Muscle blood flow and oxygen utilization measured by near-infrared spectroscopy during handgrip exercise in chronic respiratory patients

Abstract

The purpose of this study was to evaluate tissue oxygen utilization and blood flow in patients with chronic respiratory failure (CRF). [Subjects] The subjects were divided into three groups: twelve subjects with chronic respiratory failure, twelve healthy older subjects, and thirteen healthy young subjects. [Method] A near infrared spectrometer was used to monitor tissue oxygenation, and the probe was placed over the flexor muscle. The subjects performed 3min rhythmic handgrip (HG) exercise at 10 and 30% of maximum voluntary contraction force in a random order. Forearm blood flow was estimated by the rate of increase in the sum of oxy-hemoglobin (OxyHb) and deoxy-hemoglobin (DeoxyHb) during venous occlusion, and muscle oxygen utilization by the rate of decrease in the difference between OxyHb and DeoxyHb during arterial occlusion. [Results] Forearm blood flow in the CRF group was significantly lower compared to the older group during 10% HG and the younger group in 30% HG. Muscle oxygen utilization in the CRF group was significantly higher than the older and young groups in 10% HG. [Conclusion]We conclude that the CRF patients desaturate their muscles more than normal control subjects at a lower work level due to insufficiency of blood flow to the exercising muscles.