Comparison of the effects of ketamine and fentanyl-midazolam-medetomidine for sedation of rhesus macaques (Macaca mulatta)

Comparison of the effects of ketamine and fentanyl-midazolam-medetomidine for sedation of rhesus macaques (Macaca mulatta)

BMC Veterinary Research, June 2016

27277424

Henri G. M. J. Bertrand, Yvette C. Ellen, Stevie O’Keefe, Paul A. Flecknell

This study assessed the effects of sedation using a combination of fentanyl, midazolam and medetomidine in comparison to ketamine. Rhesus Macaques (Macaca mulatta), (n = 16, 5 males and 3 females randomly allocated to each treatment group) received either ketamine (KET) (10 mg.kg(-1)) or fentanyl-midazolam-medetomidine (FMM) (10 μg/kg(-1); 0.5 mg.kg(-1); 20 μg.kg(-1)) both IM. Oxygen (100%) was provided by mask and heart rate, blood pressure, respiratory rate, EtCO2 and depth of sedation were assessed every 5 min for 20 min. After the last time point, FMM monkeys were reversed with atipamezole-naloxone (0.2 mg.kg(-1); 10 μg.kg(-1)). Recovery was scored using clinical scoring scheme. Differences in physiological parameters and quality of sedation were compared using Area Under the Curve (AUC) method and either Mann-Witney or t-student tests. Heart rate (beats/min) (Ket = 119 ± 18; FMM = 89 ± 17; p = 0.0066), systolic blood pressure (mmHg) (Ket = 109 ± 10; FMM = 97 ± 10; p = 0.0313), and respiratory rate (breaths/min) (Ket = 39 ± 9; FMM = 29 ± 10; p = 0.0416) were significantly lower in the FMM group. End-tidal CO2 (mmHg) did not differ between the groups (KET = 33 ± 8; FMM = 42 ± 11; p = 0.0462). Although some depression of physiological parameters was seen with FMM, the variables all remained within the normal ranges in both groups. Onset of a sufficient degree of sedation for safe handling was more rapid with ketamine (KET = 2.9 ± 1.4 min; FMM = 7.9 ± 1.2 min; p = 0.0009), but FMM recovery was faster (KET = 21.4 ± 13.4 min; FMM = 9.1 ± 3.6 min; p = 0.0379) and of better quality (KET = 1.3 ± 0.9; FMM = 7.4 ± 1.9; p = 0.0009) most probably because of the effectiveness of the reversal agents used. FMM provides an easily reversible immobilization with a rapid and good recovery quality and may prove a useful alternative to ketamine.