Supplemental oxygen in cardiac emergencies
Historical overview
Few controversies benefi
t more from obtaining historical
perspective than that of supplemental oxygen therapy,
particularly in the context of cardiac emergencies. More
than a century ago, it was fi
rst observed that oxygen
relieved pain during episodes of angina pectoris [2]. Th
e
explanation for this phenomenon came in 1928, when
hypoxia of the myocardium was described as the cause of
angina [3]. Since then, numerous reports have empha-
sized the potential benefi
t of supplemental oxygen in
patients with impaired coronary perfusion [4-6]. How-
ever, as early as in 1950, it was suggested that oxygen
supplementation might be deleterious, as it prolonged
electrocardiographic alterations during exercise tolerance
testing [7]. In 1964, it was reported that breathing high
concentrations of oxygen (85% to 90%) for at lea