Background: Pain management after cardiac surgery has been based on parenteral long-acting opioids such as morphine. The other alternatives are paracetamol and remifentanil.
Objectives: 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.
Materials and methods: 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.
Results: 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.
Conclusions: Both PCA techniques provided effective pain scores (< 3) after cardiac surgery; but generally, PCA-paracetamol infusion has a better analgesic effect.
Keywords: Cardiac Surgery; Patient-Controlled Analgesia; Remifentanil.