title: Ordering CT pulmonary angiography to exclude pulmonary embolism: defense versus evidence in the emergency room.
abstract: OBJECTIVE
  To identify reasons for ordering computed tomography pulmonary angiography (CTPA), to identify the frequency of reasons for CTPA reflecting defensive behavior and evidence-based behavior, and to identify the impact of defensive medicine and of training about diagnosing pulmonary embolism (PE) on positive results of CTPA.
  
  
  METHODS
  Physicians in the emergency department of a tertiary care hospital completed a questionnaire before CTPA after being trained about diagnosing PE and completing questionnaires.
  
  
  RESULTS
  Nine hundred patients received a CTPA during 3 years. For 328 CTPAs performed during the 1-year study period, 140 (43 %) questionnaires were completed. The most frequent reasons for ordering a CTPA were to confirm/rule out PE (93 %), elevated D-dimers (66 %), fear of missing PE (55 %), and Wells/simplified revised Geneva score (53 %). A positive answer for "fear of missing PE" was inversely associated with positive CTPA (OR 0.36, 95 % CI 0.14-0.92, p = 0.033), and "Wells/simplified revised Geneva score" was associated with positive CTPA (OR 3.28, 95 % CI 1.24-8.68, p = 0.017). The proportion of positive CTPA was higher if a questionnaire was completed, compared to the 2-year comparison period (26.4 vs. 14.5 %, OR 2.12, 95 % CI 1.36-3.29, p < 0.001). The proportion of positive CTPA was non-significantly higher during the study period than during the comparison period (19.2 vs. 14.5 %, OR 1.40, 95 % CI 0.98-2.0, p = 0.067).
  
  
  CONCLUSIONS
  Reasons for CTPA reflecting defensive behavior-such as "fear of missing PE"-were frequent, and were associated with a decreased odds of positive CTPA. Defensive behavior might be modifiable by training in using guidelines.
authors.affiliation: Department of Emergency Medicine, Inselspital, University Hospital Bern, Freiburgstrasse, 3010 Bern, Switzerland. martin.rohacek@gmail.com
authors.forename: Martin
authors.initials: M
authors.lastname: Rohacek
authors.forename: Janet
authors.initials: J
authors.lastname: Buatsi
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Szucs-Farkas
authors.forename: Birgit
authors.initials: B
authors.lastname: Kleim
authors.forename: Heinz
authors.initials: H
authors.lastname: Zimmermann
authors.forename: Aristomenis
authors.initials: A
authors.lastname: Exadaktylos
authors.forename: Christoforos
authors.initials: C
authors.lastname: Stoupis
mesh_terms: D003675:Defensive Medicine; D003951:Diagnostic Errors / Q000517:prevention & control; D004636:Emergency Service, Hospital; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000175:diagnosis*; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D