Evaluation of anesthesia effects in a rat animal model using otoacoustic emission protocols.
Anesthesia effects on otoacoustic emission (OAE) recordings were evaluated in a group of 72 Sprague-Dawley rats (mean weight 225+/-20 gr). Two anesthesia dosages (high and normal) and two anesthetic protocols (ketamine-xylazine, ketamine-xylazine-atropine) were tested. Transient evoked OAE (TEOAE) and distortion product OAE (DPOAE) responses were recorded in 10 min intervals, for a total period of 60 min. Analyses of the data with repeated measure models indicated the following: (1) The animals receiving a high dose of anesthesia (cumulative dose 66.6 mg of ketamine and 13.2 mg of xylazine/kg of body weight) presented significant alterations of the TEOAE response level and the signal to noise ratio at 3.0 kHz; (2) the animals receiving a normal dose of ketamine-xylazine anesthesia (cumulative dose 50 mg of ketamine and 10 mg of xylazine/kg of body weight) presented TEOAE and DPOAE responses invariant in terms of time; (3) significant differences were observed in the DPOAE responses from animals anesthetized with ketamine-xylazine and ketamine-xylazine-atropine. The data support the hypothesis that the ketamine anesthesia OAE suppressing mechanism is related to middle-ear mechanics.
Center of Bioacoustics, University of Ferrara, Corso Giovecca 203, 44100, Ferrara, Italy. sdh@dns.unife.it
Stavros
S
Hatzopoulos
Joseph
J
Petruccelli
Göran
G
Laurell
Mario
M
Finesso
Alessandro
A
Martini
D000759:Adjuvants, Anesthesia / Q000008:administration & dosage; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage; D000758:Anesthesia; D000778:Anesthetics, Dissociative / Q000008:administration & dosage; D000818:Animals; D001285:Atropine / Q000008:administration & dosage; D001794:Blood Pressure; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D007649:Ketamine / Q000008:administration & dosage; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D010469:Perceptual Distortion; D051381:Rats; D017207:Rats, Sprague-Dawley; D018058:Tympanic Membrane Perforation / Q000503:physiopathology; D014991:Xylazine / Q000008:administration & dosage
D000759:Adjuvants, Anesthesia; D000316:Adrenergic alpha-Agonists; D000778:Anesthetics, Dissociative; D004338:Drug Combinations; D014991:Xylazine; D007649:Ketamine; D001285:Atropine