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Effective Health Care Program

Physiologic Predictors of Severe Injury: Systematic Review

Systematic Review

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Key Messages

Purpose of Review

To summarize evaluations of physiologic measures that can be used by emergency medical services personnel to identify patients at high risk of serious injury and inform decisions about the level of trauma care needed.

Key Messages

  • Studies examined individual measures and combinations for trauma triage, including systolic blood pressure, heart rate, shock index, lactate, base deficit, respiratory rate, oxygen saturation, and need for airway support.
  •  Included measures have:
    • Low sensitivities, so normal values on the physiologic measure (a negative test) cannot be used with confidence to determine that patients are not seriously injured.
    • High specificities, meaning abnormal values on the physiologic measure (positive test) are unlikely in patients not seriously injured.
  • Combinations of physiologic measures with measures of consciousness may perform better than physiologic measures alone, but feasibility and reliability of performance in the field are significant challenges.
  • Measures perform less well in children and older people. Changes in cut-points for these age groups may improve performance but have not yet been rigorously evaluated.
  • Research is needed on the feasibility of combination measures and how precisely physiologic parameters are measured, including use of technology.
  • Researchers should use standard definitions of serious injury to permit comparisons across studies and measures.

Structured Abstract

Objectives. To systematically identify and summarize evaluations of measures of circulatory and respiratory compromise, focusing on measures that can be used in field assessment by emergency medical services to inform decisions about the level of trauma care needed. We identified research on the ability of different measures to predict whether a patient was seriously injured and thus required transport to the highest level of trauma care available.

Data sources. We searched Ovid MEDLINE®, CINAHL®, and the Cochrane databases from 1996 through August 2017. Reference lists of included articles were reviewed for additional relevant citations.

Review methods. We included studies of individual measures and measures that combined circulatory, respiratory, and level of consciousness assessment. Evaluations included diagnostic accuracy (sensitivity and specificity) and area under the receiver operating characteristic curve (AUROC). We used data provided to calculate values that were not reported and pooled estimates across studies when feasible.

Results. We identified and included 138 articles reporting results of 134 studies. Circulatory compromise measures evaluated in these studies included systolic blood pressure, heart rate, shock index, lactate, base deficit, and heart rate variability or complexity. The respiratory measures evaluated included respiration rate, oxygen saturation, partial pressure of carbon dioxide, and need for airway support. Many different combination measures were identified, but most were evaluated in only one or two studies. Pooled AUROCs from out-of-hospital data were 0.67 for systolic blood pressure (moderate strength of evidence); 0.67 for heart rate, 0.72 for shock index, 0.77 for lactate, 0.70 for respiratory rate, and 0.89 for Revised Trauma Score combination measure (all low strength of evidence); and were considered poor to fair. The only AUROC that reached a level considered excellent was for the Glasgow Coma Scale, age, and arterial pressure (GAP) combination measure (AUROC, 0.96; estimate based on emergency department data). All of the measures had low sensitivities and comparatively high specificities (e.g., sensitivities ranging from 13% to 74% and specificities ranging from 62% to 96% for out-of-hospital pooled estimates).

Conclusions. Physiologic measures usable in triaging trauma patients have been evaluated in multiple studies; however, their predictive utilities are moderate and far from ideal. Overall, the measures have low sensitivities, high specificities, and AUROCs in the poor-to-fair range. Combination measures that include assessments of consciousness seem to perform better, but whether they are feasible and valuable for out-of-hospital use needs to be determined. Modification of triage measures for children or older adults is needed, given that the measures perform worse in these age groups; however, research has not yet conclusively identified modifications that result in better performance.

Citation

Suggested citation: Totten AM, Cheney TP, O'Neil ME, Newgard CD, Daya M, Fu R, Wasson N, Hart EL, Chou R. Physiologic Predictors of Severe Injury: Systematic Review. Comparative Effectiveness Review No. 205. (Prepared by the Pacific Northwest Evidence-based Practice Center under Contract No. 290-2015-00009-I.) AHRQ Publication No. 18-EHC008-EF. Rockville, MD: Agency for Healthcare Research and Quality; April 2018. Posted final reports are located on the Effective Health Care Program search page. DOI: https://doi.org/10.23970/AHRQEPCCER205