Unsuspected Pulmonary Embolism in Observation Unit Patients

OBJECTIVE: Many emergency department (ED) patients with cardiopulmonary symptoms such as chest pain or dyspnea are placed in observation units but do not undergo specific diagnostic testing for pulmonary embolism (PE). The role of observation units in the diagnosis of PE has not been studied. We hypothesized that there was a small but significant rate of unsuspected PE in our observation unit population. METHODS: We performed a retrospective chart review at an urban academic hospital of all ED patients with an International Classification of Diseases, Ninth Revision diagnosis of PE between January 2005 and July 2006. The number of such patients assigned to observation at any point in their stay was recorded, in addition to events leading to diagnosis and subsequent in-hospital outcomes. RESULTS: Thirteen of the 190 ED patients diagnosed with PE were placed in the observation unit. Six of these either had a known recent diagnosis of PE or had testing for PE initiated prior to placement in the observation unit. Two of the remaining seven patients with undiagnosed PE were placed in observation for undifferentiated chest pain, accounting for 0.09% of the 2190 patients under the chest pain protocol. Twelve of 13 PE patients (92%) were admitted with an average stay of 4.3 days. Of the 13 patients, five were ultimately determined after admission to not have PE, leaving a rate of confirmed PE in the observation unit population of 0.12% (8/6182), with five of eight being classified as unsuspected prior to assignment to observation (0.08% rate). CONCLUSION: We identified a small number of patients assigned to observation with unsuspected PE. The high rate of hospital admission and prolonged hospital stay suggests that patients with PE are inappropriate for observation status. Given the low incidence of unsuspected PE, there may be a need for a specific approach to screening for PE in observation unit patients.