Protruding the tongue improves posterior rhinomanometry in obstructive sleep apnoea syndrome

Abstract

In posterior rhinomanometry (PRM), oropharyngeal pressure is measured using a tube placed between the tongue and the hard palate. For valid results the patient must position the tongue and soft palate so that both the oropharynx and nasopharynx remain open. A high rate of failure of conventional PRM has been reported in normal individuals. In patients with obstructive sleep apnoea syndrome (OSAS), upper airway abnormalities may further increase the failure rate.This study proposes a modification of the technique in which protrusion of the tongue enhances pressure transmission between the nasopharynx and the mouth.In eight normal subjects, resistance was similar when measured by both methods. Of 24 OSAS patients, conventional PRM was unsuccessful in 11. In the remaining 13 patients, a significant correlation between the two methods was found, but resistance was lower by "tongue-out" than by conventional PRM, consistent with a decrease, during tongue protrusion, in retropalatal resistance, which is a component of the "nasal" resistance measured by PRM. In 26 OSAS patients, unilateral nasal resistance values measured by "tongue-out" PRM were similar to those measured by anterior rhinomanometry. When the "tongue-out" method was used routinely in 541 snorers, failure rates were 1.1% in the 272 non-OSAS patients and 3.7% in the 269 OSAS patients.These results indicate that posterior rhinomanometry with tongue protrusion is a highly effective tool for measuring nasal resistance in snorers.

Nasal obstruction as a risk factor for sleep apnoea syndrome

“…Insufficient upper airway control is frequent and has led to posterior rhinomanometry failure rates of at least 15% [18]. In our study, the posterior rhinomanometry variant described previously was used [17]. In this variant, protrusion of the tongue out of the mouth is used to facilitate pressure transmission between the nasopharynx and the mouth.…”

“…Recordings of nasal resistance to airflow were carried out using a posterior rhinomanometry method recently described [17]. Briefly, to facilitate oropharyngeal pressure evaluation, rather than a face mask, the subjects wore a nasal mask (Respironics vinyl masks, Nantes, France) and a sealed mouthpiece.…”

The nose and OSA: variable nasal obstruction may be more important in pathophysiology than fixed obstruction

“…For example, tongue protrusion has been reported to lower nasal airflow resistance in patients with OSA syndrome (OSAS) but not in normal subjects, and it is likely that the effect in OSAS reflects a lowering of resistance in the posterior nasal airway [12].…”

Segmental analysis of nasal cavity compliance by acoustic rhinometry

“…The pneumotachograph was connected to a pressure transducer (Validyne MP 45, Northridge, CA; Ϯ2 cmH2O). Oropharyngeal pressure was recorded via a catheter inserted through a hole drilled in a stopcock obstructing the cylindrical part of a modified mouthpiece, placed between the lower lip and the protruding tongue (5). One port of a differential pressure transducer (Validyne MP 45 Ϯ 14 cmH2O) was connected to the catheter of the mouthpiece, whereas the other port was connected to the nasal mask to allow transnasal pressure measurement.…”