Cardiac & Resuscitation, Patient Care

Prehospital ECG findings expedite patient care

Issue 5 and Volume 36.

North Las Vegas Fire Department and MedicWest EMS are summoned to a suburban residence to assist a patient with reported chest pain. The scene is safe, and they enter the house to find a male patient seated in a chair clutching his chest. He states that his pain had begun approximately 30 minutes prior to EMS arrival. He initially thought it was gas and took some Pepto-Bismol. Shortly after, he vomited the Pepto-Bismol and became sweaty and short of breath. His daughter-in-law summons EMS.

Prehospital Care
Providers arrive and find an alert and oriented 51-year-old male who reports a history of diabetes. He’s seated upright, clutching his chest, and is diaphoretic. He says the pain feels like pressure and is located in the left side of his chest, radiating to his left arm and neck.

He rates the pain level as a 10 on a scale of 0 to 10 and reports it began shortly after an argument with his son. He says he’s never had pain like this before and that he’s supposed to be on diabetes medication, but he hasn’t refilled his prescription in months. He smokes half a pack of cigarettes a day and drinks beer daily. He denies any medication allergies.

His vital signs are blood pressure 106/70 mmHg, pulse of 95, respirations of 20 and pulse oximetry (SpO2) of 98% on room air. His exam is essentially unremarkable other than the diaphoresis.

The crew places the ECG electrodes and obtains a 12-lead ECG, noting that the patient has marked ST-segment elevation in the anterior leads. They immediately administer an aspirin and prepare the patient for transport.

They choose not to administer nitro­glycerin because of the patient’s blood pressure. They place a saline lock and administer 5 mg of morphine and 4 mg of ondansetron (Zofran) IV. They prophylactically put defib­rillator pads in place.

The patient is quickly moved to the ambulance. While one paramedic cares for him, the other calls the University Medical Center (UMC) emergency department (ED) and notifies the staff that they’re en route, with a cardiac activation with an estimated arrival time of 12 minutes. (Note: ECGs aren’t routinely telemetered in the system because the paramedic is relied on to interpret the prehospital 12-lead ECG.) The patient’s pain level decreases from a 10 on a 10-point scale to a 5 on the scale following the medications. He remains stable throughout transport but continues to be marginally hypotensive.

Hospital Course
At the ED, the emergency medicine staff and cardiac team have prepared for the patient’s arrival. On arrival, he’s moved to a critical care bed and is evaluated. A stat 12-lead ECG is obtained, which reveals an extensive acute ST-segment myocardial infarction (STEMI) (see Figure 1).

The patient’s vital signs are blood pressure 97/60 mmHg; pulse 76, respirations 22, and SpO2 100% on 2 L per minute of oxygen via nasal cannula. The patient is screened and subsequently evaluated by cardiology.

He’s started on a heparin drip and also receives eptifibatide (Integrilin), a platelet-aggregation inhibitor. Routine laboratory tests are ordered in the ED. These are normal, with the exception of an elevated troponin-T of 31.7 ng/mL (normal =
0–0.2 ng/mL), which is consistent with STEMI. His blood glucose was elevated at 316 mg/dL (normal = 65–110 mg/dL). He is immediately taken to the cardiac cathe­terization lab.

Once in the cath lab, a femoral artery catheter is placed, is advanced to the coronary arteries, and a contrast dye is injected. At this point, the patient is somewhat hypotensive; thus, low-dose do­pamine is started.

The interventional cardiologist identified a stenotic lesion, and a thrombotic occlusion in the left anterior descending (LAD) coronary artery.

A balloon angioplasty is performed, and blood flow through the LAD was restored. A stent is then placed to keep the vessel open, and no residual stenosis is noted. The patient remains hypotensive and on do­pamine after the procedure.

Once in the cardiac care unit (CCU) the patient’s blood pressure improves, and the dopamine is weaned and discontinued. His subsequent hospital course is uncom­plicated, and he is discharged.

Percutaneous coronary intervention (PCI), in addition to new platelet-aggregation in­hibition agents, has significantly improved the outcomes of patients with acute coronary syndrome (ACS).

For patients to have the best chance for survival, the problem must be identified as soon as possible and the patient taken to a facility with interventional cardiology capabilities. In this case, the patient’s family recognized the problem and summoned EMS. The patient arrived at University Medical Center and was quickly taken to the cardiac catheterization lab where PCI was performed. His door-to-balloon time was approximately 28 minutes.

The time from paramedic contact to balloon time was 58 minutes, and the time from symptom onset to balloon time was less than 90 minutes. In this case, all aspects of the system worked well, and the patient had the best possible outcome.

Teaching Points
The saying “time is myocardium” is true. It has been well established that prompt diagnosis and treatment of ACS (STEMI, unstable angina) offer the greatest potential for myocardial salvage. In approximately 40% of STEMI patients, EMS providers are the patient’s first contact with the health system.(1,2) Delays in treatment generally occur during one of the following three phases:
1. At the onset of symptoms to patient recognition;
2. During prehospital transport; and
3. During emergency department evaluation.(3)

EMS has the potential to influence the first two categories of delay. Public education and emergency medical dispatch queries can help patients recognize that they may be suffering from ACS. Several factors have also been identified that can help avoid delays during prehospital transport.

Among these is the early acquisition of a prehospital 12-lead ECG and prompt activation of the interventional cardiology team at the receiving facility.(4)

Prehospital providers must be ever vigilant for the subtle signs and symptoms of ACS. A pointed history, physical examination and 12-lead ECG can usually identify those patients with this condition.

ACS is a medical condition in which prehospital recognition and treatment afford the patient the best chances of a good outcome. So EMS providers must be alert for its often subtle signs and symptoms, including 12-lead ECG changes. Early recognition also allows the interventional cardiology team to prepare for the patient’s arrival and rapidly move the patient to the cath lab. JEMS

1. Le May MR, So DY, Dionne R, et al. A citywide protocol for primary PCI in ST-segment elevation myocardial infarction. N Engl J Med. 2008; 358(3):231–240.
2. Stenestrand U, Lindback J, Wallentin L. Long-term outcome of primary percutaneous coronary intervention vs prehospital and in-hospital thrombolysis for patients with ST-elevation myocardial infarction. JAMA. 2006; 296(14):1749–1756.
3. O’Connor RE, Brady W, Brooks SC, et al. Part 10: Acute Coronary Syndromes; 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010; 122(Suppl 3):S787–S817.
4. Rezaee ME, Conley SM, Anderson TA, et al. Primary percutaneous coronary intervention for patients presenting with ST-elevation myocardial infarction process improvements in rural prehospital care delivered by emergency medical services. Prog Cardiovasc Dis. 2010; 53(2):210–218.

This article originally appeared in May 2011 JEMS as “The System Works: Prehospital ECG findings expedite patient’s care.”