THE EFFECT OF QUIET TIDAL BREATHING ON LATERAL CEPHALOMETRIC MEASUREMENTS

Purpose: In the evaluation of the upper airway in patients with sleep apnea it has been suggested that cephalometric radiographs be performe d at either end-inspiration or end-expiration during quiet tidal breat hing, This study sought to determine if standard soft tissue cephalome tric measurements vary significantly with tidal breathing, Patients an d Methods: In this prospective, controlled study 22 adult male patient s with the sleep apnea/hypopnea syndrome and 27 nonapneic, nonsnoring male controls had cephalometric radiographs performed at end-tidal ins piration and end-tidal expiration. The measurements obtained from each radiograph included the posterior airway space distance, the mandibul ar plane to hyoid distance, and the posterior nasal spine to tip of pa late (PNS-P) distance, Results: There were no statistically significan t differences between the inspiratory and expiratory measurements in e ither group, Only the PNS-P distance differed significantly between th e two groups, Changes in cephalometric measurements did not occur unif ormly in any one direction with tidal breathing, Conclusion: The data indicate that coordinating radiographic exposure to respiratory cycle phase is not necessary for soft-tissue measurements commonly used to a ssess upper airway patency in patients with the sleep apnea/hypopnea s yndrome.