title: Evaluating for acute mesenteric ischemia in critically ill patients: diagnostic peritoneal lavage is associated with reduced operative intervention and mortality.
abstract: BACKGROUND
  The diagnosis of acute mesenteric ischemia among intensive care unit (ICU) patients continues to be difficult and carries high mortality, and yet, it is essential that it be made expeditiously such that lifesaving operative intervention can be offered. A recent study suggested that computed tomography (CT) scan delays operative intervention. Thus, we hypothesized that diagnostic peritoneal lavage (DPL), a rapidly performed bedside procedure of established high sensitivity, is associated with reduced operative intervention, time to operative intervention, and mortality.
  
  
  METHODS
  We performed a single-institution, retrospective study of 120 patients admitted to an ICU at the University of Pittsburgh Medical Center's Presbyterian Hospital between January 1, 2002, and December 31, 2010, who were diagnosed with acute mesenteric ischemia. We defined a DPL of greater than 500 cells per cubic millimeter as diagnostic of intra-abdominal pathology. CT scan results were categorized as (1) diagnostic of mesenteric ischemia, (2) abnormal, or (3) normal. We performed multivariate logistic regression, adjusting for difference in case mix, to determine whether DPL is associated with the outcomes of mortality and operative intervention.
  
  
  RESULTS
  The cohort was severely ill, with a mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score of 21.7 (range, 0-48), and 51 patients (42.5%) died. The distribution of preoperative evaluation is as follows: CT, 67; DPL, 11; both modalities, 18; and no preoperative evaluation, 24. Those undergoing DPL were more severely ill, as evidenced by significantly higher APACHE II scores. By comparison with CT, DPL was associated with a reduced risk for operation intervention (adjusted odds ratio, 0.04; 95% confidence interval, 0.01-0.32; p = 0.002) and mortality (adjusted odds ratio, 0.09; 95% confidence interval, 0.01-0.62; p = 0.02).
  
  
  CONCLUSIONS
  DPL is associated with reduced operative intervention yet improved survival, when compared with patients evaluated with either CT or no diagnostic modality. These data support that, for critically ill ICU patients suspected of harboring intra-abdominal pathology such as acute mesenteric ischemia, DPL should be a mainstay in the preoperative diagnostic evaluation. Further investigation is needed, however, to better define the proper place and timing of DPL in evaluating the acute abdomen.
  
  
  METHODS
  Diagnostic study, level III; therapeutic/care management study, level IV.
authors.affiliation: From the Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lee
authors.forename: Jason L
authors.initials: JL
authors.lastname: Sperry
authors.forename: Matthew Randall
authors.initials: MR
authors.lastname: Rosengart
mesh_terms: D018806:APACHE; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016638:Critical Illness / Q000401:mortality* / Q000628:therapy; D005260:Female; D006801:Humans; D007422:Intestines / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000601:surgery; D007511:Ischemia / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010533:Peritoneal Lavage / Q000401:mortality / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed