Regional Tissue Oxygenation During Hemorrhage: Can Near Infrared Spectroscopy Be Used to Monitor Blood Loss?

Abstract

We investigated whether near infrared spectroscopy could be used to monitor regional tissue oxygenation during uncompensated hemorrhage in man. A Somanetics INVOS 4100 oximeter was used to measure regional hemoglobin oxygen saturation in the cerebral cortex (CsO2, left frontal area) and from the left calf muscle (PsO2) in 40 volunteers donating 470 mL of the whole blood. A Critikon 2001 Cerebral Redox Instrument was used to monitor total (tHb), oxygenated (O2Hb), and deoxygenated (HHb) hemoglobin in the right calf muscle. The oxygenation index, [HbD] = [O2Hb] - [HHb] was derived. CsO2 decreased by a mean (95% CI) of 2 (1-3.3%) (P < 0.001), PsO2 decreased by a mean (95% CI) of 3.2 (1.7-4.6%) (P < 0.001), and HbD decreased by a median (95% CI) of 6.4 (2.65-10.16) delta microM/cm (P < 0.001) during blood collection. There was an inverse correlation between blood loss and CsO2 (R = -0.59, P < 0.001), PsO2 (R = -0.61, P < 0.001), and HbD (R = -0.5, P < 0.001). Regional tissue oxygenation decreases in proportion to uncompensated blood loss. Near infrared spectroscopy may potentially be developed into a transfusion trigger.

Tissue Energetics as Measured by Nuclear Magnetic Resonance Spectroscopy During Hemorrhagic Shock

“…[3][4][5][6]. Changes in the absorptive properties of the near infra-red spectrum in tissue reflect changes in the oxidation state of carriers such as tissue-saturated hemoglobin (StO 2 ) and the copper ions of cytochrome aa3.…”

The role of cerebral oxygenation and regional cerebral blood flow on tolerance to central hypovolemia

“…As such, following oxygen exchange within the capillaries, we and others (43) interpret a decrease in the HbO 2 concentration and increase in the dHb concentration as an increase in cerebral oxygen extraction from the arterial blood supplying the tissue. Torella et al (47) reported that HbO 2 decreased, while dHb increased in proportion to mild blood loss in humans (ϳ9 -12% total blood volume). Although the magnitude of blood loss in this study was not sufficient to delineate the role of cerebral oxygen extraction on tolerance, Lewis et al (25) recently suggested that decreases in CBF would have minimal impact on tolerance to central hypovolemia due to compensatory increases in cerebral oxygen extraction; quantification of oxygen extraction dur-ing LBNP, however, was not reported.…”

Bedside monitoring of patients with shock using a portable spatially-resolved near-infrared spectroscopy

“…The NIRS devices are usually portable, permitting bedside monitoring. There have been recently exploratory studies using NIRS for shock monitor [4,[9][10][11][12][13][14][15]. Some of them were carried out on animal models [12,13] or healthy human subjects [14].…”

“…Some of them were carried out on animal models [12,13] or healthy human subjects [14]. A few were performed in patients either invasively with optical sensors inserted into subcutaneous and intramuscular sites [4,15] or noninvasively with optical probes placed on the peripheral muscles [9][10][11]. However, shock usually results in a poor peripheral blood circulation [5], leading to an insensitive measurement.…”

“…Tissue blood oxygen saturation (StO 2 ) measured at an appropriate region may be a good indicator of shock state [9][10][11]. In this study, we investigated the correlations between StO 2 and ScvO 2 , SaO 2 , and PO 2 , and explored the use of StO 2 as an indicator for shock.…”