Transitioning from CPAP to BiPAP with Bicarbonate Therapy

Indications for Switching from CPAP to BiPAP

Patients should be switched from CPAP to BiPAP when they develop hypercapnic respiratory acidosis (pH <7.35 or [H+] >45 nmol/L) that persists for more than 30 minutes despite standard medical management, as recommended by the American Thoracic Society 1
The American Academy of Sleep Medicine suggests considering BiPAP if there are continued obstructive respiratory events at 15 cm H2O of CPAP during titration 2, 3
If the patient is uncomfortable or intolerant of high pressures on CPAP, they may be tried on BiPAP, according to the American Academy of Sleep Medicine 2, 3

The European Society of Cardiology recommends considering non-invasive positive pressure ventilation (BiPAP) in patients with respiratory distress (respiratory rate >25 breaths/min, SpO2 <90%) and starting it as soon as possible to decrease respiratory distress and reduce the rate of mechanical endotracheal intubation 5

The American Academy of Sleep Medicine recommends a minimum starting IPAP and EPAP of 8 cm H2O and 4 cm H2O, respectively, in adult patients 2, 3
Typical BiPAP settings for reducing work of breathing include IPAP of 14-20 cmH2O and EPAP of 4-8 cmH2O, as suggested by the American Academy of Sleep Medicine 2, 3
The recommended minimum IPAP-EPAP differential is 4 cm H2O and the recommended maximum IPAP-EPAP differential is 10 cm H2O, according to the American Academy of Sleep Medicine 2, 3

The European Society of Cardiology recommends repeating blood gases at 30-60 minutes after initiating BiPAP to check for rising PCO2 or falling pH 1
The European Society of Cardiology suggests measuring blood pH and carbon dioxide tension (possibly including lactate) in patients with acute pulmonary edema or previous history of COPD 5
The European Society of Cardiology recommends monitoring transcutaneous arterial oxygen saturation (SpO2) continuously 5
The European Society of Cardiology suggests monitoring blood pressure regularly when using non-invasive positive pressure ventilation, as it can reduce blood pressure and should be used with caution in hypotensive patients 5

For patients with COPD or other risk factors for hypercapnic respiratory failure, the British Thoracic Society recommends checking blood gases on arrival in hospital and repeating at 30-60 minutes even if the initial PCO2 measurement was normal 1
If the PCO2 is raised but pH is ≥7.35 (H+ ≤45 nmol/L) and/or a high bicarbonate level (>28 mmol/L), the British Thoracic Society suggests maintaining target oxygen saturation range of 88-92% for these patients 1
The British Thoracic Society recommends stepping down oxygen therapy to the lowest level required to maintain a saturation range of 88-92% if a patient is suspected to have hypercapnic respiratory failure due to excessive oxygen therapy 1
The British Thoracic Society warns that sudden cessation of supplementary oxygen therapy can cause life-threatening rebound hypoxemia 1