Abstract: Disclosed are apparatus and method for preventing hypoxic damage, relieving respiratory difficulties and conditioning breathing reflexes in a living human body. More particularly, at least one sensory stimulus is imparted to the body in response to a deviation from at least one adjustable physiological variable followed sequentially by delivery of a respiration restoring gas to the vicinity of the nose and mouth of the body.

Abstract: Disclosed herein is a method for the calibration of a sensing unit for determining the partial pressure of oxygen in contact with the sensing unit. The method is of the type using a zero-calibration solution in which the partial pressure of oxygen is maintained at zero by virtue of a binding agent present in the solution for chemically combining with the oxygen. The essential steps of the method include adding to the solution a color indicator for indicating that the zero-calibration solution contains unspent binding agent, contacting the sensing unit with the zero-calibration solution containing the unspent binding agent and the color indicator, energizing the sensing unit, and adjusting the sensing unit until it indicates zero concentration.The invention also compasses within its scope a calibration agent for use in the performance of the method for supplying the zero-calibration solution upon dissolution in water, as well as a container for storing the zero-calibration solution.