Pharmacokinetic-based total intravenous anaesthesia using remifentanil and propofol for surgical myocardial revascularization

Abstract

Background and objective: We investigated the following aspects of pharmacokinetic-guided total intravenous anaesthesia with remifentanil and propofol in patients undergoing surgical myocardial revascularization: anaesthetic efficacy, haemodynamic effects, impact on extubation of the trachea and analgesia after operation.

Methods: Thirty-two patients undergoing on-pump coronary bypass surgery received intravenous anaesthesia with remifentanil and propofol. Both drugs were dosed and titrated based on computer-assisted pharmacokinetic models to maintain constant plasma concentrations. The propofol target plasma concentration was 1.2 microg mL(-1) throughout the procedure. A remifentanil target plasma concentration of 8 ng mL(-1) was achieved over 2 min for induction. After tracheal intubation, the opioid plasma concentration was reduced to 4 ng mL(-1), and then titrated up to 8 ng mL(-1) during surgery. Postoperative analgesia was managed with remifentanil infusion until 4 h after tracheal extubation, and a continuous infusion of tramadol was started 1 h before the remifentanil was stopped.

Results: After induction of anaesthesia, heart rate (-20%) and cardiac index (-6%) decreased significantly. No hypotensive episodes (mean arterial pressure < 60 mmHg) occurred. Intraoperative haemodynamics were stable. Three cases of myocardial ischaemia were detected: two by transoesophageal echocardiography and one with ST-segment monitoring. The duration of postoperative mechanical ventilation of the lungs was 95 +/- 13 min and the time to extubation was 150 +/- 18 min. Postoperative analgesia was satisfactory in all patients.

Conclusions: Pharmacokinetic-based total intravenous anaesthesia with remifentanil and propofol provides adequate anaesthesia during coronary surgery with cardiopulmonary bypass and allows safe early extubation after operation.