0517 A RETROSPECTIVE COMPARISON OF CONVENTIONAL BILEVEL POSITIVE AIRWAY PRESSURE WITH BACK UP RATE TO AVERAGE VOLUME ASSURED PRESSURE SUPPORT IN PATIENTS WITH RESPIRATORY INSUFFICIENCY RELATED TO NEUROMUSCULAR DISEASE

Abstract

Bilevel positive airway pressure with back up rate (BPAP-ST) is the most common ventilation mode in neuromuscular disease patients. The role of Average Volume Assured Pressure Support (AVAPS) has not been established. Our aim was to compare ventilatory and sleep parameters and patient preference of BPAP-ST vs AVAPS. We implemented a sequential titration protocol of BPAP-ST followed by AVAPS during polysomnography in 10 patients (all had known or suspected ALS) and retrospectively reviewed their data. Patients (50% female) averaged 66 years(± 6 SD) with maximal predicted inspiratory and expiratory pressures, and vital capacity of 46% (± 17), 36% (± 23), and 65% (± 25) respectively. At optimal titration of each device, average tidal volumes were 93.2 ml (± 61) higher on AVAPS with transcutaneous CO2 0.7 mmHg (± 2.9) higher on BPAP-ST. Average respiratory rate was 2.8 bpm (± 5) higher while nadir NREM SaO2 was 4.7% (± 8) lower on BPAP-ST with no difference in REM (0 ± 2). Tidal volumes tolerated by patients on AVAPS were 47ml (± 55) lower than those recommended per the manufacturer’s reference table (8ml/kg). The average apnea-hypopnea index was 2.9 events/hour(± 10) higher on BPAP-ST. Sleep efficiency was on average 0.7% (± 18) higher on BPAP-ST. None of the ventilatory or sleep parameters differed significantly (p> 0.05) between BPAP-ST and AVAPS. A majority of the patients preferred BPAP-ST (70%). BPAP-ST and AVAPS provided equivalent ventilator and sleep parameters during polysomnography in a neuromuscular disease patient cohort while these patients tended to prefer BPAP-ST.