degrees +/- SD: reference, 71.2 +/- 1.1; fentanyl/N2O, 70.4 +/- 0.3; isoflurane, 72.6 +/- 1.1; and ketamine, 64.9 +/- 0.6. The fentanyl group attained maximum recovery first (P > 0.05) but did not recover to a level different on the average from the reference group. The ketamine group demonstrated a poorer (P > 0.05) recovery level relative to the other anesthetic protocols.
Grissom
T E
TE
Department of Anesthesiology, Wilford Hall USAF Medical Center, Lackland Air Force Base, San Antonio, Texas.
Mitzel
H C
HC
Bunegin
L
L
Albin
M S
MS
D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D002490:Central Nervous System / Q000187:drug effects*; D005260:Female; D005283:Fentanyl / Q000494:pharmacology; D007530:Isoflurane / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology; D009609:Nitrous Oxide / Q000494:pharmacology; D011597:Psychomotor Performance / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D013119:Spinal Cord Injuries / Q000503:physiopathology*
D000777:Anesthetics; D007649:Ketamine; D007530:Isoflurane; D009609:Nitrous Oxide; D005283:Fentanyl