The Effect of a 300 mBar Increase in Barometric Pressure on Digital Microcirculation in Healthy Subjects Exposed to High Altitude: Is the Use of a Portable Hyperbaric Chamber to Treat Frostbite and/or Hypothermia in the Field Indicated? (Flow_Pulse Study)

Hypothermia and frostbite occur when there is a significant decrease in central and peripheral body temperature in individuals exposed to cold windy conditions, often at high altitude or in a mountain environment. Portable hyperbaric chambers increase the barometric pressure and thereby the partial pressure of oxygen inside the chamber, and their use is a well-known treatment for altitude illness. This study aims to show that a portable hyperbaric chamber could also be used to treat hypothermia and frostbite in the field, when rescue or descent is impossible or delayed.During a European research program (SOS-MAM, Flow Pulse study) measurements were taken from 27 healthy nonacclimatized voluntary subjects (21 men, 6 women, mean age 41 ± 17) at an altitude of 3800 m (Chamonix Mountain Lab, Aiguille du Midi, France) right before and immediately after spending 1 hour in a portable hyperbaric chamber at 300 mbar. We measured digital cutaneous temperature (Tcut), digital cutaneous blood flow (Fcut), digital tissue oxygenation (TWe observed significant increases in Tchamb: 9.3°C compared with the outside temperature, Tcut: +7.5°C (±6.2°C 71%), Fcut: +58This study shows that a portable hyperbaric chamber can be used to treat frostbite and/or hypothermia in the field at altitude when descent or rescue is impossible or even simply delayed.