Authors: Drake FT et al. Ann Surg 2014 Aug.
In an observational study, oral contrast did not improve accuracy in patients who received intravenous contrast.
In three single-center, randomized trials, oral contrast — given in addition to intravenous (IV) contrast — did not improve the diagnostic accuracy of computed tomographic (CT) scanning for suspected appendicitis. To determine whether this conclusion is generally valid, researchers analyzed a surgical database that represents 56 hospitals in Washington State. During a 2-year period, 8089 adults underwent nonelective appendectomy preceded by CT scanning; 54% received IV contrast only, 29% received both IV and enteral contrast, 13% received no contrast, and 4% received only enteral contrast.
Concordance between CT scan interpretations and pathology reports was 90% in both the IV-only and IV-plus-enteral contrast groups; concordance was slightly lower (86%) among patients who received no IV or enteral contrast. Accuracy of the two CT protocols remained similar after adjustment for potentially confounding variables and in a propensity-matched analysis. Accuracy was similar in all types of hospitals (urban or rural; teaching or nonteaching).
In this observational study that included a wide spectrum of hospitals, enteral contrast did not improve diagnostic accuracy of CT scanning in patients with suspected appendicitis who received IV contrast. The advantage of not giving enteral contrast is quicker disposition in the emergency department and avoidance of oral intake prior to general anesthesia. However, this study did not address whether enteral contrast adds useful information in patients who have abdominal pain and several plausible diagnostic alternatives to appendicitis.