Accuracy of trans-abdominal ultrasound in a simulated massive acute overdose.

Introduction: Toxic ingestions are a common cause of morbidity and mortality in the United States. In 2013, there were nearly 2 million reported ingestions and nearly 1000 deaths from poisonings. There is no well-validated imaging study for confirming the presence of pills in the stomach of an overdose patient. There are case reports of ultrasound used for confirmation of pills in the stomach, and we are aware of one prospective trial to evaluate sonography for this application.

Objective: To determine the sensitivity and specificity of transabdominal ultrasound for visualization of ingested pills.

Methods: Randomized, blinded, placebo-controlled study. Twenty Subjects were randomized to one of two groups. The experimental group ingested 50 enteric-coated placebo capsules with 1 liter of fluid. The control group ingested only 1 liter of fluid. At time 0, 60, and 90 minutes after ingestion, expert sonographers performed transabdominal ultrasound in an attempt to visualize pills in the stomach.

Results: At time 0, 60, and 90 minutes post-ingestion, ultrasound had a sensitivity of 62.5% (41.1%, 81.9%), 20.8% (4.6%, 37.1%), and 25% (7.7%, 42.3%) respectively. The specificity at time 0, 60, and 90 minutes post-ingestion were 58.3% (21.9%, 61.4%), 79.1% (62.9%, 95.5%), and 70.8% (52.6%, 89.0%) respectively.

Conclusion: There is poor sensitivity and specificity for ultrasound detection of pills in the stomach at time 0; these values fell substantially at 60 and 90 minutes post-ingestion. In this pilot study, we did not find ultrasound to be a useful screening tool for detecting pills in the stomach.