Ultrasonographic examination by emergency physicians of patients at risk for ectopic pregnancy

To evaluate a diagnostic protocol that includes the early use of endovaginal sonography (EVS) by emergency physicians of patients at risk for ectopic pregnancy.

During this prospective study, pregnant patients > or = 18 years old and at risk for ectopic pregnancy were assessed. Emergency physicians who had completed a training program performed EVS on a convenience sample of eligible women. Clinical disposition was based on predetermined clinical, laboratory, and ultrasonographic criteria. The EVS examinations were reviewed on video by a gynecologist whose interpretation was correlated with the emergency physician EVS readings and with the final clinical diagnoses. Quantitative serum beta-human chorionic gonadotropin (beta hCG) levels were determined for patients who had no definite intrauterine pregnancy (IUP) on EVS.

Of 152 patients studied during a 12-month period, four were lost to follow-up. Emergency physician ultrasonographic diagnoses included: definite IUP, 87/148 (59%); probable abnormal IUP, 17/148 (11%); definite ectopic pregnancy, 3/148 (2%); and no definite IUP, 41/148 (28%). The gynecologist agreed with 93% of the initial interpretations. Twelve of 16 patients who had the final diagnosis of ectopic pregnancy were admitted from the ED with this diagnosis. The ultrasonographic diagnosis of the other four was no definite IUP, and no mass or free fluid. For the latter four patients, the presenting serum beta hCG level was < 2,000 mIU/mL (First International Reference Preparation). They were diagnosed as having ectopic pregnancy after serial outpatient EVS and beta hCG measurements.

The application of EVS to emergency practice appears promising. Emergency physicians trained in its use and who apply this diagnostic tool in conjunction with a defined protocol can stratify the risk of patients who have the potential for ectopic pregnancy.