Prehospital Point of Care Testing for the Early Detection of Shock and Prediction of Lifesaving Interventions

Early diagnosis and treatment are essential for enhancing outcomes for the traumatically injured. In this prospective prehospital observational study, we hypothesized that a variety of laboratory results measured in the prehospital environment would predict both the presence of early shock and the need for lifesaving interventions (LSIs) for adult patients with traumatic injuries.

Adult trauma patients flown by a helicopter emergency medical service were prospectively enrolled. Using an i-STAT portable analyzer, data from 16 laboratory tests were collected. Vital signs data were also collected. Outcomes of interest included detection of shock, mortality, and requirement for LSIs. Logistic regression, including a Bayesian analysis, was performed.

Among 300 patients screened for enrollment, 261 had complete laboratory data for analysis. The majority of patients were male (75%) with blunt trauma (91.2%). The median injury severity score was 29 (IQR, 25-75) and overall mortality was 4.6%. A total of 170 LSIs were performed. The median lactate for patients who required an LSI was 4.1 (IQR, 3-5.4). The odds of requiring an LSI within the first hour of admission to the trauma center was highly associated with increases in lactate and glucose. A lactate level > 4 mmol/L was statistically associated with greater sensitivity and specificity for predicting the need for a LSI compared with shock index.

In this prospective observational trial, lactate outperformed static vital signs, including shock index, for detecting shock and predicting the need for LSIs. A lactate level > 4 mmol/L was found to be highly associated with the need for LSIs.