Introduction: The recognition and management of hypovolemic shock still remain an important task during initial trauma assessment. Recently, we have questioned the validity of the Advanced Trauma Life Support (ATLS) classification of hypovolemic shock by demonstrating that the suggested combination of heart rate, systolic blood pressure and Glasgow Coma Scale displays substantial deficits in reflecting clinical reality. The aim of this study was to introduce and validate a new classification of hypovolemic shock based upon base deficit (BD) at emergency department (ED) arrival.
Methods: Between 2002 and 2010, 16,305 patients were retrieved from the TraumaRegister DGU® database, classified into four strata of worsening BD [class I (BD≤2 mmol/l), class II (BD>2.0 to 6.0 mmol/l), class III (BD>6.0 to 10 mmol/l) and class IV (BD>10 mmol/l)] and assessed for demographics, injury characteristics, transfusion requirements and fluid resuscitation. This new BD-based classification was validated to the current ATLS classification of hypovolemic shock.
Results: With worsening of BD, injury severity score (ISS) increased in a step-wise pattern from 19.1 (±11.9) in class I to 36.7 (±17.6) in class IV, while mortality increased in parallel from 7.4% to 51.5%. Decreasing hemoglobin and prothrombin ratios as well as the amount of transfusions and fluid resuscitation paralleled the increasing frequency of hypovolemic shock within the four classes. The number of blood units transfused increased from 1.5 (±5.9) in class I patients to 20.3 (±27.3) in class IV patients. Massive transfusion rates increased from 5% in class I to 52% in class IV. The new introduced BD-based classification of hypovolemic shock discriminated transfusion requirements, massive transfusion and mortality rates significantly better compared to the conventional ATLS classification of hypovolemic shock (p<0.001).
Conclusions: BD may be superior to the current ATLS classification of hypovolemic shock in identifying the presence of hypovolemic shock and in risk stratifying patients in need of early blood product transfusion.