Two bad things at once

A female patient in her 60s arrives at the emergency department via EMS with acute CP and SOB.  The history is consistent with cardiac ischemia and the EMS ECG shows clear inferior ST elevation with reciprocal changes.  You call the cath lab and they review the ECG and agree to take the patient immediately.  Vitals stable, chest clear, normal cardiac auscultation.

The patient has not even left the EMS stretcher and is being wheeled out to the lab when one of your nurses notices an O2 sat of 92 to 93% on the final set of vitals prior to discharge.  This patient has no known respiratory disease and is a nonsmoker.  Would a STEMI cause this modest hypoxia?

Of course you stop the EMS staff to do a further assessment, knowing your door to needle time is being delayed for every second you take.  The pressure is on!  A quick bedside echo shows this:

RV dilation A4C 3

You quickly notify the cath lab that this patient has a dilated RV and there is no old echo available to say this isn’t acute.  Lung scan shows no edema.  RV infarct and PE are on the differential, with PE being the number one concern as the lungs aren’t wet but we have hypoxia.  They take the patient anyway, open up and stent a proximal RCA occlusion, then immediately get a chest CT that confirms large bilateral PE’s.

This case is a reminder to me why you should try to do a bedside echo on every ischemic sounding chest pain patient, even when the presentation seems clear cut.  Unfortunately more than one bad thing can happen at once, usually the first triggering the second.