NASAL PRONGS IN THE DETECTION OF SLEEP-RELATED DISORDERED BREATHING IN THE SLEEP APNOEA HYPOPNOEA SYNDROME/

Conventional systems to monitor oronasal how in sleep studies have tra ditionally relied on a thermistor signal. Our study was designed to ve rify whether nasal prongs (NP) connected to a pressure transducer coul d improve respiratory events detection in patients with sleep apnoea/h ypopnoea syndrome (SAHS) compared to traditional systems, Sleep episod es from a 2 h conventional polysomnographic record plus NP signal obta ined at random from eight patients (age: mean(+/-SD) 53(+/-12) yrs; bo dy mass index (BMI): 29(+/-6) kg.m(-2); apnoea/hypopnoea index (AHI): 27(+/-20) events.h(-1)) were identified and used for analysis, An abno rmal change in the pattern of any of the respiratory or neurological v ariables occurring during the observation period was defined as an epi sode, Each episode was registered and scored with concomitant scoring of the remaining variables, According to the episode definition three different profiles were established: 1) periods of reduction of ventil ation in either variable without an arousal or cyclical desaturation, named nonpathological episode (NPE); 2) an idiopathic or nonrespirator y arousal (IA); and 3) a true respiratory event (TRE) defined as reduc tion or absence of how demonstrated by either thermistor, thoraco-abdo minal bands or NP accompanied by cyclical desaturation and/or arousal. For each TRE, its detection by thermistor, thoraco-abdominal bands or NP was established, A total of 877 sleep episodes were observed (42 N PE, 30 IA and 805 TRE), When compared to single or combined thermistor and bands approach, NP had the highest respiratory events detection r ate, 779 (98.8%) versus 673 events (83.6%), respectively. Detection of respiratory-related arousals was also improved by NP and only 3% coul d account for mouth breathing respiration, It is concluded that nasal prongs improve the detection of respiratory events in patients with sl eep respiratory disorders.