ADEQUACY OF PRESCRIBING NASAL CONTINUOUS POSITIVE AIRWAY PRESSURE THERAPY FOR THE SLEEP-APNEA HYPOPNEA SYNDROME ON THE BASIS OF NIGHT TIME RESPIRATORY RECORDING VARIABLES

Background - The increased demand of full polysomnographic studies, no t only for diagnostic purposes but also for continuous positive airway pressure (CPAP) titration, has produced long waiting lists. Simpler m ethods are therefore needed to avoid having to refer all patients for full polysomnography. The hypothesis that CPAP therapy for the sleep a pnoea/hypopnoea syndrome (SAHS) can be performed exclusively on the ba sis of recording night time respiratory variables was tested. Methods - The level of CPAP in a group of 41 patients (three women) of mean (S D) age 52 (10) years, body mass index 31 . 5 (4 . 4) kg/m(2), and apno ea/hypopnoea index (AHI) 53(16) events/hour was measured. During a two week period CPAP titration was performed in a random order in two set tings: (1) in the sleep laboratory using full polysomnography; and (2) in the respiratory ward using equipment which continuously recorded a nd displayed pulse oximetry, airflow, chest and abdominal motion, and body position. The level of CPAP was increased progressively until apn oea, hypopnoea, snoring, and thoracoabdominal paradox disappeared. Res ults - No differences in CPAP levels (9 . 34(2 . 2) versus 9 . 68(2 . 1) cm H2O) were found between full polysomnography and night time resp iratory recordings. The accuracy of the measurement of both procedures showed good agreement. Only one patient showed a significant differen ce in CPAP level requirements between the two methods. Conclusions - N ight time respiratory recording is sufficient to permit a reasonable c hoice of CPAP levels to abolish all the respiratory disturbances in mo st of the patients studied.