A new study from the David Geffen School of Medicine at UCLA (yes, the David Geffen) demonstrates, using fMRI, that pumping a patient full of pure oxygen is not the best plan of action. The study concludes that it is important to have at least a little bit of CO2 in the mix when giving high concentrations of oxygen. Here’s a little bit about the study from a UCLA press release:
Harper’s team used functional magnetic resonance imaging (fMRI) to capture detailed pictures of what occurs inside the human brain during two different breathing scenarios. The technique detects subtle increases in blood flow triggered by the activation of different parts of the brain, causing these regions to glow or light up on the color scan.
The researchers scanned the brains of 14 healthy children, ages 8 to 15, and monitored their breathing and heart rates as they inhaled 100 percent oxygen through a mouthpiece for two minutes. After waiting eight minutes for the youngsters’ breathing to return to normal, the team added 5 percent carbon dioxide to the gas mixture and repeated the scan.
…”Several brain areas responded to 100 percent oxygen by kicking the hypothalamus into overdrive,” explained Harper. “The hypothalamus overreacted by dumping a massive flood of hormones and neurotransmitters into the bloodstream. These chemicals interfere with the heart’s ability to pump blood and deliver oxygen – the opposite effect you want when you’re trying to resuscitate someone.”
When the children inhaled the carbon dioxide-oxygen mix, the hypothalamus’ hyperactivity vanished from the MRI scan.
One wonders whether one can apply the physiology of children to adults, but adding 5% CO2 doesn’t seem unreasonable. Who knows, that 95% canned oxygen might have some use after all (not likely).
Read the press release here…