Clinical significance of plasma ammonia in patients with traumatic hemorrhage.
BACKGROUND
Hemorrhagic shock has been reported to elevate the concentration of ammonia in the blood of animals. However, only one clinical study, of a few surgical patients, found a similar effect. This investigation sought to determine whether ammonia is elevated in the plasma of trauma patients with hemorrhage and whether it could be used to predict serious hemorrhage.


METHODS
Subjects were consecutive trauma patients admitted to our Level I trauma center between November 2006 and April 2008 who met the inclusion criteria to determine plasma ammonia. Their blood was sampled at admission. Patients who required blood transfusion > or = 2 U or intervention for bleeding within 24 hours were classified into a bleeding group. Patients who did not require a transfusion or interventions were classified as controls. In addition to routine hemodynamic measurements, we recorded the hourly infused volume of Ringer's lactate solution (infusion volume) during emergency room treatment and total transfused blood volume within the first 24 hours.


RESULTS
The subjects were 282 trauma patients. Their mean age was 44.0 +/- 20.4 years old, and their mean injury severity score was 15.8 +/- 13.1. Ammonia was significantly correlated with systolic blood pressure, shock index at admission, infusion volume, base deficit, and injury severity score. Forty-one patients required blood transfusion and 31 needed intervention for arterial bleeding. Because some patients required both therapies, the bleeding group consisted of 46 patients. The control group consisted of 236 patients who needed neither blood transfusion nor intervention. The plasma ammonia concentration in the bleeding group (113 +/- 52.2 microg/dL) was significantly higher than in the control group (55.4 +/- 20.8 microg/dL). In the bleeding group, the ammonia concentration of patients who died from bleeding (170 +/- 68.7 microg/dL) was significantly higher than in survivors (102 +/- 40.7 microg/dL). The best ammonia concentration cutoff value that maximized sensitivity and specificity to select for the bleeding group was > or = 77 microg/dL (sensitivity, 82%; specificity, 89%).


CONCLUSIONS
Elevated plasma ammonia concentration at admission can be a clinically significant indicator for traumatic hemorrhage that requires treatment.
Hagiwara
Akiyoshi
A
Department of Traumatology and Critical Care Medicine, National Defense Medical College, Tokorozawa, Saitama, Japan. boeihagi@ndmc.ac.jp
Sakamoto
Toshihisa
T
D000328:Adult; D000641:Ammonia / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001803:Blood Transfusion; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D012771:Shock, Hemorrhagic / Q000097:blood* / Q000209:etiology / Q000628:therapy; D015599:Trauma Severity Indices; D014947:Wounds and Injuries / Q000097:blood / Q000150:complications*
D015415:Biomarkers; D000641:Ammonia