Efficacy of oxycodone combined with thoracic paravertebral block for postoperative analgesia in patients undergoing minimally invasive direct coronary artery bypass grafting

Objective To evaluate the efficacy of oxycodone combined with thoracic paravertebral block (TPVB) for postoperative analgesia in patients undergoing minimally invasive direct coronary artery bypass grafting (MIDCABG). Methods Thirty-two American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients of both sexes, aged 60-75 yr, weighing 50-85 kg, scheduled for elective MIDCABG under general anesthesia, were divided into 2 groups (n=16 each) using a random number table method: morphine plus TPVB group (group MT) and oxycodone plus TPVB group (group OT). Paravertebral catheter was placed at T4, 5 before induction of anesthesia to perform left thoracic paravertebral puncture, patients were tracheally intubated, and 0.375% ropivacaine 15 ml was injected followed by continuous infusion of 0.375% ropivacaine 5 ml/h until 0.5 h before the end of surgery.Both groups received patient-controlled analgesia (PCA) after surgery.The PCA solution contained 1 mg/ml morphine 60 ml in group MT or 1 mg/ml oxycodone 60 ml in group OT, and the PCA pump was set up to deliver a 1 mg bolus dose with a 10-min lockout interval and background infusion at 1 ml/h after a loading dose of 2 mg, with the maximum dose of 20 mg every 4 h. Pethidine 50 mg was intravenously injected as a rescue analgesic to maintain visual analog scale≤4.The intraoperative consumption of fentanyl, consumption of analgesics for PCA within 48 h after surgery, ratio of total to effective pressing times of PCA, consumption of analgesics for rescue analgesia, requirement for rescue analgesia, score of satisfactory analgesia, extubation time, duration of intensive care unit stay and length of hospital stay were recorded.The development of nausea and vomiting, pruritus, respiratory depression, atelectasis and somnolence was recorded within 72 h after surgery. Results Compared with group MT, the intraoperative consumption of fentanyl, consumption of analgesics for PCA, consumption of analgesics for rescue analgesia, requirement for rescue analgesia and ratio of total to effective pressing times of PCA were significantly decreased, the score of satisfactory analgesia was increased, the extubation time and duration of intensive care unit stay were shortened, and the incidence of nausea and vomiting, pruritus, respiratory depression and somnolence was decreased in group OT (P<0.05). Conclusion Oxycodone combined with TPVB provides safe and effective efficacy for postoperative analgesia in patients undergoing MIDCABG. Key words: Oxycodone; Analgesia, patient-controlled; Nerve block; Coronary artery bypass, off-pump