ABSTRACT
Measurements of respiratory function during sleep have increased dramatically in the past 25 years, the main driver being the belated recognition of the obstructive sleep apnoea syndrome as a major health problem. Over the same period advances in technology have encouraged wide availability of appropriate equipment, in particular simple and reliable oximeters to measure oxygen saturation and more refined methods for measuring flow and volume changes. Several compact portable recording systems for continuous monitoring overnight are now available. Unlike the situation in the conscious subject, during sleep meaningful direct measurements of resting ventilation and breathing pattern are readily made.
