Polytrauma at the Emergency Department; can we relate arterial blood gas analysis to a shock classification?

Shock is defined as a change of circulation which results in hypoxia at the tissue level. Lactate and base deficit (BD) are associated with a high risk of multiple organ dysfunction in trauma patients. In this study we evaluated the influence of early recognition of shock in trauma patients.

In a retrospective study, relevant data were collected from the Radboud University Nijmegen Medical Centre (RUNMC) database between January 2009 and December 2010. Vital parameters were taken at the accident scene, and patients were divided into four shock classes. Arterial blood gas analysis was performed on arrival in the emergency department. Statistical analysis was performed with SPSS version 17.0. Statistical significance was assumed at p ≤ 0.05.

A total of 255 patients were included. Patients who suffered from prehospital shock, and those who were intubated prior to hospital admittance showed a bad outcome, presenting with a more severe metabolic acidosis, higher ISS and higher mortality. There was a significant difference for bicarbonate and BD between shockclass I + II and shockclass III + IV, respectively 22.7 vs. 19.7 and -3.4 vs. -6.9. Intubated patients had a decreased bicarbonate and BD compared to not intubated patients, respectively 21.81 vs. 23.24 and -5.08 vs. -2.38. Mortality and ISS were higher in patients in shock class III and IV. Significant differences in serum lactate levels were not found.

Prehospital shock influences patient outcome; outcome of patients is related to initial shock classification. Further validation of our shock classification, however, is necessary.