Analgesic efficacy and safety of lidocaine administered by intravenous route vs erector spinae plane blocks following open heart surgery: An open-label, randomized clinical trial.
The erector spinae plane (ESP) block is a widely used regional analgesic technique for truncal analgesia. This randomized, open-label trial compared intravenous (IV) lidocaine to lidocaine administered via bilateral continuous ESP blocks for analgesic efficacy in the context of open heart surgery. Seventy patients (18-80 years) undergoing primary single procedure elective cardiac surgery via midline sternotomy were randomized to receive lidocaine infusion via IV or continuous bilateral ESP block routes. The primary outcomes were cumulative opioid consumption in the first 48 h postoperatively (Oral Morphine milligram equivalents- OME) and pain scores at 48 h (Numeric Rating Scale NRS). Secondary outcomes included additional timepoints for pain and opioid consumption measures within the first 48 postoperative hours and plasma lidocaine levels at various timepoints within 24 h of initiating therapy. Sixty patients were analyzed after various exclusions. Both groups achieved acceptable analgesia, but the ESP group was not found to be superior to IV lidocaine in reducing opioid consumption in the first 48 hours (MD = -12.43 [95% CI, -43.7 to 18.8], p = 0.375) or pain scores at 48 h (MD 0.05 [95% CI, -1.7 to 1.8], p = 0.878). No significant differences were found in secondary outcomes. Plasma arterial lidocaine levels exceeded 5 μg/mL in 4 patients in the IV group and 2 in the ESP group at 24 h. ESP blocks utilizing lidocaine did not demonstrate superior postoperative analgesia compared to intravenous lidocaine in patients undergoing elective primary cardiac surgery via midline sternotomy. Safety concerns regarding systemic lidocaine accumulation from both administration routes warrant further evaluation.