From the Guidelines
For a 65-year-old morbidly obese female with severe OSA (AHI of 95) and respiratory acidosis with hypoxemia, recommended initial BiPAP settings would be: IPAP (inspiratory pressure) of 25-30 cmH2O, EPAP (expiratory pressure) of 8-10 cmH2O, with a backup rate of 12-14 breaths per minute, as high inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP) settings are commonly required in patients with obesity hypoventilation syndrome (OHS) 1.
Key Considerations
- The patient's severe OSA and respiratory acidosis require high IPAP and EPAP settings to overcome upper airway obstruction and address hypoventilation associated with obesity.
- The pressure support (difference between IPAP and EPAP) should be maintained at 8-12 cmH2O to ensure adequate tidal volume.
- Supplemental oxygen should be added to maintain oxygen saturation above 90%.
- Close monitoring is essential during initiation, including arterial blood gases to assess improvement in respiratory acidosis, overnight oximetry to confirm resolution of desaturations, and comfort assessment to ensure adherence.
- The settings may need adjustment based on the patient's tolerance and clinical response, with follow-up sleep studies recommended to confirm efficacy in controlling the severe OSA.
Rationale
The recommended BiPAP settings are based on the most recent and highest quality study available, which suggests that high IPAP and EPAP settings are necessary for patients with OHS 1. The American Thoracic Society clinical practice guideline also recommends treatment with PAP during sleep for stable ambulatory patients diagnosed with OHS 1. While the guideline suggests initiating first-line treatment with CPAP therapy rather than NIV for patients with concomitant severe OSA, the patient's severe respiratory acidosis and hypoxemia require more aggressive treatment with BiPAP.
Additional Recommendations
- The patient should be closely monitored for potential complications, such as respiratory failure, and adjustments should be made to the BiPAP settings as needed.
- A weight-loss intervention should be considered to achieve sustained weight loss of 25-30% of actual body weight, which is most likely required to achieve resolution of hypoventilation 1.
From the Research
Recommended BiPAP Settings
To determine the recommended BiPAP settings for a 65-year-old morbidly obese female with severe Obstructive Sleep Apnea (OSA), Apnea-Hypopnea Index (AHI) of 95, and respiratory acidosis with hypoxemia, we can look at the following:
- The study 2 used initial inspiratory and expiratory positive airway pressures (IPAP, EPAP) set at 8 and 4 cm H2O respectively, and increased IPAP by increments of 2 cm H2O and EPAP by 1 cm H2O increments until respiratory comfort was achieved.
- The final IPAP and EPAP settings in the study 2 ranged from 14 to 18 cm H2O and 4 to 8 cm H2O, respectively.
- Another study 3 compared the effects of BiPAP (15 cmH2O Phigh and 5 cmH2O Plow) with pressure support and CPAP, and found that BiPAP increased the work of breathing in COPD patients.
Key Considerations
Some key considerations for BiPAP settings include:
- Initial settings: IPAP 8-10 cm H2O, EPAP 4-6 cm H2O 2
- Titration: increase IPAP by 1-2 cm H2O and EPAP by 1 cm H2O until respiratory comfort is achieved and oxygen saturation is maintained above 90% 2
- Monitoring: closely monitor the patient's oxygen saturation, respiratory rate, and comfort level to adjust the BiPAP settings as needed 4, 2
Additional Therapies
Additional therapies that may be considered include: