Efficacy of erector spinae plane block for minimally invasive mitral valve surgery: Results of a double-blind, prospective randomized placebo-controlled trial.

STUDY OBJECTIVE

To investigate if an erector spinae plane (ESP) block decreases postoperative opioid consumption, pain and postoperative nausea and vomiting in patients undergoing minimally invasive mitral valve surgery (MIMVS).

DESIGN

A single-center, double-blind, prospective, randomized, placebo-controlled trial.

SETTING

Postoperative period; operating room, post-anesthesia care unit (PACU) and hospital ward in a university hospital.

PATIENTS

Seventy-two patients undergoing video-assisted thoracoscopic MIMVS via right-sided mini-thoracotomy and enrolled in the institutional enhanced recovery after cardiac surgery program.

INTERVENTIONS

At the end of surgery, all patients received an ESP catheter at vertebra T5 under ultrasound guidance and were randomized to the administration of either ropivacaine 0.5% (loading of dose 30 ml and three additional doses of 20 ml with a 6 h interval) or normal saline 0.9% (with an identical administration scheme). In addition, patients received multimodal postoperative analgesia including dexamethasone, acetaminophen and patient-controlled intravenous analgesia with morphine. Following the final ESP bolus and before catheter removal, the position of the catheter was re-evaluated by ultrasound. Patients, investigators and medical personnel were blinded for the group allocation during the entire trial.

MEASUREMENTS

Primary outcome was cumulative morphine consumption during the first 24 h after extubation. Secondary outcomes included severity of pain, presence/extent of sensory block, duration of postoperative ventilation and hospital length of stay. Safety outcomes comprised the incidence of adverse events.

MAIN RESULTS

Median (IQR) 24-h morphine consumption was not different between the intervention- and control-group, 41 mg (30-55) versus 37 mg (29-50) (p = 0.70), respectively. Likewise, no differences were detected for secondary and safety endpoints.

CONCLUSIONS

Following MIMVS, adding an ESP block to a standard multimodal analgesia regimen did not reduce opioid consumption and pain scores.