Most authors agree that NIV episodes with no previous invasive ventilation should be considered different from postextubation ones. Conditions after extubation place patients in a completely different situation than that occurring when a child has not been previously ventilated [4].

Postextubation NIV can be used in three ways: (1) as an adjunct in weaning patients from conventional mechanical ventilation by early extubation directly to NIV, (2) as a preventive application for NIV in high-risk patients who are extubated at the time they fulfill standard extubation criteria, or (3) as a curative or rescue application of NIV to patients who develop acute respiratory failure (ARF) after being extubated according to standard criteria. The first two indications have been suggested by some pediatric studies to be the so-called postextubation elective NIV (e-NIV) group, which includes high-risk children treated with NIV immediately after the endotracheal tube is removed. Those patients who develop ARF within hours after extubation and receive NIV to try to avoid reintubation are considered the so-called rescue NIV (r-NIV) group [4, 5].

These two groups should be analyzed separately, according to several adult studies [6] and to some pediatric reports [4]. However, there are few studies about postextubation NIV in children. As has been previously mentioned, some studies analyzed NIV episodes with or without previous invasive ventilation [1, 2]. In the case of analyzing postextubation NIV, these studies frequently do not consider r-NIV and e-NIV separately [3].

Some studies have underlined the usefulness of NIV after some surgeries. Most of them focus on cardiac surgery, and others describe its utility after liver transplantation or scoliosis surgery [1, 7–12]. Postoperative NIV is especially useful in pediatric patients, who develop atelectasis quite frequently because of a lack of collateral pathways for ventilation and low conductance of the central airways.

Children receiving NIV after cardiac surgery are a group of patients that deserve special consideration. Early extubation is desirable and is associated with a better outcome, and thus e-NIV is increasingly being used in these cases to shorten the length of invasive ventilation. As such, NIV is frequently used to prevent extubation failure. A study by Gupta et al. [7] suggested that NIV can be successfully applied for critically ill children with heart disease to avoid reintubation. These benefits have been related to NIV improvement of existing or preexisting lung disease, diaphragmatic paralysis, and airway edema (stenting of the airway). These authors also included a sample of children with cardiac disease who received r-NIV. They found an intubation rate similar to that in patients in whom e-NIV was used. However, this study was retrospective and there were no clear criteria to initiate NIV [7].