Low versus high dosing strategies of intravenous nitroglycerin for the management of sympathetic crashing acute pulmonary edema.

BACKGROUND Acute pulmonary edema is a life-threatening condition commonly occurring as a result of acute decompensated heart failure. The current pulmonary edema guidelines recommend initiating IV NTG at 5 μg/min and titrating by 5 μg every 3 to 5 min to reduce systolic blood pressure (SBP) by 25 % within the first hour of arrival to the emergency department (ED). Current studies do not determine if the dose of IV NTG has an impact on the time to oxygen weaning. The purpose of this study is to evaluate and analyze clinical outcomes associated with oxygenation status in patients treated with either low dose or high dose IV NTG for the management of SCAPE. METHODS This was a retrospective, single center, cohort study including adult patients who arrived to the ED with the diagnosis of pulmonary edema in the setting of a hypertensive crisis. Patients were categorized into two groups: low dose IV NTG 30 %), hypotension requiring vasopressors, improvement/worsening of respiratory status, rate of intensive care unit (ICU) admission, and ICU length of stay. RESULTS This study included 441 patients who received IV NTG. Patients in the high dose group (≥100 μg/min), had a median time from initiation of infusion to oxygen weaning of 2.7 h as compared to 3.3 h in the low dose group (<100 μg/min) (p = 0.01). Patients in the low dose group had a lower likelihood of obtaining an SBP reduction by 25 % (+/- 5 %) within 60 min when compared to the high dose group (RR 0.64, 95 % CI 0.52 to 0.79). Hypotension was more common in the low dose group when compared to the high dose group (RR 1.29, 95 % CI 1.02 to 1.62). There were no significant differences in incidence of hypotension requiring vasopressors, worsening respiratory status, and ICU length of stay between the two groups. CONCLUSIONS High dose IV NTG results in an earlier weaning of oxygen when compared to low dose IV NTG. High dose IV NTG was associated with a higher likelihood of obtaining initial SBP goals without concern for an increased risk of hypotension when compared to low dose IV NTG.