[Doczilla]

As far as a "fear" of high flow O2 goes, the only rational argument against it is free radical oxygen damage to lung tissues. Some fear the COPD patient with high flow, but most know that the hypoxic drive is insufficient to rapidly cause hypoventilation in the short term setting.

In the presence of functioning hemoglobin, the increased PO2 dissolved in the blood by high flow via NRB makes a negligible contribution to oxygen delivery to tissues. There are settings in which it is more appropriate, such as where Hgb oxygen-carrying capacity is impaired (such as CO poisoning, where the Hgb has trouble carrying the oxygen, and high flow O2 also significantly decreases the time to dissociation of the CO from the Hgb, and high PO2 is the only good way to deliver oxygen to tissues. Methemoglobinemia is another example). This also will be helpful in severe anemia, where Hgb is so low that it is not carrying oxygen to the tissues. Here, the added O2 delivery from O2 dissolved in the blood will help.

So the short answer is, high flow O2 will not hurt, but will help in a minority of cases of cardiac related chest pain.

The second case that you describe sounds more like a pulmonary issue: pneumonia with CP. The t-wave inversions you mention are nonspecific. T-wave inversion in aVR is not uncommon and generally ignored for the acute setting. T-wave inversions in V1 and V2 are frequently normal findings, as they often are in lead III. Without seeing the EKG there's not much else I can say. High flow O2 may or may not be indicated here based on what else you think might be going on, but I wouldn't disagree with its application. Pneumonia, PE, dissection, etc. are diagnoses to be considered. Accelerating chest pain is not necessarily reason to increase the O2, but increasing shortness of breath or respiratory effort would be.

'zilla