Magne Tvinnereim

Plasma Radiofrequency Preceded by Pressure Recording Enhances Success for Treating Sleep‐Related Breathing Disorders

Objectives: Sleep‐related breathing disorders (SRBD) that cannot be treated conservatively are commonly treated using uvulopalatopharyngoplasty, although success rates are generally less than 70%. The purpose of this study was to assess a plasma‐mediated radiofrequency (RF)‐based coblation assisted upper airway procedure (CAUP) to treat SRBD patients determined to have obstruction localized to the upper (mid)‐pharyngeal region.

Sleep and posture

Computer‐assisted open catheter studies of 10 healthy, nose‐breathing men in dorsal and in lateral recumbent sleep demonstrated stable intrasubject transpharyngeal differential pressures and airflow resistances. They averaged 19.6 Pa (± standard deviation [SD] 11.9) and 0.103 Pa/cm3 per second (± SD 0.065) in the dorsal posture and stage II sleep during quiet breathing and were not significantly different in the lateral posture or in stage I sleep. Five subjects were snorers, and their pharyngeal airflow pressures and resistances increased substantially during quiet breathing on assumption of recumbency and much more in sleep. In the 5 subjects who were nonsnorers, postural changes were not significant and sleep increases were moderate. During snoring, transpharyngeal pressures and resistances increased even further, averaging 188 Pa and 1.02 Pa/cm3 per second for the whole group. Transpharyngeal differential pressures and hypopharyngeal transmural pressures frequently exceeded 300 Pa in inspiration and in expiration during periods of snoring. Yet, transpharyngeal differential pressures and resistances did not reveal appreciable differences between phases that would indicate compliant change of pharyngeal cross section. Breathing frequency was unchanged, but ventilation was significantly diminished at elevated upper airway resistances (P<.01). Transpharyngeal resistances and differential pressures varied independently from widely differing nasal resistances. As with our earlier studies, pressure measurements alone clearly demonstrated breathing patterns and events.

A comparison between two methods of measuring pressure in the pharyngeal airway : transducer probe versus open catheter

A new multi-transducer probe system for measuring pharyngeal pressures was compared with an established open catheter system. Pharyngeal pressure measurements were made at the same time, and site, in subjects awake, at unmodified and with artificially increased nasal airway resistances, and during sleep documented by polysomnography. The two systems yielded almost identical results. It is anticipated that the multi-transducer probe system will prove of clinical value.

In reference toPlasma Radiofrequency Preceded by Pressure Recording Enhances Success for Treating Sleep-Related Breathing Disorders

AG200 system has never been compared with any of the preexisting evaluation techniques. We recognize that the absence of a gold standard in this specific area makes this a difficult task, but it is ever more important to at least compare with current techniques (MRI, cephalometry, sleep nasendoscopy, etc.) to establish similarities and differences in measures. The use of transducers fixed at equal distances does not allow for the fact that there is some movement of the catheter with respiration despite securing it well, and therefore the transducer position is variable. Further, very little appears to be written regarding difficulties encountered with the AG200 system. There is no mention of difficulty with catheter insertion, tolerability by patients, or technical failures. The impression is that the ApneaGraph is flawless. The application of the ApneaGraph data has focused on transpalatal obstruction with apparently good effect. The more difficult subject of lower pharyngeal obstruction is not discussed. The arbitrary demarcation of over 50% upper pharyngeal obstruction being treated as palatal must include a fair number of patients with significant tongue base obstruction also. Clearly this will have a bearing on overall outcome. In summary, we recognize the potentially exciting aspect of the AG200 system, but data are lacking regarding validity (larger studies across multiple centers) to support the applicability of this newly applied tool. Currently, the results need to be interpreted with caution.