Intravenous patient-controlled remifentanil versus paracetamol in post-operative pain management in patients undergoing coronary artery bypass graft surgery

Pain management after cardiac surgery has been based on parenteral long-acting opioids such as morphine. The other alternatives are paracetamol and remifentanil. In this prospective, double-blind, randomized study, we compared the efficacy of intravenous patient-controlled analgesia (IV-PCA) paracetamol and remifentanil for post cardiac surgery pain relief. One-hundred patients scheduled for elective coronary artery bypass grafting from May to October 2011, were randomized into two groups after the surgery. For the first group (group R, n = 50, with mean age of 58.16 ± 11.80), the IV-PCA protocol was remifentanil infusion 100 μg/h; bolus of 25 μg and lockout time of 15 minutes. In the second group (group P, n = 50, with mean age of 53.8 ± 15.08), patients received paracetamol 15 mg/kg as a bolus at the end of surgery and then IV-PCA protocol was 100 μg/h, bolus of 25 μg; and lockout time of 15 minutes. Pain was assessed with visual analog scale score (VAS) in the first 24 hours after surgery for seven times. The trend of pain scores did not have any significantly difference between group R and group P except for hour 8 and hour 18 after surgery that VAS was significantly lower in group P than group R (P = 0.031, P = 0.023, respectively). Respiratory rate (RR) was also statistically lower in group R comparing to group P in all seven evaluating times. The groups were similar in terms of hemodynamic, ABG results (except for PaO2, which was significantly lower in group R than group P at 6 evaluating times), intubation time, renal function tests, and incidences of atelectasis, myocardial infarction or adverse effects. Both PCA techniques provided effective pain scores (< 3) after cardiac surgery; but generally, PCA-paracetamol infusion has a better analgesic effect.