CONTINUOUS INTRATHORACIC PRESSURE MONITORING WITH A NEW ESOPHAGEAL MICROCHIP CATHETER IN SLEEP-RELATED UPPER AIRWAY OBSTRUCTIONS

A new small-diameter microchip catheter, especially developed for cont inuous intrathoracic pressure monitoring to assess the degree of respi ratory obstruction and effort in patients with sleep-related upper air way obstructions, was investigated. The technical performance and clin ical applicability of the catheter was tested in a simplified screenin g study comprising 122 sleep recordings in patients with varying compl aints of snoring and daytime tiredness. In six obese snorers, sensitiv ity of the catheter to apneas, hypopneas, and nonapneic snoring was co mpared to the traditional assessment of respiratory events by conventi onal polysomnography. The catheter was found to be easy to handle and introduce, with technical qualities meeting the demands for overnight recordings of intrathoracic pressure variations. Patient tolerance was high (93%), and sensitivity to apneas and hypopneas was equivalent to that of traditional polysomnography. Periods with upper airway obstru ction and increased respiratory effort on the borderline between asymp tomatic obstructions and obstructions resulting in significant blood-g as changes could be detected primarily with intrathoracic pressure mon itoring. Monitoring the intrathoracic pressure variations in the esoph agus has been shown previously to reflect respiratory effort. Increase d respiratory effort might be one of the explanations for the fragment ed sleep pattern and sleep related daytime symptoms sometimes seen in patients without a pathologic respiratory index. In addition to being applicable for the detection of apneas and hypopneas, continuous noctu rnal monitoring of the intrathoracic pressure variations also detects small increases in respiratory effort and thus may constitute a valuab le tool for the understanding and diagnosis of upper airway resistance syndrome and obstructive sleep apnea syndrome.