Ragavendra R. Baliga, M.D
Assistant Professor
Division of Cardiology
University Of Michigan

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Question 9 of 39:

It is universal practice to administer oxygen because it has been well documented this therapy limits myocardial damage, reduce morbidity and mortality.

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Although it has become universal practice to administer oxygen, usually by nasal prongs to virtually all patients suspected of having acute ischemic-type chest discomfort, it is not known whether this therapy limits myocardial damage or reduces morbidity or mortality. When oxygen saturation is <90% therapy with supplemental oxygen is clearly indicated.

Laboratory data suggests that breathing oxygen may limit ischemic myocardial injury[1] and there is evidence that oxygen administration reduces ST-segment elevation in patients with MI[2]. The rationale for use of oxygen is based on the observation that even with uncomplicated myocardial infarction, some patients are modestly hypoxemic initially, presumably because of ventilation-perfusion mismatch and excessive lung water[3].

Reference:

1. Maroko PR, Radvany P, Braunwald E, Hale SL. Reduction of infarct size by oxygen inhalation following acute coronary occlusion. Circulation 1975;52:360-368

2. Madias JE, Hood WB Jr. Reduction of precordial ST-segment elevation in patients with anterior myocardial infarction by oxygen breathing. Circulation 1976;53 (suppl I):I-198-I-200.

3. Fillmore SJ, Shapiro M, Killip T. Arterial oxygen tension in acute myocardial infarction: serial analysis of clinical state and blood gas changes. Am Heart J 1970;79:620-629.