Neuromuscular Blocking Agents in Cardiac Surgery

Overview

1. Background: Neuromuscular blocking agents (NMBA) are commonly used in cardiac surgery anesthesia to facilitate airway management and ventilation, and ensure optimal operative conditions. To improve post-operative results and reduce the length of stay in the intensive care unit, the concept of "Fast track anesthesia" is coming into force, which includes all techniques that offer extubation within 1-6 hours post-operatively. Fast-track cardiac surgery is only feasible when short-acting NMBA are used and neuromuscular transmission has returned to normal by the end of the operation or just before extubation, a few hours after surgery. This requires quantitative monitoring of muscle strength, the only way to eliminate residual paralysis defined by a TOF ratio ≥ 0.9. The American Society of Anesthesiologists (ASA) and the European Society of Anesthesiology and Intensive Care (EASIC) recommend quantitative measurement of neuromuscular block until extubation.This is the only way to avoid the complications of residual paralysis, essentially postoperative pulmonary complications. The POPULAR study clearly highlighted the shortcomings of current NMBA management: out of a total population of 17150 patients, only 16.5% were extubated, with a TOF ratio greater than 0.90. Cardiac surgery patients are brought to the ICU still sedated, intubated and ventilated. Neuromuscular blocking agents are usually discontinued at the end of surgery. As awakening and extubation take place later in the ICU, clinicians often consider that the action of neuromuscular blocking agents is over, but without making a quantitative measurement as recommended by the guidelines. 2. Objectives of the clinical research project: 2.1 Primary objective: The primary objective of this single-center prospective observational study is to systematically monitor the degree of postoperative curarization up to the time of extubation, and to assess the degree of adherence of intensive care teams to extubation recommendations based on quantitative measurements of the degree of neuromuscular junction block. 2.2 Secondary objectives: Quantify NMBA doses used, duration of action, duration of recovery. 3. Methodology of the clinical research project: In this study, we will systematically check the degree of curarization of cardiac surgery patients up to the time of extubation. Prior to surgery, all patients will have an explanation of the protocol and will give written informed consent for the use of their data. Patient management is at the discretion of the anaesthetist in charge and will not be altered in any way by the protocol. All drugs used will be "standard of care". At the end of the procedure, one of the investigators will stay with the patient in intensive care and measure the degree of neuromuscular blockade with a curameter used as standard in clinical routine at Erasme Hospital (TOFScan, IdMed, Marseille, France). All measurements will be made in accordance with Good clinical research practice (GCRP) in pharmacodynamic studies of neuromuscular blocking agents III. This measurement will be carried out continuously until the patient is extubated or 100% neuromuscular transmission has been recovered. ICU staff in charge of the patient will be blinded to the measurements done by the investigators. Intensive care physicians manage the patient according to the ICU standard of care. If the patient represents a residual curarization at the time of extubation, the investigators will inform the ICU staff in order to avoid endangering the patient. No intervention will be made with regard to the anesthesia and post-operative monitoring protocol; all medications and interventions will be considered "standard of care" and will be left to the discretion of the anesthesiologist and ICU team in charge. 4. Design of the clinical research project: This is a prospective, observational study. 5. Participants: All patients undergoing cardiac surgery at Hôpital Érasme between October 1, 2024 and May 31, 2025.