RANDOMISED TRIAL OF HIGH-DOSE ISOSORBIDE DINITRATE PLUS LOW-DOSE FUROSEMIDE VERSUS HIGH-DOSE FUROSEMIDE PLUS LOW-DOSE ISOSORBIDE DINITRATE IN SEVERE PULMONARY EDEMA.

Cotter G, et al. Lancet 1998 Feb 7;351(9100):389-93.

BACKGROUND: Nitrates and furosemide, commonly administered in the treatment of pulmonary oedema, have not been compared in a prospective clinical trial. We compared the efficacy and safety of these drugs in a randomised trial of patients with severe pulmonary oedema and oxygen saturation below 90%.

METHODS: Patients presenting to mobile emergency units with signs of congestive heart failure were treated with oxygen 10 L/min, intravenous furosemide 40 mg, and morphine 3 mg bolus. 110 patients were randomly assigned either to group A, who received isosorbide dinitrate (3 mg bolus administered intravenously every 5 min; n=56) or to group B, who received furosemide (80 mg bolus administered intravenously every 15 min, as well as isosorbide dinitrate 1 mg/h, increased every 10 min by 1 mg/h; n=54). Six patients were withdrawn on the basis of chest radiography results. Treatment was continued until oxygen saturation was above 96% or mean arterial blood pressure had decreased by 30% or to below 90 mm Hg. The main endpoints were death, need for mechanical ventilation, and myocardial infarction. The analyses were by intention to treat.

FINDINGS: Mechanical ventilation was required in seven (13%) of 52 group-A patients and 21 (40%) of 52 group-B patients (p=0.0041). Myocardial infarction occurred in nine (17%) and 19 (37%) patients, respectively (p=0.047). One patient in group A and three in group B died (p=0.61). One or more of these endpoints occurred in 13 (25%) and 24 (46%) patients, respectively (p=0.041).

INTERPRETATION: High-dose isosorbide dinitrate, given as repeated intravenous boluses after low-dose intravenous furosemide, is safe and effective in controlling severe pulmonary oedema. This treatment regimen is more effective than high-dose furosemide with low-dose isosorbide nitrate in terms of need for mechanical ventilation and frequency of myocardial infarction.

INTRAVENOUS NITRATES IN THE PREHOSPITAL MANAGEMENT OF ACUTE PULMONARY EDEMA.

Bertini G, et al. Ann Emerg Med 1997 Oct;30(4):493-9.

STUDY OBJECTIVE: We sought to assess the effect of nitrates on prehospital mortality among patients with acute pulmonary edema (APE).

METHODS: The study involved a retrospective evaluation of the records of prehospital outcome in 640 patients with APE rescued by the mobile CCU (MCCU) of Florence, Italy, between January 1980 and December 1991. The MCCU serves an urban environment with a population of 400,000 in a 102-sq km area. In the years 1980 through 1983, patients were treated with oxygen, morphine, furosemide, digoxin, nitrates, aminophylline, or dopamine, according to the attending physician's judgment. From 1984 through 1991, new guidelines for the use of intravenous nitrates, based on differential treatment according to blood pressure, were in use.

RESULTS: Overall prehospital mortality rate for APE in all patients was 7.8% (50 of of 640 patients). Mortality after 1984 was significantly lower than before (5.3% versus 13%, P < .01). Nitrates were effective in reducing mortality, even in hypotensive patients. Multivariate analysis showed that outcome was significantly affected by two clinical features (dyspnea and low blood pressure), treatment with nitrates, and calendar period effects (before/after 1984).

CONCLUSION: Our findings suggest that the use of intravenous nitrates improves short-term prognosis in APE.

COMMENCTS: Note that the first study used high dose nitroglycerine, and it showed benefits. Many doctors & nurses are afraid to increase the rate once IV nitroglycerine infusion has been started, usually at 30 microgram/hr. Remember that we give patients 1200 micrograms of sublingual nitroglycerine all the time. The Lancet study above used 3 milligram boluses.