Esophageal pressure and apnea hypopnea index in sleep-disordered breathing

Severity of negative esophageal pressure (Pes) and apnea hypopnea index (AH I) were investigated in six cases of upper airway resistance syndrome (UARS ) and 11 cases of obstructive sleep apnea syndrome (OSAS). The severity of negative Pes was represented by the highest peak (Pes Max) and the number o f increased episodes (more than 13.5 cmH(2)O) per h (NPes113.5). There was no significant correlation between Pes indices and AHI. Pes Max and NPes113 .5 were not different among severe OSAS (AHI > 30), mild OSAS (AHI < 30) an d UARS. Apnea hypopnea index failed to represent the severity of negative P es, which is an important aspect of the pathophysiology of sleep-disordered breathing.