Date Published

November 22, 2012

Updated For

ALS PCS Version ALS PCS Version 5.2


Question: What are your thoughts on oxygen therapy in myocardial ischemia from a medical evidence standpoint? Even though high flow o2 is regularly administered to PTs with chest pain as per the oxygen therapy and chest pain standards in the BLS standards, there is an increasing body of evidence suggesting that in uncomplicated MI O2 is of no benefit and may cause more harm than good due to ROS and ischemia-reperfusion injury.

The recent ACLS guidelines state to only administer O2 in acute coronary syndromes if the spo2 is < 94% or the PT is in respiratory distress or obviously hypoxic and there are several recent papers and clinical guidelines that suggest a similar course of action in uncomplicated MI. Basically, the evidence is suggesting that titration to spo2 is favorable over high flow o2 due to the risk of oxidative stress injury.

Any thoughts? Obviously you still follow the protocols, but I'm just interested to see if there is any medical opinion on this. Could the standards/guidelines eventually change to reflect the newer evidence?


 Thanks for asking this question. Well done keeping informed as to the latest medical literature related to your practice! Similar questions to this were posted on July 3 and Sept 4 relating to the amount and concentration of oxygen.

Oxygen administration is a "hot topic" these days throughout the medical literature as you describe. We now know that too much oxygen may not be good in certain conditions and we need to rethink some of our indications for high flow oxygen. One of the limiting issues in this regard however is that up until now, oxygen saturation monitors have not been listed as mandatory equipment making titration of oxygen impossible for some EMS services.

For now, oxygen administration is governed by the Basic Life Support Patient Care Standards (BLS-PCS) and paramedics should comply with the directions therein.

As a glimpse to the future, our provincial regional base hospital partners have been very busy this year reviewing the latest literature regarding oxygen and specifically hyperoxia, and then painstakingly comparing their findings to the current standards within the BLS-PCS. Look for revised indications in the near future regarding oxygen administration!



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