The use of desflurane for neurosurgical procedures in rhesus macaque ( Macaca mulatta)

Volatile agents are widely used to anaesthetise laboratory non-human primates as they allow a rapid induction and recovery as well as an easy adjustment of the anaesthesia plan. Desflurane is currently the volatile agent with the lowest solubility in blood, and hence enables the most rapid onset of anaesthesia and most rapid recovery. This study aimed to investigate the suitability of desflurane for maintenance of general anaesthesia in rhesus macaques undergoing elective experimental neurosurgery. Fourteen primates (five males and nine females) were sedated with ketamine (10 mg kg^-1) and anaesthesia was induced with propofol (usually 8 mg kg^-1 IV). Anaesthesia was maintained with desflurane (5.9 ± 0.8 %) and alfentanil (0.2-0.5 µg kg^-1 min^-1 IV). Animals were mechanically ventilated. Meloxicam (0.3 mg kg^-1) and methylprednisolone infusion (5.4 mg kg^-1 h^-1) were also administered. All the primates were successfully anaesthetised and no severe complications related to the procedure or the anaesthesia regimen occurred. No major differences in physiological parameters and recovery times between the male and female groups were found. Emergence from anaesthesia was rapid (male 5.2 ± 2.4 min; female 4.1 ± 1.7 min) but its quality was assessed as equivalent to two other volatile anaesthetics, isoflurane and sevoflurane. These had previously been assessed for neuroanaesthesia in rhesus macaques. In conclusion, this study demonstrated that desflurane was suitable for maintenance of general anaesthesia for elective experimental neurosurgical procedures in rhesus macaque. However the vasodilatory action of the desflurane may limit its use in cases of severe intracranial hypertension or systemic hypotension.