Volume 19 Supplement 1

35th International Symposium on Intensive Care and Emergency Medicine

Open Access

Variations in near-infrared spectroscopy-derived oxygen downslope during a vascular occlusion test in critically ill patients: relationship with outcome

  • A Donati1,
  • E Damiani1,
  • A Carsetti1,
  • V Monaldi1,
  • E Montesi1 and
  • P Pelaia1
Critical Care201519(Suppl 1):P141


Published: 16 March 2015


Near-infrared spectroscopy (NIRS) with a vascular occlusion test (VOT) can be used to extrapolate information regarding the tissue oxygen extraction rate. We explored the meaning of variations in tissue oxygen saturation downslope (StO2down) during a VOT in critically ill patients.


In this prospective observational study, NIRS (thenar eminence) was applied every day in 93 patients admitted to the ICU. A VOT was performed using a 40% StO2 target. The slope of the desaturation curve was assessed separately for the first part (StO2 down1) and the last part (StO2 down2) of the curve and the difference between Down2 - Down1 was calculated.


No significant differences were seen in StO2 Down1 or Down2 between ICU survivors (n = 76) and ICU nonsurvivors (n = 17) over the first 10 days in the ICU, while Down2 - Down1 was higher in ICU nonsurvivors (Figure 1). Patients in the upper quartile of mean Down2 - Down1 showed the highest 90-day mortality (P = 0.014).

Figure 1


ICU nonsurvivors tended to show a flattening in the last part of the desaturation curve during a VOT, suggesting a reduced tissue oxygen extraction. This may depend on microvascular dysfunction and/or cellular hypometabolic status.

Authors’ Affiliations

Università Politecnica delle Marche


© Donati et al.; licensee BioMed Central Ltd. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.