Application of speaking valves in adult patients with tracheostomy: a protocol for a systematic review and meta-analysis

Introduction

Tracheostomy is a common emergency procedure for critically ill patients and is a common measure to ensure safe management of the patient’s airway.1 For example, tracheotomy is required for respiratory failure or respiratory depression, upper airway obstruction or lower airway secretion retention caused for various reasons.2 The number of tracheostomies performed in intensive care units (ICUs) is increasing. Some recent studies have shown that approximately 29% of ICU patients undergo tracheostomy, while only 10% earlier.3 4 However, a prospective observational study showed that the tracheostomy rate was as high as 54.2% in surgical intensive care patients.5 Tracheostomy has many advantages over long-term intubation, such as ease of oral cleaning and care,6 greater patient tolerance, improved comfort, reduced need for sedation7 and faster removal from the ventilator.8 However, prolonged tracheostomy can disrupt airway integrity and cause adverse effects on patients. Due to changes in airway resistance, loss of subglottic air pressure, weakening of the effective cough reflex and closure of the vocal cords, patients experience dysfunctions in breathing, swallowing, speech and a sense of smell after tracheostomy, and their quality of life is also affected.1 It is reported that the incidence of aspiration after tracheostomy is as high as 59%, which severely affects normal swallowing function and further increases the risk of aspiration pneumonia.9 10 In addition, there is evidence that effective personal communication and participation in medical decision-making are affected by tracheostomy.11 A mixed study has shown that tracheostomy-induced voice loss significantly affects patients’ ability to express comfort needs and care.12 Communication disorders can increase patients’ negative emotions, such as anxiety, depression, fear and powerlessness,13 and reduce their quality of life.14

There are many rehabilitation strategies available to reduce problems after tracheostomy, among which the use of speaking valves as a simple and effective technology is widely used in developed countries. The speaking valve (also known as the speech valve) is a one-way ventilation valve that attaches to the outside opening of the tracheostomy tube and causes the respiratory system to form a closed loop. The working principle of the speaking valve is that the valve opens when the patient inhales, air flows through the tracheostomy tube and into the airway; it closes when the patient exhales, and the airflow is exhaled from the tracheal tube trachea through the vocal cords and larynx from the mouth and nose, helping the patient reconstruct the subglottic pressure.15 The speaking valve mainly uses its unique ventilation device to help patients restore normal positive end-expiratory pressure and promote oxygenation and ventilation.16 Previous studies have shown that speaking valves can increase tidal volume,17 and their use during ventilator deconditioning also promotes lung resuscitation.18 It can also reshape subglottic pressure through biohydrodynamic mechanisms to improve swallowing function and prevent leakage and aspiration.19 Han et al reported that the speaking valve can increase the velopharynx maximal pressure (VP-Max), prolong the upper oesophageal sphincter relaxation duration (UES-RD) and reduce the aspiration rate of patients with acquired brain injury.20 On the other hand, the speaking valve can reconstruct the glottic closure reflex and cough reflex through the action of subglottic receptors and the remodelling of throat sensation, thus promoting speech rehabilitation and improving communication and quality of life.21 The results of a randomised controlled trial (RCT) showed that, compared with patients who did not wear speaking valves, the time from tracheostomy to establishing language communication was significantly shorter for patients wearing speaking valves.22 In addition, the use of speaking valves in patients with tracheostomy can also improve the sense of smell and reduce airway secretion.23

However, there is controversy regarding the effectiveness of speaking valves in tracheotomised patients. For example, Fernández Carmona et al reported that the use of a speaking valve can accelerate decannulation.24 However, some studies have shown that the use of a speaking valve cannot shorten the mechanical ventilation time after tracheostomy tube placement.22 25 Researchers believe that wearing a speaking valve can improve patients’ communication ability, swallowing function and mobility, thereby improving quality of life.18 25 26 However, some studies have reported that there is no significant difference in the improvement of quality of life by speaking valves.22

Only one systematic review has studied the clinical outcomes of speaking valves in patients with tracheostomy, but adverse events associated with the use of speaking valves have not been reported, and patients’ overall health and swallowing-related biomechanical parameters have not been adequately assessed.27 This systematic review included adult and paediatric patients, with a population heterogeneity. In addition, clinical studies published in this area in recent years were not included in this systematic review. This new review will incorporate additional studies. For example, a cohort study published in 2020 explored the impact of speaking valve performance on patients’ mobility.26 Therefore, a comprehensive systematic review of the available clinical practice evidence is necessary to inform clinical practice and future studies of speaking valves in adult patients with tracheostomy.