True Medical Emergencies

It is not only traumatic injuries that can be suddenly lethal to prehospital patients. There are several medical conditions which, if left undetected, or misdiagnosed and untreated, can be rapidly fatal. These conditions can easily be confused for other, more benign problems. This article reviews a few of these lethal conditions and their sometimes discrete signs and symptoms to help you better manage your patients’ care and improve their chances of survival.

Pulmonary Embolus

A clot that forms in one part of the body and travels in the bloodstream to another part of the body is called an embolus. A pulmonary embolism is a sudden blockage in a lung artery, usually due to a blood clot that traveled to the lung from the deep veins of the leg. More than 600,000 people in the United States have a pulmonary embolism each year, and more than 60,000 of them die. Most of those who die do so within 30–60 minutes after onset of symptoms.1

The majority of patients with pulmonary emboli have an underlying clinical predisposition. Fewer than 10% of the patients have no discernible cause for deep venous thrombosis (DVT) at the time of presentation.2 Deep venous thrombosis, just like it sounds, is a condition where blood clots form in the deep veins of the lower legs. Conditions like immobilization, surgery, fracture, malignancy, thrombophlebitis, trauma, estrogen therapy, obesity, myocardial infarction and stroke all increase the likelihood of DVT. Surgical patients are commonly given venous support stockings for their legs and encouraged to move around after surgery to prevent these deep clots from forming and traveling to the lungs.

In pulmonary embolism, a piece of one of these clots breaks off and returns to the heart via the inferior vena cava, traveling through the cardiopulmonary circulation until it is too big to pass through a small vessel. Similar to a myocardial infarction and stroke, the clot prevents oxygenation of any tissues beyond itself. With this pulmonary embolus, lung tissue begins to die. If left long enough, this could develop into a pulmonary infarction; however, sometimes the emboli are so large that they can cause complete occlusion of a pulmonary artery and cause sudden death.

The clinical diagnosis of a pulmonary embolism is very difficult, therefore the prehospital provider’s level of suspicion must be high. The symptoms and signs of pulmonary embolus are nonspecific. Historically, a classical clinical triad was hemoptysis (coughing up blood), pleuritic chest pain (pain that increases with inhalation and decreases with exhalation) and difficulty breathing; however, this occurs in 20% or less of cases.2

The physical examination is equally unhelpful in diagnosing pulmonary embolus. The great majority of patients demonstrate an increased respiratory rate. The remainder of physical signs, which include an increased heart rate, elevated temperature, physical evidence of phlebitis, diaphoresis, edema, cardiac murmur, rales and cyanosis, are found in fewer than 50% of the patients who present with pulmonary embolus.2 Unexplained sudden onset of anxiety in a patient has been recognized as a common symptom of pulmonary embolus. In addition, for agencies that use pulse oximeters, a room air SpO2 of

Prehospital treatment is mainly oxygen therapy. ALS agencies may start an intravenous line, but there is no specific prehospital treatment regimen.

Emergency department and hospital diagnosis has been just as tricky. Chest x-rays of patients who are later confirmed to have had a pulmonary embolus are often abnormal, but in ways that are not specific enough to conclusively diagnose PE. Previously, the most reliable and sensitive tool has been pulmonary angiography—injection of dye into the pulmonary vessels—which is a complicated procedure with its own set of risks. Recent advances in computerized tomography (CT) scan technology have approached making spiral or helical CT scan the gold standard in diagnosing pulmonary embolus. In addition, a blood test known as d-dimer has been developed as a rapid screening test that measures a protein fragment left over after formation of a thrombus. This test has been used to triage patients into those who need advanced imaging and those who do not.