Comparison of S(+)-ketamine and ketamine, with medetomidine, for field anaesthesia in the European brown hare (Lepus europaeus).
OBJECTIVE
To compare anaesthesia and recovery parameters of racemic ketamine or S(+)-ketamine in combination with medetomidine for intramuscular (IM) field anaesthesia in the European brown hare (EBH) (Lepus europaeus).


METHODS
Randomized, prospective, blinded clinical trial.


METHODS
20 adult EBH (eight male, 12 female), mean ± SD weight 3360 341).


METHODS
Medetomidine (0.2 mg kg(-1) ) and ketamine (30 mg kg(-1) ) (K-M group) or S(+)-ketamine (15 mg kg(-1) ) (S-M group) were administered by IM injection. Time until first effect and loss of righting reflex were recorded. During sedation and anaesthesia heart rate, saturation of arterial haemoglobin, respiratory rate, side stream end tidal CO(2) (Pe'CO(2) ), non invasive blood pressure, body temperature, cardiorespiratory parameters, palpebral reflex, jaw tone and nociception were recorded every 5 minutes. Medetomidine was antagonized with IM atipamezole (1 mg kg(-1) ) 45 minutes after treatment injection. Time until first head lift, standing and total recovery time (T-Recov) were recorded. Incidences of falling and involuntary movements during recovery were counted. Recovery quality was scored by visual analogue scale. Descriptive statistics were used to visualize maintenance data. All other data were included in multiple linear regression models.


RESULTS
Surgical anesthesia was not produced reliably with either protocol. Hypoxaemia occurred in both groups (SpO(2) < 90%). During recovery, falling was noted significantly less often (p < 0.001) in the S-M group (13 ± 7) versus the K-M group (27 ± 13). T-Recov was long, lasting for more than 3 hours in individuals with no significant differences between groups.


CONCLUSIONS
S(+)-ketamine showed only minor advantages over racemic ketamine. Surgical anaesthesia was not achieved reliably with either protocol. Oxygen supplementation should be considered to prevent hypoxaemia. Further research is needed to develop an injectable field protocol adequate for surgical procedures, but with a rapid smooth recovery.
Research Institute of Wildlife Ecology, University of Veterinary Medicine, A-1160 Vienna, Austria. hanno.gerritsmann@fiwi.at
Hanno
H
Gerritsmann
Gabrielle L
GL
Stalder
Katharina
K
Seilern-Moy
Felix
F
Knauer
Chris
C
Walzer
D000777:Anesthetics / Q000008:administration & dosage / Q000494:pharmacology*; D019162:Anesthetics, Combined / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D005260:Female; D034621:Hares; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology*; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D020926:Medetomidine / Q000008:administration & dosage / Q000494:pharmacology*
D000777:Anesthetics; D019162:Anesthetics, Combined; D006993:Hypnotics and Sedatives; D007649:Ketamine; D020926:Medetomidine