Stages of Pulmonary Embolism

They divided the patients into two groups: one to develop the rule and the other to verify their conclusions.

A pulmonary embolism involves a clot that travels through the bloodstream and suddenly blocks an artery of the lung. The most common type begins in either a leg or pelvic vein. Once a clot breaks loose, it tends to travel to the lung. The researchers looked at 11 patient factors independently associated with 30-day patient mortality from pulmonary embolism. These were two demographic factors (age and male sex); three illnesses (cancer, heart failure, and chronic lung disease); and six clinical findings on measurements of pulse, systolic blood pressure, respiratory rate, temperature, altered mental state (disorientation, lethargy, stupor), and arterial oxygen saturation level. Each of these parameters was assigned a numerical score to quantify it with the potential for death.

According to the authors, the rule identifies patients who are at either low or high risk of fatal and nonfatal medical outcomes associated with pulmonary embolism. For example, the 30-day mortality rate for a class I score was 1.6% or less. For class II, it was 3.5%. At class V, it ranged from 10-24.5%. Through outpatient management or early hospital discharge of patients identified as very low risk in class I or low-risk in class II, the rule could save costs without adding risk to the patient, once its usefulness has been confirmed in a prospective study.

The study was led by Drahomir Aujesky of the Centre Hospitalier Universitaire Vadois in Lausanne (Switzerland). The findings were published in the second issue for October 2005 of the American Journal of Respiratory and Critical Care Medicine.