The outfitter/lead guide organized nightly oximeter and pulse readings. The readings were not specifically "used" for anything per se while we were on the mountain(though I suppose if someone's readings had been really low, perhaps that would have informed action somehow). I found, personally, that that readings correlated with other indications of how well I was doing with altitude (e.g., the quality of sleep I would have that evening, likeliness of headaches, tendency to spaciness, etc.).
More than anything, it was the extremeley horrible, pulsating, frontal lobe headache that I experienced during a rest stop just as we were nearing our camp (at 16,300') the afternoon before our summit attempt that encouraged me to revisit my very low Diamox dosage (when hiking in the Sierras, I usually take about 1/4 to 1/8 of the "normal" dosage, specifically to address periodic breathing at night, which I do experience above 11,000 feet). I had never, either on Kili, or anywhere else, experienced such a headache before. I observed that, after I increased my Diamox dosage on Kilimanjaro, not only did I feel better, and not experience any further headaches (whether mild or pulsating), but my readings also improved substantially (91% 02, 62 resting pulse, at 16,300 feet, up from 74%, and a 105 resting pulse). I am not suggesting anything scientific, like direct cause and effect, of course, but just reporting an observation.
