Association Between Train-of-Four Values and Gas Exchange Indices in Moderate to Severe Acute Respiratory Distress Syndrome

Abstract

Background: Acute respiratory distress syndrome (ARDS) is associated with a mortality rate of approximately 40%. Neuromuscular blockade is associated with an improvement in oxygenation and a reduction in mortality in ARDS. Objective: The goal of this evaluation was to determine if the depth of paralysis, determined by train-of-four (TOF) monitoring, correlates with gas exchange in moderate to severe ARDS. Methods: This was a retrospective review of moderate to severe ARDS patients who were prescribed >12 hours of continuous infusion cisatracurium between January 1, 2013, and December 31, 2014, with a PaO₂:FiO₂ ratio <150 and documented TOF and arterial blood gases. Patients were evaluated for inclusion at 12, 24, and 48 hours after initiation of neuromuscular blockade. Results: A total of 378 patients were screened for inclusion, with 107 evaluable patients meeting criteria at baseline. Poor correlation existed between TOF and oxygenation index (OI) at 12 (τ = 0.03), 24 (τ = 0.15) and 48 hours (τ = 0.08). When controlling for proning and baseline OI, the depth of paralysis did not have a significant effect on OI at 12, 24, or 48 hours. Conclusions: This evaluation demonstrates that the use of TOF monitoring for neuromuscular blockade does not correlate with gas exchange markers in moderate to severe ARDS.