High-Dose Nitroglycerin Infusion in Sympathetic Crashing Acute Pulmonary Edema (SCAPE)

January 9, 2023

Written by Nickolas Srica

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This study suggests that high-dose nitroglycerin infusion may be a safe alternative to intermittent bolus dosing for SCAPE, but prospective trials are needed to determine optimal initial rates and titration strategies, as well as the proper use of other adjunct therapies.

Why does this matter?
SCAPE is an emergent condition which occurs when severe, acute elevation in blood pressure leads to acute heart failure and pulmonary edema, which can lead to respiratory failure if not promptly recognized and treated. High-dose nitroglycerin (HDN) is commonly used in the treatment of SCAPE, but what is the optimal dosing and administration strategy?

Escape SCAPE with high-dose nitroglycerin
This was a retrospective chart review performed at a single academic emergency department on 67 total adult patients with initial systolic blood pressure (SBP) ≥160 mmHg, noted respiratory distress/pulmonary edema, and a HDN infusion initiated at a rate of ≥100 mcg/min. Baseline characteristics and other data on interventions in the ED were collected and compared including: NIPPV, use of sublingual or IV bolus nitroglycerin prior to HDN infusion, initial and maximum HDN rates within first hour, loop diuretic usage and doses, and ACE inhibitor/angiotensin II receptor blocker use, followed by 48-hour monitoring to assess for unfavorable outcomes.

Characteristics and interventions were compared between those who did (31%) and did not (69%) have an unfavorable outcome, defined as intubation (21%), hypotension (4%), or acute kidney injury (13%). Initial oxygen saturation was significantly lower in those with an unfavorable outcome (94% vs. 98%, p = 0.004). Higher HDN infusion rates ≥200 mcg/min in the first hour were also statistically significantly associated with an unfavorable outcome (71% vs 41%, p = 0.02). The remainder of characteristics and interventions did not show statistically significant differences, though the small sample size may have played a role in that.

The bottom line is the retrospective nature of this study means no true causal relationship can be made between interventions and outcomes, but it – at least – suggests that HDN infusion may be a safe strategy warranting further prospective investigation.

Source
High-dose nitroglycerin infusion description of safety and efficacy in sympathetic crashing acute pulmonary edema: The HI-DOSE SCAPE study. Am J Emerg Med. 2022 Oct 18;63:74-78. doi: 10.1016/j.ajem.2022.10.018. Epub ahead of print.