American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference definitions of the systemic inflammatory response syndrome and allied disorders in relation to critically injured patients

Abstract

Objectives: To determine the frequency of the proposed definitions for the systemic inflammatory response syndrome (SIRS), sepsis and septic shock, and to further define severe SIRS and sterile shock as determined at 24 hrs of admission to an intensive care unit (ICU) in critically ill trauma patients without head injury, and their relationships to mechanism of injury, Acute Physiology and Chronic Health Evaluation (APACHE) II score, risk of death, Injury Severity Score (ISS), number of organ failures, and mortality rate.

Design: Prospective, inception cohort analysis.

Setting: Sixteen-bed surgical ICU in a teaching hospital.

Patients: Four hundred fifty critically injured patients without associated head trauma. Penetrating trauma accounted for 70% (gunshot 202; stab 113) and nonpenetrating trauma for 30% (motor vehicle collision 103; blunt 32) of admissions. Three hundred ninety-four (88%) patients underwent surgical procedures.

Interventions: None.

Measurements and main results: Infective and noninfective insults were distinguished by the need for therapeutic or prophylactic antibiotics, respectively, based on an established antibiotic policy. Three hundred ninety-five (87.8%) patients fulfilled a definition of the SIRS criteria. The frequency of the definitive categories was SIRS 21.8%, sepsis 14.4%, severe SIRS 8.4%, severe sepsis 13.6%, sterile shock 9.3%, and septic shock 20.2%. Patients with penetrating trauma had a significantly higher frequency of sepsis, severe sepsis, and septic shock (p < .01). The APACHE II score, risk of death, and number of organ failures increased significantly in both infective and noninfective groups with increasing severity of the inflammatory response. Sterile shock was associated with a significantly higher APACHE II score (p < .02), risk of death (p < .01), and number of organ failures (p = .03) compared with septic shock. Only sterile shock was associated with a significantly higher ISS (p < .01). Organ system failure was significantly (p < .001) higher in nonsurvivors compared with survivors in all categories. The only significant (p < .001) difference in mortality rate was found between patients in shock and all other categories.

Conclusions: The current definitions of SIRS, sepsis, and related disorders in critically injured patients without head trauma show a significant association with physiologic deterioration and increasing organ dysfunction. The only significant association with mortality, however, is the presence of shock. The definitions require refinement, with the possible inclusion of more objective gradations of organ system failure, if they are to be used for stratifying severity of illness in seriously injured patients.