A Sufficiently Effective and Low-Risk Plane Block: A Randomized Controlled Trial Evaluating the Modified Parasternal Block in Off-Pump Coronary Artery Bypass Grafting with Sternotomy.

Background: This study aims to assess the effectiveness and safety of modified parasternal nerve block (MPSB) in providing perioperative analgesia and improving postoperative recovery in patients undergoing off-pump coronary artery bypass grafting (OPCABG). Methods: Sixty-five patients scheduled for OPCABG were randomly assigned to either the intervention group (MPSB group), which received a preoperative modified parasternal block, or the control group. The primary outcome measured was intraoperative opioid consumption. Secondary outcomes included levels of inflammatory markers, postoperative pain scores (assessed using the Visual Analog Scale, VAS), incidence of postoperative nausea and vomiting (PONV), total plasma ropivacaine concentration, gastrointestinal recovery parameters, mobilization metrics, intensive care unit (ICU) parameters (mechanical ventilation duration, ICU length of stay, requirement for rescue analgesics), length of hospital stay, incidence of postoperative pulmonary complications (PPCs), and chronic pain. Results: Intraoperative sufentanil consumption was significantly reduced in the MPSB group (130.0 [IQR, 110.0-167.5] μg vs. 280.0 [IQR, 192.5-327.5] μg; p < 0.01). Inflammatory markers were consistently lower in the MPSB group. Pharmacokinetic analysis revealed a mean peak plasma ropivacaine concentration of 0.88 μg/mL, with the maximum individual concentration reaching 1.76 μg/mL at 5 min post-administration. The MPSB group demonstrated superior postoperative outcomes, including lower VAS pain scores, earlier return of gastrointestinal function, reduced duration of mechanical ventilation, decreased rescue analgesic requirements in the ICU, shorter hospital stays, and lower incidence of PPCs. Conclusions: Preoperative modified parasternal block significantly reduced perioperative opioid consumption in cardiac surgery patients. This intervention demonstrated benefits in facilitating rapid postoperative recovery. The conventional ropivacaine dosing regimen was a safe and effective analgesic approach, associated with a low risk of local anesthetic systemic toxicity.