ResMed develops, makes, and distributes medical equipment used to diagnose and treat respiratory disorders that occur during sleep, such as sleep apnea. Most of its products treat obstructive sleep apnea (OSA), a condition in which a patient's air flow is periodically obstructed, causing multiple disruptions during sleep that can lead to daytime sleepiness and other conditions such as high blood pressure. Its products include air-flow generators, face masks, diagnostic products, and accessories. ResMed sells directly and through distributors worldwide to home health equipment dealers, sleep clinics, and hospitals. ResMed was founded in Australia in 1989 by Peter C. Farrell, who remains chairman.