PICOTS:

• P = Adults with suspected acute coronary syndrome (ACS) with a normal pulse ox ≥ 90%
  
• I  = Supplemental oxygen by nasal cannula or facemask
• C = No supplemental oxygen
• O = Reduction in mortality, progression of myocardial infarction, angina, and/or CV related complications
• T = Acute setting (within 12 to 24 hours up to 30 days)
• S = Pre-hospital care or emergency department

Note: PICOTS stands for (P) for patient, (I) for intervention of interest, (C) for comparison, (O) for outcome(s) of interest or relevance, (T) for timing, and (S) for setting.

Summary:

Patients with acute coronary syndrome (ACS; unstable angina, NSTEMI, STEMI) should initially receive 2-4 L/min supplemental oxygen (O2) per nasal cannula if they have an oxygen saturation by a pulse oximetry < 90%, are experiencing dyspnea, or have heart failure, as there is conflicting evidence about possible harm in normoxic patients. 

• Current guidelines by the American Heart Association (AHA) do not recommend supplemental oxygen use in normoxic patients with suspected ACS.
  
• A Cochrane review of 4 trials in patients with acute MI is concerning for a possible greater risk of death in patients getting supplemental O2. However, there is conflicting evidence, and thus the use of supplemental oxygen should be studied in a clinical trial to verify its effect on morbidity and mortality.  The current AHA guidelines both recommend its use in the above situations. 
• There is some evidence in patients with stable CAD undergoing elective cardiac cath that supplemental O2 (breathing 100% FiO2 at 15 L/min via face mask) may increase coronary vascular resistance, reduce coronary blood flow, and increase mortality risk.
  
• Could also reduce respiratory drive in patients with known COPD or chronic hypercapnia, thereby worsening carbon dioxide retention and risk for respiratory acidosis.

Author: Anthony J. Busti, MD, PharmD, FNLA, FAHA
Editors:  Dylan Kellogg, MD
Last Reviewed:  December 2016