Effect of Neuromuscular Blockade on Pulmonary Complications in Elective Cardiac Surgery

Prospective, Randomized Trial Comparing Effect of General Anesthesia With and Without Neuromuscular Blockade on Postoperative Pulmonary Complications in Elective Cardiac Surgical Patients

The investigators will conduct a prospective, randomized trial to assess the impact of neuromuscular blockade on early (<72 hours post-ICU admission) postoperative respiratory complications in cardiac surgical patients. The study will compare continual neuromuscular blockade with cisatracurium to a single dose of succinylcholine during general anesthesia for cardiac surgery.

Residual neuromuscular blockade during the immediate postoperative period is an important patient safety issue. Although used to facilitate the technical performance of surgery, clinical studies have associated neuromuscular blockade (NMB) with increased incidence of postoperative respiratory complications. This effect is likely mediated by residual neuromuscular blockade interfering with airway tone and respiratory effort, leading to postoperative pneumonia, atelectasis or aspiration. However, the vast majority of these studies have involved non-cardiac patient populations, yet patients undergoing cardiac surgery are even more susceptible to the detrimental effects of residual neuromuscular blockade for a number of reasons. Despite widespread utilization of paralysis during cardiac surgery, very little is known about residual neuromuscular blockade in patients following cardiac surgery. Previously published clinical studies date from over a decade ago or are based on retrospective databases from non-cardiac surgery patients, precluding generalizable conclusions. Given the substantial role of neuromuscular blockade in the traditional management of cardiac surgical patients, prospective data is needed to determine the veracity of this association as well as the surgical tolerability of protocols that minimize intraoperative paralysis. The investigators will conduct a prospective, randomized trial to assess impact of neuromuscular blockade on early (<72 hours post-ICU admission) postoperative respiratory complications.

Continual neuromuscular blockade (standard therapy) during general anesthesia will be provided with cisatracurium (CIS), with 0.2mg/kg IV given as an initial dose and repeated dosing determined by neuromuscular blockade monitoring (peripheral nerve stimulator maintained at 1-2 twitches).

A single dose of neuromuscular blockade (experimental group) will be provided at the start of anesthesia with succinylcholine (SUX), with 1mg/kg IV given as an initial dose and no repeat dosing.

Succinylcholine will be used to facilitate endotracheal intubation for general anesthesia in the operating room. No additional neuromuscular blockade will be provided during general anesthesia.

Having at least one of the following complications, determined according to pre-specified criteria: extubation delayed >24hrs, reintubation, mechanical respiratory support, pneumonia, aspiration, ARDS (Acute Respiratory Distress Syndrome), or mortality from respiratory arrest.

Assessed by surgeon questionnaire designed for study to determine any negative effects impeding the progress of surgery or safety, on scale of 1=poor to 5=excellent

Inclusion Criteria: Elective cardiac surgery (CABG, valve replacement, CABG + valve) requiring cardiopulmonary bypass Exclusion Criteria: Emergency surgery Extremes of age Previous cardiac surgery Clinical contraindications to succinylcholine or cisatracurium Anticipated difficult tracheal intubation Preoperative mechanical ventilation Preoperative pharmacologic/mechanical hemodynamic support