(1237) Comparing Titration of Continuous Neuromuscular Blockers in Acute Respiratory Distress Syndrome

Introduction: Neuromuscular blocking agents (NMBA) are recommended in moderate to severe ARDS to improve ventilator synchrony. A recent study found NMBAs titrated to ventilator synchrony (VS) may demonstrate similar efficacy to train of four (TOF) and fixed dose (FD) with less cumulative drug. However, impacts on oxygenation have not been directly compared between VS and TOF titration. The purpose of this study was to assess the oxygenation change in ARDS patients that received continuous NMBAs titrated to non-protocolized VS compared to TOF.

Methods: This multicenter, propensity matched, retrospective cohort study assessed patients with ARDS on a NMBA infusion for 24 hours. The primary endpoint was the percent change in PaO2:FiO2 ratio at 24 hours. Secondary endpoints included percent change in PaO2:FiO2 ratio from baseline to 12 and 48 hours, cumulative dose of cisatracurium, duration of mechanical ventilation, hospital and ICU length of stay, and 28-day mortality.

Results: A total of 191 patients were included in this propensity score matched analysis (VS=72; TOF=119) who were mostly Caucasian (51.3%) males (58.1%) with severe ARDS (60.2%) on cisatracurium (92.1%). As compared to TOF titration, VS titration implemented more prone positioning (65.3 vs 41.2%), low tidal volume ventilation (97.2 vs 94.1%), and steroid utilization (90.3 vs 85.7%), and had less plateau pressure maintained at < 30 cm H2O (50.0 vs 73.1%). A similar percentage change in PaO2:FiO2 ratio at 24 hours was found (VS=+23.5%, TOF=+23.2%, p=0.459). Comparing VS and TOF titration, reported secondary results are median percent change in PaO2:FiO2 ratio from baseline to 12 (+25.0 vs +25.5%) and 48 (+31.2 vs +31.2%) hours, cumulative cisatracurium dose (157.2 vs 164.7 mg), mechanical ventilation duration (369.1 vs 336.0 hours), hospital (19.5 vs 23 days) and ICU (18 vs 18 days) length of stay. Comparing NMBA titration strategies, a 17.4% difference in 28-day mortality was found (VS=61.1%, TOF=43.7%, p=0.029).

Conclusions: In ARDS patients who received NMBA infusions, those titrated to TOF had similar improvement in PaO2:FiO2 ratio at 24 hours with significantly reduced 28-day mortality, as compared to non-protocolized VS titration. Prospective studies are warranted to validate and further investigate the optimal NMBA titration strategy.