Bedside visual colorimetry of peritoneal lavage fluid in abdominal trauma patients

Abstract

Abdominal injuries account for an important fraction of deaths from trauma. Some patients with abdominal trauma who need emergency surgery are difficult to identify because bedside diagnosis based on physical findings alone is often misleading. ‘+2 When the need for laparotomy is initially unclear physicians currently rely on clinical laboratory determinations, particularly the automated red blood cell count (RBC) count of fluid obtained by peritoneal lavage.3 Unfortunately, the time required by the clinical laboratory to process and assay these specimens may sometimes delay essential surgical intervention. In a prior in vitro study we investigated the feasibility of using visual calorimetry as a rapid method for estimating the RBC count in simulated peritoneal lavage fluid.4 Here, we report the successful application of this method to the bedside evaluation of trauma patients at a level I trauma center. METHODS A simple visual colorimete?-8 was built in a home woodworking shop (Figures 1 through 4). This device permits direct comparison of light transmitted through pairs of glass test tubes containing colored fluids, while reducing ambient room light and reflections. To prepare stable color comparison standards, a stock solution of simulated peritoneal lavage fluid was made as follows: whole blood was obtained in 7-mL Vacutainer (Becton Dickinson, Rutherford, NJ) tubes containing ethylenediamine tetraacetic acid from a single healthy volunteer donor known to be human immunodeficiency virus-negative, at low risk for acquired immunodeticiency syndrome, and willing to donate blood periodically. The complete blood count was determined in triplicate using a Sysmex NE-8000 automated cell counter (TOA Medical Electronics Co, Ltd, Kobe, Japan). The mean RBC count for this donor was 5.71