STABILITY OF THE INFANT RESPIRATORY SYSTEM: A MODEL STUDY.

A model has been adapted to explain periodic breathing in infants during sleep. Using parameter values determined in various studies by others, it is shown that the respiratory control system of certain infants is marginally stable so that a small change in one or more of the parameters can cause periodic breathing with a period of about 14 seconds. The effect of changing the percentages of inhaled O//2 and CO//2 on the stability of the system is also studied. It was found that inhalation of 25% O//2 or 2% CO//2 eliminates periodic breathing, while inhalation of 15% O//2 could cause periodic breathing. The model shows that the peripheral controller is the predominant one, with control of respiration being shared between the peripheral O//2 and CO//2 components.