Stavitsky Y

Hyperbaric oxygen reduced time to pain relief in patients following acute myocardial infarction.

Clinical Bottom Line:

1. The time to pain relief following myocardial infarction was reduced following the addition of hyperbaric oxygen to the treatment protocol.

2. There was no significant improvement in other measures of outcome, although there was a trend to lower CPK levels, LVEF and mortality.

Appraised by: Mike Bennett, Dept. of Diving and Hyperbaric Medicine, Prince of Wales Hospital

Sydney; Friday, 4 June 1999

Clinical Scenario: A patient with acute myocardial infarction.

Three-part Question: In patients with acute myocardial infarction, does the early administration of hyperbaric oxygen, in addition to a standard care protocol including thrombolysis, result in any demonstrable improvement in outcome?

Search Terms: myocardial infarction, thrombolysis

The Study:

Non-blinded randomised controlled trial without intention-to-treat.

Patients with AMI diagnosed by ECG changes and clinical features and who were eligible for thrombolysis.

Control group (N = 69;63 analysed (41 all data)): Standard care including thrombolytics and aspirin. No sham treatment.

Experimental group (N = 69;59 analysed (40 all data)): As above, but immediately following diagnosis, patients were given hyperbaric oxygen at 2ATA on 100% for a total chamber time of 2 hours.

The Evidence:

Outcome	Time to Outcome	Control group	HBO group	Relative risk reduction	Absolute risk reduction	NNT
Death	Discharge	0.032	0.017	47%	0.015	67
95%CI:				-100% to 100%	-0.04 to 0.07	NNT=14 to INF NNH=25 to INF

Non-Event Outcomes Time to outcome Control group HBO group P-value

Time to pain relief

(mins) variable 614 261 <0.001

CPK (activity units) 12 hours 1,828 1,690 >0.05

Comments:

1. Multicentre study with considerable loss of data, no intention to treat analysis and no blinding. There is some danger of bias.

2. All outcomes except time to pain relief show a non-significant trend in favour of the HBO group. A larger study may confirm a treatment effect.

Expiry date: October 2004

References:

1. Stavitsky Y, Shandling AH, Ellestad MH, Hart GB, Van Natta B, Messenger JC, Strauss M, Dekleva MN, Alexander JM, Mattice M, Clarke D. Hyperbaric oxygen and thrombolysis in myocardial infarction: the 'HOT MI' randomised multicenter study. Cardiology 1998; 90:131-136.

2. Dekleva MN, Ostojic M, Vujnovic D. Hyperbaric oxygen and thrombolysis in acute myocardial infarction: a preliminary report. In: Sitinen SA, Leinio M, eds. Proceedings of the Twenty-first Annual Meeting of the European Underwater and Baromedical Society (EUBS), Helsinki, Finland 1995:9-13.