Shock index is associated with mortality in canine vehicular trauma patients.

Objective: To calculate and compare shock index (SI) in healthy dogs and vehicular trauma dogs (VT), determine the prognostic value of SI in VT dogs, and to assess the correlation between SI and the animal trauma triage score, modified Glasgow Coma Scale score, and lactate in VT dogs.

Design: Retrospective study from April 2016 to February 2018.

Setting: Twenty-four-hour tertiary referral level II trauma center.

Animals: One hundred twenty-one dogs presented to the emergency service for VT and 60 healthy control dogs.

Interventions: None.

Measurements And Main Results: Heart rate and systolic blood pressure were measured on each patient and used to calculate SI. SI was significantly higher in VT dogs compared to healthy control dogs (median SI, 1.0 vs 0.75; P < 0.0001). SI was significantly higher in those that died versus those that survived to discharge (median, 1.27 vs 0.96; P = 0.017). SI positively correlated with animal trauma triage score (95% confidence interval, 0.039-0.49; P = 0.019; r = 0.26) but did not with plasma lactate level at presentation (P = 0.068; r = 0.22) or modified Glasgow Coma Scale (P = 0.85; r = -0.021, 95% confidence interval, -0.24 to 0.20).

Conclusions: SI is easy to calculate during triage of a trauma patient. Given its significant relationship with mortality, higher SIs should prompt the clinician to pursue additional monitoring, diagnostics, and intervention.