Smith and colleagues,1 to continue to establish the legitimacy of surgeon-performed ultrasonography, have produced another excellent study. Their methods for evaluating the learning curve in senior surgical residents were very interesting, and the results continue to corroborate the use of this practice in trauma centers; however, some methodological issues should be discussed further.
The authors stated that the standard criteria for the evaluation of the sonographic examination's accuracy in their study was computed tomography, diagnostic peritoneal lavage, operative exploration (OE), or observation. During the study period, 85.8% of the patients were either observed or operatively explored. Possibly, those who underwent OE were different from those who did not. Since the accuracy of the OE in detecting free fluid is higher as compared with observation, the standard criteria could systematically differ and the measurement bias could alter the results. The more severe cases, in which was probably easier to detect free fluid during the sonographic examinations, had more often undergone OE, with higher chances of confirming a true-positive examination. The milder cases, in which it was probably more difficult to detect free fluid, underwent OE less often, with lower chances of confirming a false-negative examination. Both situations would contribute to spuriously overestimate the accuracy of the sonographic examinations, although the magnitude of such effect could not be estimated. This study offers another evidence of the benefit of surgeon-performed ultrasonograms, although some limitations should be observed when evaluating the results.