In a randomized, controlled trial, Ferrer et al. [4] assessed the efficacy of NIPPV in patients with persistent weaning failure. In 43 mechanically ventilated patients, with the majority being ventilated secondary to exacerbation of COPD and who had failed a conventional weaning trial for 3 consecutive days, NIPPV led to earlier extubation, shorter mechanical ventilation and length of ICU and hospital stay, less need for tracheostomy, lower incidence of complications, and improved ICU survival [4]. A meta-analysis of five studies and 171 patients reported that the use of NPPV facilitates weaning with a consistent positive effect of noninvasive weaning on mortality [5]. A large body of clinical evidence suggests that NIPPV can be beneficial for weaning COPD patients who fail weaning from invasive mechanical ventilation. In a randomized, controlled study of 50 patients invasively ventilated for acute exacerbation of COPD and who failed a spontaneous breathing trial, Nava et al. [6] showed that NIPPV facilitated extubation within 48 h, shortened the length of stay in the ICU, decreased the incidence of nosocomial pneumonia, and improved the 60-day survival rates. Trevisan et al. [7] assessed the use of NIPPV during weaning from mechanical ventilation. The majority of their patients (35 %) were patients COPD patients. They showed that in patients who failed spontaneous ventilation trial when weaning was attempted, NPPV is a good alternative that resulted in better outcome, fewer complications, and less need for tracheostomy [7]. In a prospective, randomized and controlled study, Prasad et al. [8] evaluated the effectiveness of NIPPV as a weaning method in patients with COPD receiving invasive mechanical ventilation. Thirty COPD patients were randomized to be weaned with either NIPPV or invasive pressure support ventilation (PSV). In patients who failed a weaning trial, NIPPV resulted in faster weaning and a decrease in ICU stay, complications, and mortality [8]. Mishra et al. [9] evaluated the usefulness of NIPPV in weaning COPD patients from invasive mechanical ventilation in a prospective, randomized, and controlled study. They included 50 patients who failed an initial weaning trial and subsequently were either extubated to be weaned with NIPPV (25 patients) or remained on invasive mechanical ventilation for further weaning with PSV. NIPPV resulted in shorter duration of weaning and ventilation, shorter ICU stay, less incidence of nosocomial pneumonia, and lower ICU mortality [9].

Another factor for the success of NIPPV in weaning COPD patients is the proper utilization and adjustment of the device providing NIPPV. The mode of NIPPV as well as other relevant parameters (i.e., inspiratory positive airway pressure (IPAP), expiratory positive airway pressure (EPAP), back-up rate (RR) as well as fraction of inspired oxygen (FiO₂)) are parameters and variables that need to be adjusted dynamically according to the patient’s needs. In general, most COPD patients are managed with BiPAP in the spontaneous/timed (S/T) mode where the patient is triggering the device except during apneas/hypopneas, where the preset back-up RR (usually 12–14 breaths/min) guarantees adequate ventilatory support [6–9]. Initial levels of IPAP (10–25 cmH₂O) and EPAP (5–10 cmH₂O) are usually decided on achieving adequate tidal (approximately 5–6 ml/kg), total respiratory rate less than 25 breaths/min, acceptable arterial blood gas values, and patient tolerance and comfort. When managing and adjusting IPAP and EPAP levels during the course of ventilatory support, clinicians should consider the difference between IPAP and EPAP as well as their individual values. The difference between IPAP and EPAP (sometimes referred to as PSV) per se and not the absolute values has a direct effect on the delivered tidal volume [10]. Increasing the difference between IPAP and EPAP usually results in an increase in tidal volume and vice versa. EPAP, however, has a similar physiological effect as positive end-expiratory pressure (PEEP). It has a direct effect on oxygenation by restoring functional residual capacity and partially recruits collapsed alveoli. In addition, EPAP can stabilize recruited alveoli and prevent derecruitment [10]. For patients with COPD, EPAP decreases the work of breathing by minimizing the effect of auto-PEEP that is frequently seen and manifested in COPD patients [10]. With the emerging technologies of NIPPV, clinicians can provide accurate and adequate FiO₂ with the use of oxygen-air blenders incorporated in the new BiPAP machines. With the old BiPAP technologies where the FiO₂ was a result of air and oxygen flows mixing, it was always a challenge to provide adequate, accurate, and stable FiO₂ best suited to COPD patients.