ABSTRACT
Noninvasive ventilation has been used for the long-term therapy of respiratory failure dating back to the polio epidemics of the 1920s and 1930s (1). Negative pressure ventilation was the main ventilatory mode used until the 196Os, when positive pressure techniques gained favor. Although noninvasive positive pressure ventilation (NPPV) was used for long-term ventilation at some centers dating back to the 1960s (2), use of invasive techniques predominated at most centers. During the late 1970s and early 1980s, several reports described the successful long-term application of intermittent nocturnal negative pressure ventilation for patients with restrictive thoracic diseases (3-5), but these techniques were not used at most centers (6).
