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Evidence for misleading decision support in characterizing differences in tolerance to reduced central blood volume using measurements of tissue oxygenation.

  • Schlotman, Taylor E1
  • Akers, Kevin S1
  • Cardin, Sylvain2
  • Morris, Michael J3
  • Le, Tuan1
  • Convertino, Victor A1
  • 1 Battlefield Health & Trauma Center for Human Integrative Physiology, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas.
  • 2 Naval Medical Research Unit, JBSA Fort Sam Houston, Texas.
  • 3 Brooke Army Medical Center, JBSA Fort Sam Houston, Texas.
Published Article
Wiley (Blackwell Publishing)
Publication Date
Jun 01, 2020
60 Suppl 3
DOI: 10.1111/trf.15648
PMID: 32478865


The physiological response to hemorrhage includes vasoconstriction in an effort to shunt blood to the heart and brain. Hemorrhaging patients can be classified as "good" compensators who demonstrate high tolerance (HT) or "poor" compensators who manifest low tolerance (LT) to central hypovolemia. Compensatory vasoconstriction is manifested by lower tissue oxygen saturation (StO2 ), which has propelled this measure as a possible early marker of shock. The compensatory reserve measurement (CRM) has also shown promise as an early indicator of decompensation. Fifty-one healthy volunteers (37% LT) were subjected to progressive lower body negative pressure (LBNP) as a model of controlled hemorrhage designed to induce an onset of decompensation. During LBNP, CRM was determined by arterial waveform feature analysis. StO2 , muscle pH, and muscle H+ concentration were calculated from spectrum using near-infrared spectroscopy (NIRS) on the forearm. These values were statistically indistinguishable between HT and LT participants at baseline (p ≥ 0.25). HT participants exhibited lower (p = 0.01) StO2 at decompensation compared to LT participants. Lower StO2 measured in patients during low flow states associated with significant hemorrhage does not necessarily translate to a more compromised physiological state, but may reflect a greater resistance to the onset of shock. Only the CRM was able to distinguish between HT and LT participants early in the course of hemorrhage, supported by a significantly greater ROC AUC (0.90) compared with STO2 (0.68). These results support the notion that measures of StO2 could be misleading for triage and resuscitation decision support. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

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