Noninvasive assisted pressure-controlled ventilation: As effective as pressure support ventilation in chronic obstructive pulmonary disease?

Background: Noninvasive ventilation ( NIV) is being increasingly used in hypercapnic chronic obstructive pulmonary disease ( COPD) patients but the most appropriate ventilation mode is still not known. Objectives: The aim of this study was to investigate if assisted pressure-controlled ventilation ( APCV) can be a better alternative to pressure-support ventilation ( PSV) for NIV in COPD patients with acute hypercapnic respiratory failure ( AHRF). Methods: In this prospective randomized study, we evaluated the early effects of noninvasive APCV and PSV in 34 consecutive COPD patients with AHRF. Patients were randomized into 1 of the 2 modes, and respiratory and hemodynamic values were compared before and after 1 h of NIV. Results: Baseline values did not differ between the 2 groups. There were significant improvements in partial arterial carbon dioxide pressure and pH levels in the APCV group when compared with baseline ( p < 0.05). Cardiac output and cardiac index decreased in both groups ( p < 0.05) but more significantly in the PSV group p < 0.0001). The decreases in stroke volume index and increases in arterial oxygen content after NIV were also considerable in both groups ( p < 0.05). Central venous pressure and systemic vascular resistance index values increased notably only after PSV ( p < 0.05). Conclusions: From these data, we deduce that APCV can be a better alternative to PSV for NIV in COPD patients with AHRF owing to its more beneficial physiological effects. Copyright (C) 2007 S. Karger AG, Basel