Efficacy of bilateral catheter superficial parasternal intercostal plane blocks using programmed intermittent bolus for opioid-sparing postoperative analgesia in cardiac surgery with sternotomy: A randomized, double-blind, placebo-controlled trial.

ABSTRACT

STUDY OBJECTIVE: This study investigated whether catheter superficial parasternal intercostal plane (SPIP) blocks, using a programmed intermittent bolus (PIB) with ropivacaine, could reduce opioid consumption while delivering enhanced analgesia for a period exceeding 48 h following cardiac surgery involving sternotomy. DESIGN: A double-blind, prospective, randomized, placebo-controlled trial. SETTING: University-affiliated tertiary care hospital. PATIENTS 60 patients aged 18 or older, scheduled for cardiac surgery via sternotomy. INTERVENTIONS: The patients were randomly assigned in a 11 ratio to either the ropivacaine or saline group. After surgery, patients received bilateral SPIP blocks for 48 h with 0.4% ropivacaine (20 mL per side) for induction, followed by bilateral SPIP catheters using PIB with 0.2% ropivacaine (8 mL/side, interspersed with a 2-h interval) or 0.9% normal saline following the same administration schedule. All patients were administered patient-controlled analgesia with hydromorphone. MEASUREMENTS The primary outcome was the cumulative morphine equivalent consumption during the initial 48 h after the surgery. Secondary outcomes included postoperative pain assessment using the Numeric Rating Scale (NRS) at rest and during coughing at designated intervals for three days post-extubation. Furthermore, recovery indicators and ropivacaine plasma levels were diligently documented. MAIN RESULTS: Cumulative morphine consumption within 48 h in ropivacaine group decreased significantly compared to saline group (25.34 ± 31.1 mg vs 76.28 ± 77.2 mg, respectively; 95% CI, -81.9 to -20.0, P = 0.002). The ropivacaine group also reported lower NRS scores at all recorded time points (P < 0.05) and a lower incidence of nausea and vomiting than the saline group (3/29 vs 12/29, respectively; P = 0.007). Additionally, the ropivacaine group showed significant improvements in ambulation (P = 0.018), respiratory exercises (P = 0.006), and self-reported analgesia satisfaction compared to the saline group (P = 0.016). CONCLUSIONS: Bilateral catheter SPIP blocks using PIB with ropivacaine reduced opioid consumption over 48 h, concurrently delivering superior postoperative analgesia in adult cardiac surgery with sternotomy.