The definition of polytrauma: variable interrater versus intrarater agreement--a prospective international study among trauma surgeons.

Background: The international trauma community has recognized the lack of a validated consensus definition of "polytrauma." We hypothesized that using a subjective definition, trauma surgeons will not have substantial agreement; thus, an objective definition is needed.
Methods: A prospective observational study was conducted between December 2010 and June 2011 (John Hunter Hospital, Level I trauma center). Inclusion criteria were all trauma call patients with subsequent intensive care unit admission. The study was composed of four stages as follows: (1) four trauma surgeons assessed patients until 24 hours, then coded as either "yes" or "no" for polytrauma, and results compared for agreement; (2) eight trauma surgeons representing the United States, Germany, and the Netherlands graded the same prospectively assessed patients and coded as either "yes" or "no" for polytrauma; (3) 12 months later, the original four trauma surgeons repeated assessment via data sheets to test intrarater variability; and (4) individual subjective definitions were compared with three anatomic scores, namely, (a) Injury Severity Score (ISS) of greater than 15, (b) ISS of greater 17, and (c) Abbreviated Injury Scale (AIS) score of greater than 2 in at least two ISS body regions.
Results: A total of 52 trauma patients were included. Results for each stage were as follows: (1) κ score of 0.50, moderate agreement; (2) κ score of 0.41, moderate agreement; (3) Rater 1 had moderate intrarater agreement (κ score, 0.59), while Raters 2, 3, 4 had substantial intrarater agreement (κ scores, 0.75, 0.66, and 0.71, respectively); and (4) none had most agreement with ISS of greater than 15 (κ score, 0.16), while both definitions ISS greater than 17 and Abbreviated Injury Scale (AIS) score of greater than 2 in at least two ISS body regions had on average fair agreement (κ scores, 0.27 and 0.39, respectively).
Conclusion: Based on subjective assessments, trauma surgeons do not agree on the definition of polytrauma, with the subjective definition differing both within and across institutions.