Assessment of increased upper airway resistance in snorers. Methodological and diagnostic considerations.

Sleep-related partial upper airway obstruction may cause increased morbidity and mortality, but diagnosis and treatment of patients is varying and inconsistent. The present studies were aimed to evaluate presently applied indirect methods for assessing respiratory ventilation and to investigate the value and accuracy in estimating upper airway resistance during sleep by measuring intrathoracic pressure variation with a microchip catheter in the esophagus.Furthermore, differential upper airway pressures and the relation between episodes of increased upper airway resistance and arousals were studied in subjects with habitual non-apneic snoring and daytime tiredness. During physical exercise in adults, the trend in changes of arterial oxygenation was found to be relatively well revealed by continous transcutaneous measuring of PO2. Overnight studies did not reveal any significant difference in accuracy between transcutaneous measurement of SAO2 and PO2. Continous measurement of of intrathoracic pressure variat