Related Experiment Video
Updated: Jun 13, 2025

Integration of Brain Tissue Saturation Monitoring in Cardiopulmonary Exercise Testing in Patients with Heart Failure
Published on: October 1, 2019
Hemodynamics and vascular oxygenation measured at the forehead during changes in respiration: A SPA-fNIRS study
Sabino Guglielmini1, Elena Wiggli2, Felix Scholkmann3
1Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland; Biomedical Family Larsson-Rosenquist Foundation Center for Neurodevelopment, Growth and Nutrition of the Newborn, Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Significance:
Cerebral blood flow is influenced by respiration, primarily through changes in the CO2 concentration of arterial blood.
Aim:
The objective of this study was to investigate the effect of changes in arterial CO2 concentration induced by respiratory changes on oxygenation and hemodynamics in the cerebral and extracerebral tissue layers of the forehead.
Approach:
We used systemic physiology augmented functional near-infrared spectroscopy (SPA-fNIRS) to assess changes in forehead hemodynamics and oxygenation as well as systemic physiology in 20 healthy subjects. All participants performed two respiratory tasks (breath-holding and hyperventilation).
Results:
In our SPA-fNIRS study we found that changes in breathing affected hemodynamics and oxygenation in both the extracerebral and cerebral tissue layers of the forehead in characteristic ways, depending on the two respiratory tasks.
Conclusion:
The results show that extracerebrovascular reactivity (ECVR) exists in parallel with the well-known cerebrovascular reactivity (CVR). CVR and ECVR must be considered when performing fNIRS neuroimaging studies involving changes in respiration.
More Related Videos
14:28Non-Invasive Monitoring of Microvascular Oxygenation and Reactive Hyperemia using Hybrid, Near-Infrared Diffuse Optical Spectroscopy for Critical Care
Published on: May 10, 2024
07:51Standardized Hemorrhagic Shock Induction Guided by Cerebral Oximetry and Extended Hemodynamic Monitoring in Pigs
Published on: May 21, 2019
Related Concept Videos
Assessment of Diffusion and Perfusion
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this...
Pulse Oximetry
Purpose
Average SpO2 values are greater than 95%. If the readings fall below 90%, it indicates that...
Special considerations while measuring oxygen saturation
Ensuring accuracy in vital sign recordings while prioritizing patient comfort and minimizing anxiety is...
Guidelines For Measuring Vital Signs
Before taking a patient's vital signs, a nurse would consider and assess the patient's comfort level and ensure appropriate equipment is available.