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Noninvasive ventilatory support (NVS) is sometimes reported as suboptimal in patients with neuromuscular disease (NMD). The reasons for this include inadequate ventilator settings and/or lack of interface tolerance. NVS has been used for many years in patients with NMD disorders as a viable alternative to continuous ventilatory support via a tracheostomy tube. The mouthpiece ventilation (MPV) is a ventilatory mode that is used as daytime ventilatory support in combination with other ventilatory modalities and interfaces for nocturnal NVS. However, there is still a poor understanding of this method’s benefits compared with other modalities. This review aims to highlight the indications and advantages along with the disadvantages of MPV.

The aim of our study was to evaluate efficacy and reliability of currently available ventilators for mouthpiece ventilation (MPV). Five life-support home ventilators were assessed in a bench test using different settings simulating the specificities of MPV, such as intermittent circuit disconnection and presence of continuous leaks. The intermittent disconnection of the circuit caused relevant swings in the delivered tidal volume ( VT), showing a VT overshoot during the disconnection periods and a VT decrease when the interface was reconnected to the test lung. The five ventilators showed substantial differences in the number of respiratory cycles necessary to reach a stable VT in the volume-controlled setting, ranging from 1.3 ± 0.6 to 7.3 ± 1.2 cycles. These differences were less accentuated in the volume-assisted setting (MPV-dedicated mode, when available). Our data show large differences in the capacity of the different ventilators to deal with the rapidly changing respiratory load features that characterize MPV, which can be further accentuated according to the used ventilator setting. The dedicated MPV modes allow improvement in the performance of ventilators only in some defined situations. This has practical consequences for the choice of the ventilator to be used for MPV in a specific patient.

Mouthpiece ventilation (MPV) allows patients with neuromuscular disease to receive daytime support from a portable ventilator, which they can disconnect at will, for example, for speaking, eating, swallowing, and coughing. However, MPV carries a risk of underventilation. Our purpose here was to evaluate the effectiveness of daytime MPV under real-life conditions. Eight wheelchair-bound patients who used MPV underwent daytime polygraphy at home with recordings of airflow, mouthpiece pressure, thoracic and abdominal movements, peripheral capillary oxygen saturation (SpO2), and transcutaneous partial pressure of carbon dioxide (PtcCO2). Times and durations of tasks and activities were recorded. The Apnea–Hypopnea Index (AHI) was computed. Patient–ventilator disconnections ≥3 minutes and episodes of hypoventilation defined as PtcCO2>45 mmHg were counted. Patient–ventilator asynchrony events were analyzed. The AHI was >5 hour−1 in two patients. Another patient experienced unexplained 3% drops in arterial oxygen saturations at a frequency of 70 hour−1. Patient–ventilator disconnections ≥3 minutes occurred in seven of eight patients and were consistently associated with decreases in SpO2 and ≥5-mmHg increases in PtcCO2; PtcCO2 rose above 45 mmHg in two patients during these disconnections. The most common type of patient–ventilator asynchrony was ineffective effort. This study confirms that MPV can be effective as long as the patient remains connected to the mouthpiece. However, transient arterial oxygen desaturation and hypercapnia due to disconnection from the ventilator may occur, without inducing unpleasant sensations in the patients. Therefore, an external warning system based on a minimal acceptable value of minute ventilation would probably be useful.