Digital recording and analysis of esophageal pressure for patients with obstructive sleep apnea-hypopnea syndrome

To evaluate sleep-related obstructive breathing events in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS), we developed a technique for digital recording and analysis of esophageal pressure (Pes) and elucidated the Pes parameters. Pes was recorded overnight with a microtip-type pressure transducer in 74 patients with OSAHS. Simultaneously, in all patients digital polysomnography was recorded. The mean nadir end-apneic Pes swing (Pes Nadir) ranged from -20.2 to -147.4 cmH₂O, with a mean of -53.6±2.9 cmH₂ O. Correlation of the mean Pes Nadir indicated a linear relationship with the mean ratio of maximal Pes swing to apnea duration (r² =0.70) and the mean area of the Pes (Pes Area) (r²=0.82). Significant correlations were noted between the mean Pes Nadir and apnea-hypopnea index (AHI, ranging from 7.9 to 109.5 per hour; r²=0.66), minimum SpO₂ (r²=0.60), oxygen desaturation index (ODI) of more than 3 (r²=0.65), arousal index (r²=0.54), and between the mean Pes Area and AHI (r²=0.63), minimum percutaneous arterial oxygen saturation (SpO₂; r²=0.57), ODI (r² =0.69), and arousal index (r²=0.41). Pes parameters were found to be significant in the evaluation of the severity of the respiratory effort during the sleep-related obstructive breathing events for patients with OSAHS.