• 
• 

Three Part Question

In [patients with acute LVF] is [NIPPV better than alternative treatment strategies] at [avoiding intubation and improving mortality]?

Clinical Scenario

A 76 year old male is brought in to A&E in a collapsed state. He has a history of ischaemic heart disease. He is agitated, tachypnoeic and sweating profusely. His neck veins are distended and there are widespread coarse crepitations in his chest. He has a diminshed oxygen saturation. You make a clinical diagnosis of acute cardiogenic pulmonary oedema. In addition to vasodilator treatment and opiates, you wonder whether you should administer non-invasive positive pressure ventilation (NIPPV).

Search Strategy

Medline 1966-08/01 using OVID interface.
[exp pulmonary edema/ or "pulmonary edema".mp or exp ventricular dsyfunction, left/ or exp heart failure, congestive/ or exp myocardial infarction/ or "Left ventricular failure".mp or "lvf".mp] AND [exp positive-pressure respiration/ or exp intermittent positive-pressure ventilation/ or exp respiration, artificial/ or "non-invasive ventilation".mp or "bilevel".mp or "BiPAP".mp or "pressure support".mp] LIMIT to (human and english language) AND maximally sensitive RCT filter.

Search Outcome

208 papers were found, of which 4 randomised controlled trials directly addressed the three part question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Mehta S et al, 1997, USA	27 patients with ACPO NIPPV vs CPAP	Prospective randomised controlled trial	Clinical variables	BP and PaCO2 lower in NIPPV group (p<0.05)	Small numbers Study stopped early due to MI differences. NIPPV had more chest pain at baseline
			Incidence of myocardial infarction	10/14 in NIPPV group vs 4/13 with CPAP (p=0.05)
			Length of ICU/hospital stay, intubation rates, mortality	N/S differences between groups
Sharon A et al, 2000, Israel	40 patients with ACPO NIPPV and low dose nitrates vs high dose nitrates alone	Prospective randomised controlled trial	Mortality	2/20 in NIPPV group vs 0/20 (N/S)	No power calculation Study stopped early due to differences in rate of intubation Pre-hospital setting
			Intubation rate	16/20 in NIPPV group vs 2/20 (p=0.0004)
			Incidence of myocardial infarction	11/20 in NIPPV group vs 2/20 (p=0.006)
			SaO2, pulse and respiratory rates	Improvement significantly slower with NIPPV
Masip J et al, 2000, Spain	40 patients with ACPO NIPPV vs O2	PRCT	Mortality	Control 2/18 Intervention 0/18	Not analysed on basis of intention to treat Small numbers with likely effect of underpowered study
			Intubation	Control 6/18 Intervention 1/19 (P=0.04)
			Hospital stay	No significant difference between groups
Park M et al, 2001, Brazil	26 patients with ACPO O2 vs BiPAP vs CPAP	PRCT	Clinical variables (e.g. RR,HR etc.)	No difference at 60 mins	Small numbers No power calculation No clear randomisation
			Intubation	O2 – 4/10 CPAP – 3/9 BiPAP – 0/7
			Death	O2 – 0 CPAP – 1 (day 3) BiPAP - 0

Comment(s)

This group of trials compared NIPPV with different alternative treatments; oxygen, continuous positive airways pressure (CPAP) or high dose medical therapy. One study showed a benefit in the reduction of intubation rates when NIPPV is compared to oxygen alone, but others have reported evidence of harm with an increased incidence of myocardial infarction in the NIPPV groups. CPAP has already been shown to be of benefit in this patient group (5).

Clinical Bottom Line

The evidence for the use of NIPPV in acute pulmonary oedema is moot. At present CPAP is the safer proven option.

References

1. Mehta S, Jay GD, Woolard RH, et al. Randomized, prospective trial of bilevel versus continuous positive airway pressure in acute pulmonary edema. Crit Care Med 1997;25(4):620-8.
2. Sharon A, Shpirer I, Kaluski E, et al. High-dose intravenous isosorbide-dinitrate is safer and better than Bi-PAP ventilation combined with conventional treatment for severe pulmonary edema. J Am Coll Cardiol 2000;36(3):832-7.
3. Masip J, Betbese AJ, Paez J, et al. Non-invasive pressure support ventilation versus conventional oxygen therapy in acute cardiogenic pulmonary oedema: a randomised trial. Lancet 2000;356(9248):2126-32.
4. Park M, Lorenzi-Filho G, Feltrim MI, et al. Oxygen therapy, continuous positive airway pressure, or non-invasive bilevel positive pressure ventilation in the treatment of acute cardiogenic pulmonary edema. Arquivos Brasileiros de Cardiologia 2001;76(3):221-30.