Target-Controlled Infusion of Remifentanil Without Muscle Relaxants Allows Acceptable Surgical Conditions During Thoracotomy Performed Under Sevoflurane Anesthesia

Abstract

Objectives: To test the hypothesis that the use of a nonmuscle relaxant anesthetic technique (NMRT) during thoracotomy would be associated with comparable surgical conditions with the standard use of neuromuscular blocking drugs.

Design: A prospective, randomized, single-blind, controlled study.

Setting: A single university hospital.

Participants: Sixty-six patients scheduled for open thoracotomy under sevoflurane anesthesia with a target-controlled infusion (TCI) of remifentanil.

Interventions: After ethical approval, patients were randomly assigned to receive cisatracurium or saline (n = 33 for each group) during the entire study period.

Measurements and main results: The four-point ordinal surgical rating scale, the intubating conditions, the use of anesthetics and vasopressors, the incidence of light anesthesia (defined as an episode with state entropy values that exceeded 50 and/or mean arterial blood pressure and heart rate values that exceeded the baseline by 20% and lasted for more than 3 consecutive minutes), and the times to clinical recovery and postanesthesia care unit (PACU) discharge, hospital stays, and postoperative residual curarization (PORC) were recorded. Compared with the use of cisatracurium, the use of NMRT resulted in comparable good-to-excellent surgical rating scales (90.9% v 94.0%, respectively; p = 0.642), good-to-excellent laryngoscopy and endobronchial intubating conditions (93.9% v 100%, respectively; p>0.09), use of anesthetic and vasopressor medications, and hospital stays, together with shorter clinical recovery, extubation times (7.6 [95% CI 6.82 to 8.39] v 19.0 [95% CI 15.76 to 22.23] minutes, respectively; p<0.001), and PACU stays (37.4 [95% CI 35.09 to 39.79] v 70.9 [95% CI 56.90 to 84.91] minutes, respectively; p<0.001). The use of cisatracurium resulted in a nonstatistical number of light anesthesia episodes upon positioning, skin incision, and rib separation (p>0.624, with Fisher's exact test). There were no failed intubations in the 2 groups. No patient received cisatracurium in the NMRT group. Two patients (6.1%) in the cisatracurium group experienced PORC that required tracheal intubation in the PACU.

Conclusion: The use of TCI of remifentanil with NMRT offers acceptable laryngoscopy, intubating, and surgical conditions during sevoflurane anesthesia for open thoracotomy, especially when. the anesthesiologists have more than 10 years' experience.

Keywords: nonmuscle relaxants; remifentanil; surgical conditions; target-controlled infusion; thoracic surgery.