Prolonged recovery and respiratory depression after fentanyl infusion in a sheep undergoing mitral valve reconstruction

Abstract

SummaryA sheep was anaesthetized for implantation of a novel device (MitroFast s ) to replace the posterior leaflet of the mitral valve. Anaesthetic management included a balanced anaesthetic protocol and consisted of propofol or isoflurane combined with fentanyl infusion (0.15-0.4 mg/kg/min). Deliberate hypothermia during cardiopulmonary bypass was set at 34.5-35.51C. Surgery proceeded uneventfully. Total time of aortic cross-clamping was 35 min and total time on extracorporeal circulation was 60 min. Visual inspection, intracardiac pressure testing and transesophageal echocardiography indicated proper functioning of the device. The anaesthetic period was uneventful, but recovery was prolonged with central nervous and respiratory depression and marked hypoxaemia. Administration of naloxone (1.5 mg/kg, repeated twice at 15-20 min intervals) reversed the central nervous and attenuated the respiratory depressions. An initially low rate of urine production normalized after rewarming and a single intravenous administration of furosemide.

Anaesthetic and cardiorespiratory effects of a constant rate infusion of fentanyl in isoflurane-anaesthetized sheep

“…This is contrary to the low PaO 2 value found by Kronen et al. (), in a sheep undergoing mitral valve reconstruction. A progressive increase of PaO 2 along the anaesthesia was observed in both groups probably due to the administration of high inspired concentrations of oxygen during anaesthesia.…”

“…The more rapid recovery times in our study compared to the study of Kronen et al. () could be due to a lower plasma fentanyl concentration since in our study the fentanyl administration time was shorter.…”

“…Kronen et al. () observed a prolonged recovery in a sheep after high doses (0.15–0.4 μg kg −1 minute) of fentanyl CRI. In our study, no significant differences were found between groups in any of the recovery times measured.…”

“…), and sheep (Kronen et al. ). However, in this current study no significant difference in PaCO 2 was shown when fentanyl was administered, although a decrease in f R was observed.…”

“…The use of fentanyl CRI during inhalation anaesthesia in sheep has only been described in cardiac surgery (Kronen et al. ; Schauvliege et al. ; Levionnois & Kronen ), but to the authors’ knowledge, currently there are no studies in the literature using fentanyl CRI during inhalation anaesthesia in sheep undergoing experimental orthopaedic surgery.…”