Use of Near-InfraRed Spectroscopy (NIRS) during Vascular Occlusion Test (VOT) for predicting an increase in oxygen consumption after fluid challenge in circulatory shock patients

Background: The goal of fluid challenge (FC) is to increase cardiac output (CO) and oxygen delivery (DO2) (known as responders) correct tissue hypoxia. To optimize administration, during dependence consumption on (VO2/DO2 dependency) would hypoxia confirmed by an (VO2) after FC VO2 get more benefit from a reduction in Markers anaerobic metabolisms, such blood lactate concentration or the ratio venous-arterial CO2 tension difference (P(cv-a)CO2) over arterial-to-venous content (C(a-cv)O2), can predict responders but still have several limitations. Therefore, near-infrared spectroscopy (NIRS) has been developed evaluate perfusion, presented saturation (StO2), at bedside. Combining StO2 with vascular occlusive test (VOT) introducing short period forearm ischemia non-invasive technique examine microvascular alterations However, study validating ability these variables response not conducted. Methods: We plan conduct single-center prospective circulatory failure patients. index (CI), (DO2), (VO2), arterial lactate, central venous (ScvO2), carbon dioxide arterial-to-central (P(cv-a)CO2/ C(a-cv)O2), measured probe occlusion (NIRS-VOT variables) will be collected before challenge. Hypothesis: hypothesize that markers reactive hyperemia NIRs patients shock. Ethics: protocol approved ethics committee faculty medicine, Ramathibodi Hospital, Mahidol University (COA. MURA2022/80).