Nasal ventilation was achieved with a volume-cycled portable home ventilator (PLV 100 Life Products). Room air without humid-ification was driven through dear corrugated tubing to the patient via a nose mask. The nose mask was customized with a lightweight sandsplint shell and a Neoprene seal. Each patient underwent at least one daytime laboratory assessment in which resting ventilation was measured by attaching a pneumotachygraph to the expiratory port of the face mask. Expired flow was integrated to display volume. Simultaneously the diaphragmatic and sternocleidomastoid EMGs were monitored with surface electrodes. The criteria used for effective ventilatory support were a reduction of at least 50 percent in the EMG signals accompanied by a decrease in Pco, and an increase Sa02. buy yasmin online
Nasal ventilation was started during the day under no supervision of a respiratory therapist. The time during which a patient received ventilatory support was increased gradually over several days. When the patient could tolerate several hours of ventilation, daytime ventilation was discontinued and nighttime ventilation commenced. The duration of ventilation was increased until patients could tolerate 6 h each night for at least six nights each week. On the initial nights, nocturnal SaOt and Pco2 were monitored continuously. All baseline measurements were repeated eight weeks following hospital discharge (equivalent to 12 to 14 weeks of ventilation and again following 14 months of ventilation). Statistical analysis between baseline and the initial post intervention measurements was by paired t test with an alpha of 0.05.