BiPAP to CPAP: Is switching safe?
Switching from bilevel positive airway pressure (BiPAP) to continuous positive airway pressure (CPAP) ventilation therapy may be safe and cost-effective in patients with obesity hypoventilation syndrome and sleep apnoea, a small study presented at the ERS 2017 has shown.
“We all felt pretty neutral on this when we started, but our results were very positive,” said primary investigator Dr María Paola Arellano-Maric from the Pontifical Catholic University of Chile in Santiago, Chile.
It was thought that patients with a pressure gradient for inhalation and exhalation, which is the key feature of the BiPAP devices, would have easier time to get air in and out of the lungs. On the contrary, CPAP devices can only be set to a single pressure and exhaling against the constant, singular, continuous stream of pressurized air may be difficult for most patients. “However, our patients did not experience respiratory insufficiency with CPAP,” said Arellano-Maric. “This was after they were stabilized on BiPAP for at least 3 months.”
Current guidelines do not recommend automatic titrating of CPAP machines for COPD and apnoea patients. To add to that, there is a dearth of studies on BiPAP being switched to CPAP therapy.
Arellano-Maric and colleagues sought to determine if switching to CPAP after >3 months of BiPAP is safe in patients with obesity hypoventilation syndrome and sleep apnoea. [ERS 207, abstract OA4427]
Patients (n=42) had been receiving noninvasive BiPAP ventilation at home for an average of 3-4 months. All had apnoea and more than half had chronic obstructive pulmonary disease (COPD) of either GOLD stage I or II. Average BMI was 45.1 kg/mg². Eight out of 10 were either current or former smokers. They spent a night in the hospital and were hooked to an automatic positive airway pressure (APAP) device. Once stabilized, they were sent home with a CPAP device.
“The pressure was set at 14 cm of water. It was high … we’re worried they couldn’t sleep at all,” said Arellano-Maric. Three weeks after CPAP therapy, patients were subjected to polysomnography and reported that they were sleeping better. Fifty-seven percent of patients expressed preference for CPAP therapy, despite high levels of pressure (mean, 13.8 mbar).
Of note, levels of partial pressure of carbon dioxide in arterial blood (PaCO2) stabilized at 45 mm Hg (normal value: 35-45 mm Hg) in 71 percent of patients after 6 weeks of CPAP therapy.
Switching to CPAP may not only be safe and effective, it has also far-ranging implications in terms of cost and compliance, Arellano-Maric said. As the BiPAP device is more expensive, “patients could rent the device for a short period and then purchase a CPAP device for home use” to improve treatment adherence.