Impact of Patient Controlled Positive End-expiratory Pressure on Speech in Tracheostomized Ventilated Patients

Context :

Allowing a functional communication is a major issue in order to preserve quality of life in tracheostomized ventilator-dependent patients.

We showed in a previous study that the use of a positive end-expiratory pressure (PEEP) in neuromuscular tracheostomized ventilator-dependent patients improved speech as it allows the patient to expire (at least partly) through the upper airways therefore to speak during expiration. The use of PEEP has been compared to the use of a phonation valve placed on the ventilator circuit which allows a complete expiration through the upper airways and therefore speech. Both techniques seem similar in terms of efficiency on speech; PEEP, however, is better tolerated and seems to be more secure (the system remains open during expiration decreasing the risk of high pressure, it does not require any handling of the ventilator circuit).

Optimal PEEP level allowing the patient to expire the total expiratory volume through the upper airways PEEPeff may vary from one patient to the other. We seek to determine individual PEEPeff and to compare it to 50% of its value (PEEPef50). Indeed, while PEEPeff may constitute the best level for expiratory speech as it mimics the mechanisms of a phonation valve without some of its fallbacks, by preventing expiration through the expiratory circuit of the ventilator, it also may lengthen expiration, delaying inspiration which allows speech, and facilitate hyperinflation leading to respiratory discomfort as we have previously observed with some patients using a phonation valve. Optimal PEEP level would be the best compromise between best possible phonation and best possible respiratory comfort and therefore could be lower than PEEPeff.

In order to improve respiratory comfort with higher PEEP level, we developed a prototype ventilator in which PEEP is activated by a switch under the control of patients who may activate it only when needed (during speech period).

Objective :

The main objective of the study is to optimize PEEP use both by determining individually its most appropriate level and by evaluation its use overtime to allow the best possible speech with the best respiratory comfort and the most secure condition for tracheostomized ventilated patients. Different PEEP levels will be evaluated and PEEP activation will be controlled by the patients.

Methods:

Open randomized monocentric cross-over study (the patients are their own control).

Optimal PEEP level (PEEPeff), defined as PEEP-level allowing complete expiration through the upper airways, will be determined for each patient. Speech and respiratory parameters were studied without PEEP, with PEEPeff and an intermediate PEEP-level(PEEP50). Flow and airway pressure will be measure and upper airways resistance will be calculated. Microphone speech recordings were subjected to both quantitative measurements and qualitative assessments of speech.

For each PEEP level the following protocol will be conducted: 5 minutes of quiet breathing with PEEP, 10 minutes spontaneous conversation, then speech trial(maximal sustained sound, glissando, text reading).

Subjective evaluation of speech and respiratory comfort(by the patient) and objective evaluation of speech improvement according to PEEP level (reading duration, phonation duration, voice quality, assessments of speech including an intelligibility score, a perceptual score and an evaluation of prosody analyzed by two experimented speech therapists blinded to PEEP level). Evaluation of the PEEP control button use by the patient.

Inclusion criteria

Neuromuscular adult patients, tracheotomized and on long-term ventilation with a cuffless tube, on assist-control volumetric ventilation, in stable state at the time of the study.

Number of patients, center:

Considering it is a pilot study, 14 subjects will be included for the study. The subjects will be recruited in the home ventilation unit of the intensive care department of the R. Poincare teaching hospital (Garches, France) during their usual follow-up for their chronic respiratory failure.

Duration of study: 12 months. Duration of participation for each patient will be 1h30.

Inclusion criteria

• Adult patient
• Stable state upon inclusion
• Neuromuscular patients, tracheostomized and on long term ventilation with a cuffless tube
• Assist control volumetric ventilation mode
• Signed consent form

Exclusion criteria

• Pregnancy
• Patients unable to read
• Acute respiratory failure
• Contra-indication of PEEP use
• Lack of social security coverage