Negative-pressure ventilation: is there still a role?

Negative-pressure ventilation (NPV) was the primary mode of assisted ventilation for patients with acute respiratory failure until the Copenhagen polio epidemic in the 1950s, when, because there was insufficient equipment, it was necessary to ventilate patients continually by hand via an endotracheal tube. Thereafter, positive-pressure ventilation was used routinely. Since it was also observed that patients with obstructive sleep apnoea could be treated noninvasively with positive pressure via a nasal mask, noninvasive positive-pressure ventilation (NPPV) has become the most widely used noninvasive mode of ventilation. However, NPV still has a role in the treatment of certain patients. In particular, it has been used to good effect in patients with severe respiratory acidosis or an impaired level of consciousness, patients that to date have been excluded from all prospective controlled trials of NPPV. NPV may be used in those who cannot tolerate a facial mask because of facial deformity, claustrophobia or excessive airway secretion. NPV has also been used successfully in small children, and beneficial effects on the cardiopulmonary circulation maybe a particular advantage in children undergoing complex cardiac reconstructive surgery. This review is divided into two parts: the first is concerned with the use of negative-pressure ventilation in the short term, and the second with its use in the long term.