Role of plasma ammonia level in detecting intra-abdominal hemorrhage following blunt abdominal trauma

Background: Blunt abdominal injury is a leading cause of death in trauma patients. A reliable test predicting intra-abdominal hemorrhage would be a novel method. The study objective was to assess the diagnostic accuracy of plasma ammonia in detection of intra-abdominal bleeding in patients with blunt abdominal trauma (BAT). Materials and Methods: In this observational study, all patients suffering from BAT, referred to our university teaching hospital included. The levels of ammonia were measured at the time of emergency department admission and 1 h after initial treatment. Demographic data, vital signs, and venous blood gas reports were recorded. Findings of contrast-enhanced abdominopelvic computed tomography scan and laparotomy were assumed as a gold standard for abdominal injuries. Results: A total of 104 patients was enrolled in the study. 15 patients (14.4%) had intra-abdominal hemorrhage and the mean plasma ammonia level in this group was significantly higher than the other patients on admission time (101.73 ± 5.41 μg/dL vs. 47.36 ± 26.31 μg/dL, P < 0.001). On receiver-operator characteristic curve analysis, in cutoff point of 89 μg/ dL, the sensitivity, specificity, positive and negative likelihood ratios were 100% (95% confidence interval [CI], 79.6-100), 93.26% (95% CI, 86-96.8), 14.83 (95% CI, 6.84-32.12), and 0, respectively. Conclusion: The study findings suggest the measurement of ammonia level at the time of admission in the patients with BAT would be a useful test predicting intra-abdominal hemorrhage. Furthermore, decrease in the ammonia level could be a useful marker for monitoring response to treatment in these patients.