Hypoxia and Medicine

Oxygen saturation vs Blood Pressure!?

Can someone explain why the blood pressure goes down when the oxygen saturation is great. Also when the saturation is poor, the blood pressure is normal. Does this have anything to do with cardiac output or optimal peep?

Public Comments

1. I haven't heard of such a relationship, and I'm not sure that I have seen much evidence of it in clinical practice either. I can, however, suggest two theories: 1. Hypoxia leads to higher respiratory drive, which may manifest in distress for the patients. The state of stress & discomfort itself can certainly lead to catecholamine levels that raise the BP. Reversal of hypoxic states (eg. by giving O2) may in fact reverse this process to some degree. Once again, I cannot say that I've noticed it for sure. 2. Hypoxia leads to reflex vasoconstriction in lung vessels (mostly arterioles). Correction of hypoxia has been shown to result in relaxation of this constriction. If in fact there is a correlate in the systemic circulation (and this is something I do not know of), then we have a mechanism of lowered BP with correction of hypoxia. Hope that helps!