Aims & Objectives:
Accurate technique to detect changes in global and regional tissue perfusion is the cornerstone of hemorrhagic shock management. Measurement of mixed venous oxygen saturation (SvO2) is an indicator of balance between oxygen delivery and oxygen consumption, hence does not provide continuous monitoring with significant disadvantages. Near infrared spectroscopy (NIRS) is a noninvasive optical technology that relies on the relative transparency of biological tissues to near infrared light (700–900 nm) to determine regional tissue oxygenation.
The aim of this study was to find out the use of cerebral NIRS in estimating invasively measured SvO2 during hemorrhagic shock and volume loading.
We studied eleven Sus scrofa under various hemodynamic conditions. Blood removal was performed to induce hemorrhagic shock, and then animal models were given volume loading. Macrohemodynamic parameters were monitored using the transpulmonary thermodilution technique with central venous injection of ice-cold saline. Serial blood sampling were taken to invasively measured SvO2, while continuous monitoring of cerebral tissue oxygenation using NIRS were performed throughout the experiment.
There were linear trends between changes of cerebral NIRS and SvO2 during all phases. The correlation coefficient between changes in cerebral NIRS and SvO2 during hemorrhagic shock was 0.52 (p>0.05). The correlation coefficient between changes in cerebral NIRS and SvO2 during volume loading was statistically not significant (p>0.05).
The cerebral NIRS monitoring is not a reliable method of estimating SvO2 of Sus Scrofa model of hemorrhagic shock.