Pulse Oximetry and Breathing Training1
Small pulse oximeters have become widely available and can be useful for noninvasive monitoring of blood oxygen saturation by nonmedical personnel. When training control of breathing, an oximeter helps to reassure clients who hyperventilate that their oxygenation is adequate, offsetting their perception that they are not getting enough air. Low saturation may indicate a medical condition that impairs oxygen absorption. In that case, hyperventilation is a biological compensation that should not be tampered with.
Illustration of the effect of normal breathing disrupted in opposite directions: approximately 2 minutes of hyperventilation (A) and holding one's breath (B) followed by resuming normal breathing pattern. Reducing CO2 through overbreathing raises O2 saturation (A), which decreases release of O2 to the tissues; raising CO2 by holding one's breath lowers O2 saturation (B), which increases release of O2 into the tissues. The drop to zero in the bottom CO2 trace is an artifact of exhalation being interrupted, so no end-tidal values are available.
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