Near-Infrared Spectroscopy Usefulness in Validation of Hyperventilation Test.

Background: The hyperventilation test is used in clinical practice for diagnosis and therapeutic purposes; however, in the absence of a standardized protocol, the procedure varies significantly, predisposing tested subjects to risks such as cerebral hypoxia and ischemia. Near-infrared spectroscopy (NIRS), a noninvasive technique performed for cerebral oximetry monitoring, was used in the present study to identify the minimum decrease in the end-tidal CO2 (ETCO2) during hyperventilation necessary to induce changes on NIRS. Materials and Methods: We recruited 46 volunteers with no preexisting medical conditions.

Model-driven gas exchange monitoring in the critically ill.

Understanding pulmonary gas exchange performance is a dynamic process which, depending on clinical context, exhibits different levels of complexity. Global tools such as tension-based indexes yield clinically crucial information under very specific conditions. Yet, accurate mechanistic insight can only originate in model-based tools.