A study on the effect of oxygen bolus breathing or pressure breathing on oxygen saturation, at rest or under physical strain (bicycle ergometer) at 14,000 ft altitude.

At an altitude of about 3000 m even healthy people suffer from hypoxemia due to the low oxygen partial pressure. As a physiological countermeasure the oxygen partial pressure is increased. In the present study the following procedures are looked into: 1. Pressurized breathing, 2. Oxygen bulus breathing. It was found out that both procedures are appropriate to increase the oxygen partial pressure efficiently. However, bolus breathing is more effective, since an almost 100% hemoglobin saturation may be achieved even with small bolus volumes when the subject is at rest or under little physical strain. Pressurized breathing seems to be an appropriate emergency measure when a sudden pressure loss occurs in an aircraft for a short while provided that the subject is familiar with the breathing technique.