Mouth closing device (chinstrap) reduces mouth leak during nasal CPAP

Abstract

Background and purpose: Mouth leak occasionally complicates continuous positive airway pressure (CPAP) therapy, which leads to discomfort. While a chinstrap prevents the mouth from opening during sleep, its efficacy in diminishing mouth leak has not been studied.

Patients and methods: Fifteen patients with mouth leak complaining of mouth dryness and nasal obstruction underwent two consecutive overnight polysomnographies, one with a chinstrap, in random order. Cephalometry with and without a chinstrap was randomly performed on six patients.

Results: With the chinstrap, both mouth leak and the arousal index decreased significantly, from (mean±SD) 42.9±23.5 to 23.8±13.3% of total sleep time (TST), and from 33.4±18.6 to 23.6±9.3/sleep hour, respectively. However, snoring time showed a concomitant increase from 6.7±14.3 to 24.0±13.2% of TST. The arousal index was significantly higher during leak periods, and its changes correlated positively with changes in mouth leak. Cephalometric measures showed a significant decrease in anterior lower facial height.

Conclusions: The chinstrap, by closing the mouth during CPAP, reduces mouth leak and therefore the arousal index in most patients. Nevertheless, the indices remained unacceptably high. The chinstrap may also increase snoring and, in rare cases, can worsen the respiratory disturbance index. Consideration of these potential effects is important before instituting regular home use of the chinstrap.

Introduction

Continuous positive airway pressure (CPAP) therapy for sleep-disordered breathing (SDB) is traditionally given via a nose mask. Ideally, patients should keep their mouths closed; however, the mouth may fall open during sleep causing leaks in 10–15% of cases [1]. The CPAP generator increases nasal airflow to compensate for air leaks, in turn increasing the need for nasal mucous membranes to warm and humidify air, leading to nasal inflammation and edema, nasal and oral drying, and nasal obstruction. Such changes can potentially lead to CPAP intolerance [2], [3], [4], [5], [6], [7]. When mouth leak is minimized arousals may be reduced and rapid eye movement (REM) sleep markedly increased [8].

Since effective CPAP pressure is obtained when constant pressure is applied through the nasal or oral route [9], the face mask offers potential reduction of symptoms associated with mouth leak, but does not address the problem of decreased CPAP compliance [10]. By contrast, nose masks are considered to be more comfortable [10].

To improve CPAP compliance, expensive, high-technology features such as ‘intelligent’ CPAP and humidification are the subject of several studies. Basic educational and behavioral support and low-technology tools (e.g. chinstrap, mask re-fitting) also appear promising but are currently being less rigorously evaluated [11].

The chinstrap, a piece of tissue that prevents the patient's mouth from opening, is placed around the chin and attached to the headgear of the nasal mask. While many sleep centers use the chinstrap, a search of the literature failed to identify a single peer-reviewed study of this device. We therefore report the effect of chinstrap use on 15 patients with CPAP mouth leak who also complained of mouth dryness and nasal obstruction.