Can you point us to where in that article it says an alarm response would be triggered because of insufficient oxygen supply?
From the PPH 2012:
Hello,
It is true, the human body has more than 300 so called chemo receptors/sensors and amongst them are also receptors/sensors that meassure O2 partial pressure in the blood and tissue. However, it's not gonna matter much because in the case of exit-back, the O2 level drops suddenly and unconsciousness sets in faster than the receptor/sensor can react, and in case of the full-body-bag it would be too late for the receptor's response as well because a level of 11% O2 as given in the test chamber to potentially trigger any sensor response, would be the equivalent of a 56% O2 saturation in humans blood, which would be classified as severe hypoxia. And one would simply get to that point while sleeping with a pill or before hand sleep-deprivation. The O2 receptor/sensor only reacts at a certain O2 level cross point (on its way downward). Experiments on pigs have shown that the O2 receptor/sensor caused pulse and respiration rate to increase to compensate at a level of 11% O2 , down from there the compensation mechanism stopped.
The steps checked were 21%, 11% and 7% within 45 minutes with N2 increased at a flow rate of 5-10 l/min in a 833 liter chamber.
"(...) We found in our study results that the oxygen saturation values from the pulse oximetry differed from those in the artery blood (from the blood gases examination). The oxygen saturation on pulse oximetry decreased by 44% when the chamber oxygen level decreased from 21% to 7%. If human oxygen saturation in a normal chamber was assumed to be 100%, the oxygen saturation in a chamber with an oxygen level of 7% would be 56%. The peripheral oxygen saturation of 56% is categorized as severe hypoxia [22]. On the other hand, the oxygen saturation measured from the blood gas examination decreased by 62%. If human oxygen saturation in a normal chamber was assumed to be 100%, the oxygen saturation in a chamber with an oxygen level of 7% would be 38%. The peripheral oxygen saturation of 38% is categorized as extreme hypoxia [22]. Human body tissues have various time windows of tolerance to hypoxia: brain tissues can tolerate less than 3 minutes, the liver and kidney can tolerate between 15 and 20 minutes, and skeletal muscles can tolerate between 60 and 90 minutes. In the case of patients with acute respiratory distress syndrome, the oxygenation level should be maintained at 85% of oxygen saturation, and the patient should be kept in the intensive care unit [23]. For humans with an oxygen saturation level of 38%, if they are not immediately given intensive care, their hypoxic condition can cause the death of vital organs such as the brain, liver, and kidneys. (...)"
Source: h t t p s://iopscience.iop.org/article/10.1088/1742-6596/1073/4/042023/pdf
All information in here for educational purpose only!
