Clinical utilization of perfusion lung scans in the diagnosis of pulmonary emboli.

To study the utilization of perfusion lung scans, the records of 116 consecutive patients who had "pulmonary embolus" (PE) as a discharge diagnosis were reviewed. The PE group was identical to the control group in the percent of male patients and of white patients. However, the PE group was older (60.4 versus 47.5 years), had a higher percentage of smokers (53.1 versus 34), and had a higher proportion of obese individuals (39.6 versus 25) than controls. Mortality was significantly greater in the PE patients (9.5% versus 1%) as was the length of hospital stay (21 versus 9 days). The PE group had more chest x-rays than did controls (6.1 versus 1.8) and had a higher percentage of lung scans (95.7 versus 5). While 95.7% of the patients diagnosed as having PE were studied by perfusion lung scans, 4.3% had none. Further, 18.1% had only one lung scan. Of 111 patients with perfusion lung scans, 3.6% were discharged with a diagnosis of PE despite a negative study. While clinical acceptance of perfusion lung scans is high, some patients diagnosed as having pulmonary emboli did not have a scan but underwent other diagnostic tests, while a small group of others were assigned the diagnosis despite a negative lung scan. This points to the need for better communication with referring clinicians.