in the present issue of critical care , the use of noninvasive positive - pressure ventilation ( nppv ) as a facilitative weaning technique has been clinically assessed by trevisan and colleagues . sixty - five patients on invasive mechanical ventilation for > 48 hours and with t - piece weaning trial failure were randomly assigned to receive bilevel nppv by facemask or to continue the weaning process with invasive ventilation . chronic obstructive pulmonary disease ( copd ) aggravation , postoperative acute respiratory failure ( arf ) , and heart disease were the most frequent causes for the use of invasive ventilation support in both groups . the results of the trial showed that patients of the two groups had similar gas measurements throughout the study . the length of stay in the intensive care unit , the duration of mechanical ventilation after randomization , and the mortality were not statistically different when comparing the groups . furthermore , the percentage of complications in the nppv group was lower ( 28.6% versus 75.7% ) , with a lower incidence of pneumonia ( 3.6% versus 45.9% ) and tracheotomy ( 0% versus 18.9% ) , than in the invasive ventilation group . these results led the authors to conclude that early extubation and nppv is a valid alternative for ventilation in a group of heterogeneous patients that initially failed weaning . nppv is increasingly being proposed in the management of the ventilator weaning process , to avoid the complications of endotracheal intubation , and thereby to potentially lower morbidity and mortality rates in selected patients with arf . the first report to assess the role of nppv as a weaning technique dates back to 1992 , when nppv was successfully used in assisting the return of spontaneous breathing in a small group of 22 patients with chronic respiratory insufficiency and weaning difficulties . several trials have been performed thereafter to further determine the benefit of nppv in permitting early extubation in patients who fail to meet standard extubation criteria [ 6 - 9 ] ( facilitation technique ) , in avoiding reintubation in patients who fail extubation [ 10 - 13 ] ( rescue or curative technique ) , and in preventing extubation failure in nonselected patients   and selected patients   ( preventive or prophylactic technique ) . a recent meta - analysis of five studies enrolling a total of 171 patients was performed to investigate the role of nppv in facilitating early extubation . compared with weaning strategies that involved invasive mechanical ventilation alone , noninvasive weaning was associated with a significant decrease in mortality , in the incidence of ventilator - associated pneumonia , and in the total duration of mechanical ventilation . in a subgroup analysis , earlier trials on postextubation arf in copd patients   and in postoperative patients after lung resection   showed a significant decrease in the need for reintubation using nppv compared with standard medical treatment . despite these encouraging results , two subsequent studies evaluating the effectiveness of nppv as a curative or rescue technique to treat the occurrence of postextubation arf in nonselected populations failed to show improved outcomes . a number of trials have investigated the preventive or prophylactic use of nppv immediately after extubation in avoiding extubation failure in comparison with standard medical therapy . in one early study on the indiscriminate use of nppv in extubated patients , no significant difference in the rate of reintubation for either strategy was found . in two subsequent studies , nppv was found to prevent arf after extubation and to decrease the need for reintubation in selected patients at risk of developing postextubation arf , especially those patients with hypercapnia during their spontaneous breathing trial . it is important that caregivers clearly differentiate among these application modalities of nppv ( facilitative , curative and preventive ) in the management of patients with tracheal intubation in clinical practice , and be aware of the benefit that each of these modalities can provide . trevisan and colleagues have made an important contribution to the continually evolving research on the use of nppv in the management of weaning from mechanical ventilation . their results extend the conclusions of other authors that nppv can be a useful adjunct to conventional weaning strategies [ 6 - 9 ] . in their study , trevisan and colleagues aim to assess the nppv benefits in the weaning process of a heterogeneous group of patients . despite the great interest of these findings for all practicing clinicians , the number of patients enrolled in the study was small , hence limiting the generalizability of its conclusions . currently available data suggest that the potential effectiveness of nppv for facilitating ventilator weaning and early extubation varies across patient population , and that the benefit seems greatest for copd patients . further studies are needed to better identify those subcategories of patients with non - copd arf who are most likely to benefit from nppv during the weaning process and those who are at highest risk of adverse consequences . the skills and expertise of both medical and nonmedical personnel represent some of the most important factors for the success of nppv in the ventilator weaning process . it is crucial that caregivers can identify patients who are likely to benefit from early extubation with nppv and exclude those patients for whom this approach would be unsafe . once the decision to institute nppv has been taken , an interface and ventilatory mode must be chosen , and close monitoring in an appropriate hospital location must be provided . finally , arf = acute respiratory failure ; copd , chronic obstructive pulmonary disease ; nppv = noninvasive positive - pressure ventilation .
to avoid the complications associated with endotracheal intubation , noninvasive positive - pressure ventilation ( nppv ) has been proposed in the management of ventilator weaning in patients with acute respiratory failure ( arf ) of various etiologies . 
 several studies have been performed to assess the benefit of nppv in various weaning strategies , including permitting early extubation in patients who fail to meet standard extubation criteria ( facilitation use ) , avoiding reintubation in patients who fail extubation ( curative use ) , and preventing extubation failure in nonselected and selected patients ( preventive use ) . 
 nppv has been successfully used in facilitating early extubation , particularly in patients with chronic obstructive pulmonary disease . 
 in contrast , applying curative nppv to treat postextubation arf in nonselected populations may not be effective and could even be deleterious . 
 early use of nppv was successful in preventing arf after extubation , and decreased the need for reintubation in selected patients at risk of developing postextubation arf . 
 it is important that caregivers clearly differentiate among these application modalities of nppv . 
 the skills and expertise of both medical and nonmedical personnel are crucial predictive factors for the success of nppv in the ventilator weaning process .