| [ Summary ] |
Sleep is associated with definite changes in respiratory physiology and function in normal subjects. The functions of the respiratory center of the medulla, central and peripheral chemoreceptors responding to arterial blood gas changes, mechanical receptors in the lung and chest wall and behavioral control systems in the higher cortical center are regulated and suppressed by sleep. It has been reported in many studies that minute ventilation appears to decrease with decreases in tidal volume and patterns of breathing are also altered during sleep. Lung volume, such as functional residual capacity (FRC), decreases due to elevation of the diaphragm and airway resistance increases following compression of the upper airway by the effects of gravity in the supine sleeping position.
Hypoxic ventilatory responses, and hyper capnic ventilatory responses were markedly supressed during sleep, compared to wakefullness in adults. Arterial O2 tension (Pao2) decreased an arterial CO2 tension (Pao2) increased slightly as reflected by changes in respiratory function. Understanding of changes in respiratory function during sleep is very important clinically, particularly in respiratory medicine and conditions associated with sleep disorders and breathing. |