The ATLS(®) classification of hypovolaemic shock: a well established teaching tool on the edge?

Uncontrolled bleeding is the leading cause of shock in trauma patients and delays in recognition and treatment have been linked to adverse outcomes. For prompt detection and management of hypovolaemic shock, ATLS(®) suggests four shock classes based upon vital signs and an estimated blood loss in percent. Although this classification has been widely implemented over the past decades, there is still no clear prospective evidence to fully support this classification. In contrast, it has recently been shown that this classification may be associated with substantial deficits. A retrospective analysis of data derived from the TraumaRegister DGU(®) indicated that only 9.3% of all trauma patients could be allocated into one of the ATLS(®) shock classes when a combination of the three vital signs heart rate, systolic blood pressure and Glasgow Coma Scale was assessed. Consequently, more than 90% of all trauma patients could not be classified according to the ATLS(®) classification of hypovolaemic shock. Further analyses including also data from the UK-based TARN registry suggested that ATLS(®) may overestimate the degree of tachycardia associated with hypotension and underestimate mental disability in the presence of hypovolaemic shock. This finding was independent from pre-hospital treatment as well as from the presence or absence of a severe traumatic brain injury. Interestingly, even the underlying trauma mechanism (blunt or penetrating) had no influence on the number of patients who could be allocated adequately. Considering these potential deficits associated with the ATLS(®) classification of hypovolaemic shock, an online survey among 383 European ATLS(®) course instructors and directors was performed to assess the actual appreciation and confidence in this tool during daily clinical trauma care. Interestingly, less than half (48%) of all respondents declared that they would assess a potential circulatory depletion within the primary survey according to the ATLS(®) classification of hypovolaemic shock. Based on these observations, a critical reappraisal of the current ATLS(®) classification of hypovolaemic seems warranted.