Efficacy and comfort of volume-guaranteed pressure support in patients with chronic ventilatory failure of neuromuscular origin

Background and objective: Although non-invasive ventilation is widely used for the management of patients with neuromuscular disease, it remains unclear which ventilatory mode is associated with optimal patient-ventilator interaction and provides more effective gas exchange. The effects of volume-guaranteed pressure support (PSV-VTG) as compared with pressure support ventilation (PSV) and assisted pressure controlled ventilation (APCV) on breathing pattern and patient-ventilator synchrony during sleep, blood gases and subjective comfort were evaluated in a group of stable patients with neuromuscular disease. Methods: PSV-VTG, PSV and APCV were applied in random order on three consecutive nights, during which cardio-respiratory monitoring was performed. Arterial blood gases were measured at the end of each ventilatory session. Evaluation of subjective sleep quality, comfort and perception of patient-ventilator synchrony was performed using a 10-item visual analogue questionnaire. Results: Twenty-eight patients were included in the study. The different ventilatory modes showed similar effects on breathing pattern during sleep, arterial blood gases and degree of subjective comfort. Ineffective efforts were only observed during PSV-VTG and were inversely correlated with the variability of leaks (r = -0.61, P = 0.015). A greater number of prolonged inspirations was observed with PSV-VTG and PSV compared with APCV (P = 0.048 and 0.029, respectively). There were no correlations between patient comfort and physiological variables or ventilator setting. Conclusions: PSV-VTG did not outperform older modes of ventilation in terms of efficacy on breathing pattern and blood gases. In addition, application of PSV-VTG was associated with a higher rate of patient-ventilator dyssynchrony.