Diagnostic peritoneal lavage: is 100,000 RBCs a valid figure for penetrating abdominal trauma?

BACKGROUND: Controversy exists regarding the interpretation of diagnostic peritoneal lavage results. This is especially true in the evaluation of patients sustaining penetrating trauma, specifically stab wounds to the lower chest and abdomen. Ideally one wants to avoid missed injuries and minimize unnecessary operations. METHODS: This is a retrospective review of 195 patients sustaining stab wounds to the anterior lower chest and abdomen at Parkland Memorial Hospital between 1993 and 2005, looking at missed injuries and false positive rates using red cell counts of 100,000, 10,000, and the standard criteria for blunt trauma including >500 white blood cells (WBCs), amylase, and/or bile. RESULTS: The first analysis used >100,000 red blood cells (RBCs)/mm3 as a positive value. The false positive rate was 12.2%. The second analysis used >10,000 RBCs/mm3 as a positive value with a false positive rate of 44%. When considering the entire study population (195 patients), the false positive rate increased when using the lower number (>10,000) from 2.5% to 15.8% (p < 0.001). There were no missed injuries when using >100,000 red cells and/or >500 white cells, the presence of bile or amylase. CONCLUSION: Decreasing the red blood cell count from >100,000 to >10,000 as the criteria for operating on patients with stab wounds to the anterior lower chest and/or abdomen will significantly increase the number of nontherapeutic procedures. Based on this study, >100,000 RBCs/mm3 appears to be a valid and safe number to use when evaluating these patients, particularly when used with other positive criteria such as increased white cells, bile, and amylase.

Effect of sleep deprivation on the performance of simulated laparoscopic surgical skill.

BACKGROUND: Resident work hours may impact patient care. We hypothesized that "call-associated" acute sleep deprivation has no effect on technical dexterity as measured on a minimally invasive surgery trainer, virtual reality (MIST VR) surgical simulator. METHODS: Thirty-five surgical residents were prospectively evaluated pre-call (rested), on-call (rested), and post-call (acutely sleep deprived). Participants completed questionnaires regarding sleep hours and level of fatigue. Technical skill was assessed using the MIST VR. Speed, errors, and economy of motion were automatically recorded by the MIST VR computer simulator. Data were analyzed by paired Student t test and analysis of variance. RESULTS: Estimated hours of sleep and subjective indicators of fatigue were different between rested and sleep-deprived residents. The number of errors and time to complete all tasks increased at the post-call assessment. CONCLUSIONS: Resident work schedules lead to sleep deprivation and fatigue. Call-associated sleep deprivation and fatigue are associated with increased technical errors in the performance of simulated laparoscopic surgical skills.