Derivation of a Clinical Prediction Model for the Emergency Department Diagnosis of Ectopic Pregnancy

Abstract

Abstract. Objective: To derive a clinical prediction model for estimating the pretest probability of ectopic pregnancy in ED patients with first-trimester abdominal pain or vaginal bleeding. Methods: All hemodynamically stable first-trimester patients presenting to the ED of a tertiary care military teaching hospital over a 14-month period with a chief complaint of abdominal pain and/or vaginal bleeding had clinical data coded prior to determining outcome. They were then followed longitudinally until a criterion standard pregnancy outcome was established. Results: Of the 486 patients enrolled, 280 (58%) had viable intrauterine pregnancies, 167 (34%) had nonviable intrauterine pregnancies, and 39 (8%) had ectopic pregnancies. Using a recursive partitioning model, a high-risk group was derived (that was separated from intermediate and low-risk groups), consisting of patients with abdominal peritoneal signs or definite cervical motion tenderness, with a sensitivity of 31% .(95% CI: 17-48%), a specificity of 93% (95% CI: 90-95%), a positive likelihood ratio of 4.3, and a negative likelihood ratio of 0.74. A low-risk group, consisting of patients with either fetal heart tones or tissue a t the cervical os, or the absence of pain other than midline menstrual-like cramping and lacking any pelvic tenderness, was differentiated from a n intermediaterisk group, with a sensitivity of 96% (95% CI: 81-loo%), a specificity of 22% (95% CI: 18-26%), a positive likelihood ratio of 1.2, and a negative likelihood ratio of 0.17. Conclusion: A clinical prediction model for estimating the probability of ectopic pregnancy in ED patients has been derived. I t may prove to have practical clinical application for estimating pretest probability of ectopic pregnancy as well as assisting in medical decision making when laboratory and ultrasonographic findings are nondiagnostic. Clinical application should await prospective validation in a n independent sample. Key words: ectopic pregnancy; prediction model; abdominal pain; vaginal bleeding. ACADEMIC EMERGENCY MEDICINE 1998; 5: 951-960 CTOPIC pregnancy is the leading cause of pregnancy-related death in the first trimesterl and a common E D diagnostic and management dilemma. The incidence of ectopic pregnancy

Beta‐Human Chorionic Gonadotropin Levels and the Likelihood of Ectopic Pregnancy in Emergency Department Patients with Abdominal Pain or Vaginal Bleeding

“…The rate of ectopic rupture in this study was quite high at 49 out of 96 (51%). Buckley et al 30 and Mol et al 32 had rupture rates of 12 in 39 (31%) and 65 in 288 (23%), respectively. However, their populations were very different from ours.…”

“…3,6,[29][30][31] Since we report likelihood ratios in addition to prevalences, we hope that our results will be useful in settings with different rates of ectopic pregnancy. The rate of ectopic rupture in this study was quite high at 49 out of 96 (51%).…”

Reporting Clinical Prediction Rules

“…3,6,7 A preliminary report of our validation set results was presented at last October's Research Forum at the American College of Emergency Physicians' Scientific Assembly. 8 We agree that ultrasonography is critical in the evaluation of symptomatic first-trimester patients. However, should the emergency physician remove any consideration of clinical findings from the medical decision making process when ultrasonography is neither diagnostic nor readily available?…”

Kidney Rupture Following Extracorporeal Shock Wave Lithotripsy

“…Case reports describe scrotal hematoma 1 and acute renal failure from subcapsular hematoma 2 as complications of ESWL. Perirenal hematoma, 3 rupture of the kidney, 4 and kidney lacerations 5 following ESWL procedure have also been reported.…”

“…Both of these were thoroughly discussed in our paper. 1 Nonetheless, it is important that they be highlighted and emphasized again. We chose to use recursive partitioning, rather than regression, because it allows a clinically intuitive algorithm to be constructed rather than a weighted score.…”