High-intensity non-invasive ventilation: a brief review and update

Long-term noninvasive ventilation (NIV) to treat chronic hypercapnic respiratory failure is still controversial in severe chronic obstructive pulmonary disease (COPD) patients. However, with the introduction of high-intensity NIV, important benefits from this therapy have also been shown in COPD. High-intensity NIV was originally described for chronic hypercapnic COPD, and refers to a specific ventilatory approach whereby NIV settings are aimed at achieving the lowest arterial partial pressure of carbon-dioxide (PaCO2 outcomes) values possible. Thus, high-intensity NIV requires ventilator settings to be increased in a stepwise approach to either an individually tolerated maximum, or to the levels necessary to achieve normocapnia. This differs from the classic approach to low-intensity NIV, which comprises considerably lower ventilator settings and typically fails to lower elevated PaCO2 values. There is now increasing evidence to suggest that high-intensity NIV can improve important physiological parameters such as blood gases and lung function, as well as health-related quality of life. Moreover, this approach improves survival rates in stable COPD patients, and admission-free survival in patients with persisting hypercapnia. Nevertheless, despite these positive findings, the application of long-term NIV in patients with severe COPD should be considered carefully, as knowledge gaps remain with regard to patient selection, the optimal place to initiate NIV and the optimal ventilatory settings to be used. The aim of this review was to update the current status of high-intensity NIV, in relation to its clinical and physiological effects, mainly in chronic hypercapnia in the COPD patient, but also in acute hypercapnia in COPD and other hypoventilation situations.