engleski

OXYGEN - MEDICATION WITH SIDE EFFECTS

Oxygen (O2) is one of the most prescribed therapeutic agents worldwide. However, it is often overlooked that O2 is a true drug, with specific biological and physiological actions, dose-dependent beneficial and adverse effects. Although the practice to apply O2 to all patients having an acute myocardial infarction (AMI) is a century old, this paradigm is changing. Today is recognized that the guidelines regarding the routine use of O2 to all patients having AMI, (class IIa, LOE C), are based on non-critical judgment and should be revised. Non-hypoxemic patients are at high risk to be acutely exposed to hyperoxia. Hyperoxia can raise blood pressure, lower cardiac index, heart rate and cardiac oxygen consumption. Indeed, although hyperoxia slightly increases arterial blood oxygen content, it actually decreases tissue oxygen delivery, due to constriction of the coronary, cerebral, renal and other key vasculatures. The mechanisms of hyperoxia-induced vasoconstriction are not completely understood. Increased oxidative stress after hyperoxia, and subsequent inhibition of vasodilators, like nitric oxide, is one plausible mechanism. However, hyperoxia-induced modulation of function of potassium / calcium channels and raised levels of angiotensin II and endothelin-1, could also contribute to this adverse effect. In order to fully understand the efficiency and safety of O2, new randomized, doubleblinded, controlled clinical trials are warranted in the future.

oxygen; vasoconstriction; oxidative stress; nitric oxide

nije evidentirano