Bioavailability of oxycodone by mouth in coronary artery bypass surgery patients - a randomized trial.

OBJECTIVE: Pain after coronary artery by-pass (CAB) surgery is severe. Analgesic administration by mouth is unreliable until after gastrointestinal function has recovered. We evaluated the bioavailability of oxycodone co-administered with naloxone by mouth in patients after CAB surgery using either a conventional extracorporeal circulation (CECC) or off-pump surgery (OPCAB). METHODS: Twenty-four patients, 50-73 years, 12 with CECC and 12 with OPCAB, were administered a 10/5 mg oxycodone-naloxone controlled-release tablet by mouth on the preoperative day and for the first seven postoperative days (PODs) thereafter. Blood samples were collected up to 24 h after the preoperative administration, and then randomly either on POD1 and POD3 or on POD2 and POD4. The oxycodone concentration in plasma was analyzed using liquid chromatography-mass spectrometry. RESULTS: On POD1 oxycodone absorption was markedly delayed in five of six patients after CECC and in all six patients after OPCAB surgery; median of tmax after CECC 630 [range 270-1420] minutes and after OPCAB 1020 [720-1410] minutes, compared to median of 120-315 min preoperatively and on POD2-POD4. The carry-over corrected AUC0-24 values on the PODs did not differ from the preoperative values, but were higher on POD3 compared with POD1 in both CECC and OPCAB groups. The rate and extent of oxycodone absorption equaled preoperative values on POD2 and onwards in patients with CAB surgery. CONCLUSIONS: Bioavailability of oxycodone by mouth was similar after CAB surgery via CECC or having OPCAB. Data indicate that POD2 is an appropriate time to start oxycodone administration by mouth after CAB surgery.

Continuous Ropivacaine Infusion Offers No Benefit in Treating Postoperative Pain After Cardiac Surgery.

OBJECTIVE: One multimodal pain management method for reducing postoperative opioid need after cardiac surgery is to continuously infuse local anesthetic into a median sternotomy wound. Previous studies have shown contradictory results with this method; therefore, no consensus exists on its effectiveness. The authors tested the effectiveness of continuous 0.2% ropivacaine infusion into a sternotomy wound after cardiac surgery. DESIGN: Prospective, randomized, double-blinded, placebo-controlled trial. SETTING: Single-institution, tertiary-level, university hospital. PARTICIPANTS: Total of 90 patients undergoing coronary artery bypass grafting or heart valve surgery. INTERVENTIONS: Patients were assigned randomly to receive 0.2% ropivacaine or placebo into a sternotomy wound for 48 hours postoperatively. Pain was controlled with standardized oxycodone boluses after surgery and patient-controlled analgesia oxycodone after extubation; total oxycodone consumption was recorded. Pain was assessed 3  times daily, at rest and during deep breathing, with the visual analogue scale. MEASUREMENTS AND MAIN RESULTS: Forty-seven patients were assigned to receive ropivacaine and 43 to receive placebo infusion. Cumulative oxycodone consumption was 97 ± 27 mg with ropivacaine and 96 ± 29 mg with placebo (p = 0.813). Pain scores were similar between groups, both at rest (p = 0.630) and during deep breathing (p = 0.793). Adverse event incidences and surgical wound infection rates were similar between groups. CONCLUSION: Continuous 0.2% ropivacaine infusions at the median sternotomy wound did not reduce postoperative pain or opioid consumption during the first 48 hours after cardiac surgery. This technique apparently was not beneficial for post-sternotomy pain treatment.