Please see Bibliography of References for a list of abstracts, manuscripts and posters.
Larsson A, Uusijärvi J, Lindholm P. Annual Scientific Meeting of the Undersea and Hyperbaric Medical Society (UHMS); June 18-27, 2008 Salt Lake City, UT.
Introduction: To evaluate the possible use of near-infrared spectroscopy (NIRS) to measure tissue oxygenation in patients receiving hyperbaric oxygen therapy, we tested an Inspectratm StO2 monitor on healthy subjects during normobaric oxygen (NBO) and hyperbaric oxygen (HBO).
Methods: Nine healthy volunteer (1 female) age 25-37, were tested. Subjects’ rested supine breathing in an oxygen hood (CASTAR, STARMed) supplied with either air or oxygen during the experiment. Tissue oxygenation (NIRS) was monitored with an Inspectratm StO2 monitor Hutchinson Technology, MN, USA, using the probe at the thenar eminence (thumb). Subjects were blinded to when they were breathing air or oxygen. Different partial pressures were administered in the following 10 minute intervals: 21kPa, 101kPa, 21kPa, (compression to 2.8 ATA), 59kPa, 280 kPa, 59kPa, (decompression), 21kPa. Data reported was averaged over the last 5 minutes at each pressure.
Results: When switching from air to NBO StO2 increased from 83±3.6% to 85±2.2% (p<0.05), when switching from air at pressure (59kPa O2) to HBO (280kPa) StO2 increased from 85±2.1% to 88±1.9% (p<0.001). There was no difference between baseline StO2 at air breathing and air breathing after decompression. Values did not reach the maximal value 99% at any point. Heart rate decreased when switching from air to NBO from 64±8 to 60±9 beats/min (p<0.001) and decreased when switching from air at pressure to HBO from 61±8 to 54±8 (p<0.001). Diastolic blood pressure did not change between conditions.
Conclusion: Tissue oxygenation increased during NBO and HBO in healthy resting subjects as measured with the Inspectratm StO2 method for NIRS.Changes in StO2 followed inspired PO2 changes.