Noninvasive Positive Ventilation
INTRODUCTION In the early 1960s and 1970s limited experience with the long-term use of mechani cal ventilation at home was acquired to replace or complement the ventilatory function after acute poliomyelitis and other neuromuscular or even lung diseases. Depending on the medical centers the three main methods for delivering mechani cal tidal volume were used: intermittent negative pressure ventilation with iron lung or chest shell (1-3), intermittent positive pressure ventilation (IPPV) via a tracheostomy (3,4) or via a mouthpiece (5,6). In the early 1980s in spite of obvious clinical positive results, clinicians were reluctant to use these techniques, consider ing them as much too invasive (tracheostomy) or cumbersome and of limited efficacy (negative pressure) (7). It is now recognized, after the explosive experience of nasal continuous positive airway pressure (CPAP) to treat obstructive apnea (8), that IPPV could also be comfortably and efficiently delivered, noninvasively [noninvasive positive pressure ventilation (NIPPV)] through facial interfaces. Positive pressure is applied to the airway during inspiration at higher value than during expiration. Thus, NIPPV brings a part or even the whole tidal volume. Depending on the underlying diseases either IPPV is continuously mandatory to avoid death in case of complete or quasi-complete paralysis or is used nightly, pro ducing enough improvement to allow free time during the daytime for spontaneous breathing. This chapter will address the use of NIPPV (to the exclusion of CPAP) in the different diseases for which it is currently proposed: principally in diseases responsible for chronic hypoventilation and incidentally in others such as obstruc tive sleep apnea (OSA) or problems of central drive (Cheyne-Stokes breathing, Ondine's curse). NIPPV, which is now a predominant technique, allows a progres sive generalization for long-term home ventilation (9).