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Cardiac chest pain
KALANI OLMSTED AND DEBORAH B. DIERCKS
n Agents
n Oxygen
n Beta-blockers
n Nitrates
n Opioids
n Benzodiazepines
n Evidence
Though oxygen has long been used for patients with acute coronary syn-
drome (ACS), its use for ACS has become somewhat controversial.
Intuitively, it seems that increasing blood oxygenation would decrease both
ischemia and pain. However, studies are contradictory, and some suggest
supplemental oxygen may exacerbate ischemia by decreasing coronary perfusion.
1 Coronary perfusion decrease could be a result of oxygen’s hemodynamic
effects of decreased stroke volume and cardiac output (accompanied
by increased vascular resistance). 1
The American College of Cardiology/American Heart Association (ACC/
AHA) guidelines recommend supplemental oxygen for peripheral SpO2 less
than 90%. 2,3 This may be a reasonable strategy but acute care clinicians are
(appropriately) uncomfortable with values in the low 90s SpO2 in patients with
ACS. The extensive use of short-term oxygen therapy in ACS, with rarely
reported adverse effects and frequent cases of anecdotal benefit, supports oxygen
administration as a benign intervention for cardiac patients with pain and
subnormalperipheralpulseoximetry(SpO2). 4 Oxygen administration may, in
fact, be associated with a significant “placebo” effect in reducing anginal pain. 1
Intuitively, the short-term use of oxygen in the highest-risk ACS group –
those with refractory pain and the need for thrombolysis or cardiac catheterization
– is an indicated intervention. Accordingly, the ACC/AHA guidelines