EMS is called to the scene of a 58 year old male complaining of chest pain.
- Past medical history: Dyslipidemia (high cholesterol)
- Medication:Â Atorvastatin (Lipitor)
On arrival, the patient is found tripoding in a chair. He is pale, diaphoretic, and appears acutely ill. He is anxious but alert and oriented to person, place, time and event.
- Onset: Pain started after carrying luggage up stairs 15 minutes prior to EMS arrival.
- Provoke: Nothing makes the pain better or worse.
- Quality: Pain is described as “burning”.
- Radiate: Patient denies radiation of the pain but complains that the BP cuff is hurting his right arm, even when it’s not inflated.
- Severity: 9/10.
- Time:Â No previous episodes.
He admits to mild dyspnea. He is nauseated but has not vomited. No jugular venous distension while sitting upright. No pedal edema.
- RR: 20
- HR: 64
- NIBP: 199/98
- SpO2: 95% on room air.
Breath sounds are clear bilaterally.
The cardiac monitor is attached.
A 12-lead ECG is acquired.
Due to equipment and/or network problems the ECG is not able to be transmitted over the LIFENET.
What is your impression?
This ECG shows acute inferior-posterior-lateral STEMI. ST-segment elevation is present in leads II, III, aVF, V5, and V6. Reciprocal changes are present in leads I, aVL, V1, and V2.
The patient was placed on oxygen via nasal cannula at 4 LPM.
The AVOID trialÂ (published in 2015) showed that supplemental oxygen for patients with ST-segment elevation myocardial infarction but without hypoxia may increase myocardial injury and was associated with larger infarct size at 6 months.
Have you changed your protocols?
The patient was given 4 baby aspirin. An IV was started and nitroglycerin was administered.
The patient was sent to the cardiac cath lab. It is unknown whether the culprit artery was the right coronary artery (RCA) or circumflex (LCX).
Stub D, Smith K, Bernard S et al. Air Versus Oxygen in ST-Segment-Elevation Myocardial Infarction. Circulation. 2015;131(24):2143-2150. doi:10.1161/circulationaha.114.014494.