Use of a passive exhalation port for long-term tracheostomy ventilation in patients with Amyotrophic Lateral Sclerosis: a randomized control trial

Background: Long-term Tracheostomy Ventilation (TV) is utilized to prolong survival of individuals with Amyotrophic Lateral Sclerosis (ALS). Due to the potential risk of CO2 rebreathing and the lack of direct measurement of Tidal Volume, the use of a passive exhalation port in this setting remains uncommon. AIMS AND OBJECTIVES: To investigate the use of a passive exhalation port in comparison to an active exhalation valve for long-term TV in ALS patients. Methods: Following tracheostomy for progressive ventilatory failure, 20 consecutive, clinically stable ALS pts were randomly assigned to receive Volume-Assured Pressure Support (VAPS) (Trilogy 100, Philips Respironics) using a passive exhalation port (Whisper Swivel II) (group A) or Pressure Support Ventilation +Target Volume (Vivo 50, Breas GE) using a nonrebreathing expiratory valve (group B). Primary study end-point was PaCO2 level after a 60-day follow-up; the level of dyspnea and care-giver burden were also assessed. Results: Optimal ventilator setting was established within the first 8 hrs of treatment in 8/10 pts in group A. No significant differences in PaCO2 level (38.5±1.34 vs 42.8±1.77 mmHg; p=0.2239), Borg Dyspnea Scale (2±0.29 vs1.5±0.26; p=0.296), and Relative Stress Scale (48±3.87 vs 52±9.42; p=0.316) were apparent at the end of follow-up period, regardless of the exhalation system used. One patients in group A reported minor technical problems with the ventilator. Conclusions: The use of a passive exhalation port had a similar effect on gas exchange, dyspnea and care-giver burden compared to an active exhalation valve in ALS patients receiving long-term TV.