Validation of a suprasternal pressure transducer for apnea classification during sleep

Study objectives: To validate a new method of evaluation of respiratory efforts during polysomnographic recordings. Setting: NA Participants: 26 patients with sleep apnea syndrome, either during diagnostic assessment (n=16) or under nasal continuous positive airway pressure (n=10). Methods: This method consists of measuring suprasternal pressure by a pressure transducer placed over the trachea above the sternal notch (Pst). It was compared to the reference method (ie, esophageal pressure) during the same polysomnogram. Results: The analysis was based on 3,261 episodes of apnea, classified as obstructive in 2,556 cases, mixed in 347 cases, and central in 358 cases according to the esophageal pressure monitor. The concordance between the two methods was very good, with a sensitivity of Pst of 99.4% for the detection of apneas with respiratory efforts and a specificity of 93.6%. Twenty-three (6.4%) of the 358 central apneas were classified by Pst as apneas with respiratory efforts and 18 of the 353 central apneas classified by Pst were actually apneas with respiratory efforts on the esophageal pressure monitor. Conclusion: The suprasternal pressure transducer, which presents a good sensitivity and a good specificity for identification of respiratory efforts, can be used to classify apneas during polysomnographic recordings in clinical practice.