Speaking valves in tracheostomised ICU patients weaning off mechanical ventilation--do they facilitate lung recruitment?

Anna-Liisa Sutt,Lawrence R Caruana,Chris M Anstey,John F Fraser,Petrea L Cornwell,Kimble R Dunster

doi:10.1186/s13054-016-1249-x

Abstract

BackgroundPatients who require positive pressure ventilation through a tracheostomy are unable to phonate due to the inflated tracheostomy cuff. Whilst a speaking valve (SV) can be used on a tracheostomy tube, its use in ventilated ICU patients has been inhibited by concerns regarding potential deleterious effects to recovering lungs. The objective of this study was to assess end expiratory lung impedance (EELI) and standard bedside respiratory parameters before, during and after SV use in tracheostomised patients weaning from mechanical ventilation.MethodsA prospective observational study was conducted in a cardio-thoracic adult ICU. 20 consecutive tracheostomised patients weaning from mechanical ventilation and using a SV were recruited. Electrical Impedance Tomography (EIT) was used to monitor patients’ EELI. Changes in lung impedance and standard bedside respiratory data were analysed pre, during and post SV use.ResultsUse of in-line SVs resulted in significant increase of EELI. This effect grew and was maintained for at least 15 minutes after removal of the SV (p < 0.001). EtCO2 showed a significant drop during SV use (p = 0.01) whilst SpO2 remained unchanged. Respiratory rate (RR (breaths per minute)) decreased whilst the SV was in situ (p <0.001), and heart rate (HR (beats per minute)) was unchanged. All results were similar regardless of the patients’ respiratory requirements at time of recruitment.ConclusionsIn this cohort of critically ill ventilated patients, SVs did not cause derecruitment of the lungs when used in the ventilator weaning period. Deflating the tracheostomy cuff and restoring the airflow via the upper airway with a one-way valve may facilitate lung recruitment during and after SV use, as indicated by increased EELI.Trial registrationAnna-Liisa Sutt, Australian New Zealand Clinical Trials Registry (ANZCTR). ACTRN: ACTRN12615000589583. 4/6/2015.

Highlights

Patients who require positive pressure ventilation through a tracheostomy are unable to phonate due to the inflated tracheostomy cuff
The key concern raised by physicians is that by deflating the cuff, and losing positive end-expiratory pressure (PEEP) this could lead to loss of lung volume through alveolar collapse
When speaking valve (SV) were used in this cohort of cardio-respiratory patients, we observed no evidence of lung de-recruitment whilst weaning from mechanical ventilation

Summary

Introduction

Patients who require positive pressure ventilation through a tracheostomy are unable to phonate due to the inflated tracheostomy cuff. Whilst a speaking valve (SV) can be used on a tracheostomy tube, its use in ventilated ICU patients has been inhibited by concerns regarding potential deleterious effects to recovering lungs. Speaking valves (SVs) can be used in-line with mechanical ventilation, but use of these requires deflation of the tracheostomy cuff [1]. Cuff deflation causes a leak in the ventilator circuit, which has been considered detrimental to patients’ ventilation, and potentially deleterious to weaning. The key concern raised by physicians is that by deflating the cuff, and losing positive end-expiratory pressure (PEEP) this could lead to loss of lung volume through alveolar collapse. Practices that may cause loss of lung volume must be used with some degree of caution

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