Post-poliomyelitis patients may develop insidious respiratory failure. Chronic alveolar hypoventilation symptoms are often misdiagnosed and the condition is frequently treated inappropriately by oxygen therapy. Physicians are often at a loss to offer assisted ventilation by noninvasive methods and tracheostomy and long-term tracheostomy intermittent positive pressure ventilation is often refused. We studied the use of two noninvasive positive airway pressure alternatives for the nocturnal ventilatory support of 31 post-poliomyelitis patients. These methods were intermittent positive pressure ventilation via nasal access (NIPPV) and via a strapless oral-nasal interface (SONI IPPV). The use of custom fabricated interfaces was also evaluated. Practical alternatives for assisted daytime ventilation included glossopharyngeal breathing, the pneumobelt ventilator and mouth intermittent positive pressure ventilation. Overnight sleep monitoring was performed on 10 patients breathing autonomously or with body ventilators then repeated on NIPPV and/or SONI IPPV. The mean sleep oxygen saturation (SaO2) increased from 87.5 +/- 9.1% on unassisted breathing or body ventilators to 96.2 +/- 2.0% (P less than 0.01) on NIPPV or SONI IPPV. Of 12 other patients with a mean vital capacity of 472 +/- 480 ml and no significant free time supine, 11 patients also maintained SaO2 greater than 94% during sleep supine on NIPPV and/or SONI IPPV. Twenty-one patients have been on nocturnal NIPPV for an average of 23 (3-70) months. Six have been on nocturnal SONI IPPV for an average of 35 (5-66) months. All patients' hypoventilation symptoms were relieved. In conclusion, NIPPV and SONI IPPV can improve the nocturnal ventilation of post-poliomyelitis patients with chronic alveolar hypoventilation.(ABSTRACT TRUNCATED AT 250 WORDS)