The Incidence of hypotension with continuous infusion atracurium compared to cisatracurium in the Intensive Care Unit

BACKGROUND: A drug shortage of cisatracurium led to use of atracurium as an alternative neuromuscular blocker (NMB). Cisatracurium may be preferred due to less histamine release and potentially less hypotension. The study purpose is to compare the incidence of hypotension with continuous infusion atracurium to continuous infusion cisatracurium in ICU patients. MATERIALS AND METHODS: This retrospective cohort analysis reviewed 119 ICU patients who received either continuous infusion atracurium (56) or cisatracurium (63). The primary outcome was the incidence of hypotension (mean arterial pressure <60mmHg). Secondary outcomes included: incidence of blood pressure decrease of >20% from baseline, time to first hypotensive episode, treatment for hypotension during NMB use, hospital mortality, ICU and hospital length of stay (LOS), duration of mechanical ventilation (MV), and NMB duration. RESULTS: Hypotension occurred in 64.3% of atracurium patients and 58.7% of cisatracurium patients (P = 0.58), with 60.7% experiencing >20% drop in blood pressure in atracurium group and 54.0% in cisatracurium (P = 0.58). Median time to first hypotensive episode was 9.4[Interquartile range 1.17-19.7] hours atracurium and 4.4[1.5-13.9] hours cisatracurium (P = 0.36). There were no differences between atracurium and cisatracurium groups respectively for median ICU LOS (10.5 days and 12.4 days, P = 0.34), hospital LOS (14.0 days and 17.7 days, P = 0.37), MV duration (9.3 days and 10.5 days, P = 0.43), infusion duration (34.5 hours and 25 hours P = 0.27), or hospital mortality (62.5% and 53.9%, P = 0.336). Hypotension treatment was similar between groups. CONCLUSIONS: The incidence of hypotension was similar between atracurium and cisatracurium. Critical drug shortages may provide an opportunity to study alternative drug therapy.