The Effect of Repeated Bilateral Deep Parasternal Intercostal Plane Catheter Boluses on Analgesia After Cardiac...

Median sternotomy for cardiac surgery is associated with significant postoperative pain. We evaluated whether repeated ropivacaine boluses via bilateral deep parasternal intercostal plane (DPIP) catheters improve analgesia after cardiac surgery.

In this randomized, placebo-controlled trial, 120 adult patients undergoing elective coronary artery bypass grafting or heart valve replacement were allocated to receive repeated boluses of either ropivacaine (R) or saline (P) via bilateral DPIP catheters for 72 hours postoperatively. Patients, researchers, and clinical staff were blinded to group allocation. The primary endpoint was postoperative pain intensity, assessed by the visual analog scale or, in sedated patients, the behavioral pain scale. Secondary endpoints included cumulative oxycodone consumption, adverse events, postoperative sedation, and mechanical ventilation.

Pain trajectories over the 72-hour postoperative period did not differ between groups (group × time interaction P = .77 at rest; P = 1.00 with movement). No statistically significant differences were observed between groups in cumulative opioid consumption. For the first 12 hours, the median (95% confidence interval [CI] for median) oxycodone dose was 24 mg (18-27) (P = .55) and from 12 to 24 hours, 24 mg (21-30) in the placebo group and 30 mg (24-39) in the ropivacaine group (P = .32). Corresponding values from 24 to 48 hours were 39 mg (33-45) and 48 mg (39-66) (P = .23), and from 48 to 72 hours 18 mg (12-24) and 24 mg (12-33), respectively (P = .21). Postoperative nausea and vomiting was the most common adverse event, occurring in 38% overall: 18 of 60 (30%) in the placebo group and 28 of 60 (46.7%) in the ropivacaine group, with a higher incidence among ropivacaine-treated valve surgery patients (placebo 9/34 [26.5%] vs ropivacaine 20/33 [60.6%], P = .012). Five patients had symptoms suggestive of local anesthetic systemic toxicity; all cases were self-limiting. Four pneumothoraces occurred, one of which was clearly surgically related. The catheter became dislodged in nine patients. Also, among the dropouts, three patients reported pain during injection of the study drug indicating suboptimal catheter positioning. Postoperative sedation and mechanical ventilation times did not differ between groups. Median (interquartile range and 95% CI for median) time until extubation was 348 minutes (278-412 minutes; CI 337-446 minutes) in the placebo group and 340 minutes (289-539 minutes; CI 400-650 minutes) in the ropivacaine group.

Repeated ropivacaine boluses via DPIP catheters did not improve postoperative pain control or reduce opioid consumption compared with placebo after median sternotomy. Routine use of DPIP catheters after cardiac surgery should therefore be avoided. Further research is warranted to determine whether continuous infusion techniques or selective use in high-risk patients may yield greater benefit.