Systematic review of studies of the effect of hyperoxia on coronary blood flow.

Abstract

BACKGROUND:

International guidelines recommend the routine use of oxygen in the initial treatment of myocardial infarction, yet it is uncertain what effect this might have on physiologic and clinical outcomes.

METHODS:

We undertook a systematic search of Medline, Cochrane Database of Systematic Reviews, EMBASE, and CINHAL using the key words "oxygen," "coronary blood flow," "hyperoxia," and "coronary circulation" to identify human studies involving a measure of coronary blood flow while breathing oxygen and room air. The primary outcome measure was coronary blood flow; secondary outcomes included coronary vascular resistance and myocardial oxygen consumption.

RESULTS:

From 2,072 potential publications, there were 6 studies from 4 publications that met the inclusion criteria, with 6 healthy subjects and 61 subjects with cardiac disease. It was not possible to undertake a meta-analysis due to methodological limitations. In the 6 studies, high-concentration oxygen therapy resulted in hyperoxia, with a range in mean Pao(2) of 273 to 425 mm Hg. Hyperoxia caused a significant reduction in coronary blood flow (mean change -7.9% to -28.9%, n = 6 studies). Hyperoxia caused a significant increase in coronary vascular resistance (mean change 21.5% to 40.9%, n = 4 studies) and a significant reduction in myocardial oxygen consumption (mean change -15.3% to -26.9%, n = 3 studies).

CONCLUSIONS:

Hyperoxia from high-concentration oxygen therapy causes a marked reduction in coronary blood flow and myocardial oxygen consumption. These physiologic effects may have the potential to cause harm and are relevant to the use of high-concentration oxygen therapy in the treatment of cardiac and other disorders.

• Authors: Hamish Farquhar, Mark Weatherall, Meme Wijesinghe, Kyle Perrin, Anil Ranchord, Mark Simmonds, Richard Beasley
• Journal: American heart journal (Am Heart J) Vol. 158 Issue 3 Pg. 371-7 (Sep 2009) ISSN: 1097-6744 [Electronic] United States
• PMID: 19699859 (Publication Type: Journal Article, Review, Systematic Review)

Topics

• Coronary Circulation (physiology)
• Heart (physiopathology)
• Humans
• Hyperoxia (physiopathology)
• Myocardial Infarction (therapy)
• Myocardium (metabolism)
• Oxygen Consumption (physiology)
• Oxygen Inhalation Therapy (adverse effects)
• Vascular Resistance (physiology)