[Assess respiratory drive by esophageal pressure measurement].

OBJECTIVE

To evaluate the difference between the classificatory results of esophagus pressure monitor and thorax and abdomen belt.

METHODS

From Nov. 2000 to Jan. 2001, 34 patients received polysomnographic examination in Beijing Tongren Hospital. The aero digestive pressure was monitored simultaneously at 4 different points, i.e., the distal part of esophagus, hypopharynx, oropharynx and nasopharynx. Respiratory events were classified based on measurement of thorax and abdomen movements and esophageal pressure, and two classification results were compared.

RESULTS

Four patients were excluded from comparing classification results because of apnea hypopnea index < 5, or deformity in face and low sleep efficiency. Other 30 patients, 26 men and 4 women, at age of 45.4 +/- 9.5 (30-66), were enrolled. Classificatory difference was found in 9.7% (1,183 out of 12,238) of the respiratory events between two methods. The largest part of apneas reclassified by esophageal pressure measurement were mixed apneas reclassified as obstructive apnea (600). The difference of respiratory drive restore time measured by two methods was found between mixed reclassified obstructive apneas and mixed apneas confirmed by two methods, P = 0.028. No difference between mixed reclassified obstructive apneas and obstructive apneas confirmed by two methods. Difference of apnea classifications was due to the changes of respiratory drive restore time caused by different sensitivity of respiratory drive measurement. The number of difference was related to sensitivity of thorax and abdominal channel (P = 0.000, r2 = 0.653).

CONCLUSION

Apneas are easy to be misclassified due to the low sensitivity of thoracic and abdominal channel, and this problem can be solved by using esophageal pressure measurement. All kinds of apneas have anatomic and neuro-muscular factor in common.