Ordering CT pulmonary angiography to exclude pulmonary embolism: defense versus evidence in the emergency room

Intensive Care Med. 2012 Aug;38(8):1345-51. doi: 10.1007/s00134-012-2595-z. Epub 2012 May 15.


Purpose: 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).

Conclusion: 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.

MeSH terms

  • Defensive Medicine*
  • Diagnostic Errors / prevention & control
  • Emergency Service, Hospital
  • Female
  • Fibrin Fibrinogen Degradation Products / analysis
  • Humans
  • Male
  • Middle Aged
  • Practice Patterns, Physicians' / statistics & numerical data*
  • Pulmonary Artery / diagnostic imaging*
  • Pulmonary Embolism / diagnosis*
  • Surveys and Questionnaires
  • Tomography, X-Ray Computed


  • Fibrin Fibrinogen Degradation Products
  • fibrin fragment D