Intermittent abdominal pressure ventilator in a regimen of noninvasive ventilatory support

The purpose of this work is to present 640 patient-years of experience using the intermittent abdominal pressure ventilator (IAPV) in a regimen of noninvasive ventilatory support for patients with paralytic/restrictive respiratory insufficiency. Fifty-two of the 54 patients who used the IAPV used 24-hour noninvasive ventilatory support. Thirty-eight of the 52 patients could tolerate less than 15 minutes of free time off their ventilators except by the successful use of glossopharyngeal breathing (GPB). No patient, however, retained an indwelling tracheostomy and none required or used supplemental oxygen therapy. Forty-eight of the 54 patients used the IAPV for daytime support for a mean of 12.9 +/- 11.5 years (3 months to 39 years) while using other forms of noninvasive support overnight. All 48 patients maintained normal minute ventilation and end-tidal PCO2 on the IAPV. One patient used the IAPV only for nocturnal ventilatory support for six months. Five patients relied on the IAPV as their sole method of ventilatory support 24 hours a day for a mean of 13.4 +/- 11.2 years (range, 2 to 31 years). Three of these five patients had no free time and were studied by nocturnal SaO2 monitoring that demonstrated a mean SaO2 of 95 percent or greater and a minimum SaO2 of 86 percent. The maximum end-tidal PCO2 was 49 mm Hg during sleep on the IAPV. The 48 patients receiving daytime IAPV support reported few difficulties. However, two of the five patients using the IAPV 24 hours a day had development of sacral decubiti. The IAPV became ineffective for 12 patients after 12.3 +/- 9.5 years of use. These patients then switched to daytime mouth IPPV. We conclude that the IAPV is a safe and effective method of long-term daytime ventilatory support for patients with paralytic/restrictive respiratory insufficiency. Its use is optimized when employed in combination with other noninvasive methods of ventilatory support, thus eliminating the need for tracheostomy, and optimizing the use of GPB. Regular follow-up is important because the IAPV can become less effective with time.