Pilot study evaluated treatment with high-dose nitroglycerin and non-invasive ventilation.
Hypertensive acute heart failure is a subgroup of acute congestive heart failure (CHF) patients.
Physiologically, there is increased afterload and decreased venous capacitance both leading to fluid shifts resulting in pulmonary vascular congestion.
Sympathetic crashing acute pulmonary edema (SCAPE) is a severe form of hypertensive acute CHF. It is a completely clinical diagnosis with no formal test or criteria. The rapidity and severity of this illness leaves a very narrow period of time for therapeutic intervention before subsequent deterioration.
Therapeutic intervention includes vasodilators such as high-dose nitroglycerin (NTG) and non-invasive ventilation (NIV). Both therapies can result in reduced work of breathing, decreased preload/afterload and prevention of endotracheal intubation. There is a paucity of high-level literature on this topic.
A single tertiary care emergency department conducted a prospective, observational pilot study evaluating treatment with high-dose nitroglycerin and non-invasive ventilation. The protocol they used is below (recreated from publication). [1]
This was a small study of only 25 patients with a mean duration of symptoms of 3.2 hours. The mean nitroglycerin bolus was 872ug and the mean cumulative dose of nitroglycerin given was 35mg.
There was no incidence of hypotension after the bolus dose of nitroglycerin. Only two out of 25 patients had transient hypotension during the infusion of nitroglycerin that improved with small fluid boluses and stopping the nitroglycerin drip.
For the non-invasive ventilation component, six out of 25 patients had a maximum inspiratory positive airway pressure of 16cmH20 and 12 out of 25 patients required low dose opioids (fentanyl 50ug) to improve mask tolerability.
All but one patient had resolution of their symptoms within six hours (11/25 patients had resolution of symptoms at three hours). Only one patient required intubation within six hours due to not tolerating the non-invasive mask.
Amazingly, 24 out of 25 patients were discharged from the ED after a brief period of observation (Average length of stay was 15 hours). Most of these patients would be admitted at my institution. It is unclear how many of these patients bounced back to the ED, which is a major limitation of this study. For example, if 23 out of 24 patients returned in the ensuing 24 hours would this still be a good protocol to use?
An important point to understand in treating this disease process is most patients with SCAPE are euvolemic, where diuresis will have little role (i.e. weight gain does not typically occur in such a rapid fashion, and typically does so after changes in filling pressure rather than preceding it).
This is why the use of high dose nitroglycerin and non-invasive ventilation make more physiologic sense in the acute treatment of this disease. [2][3][4]
The biggest challenge in the use of non-invasive ventilation is often patient tolerability. Use of low dose opioids (i.e. morphine 2mg or fentanyl 50ug) may help with this as was seen in this trial.
Although this is a very small trial, it supports what many have anecdotally seen. In patients presenting with SCAPE, the use of high dose nitroglycerin (600mcg to 1000mcg) bolus plus a nitroglycerin drip (100ug/min) in addition to non-invasive ventilation is a safe, objective practice to help reduce the incidence of intubation and ICU admission.
References:
- Mathew R et al. High-Dose Nitroglycerin Bolus for Sympathetic Crashing Acute Pulmonary Edema: A Prospective Observational Pilot Study. JEM 2021. PMID: 34215472 [Access on Read By QxMD]
- Zile MR et al. Transition from Chronic Compensated to Acute Decompensated Heart Failure: Pathophysiological Insights Obtained from Continuous Monitoring of Intracardiac Pressures. Circ 2008. PMID: 18794390
- Chaudhry SI et al. Patterns of Weight Change Preceding Hospitalization for Heart Failure. Circ 2007. PMID: 17846286
- Fallick C et al. Sympathetically Mediated Changes in Capacitance: Redistribution of the Venous Reservoir as a Cause of Decompensation. Circ Heart Fail 2011. PMID: 21934091
- Wilson SS et al. Use of Nitroglycerin by Bolus Prevents Intensive Care Unit Admission in Patients with Acute Hypertensive Heart Failure. AJEM 2017. PMID: 27825693
