A Cochrane review suggests that the therapeutic benefit of mechanical ventilation in patients with neuromuscular and chest wall disease is weak but consistent, indicating short duration relief in the symptoms of chronic hypoventilation [4]. Buyse et al. [5] found that in kyphoscoliosis, NIPPV demonstrated an increase in PaO₂ by 54 %, a fall in PaCO₂ by 21 %, and a rise in vital capacity and maximal static inspiratory mouth pressure by 47 % and 33 %, respectively, but these improvements were not present in patients who received long-term oxygen therapy (LTOT). In the NIV group, the 1-year survival was higher compared with the LTOT group (100 % versus 66 %).

Budweiser and coworkers [6] found that pressure support > 15 cmH₂O accentuated the fall in PaCO₂ during long-term follow-up in patients with restrictive chest wall diseases. They showed that the inspiratory positive airway pressure (IPAP)–expiratory positive airway pressure (EPAP)/weight ratio correlated with the fall in PaCO₂ at the first visit after hospital discharge with long-term NIV. Domiciliary NIV significantly improves quality of life, including dyspnea, fatigue, and emotional status in patients with chest wall disease. Application of NIV improves clinical and physiological response to exercise by alleviating acidosis, hypoxia, and hypercapnia along with a reduction in perception of breathlessness and effort. NIV leads to marked improvement in diurnal arterial oxygen and carbon dioxide tensions (PaO₂ and PaCO₂) along with a decrease in the days for hospital admission for respiratory failure in patients with kyphoscoliosis or sequelae of previous tuberculosis. Better quality of sleep was reported by 62 % of the patients and 70 % reported improvements in activities of daily living [7].

Significant improvement in respiratory and peripheral muscle endurance along with improvement in arterial blood gases has been seen after administration of NIV for 3 months among patients with post-tuberculosis sequelae and scoliosis [8]. An increase in maximal inspiratory pressure of 33–80 % along with a rise in maximal expiratory pressures by 16 % has been observed in patients with chest wall diseases.

In a randomized cohort study in an intensive care unit (ICU), the success rate of NIV in kyphoscoliosis patients with acute respiratory failure was found to be 76.4 % [9]. The frequency of sepsis and septic shock in patients with NIV failure was greater than in patients with NIV success. The mortality rate was higher in patients in the ICU with NIV failure compared with those patients who were initially put on invasive ventilation. The predictors of NIV failure were significantly higher Acute Physiology and Chronic Health Evaluation (APACHE) II score and increased respiratory rate, with lower Glasgow Coma Scale and pH values. Lung functions and 6-min walk distance were found to improve with pressure support of around 15 cm H₂O with pressure-cycled NIV devices during long-term treatment. PaCO₂ ≥ 50 mmHg at 1 month of home ventilation and comorbidity (Charlson comorbidity index ≥3) were independent predictors of mortality in chest wall disease treated with noninvasive home mechanical ventilation [10].

Newer modes of ventilation such as average volume-assured pressure support are an effective treatment option in kyphoscoliotic patients with chronic respiratory failure, leading to an immediate and long-term improvement of daytime and nocturnal blood gas exchange. This mode has shown a significant improvement of diurnal PaO₂ and PaCO₂, mean blood oxygen saturation during sleep on the 5th day of NIV and after 1 year of NIV, along with increase in forced vital capacity after 1 year [11]. Petitjean et al. [12] found that discontinuation of NIV in patients, initially stabilized on NIV, with chronic ventilatory failure (PaCO₂ > 50 mmHg) due to restrictive chest wall diseases (total lung capacity ≤ 65 % of predicted), subjects them rapidly to nocturnal respiratory failure and, within days, to diurnal respiratory failure. Withholding of NIV for more than 24 – 48 h is not recommended.

Patients are usually compliant with NIV, with average daily use significantly higher in post-tuberculosis sequelae and post-poliomyelitis patients in comparison with patients with kyphoscoliosis (9 vs 6 h per day). At present, the compliance rate of NIV in patients with kyphoscoliosis and polio is reported to be around 80–90 %. Mortality rate in patients with kyphoscoliosis on long-term home NIV has been reported as 21 % over 4 years.