John, a 65-year-old male, is sitting in a chair in the corner of the room as you and your partner enter his house. John tells you he’s the only one home and called 9-1-1 because he can’t breathe and his chest is killing him.
His skin is ashen and his breathing is rapid. You can palpate a weak irregular pulse and you note his skin is warm and diaphoretic. He describes his shortness of breath as increasing in severity over the last couple of hours with the chest discomfort. With a pulse oximetry reading of 78% on room air, you apply oxygen via a non-rebreathing mask.
Physical exam reveals bibasilar crackles on pulmonary auscultation. His pulse rate is 86 and remains irregular, blood pressure is 84/68 and he’s tachypneic at 24 breaths per minute. He says he feels dizzy but can’t breathe when he tries to lie down. He does say the oxygen is making him feel better and his pulse oximetry reading has increased to 91%. Your partner collects John’s prescription medications, which include Lopressor (metoprolol), Crestor (rosuvastatin), aspirin and nitroglycerin.
You and your partner quickly realize this patient is critical and advanced level care is needed. You decide to begin transporting to the closest hospital, which is 30 minutes away, and rendezvous with the ALS EMS service in the next county on the way. John is breathing better with the oxygen but he’s still short of breath with chest pain. His blood pressure is too low for him to receive nitro or continuous positive airway pressure. You have John chew and swallow three 81 mg aspirin tablets as you begin your emergent transport.
Ten minutes after you leave the scene you reach your ALS rendezvous point just as John goes unconscious. He’s struggling to breathe and you can’t palpate his blood pressure, but he still has carotid pulses. Sputum is frothing from his mouth. You quickly suction his airway and begin bag-mask ventilations as the paramedics from the ALS ambulance jump into your ambulance.
During the transport to the cardiac center, the patient is orally intubated and begins receiving dobutamine at 200 mcg/min. John’s 12-lead ECG reveals an anterior/lateral wall myocardial infarction (MI) pattern. At the hospital, John is quickly transferred to the cardiac catheterization suite for successful placement of three coronary stents and is discharged four days later.
This became a tricky call for providers as the patient’s condition quickly deteriorated, leaving providers with limited ability to intervene. MIs can all present differently. In this case, the left ventricle was affected, resulting in a decreased output into the aorta and systemic system, and a backup of blood into the pulmonary system. The increase pulmonary pressure resulted in acute pulmonary edema, or the movement of fluid into the alveoli, and shortness of breath.
Oxygen administration is a must in patients with hypoxia. Nitroglycerin may have helped relieve the pulmonary edema but the patient’s blood pressure was too low. Common methods to increase the patient’s blood pressure, such as placing them supine or giving them an IV fluid bolus, must be done with caution or avoided with these patients secondary to worsening their condition.
If a patient has an MI affecting their right ventricle, there’s a different set of concerns. With right ventricular failure, the blood backs into the systemic system, which rarely causes an acute emergency. The concern is the acute loss of preload, which is the amount of blood entering the right ventricle. A decrease in preload can result in a decrease in blood pressure. In these patients, hypotension can be managed by laying the patient supine or by giving an IV fluid bolus. Oxygen may not be necessary as long as the patient’s pulse oximetry remains above 94%. Nitro may have a detrimental effect, and should be avoided, as it can cause a rapid, dramatic decrease in blood pressure.
Complaints of discomfort will vary from patient to patient. Any complaint of pain or discomfort between the umbilicus and nose should be considered to be a possible MI until proven otherwise.
Pain may be a poor predictor of disease or illness and the severity of pain, or lack of pain doesn’t necessarily correlate to patient severity. Providers should remember that some patients experiencing an MI may not present with any pain. Consider an MI in patients with other signs of cardiovascular compromise such as hypotension, shortness of breath, syncope and restlessness.
We sometimes attempt to standardize all treatment for all patients. It’s not that simple. Treatment for patients suffering from MIs may vary. Some patients with MIs need oxygen and others don’t. Oxygen administration must be based on patient presentation. Fluid is helpful for blood pressure management in some MI patients and harmful in others.
Aspirin is beneficial as long as the patient with no contraindications can chew, swallow, follow commands and protect their airway. The goal of EMS should then be to get the patient to a facility where they can receive reperfusion therapy.
Work within your system to seamlessly move patients from the scene to advance cardiac care. Keep patients comfortable, oxygenated as appropriate and help them maintain perfusion on the way. Quickly recognize patient severity and know your limitations and be prepared for the deterioration of the patient. We work best as a team.