What are the optimal initial settings for Continuous Positive Airway Pressure (CPAP) therapy, including expiratory positive airway pressure and fraction of inspired oxygen (FiO2)?

From the Guidelines

For starting CPAP therapy, I recommend initial settings of 8 cmH2O for continuous positive airway pressure with an expiratory positive airway pressure (EPAP) of 4 cmH2O if using bilevel positive airway pressure (BiPAP), as supported by the American Academy of Sleep Medicine guidelines 1. The FiO2 should be set at 21% (room air) initially for most patients without hypoxemia, increasing to 30-40% if oxygen saturation is below 90%.

Key Considerations

• The recommended minimum starting CPAP should be 4 cm H2O for pediatric and adult patients, and the recommended minimum starting IPAP and EPAP should be 8 cm H2O and 4 cm H2O, respectively, for pediatric and adult patients on BPAP 1.
• The recommended minimum starting pressure support (difference between IPAP and EPAP) should be 4 cm H2O, with a maximum pressure support of 20 cm H2O 1.
• For obstructive sleep apnea, start with CPAP mode at 8 cmH2O and increase by 1-2 cmH2O increments until obstructive events are eliminated.
• A properly fitted mask is essential to prevent air leaks and ensure therapy effectiveness.

Titration and Adjustments

• These settings should be titrated based on patient response and comfort.
• Adjustments should be made based on objective measures like the apnea-hypopnea index, oxygen saturation, and patient comfort during follow-up evaluations.
• The minimum and maximum incremental changes in pressure support during NPPV titration should be 1 and 2 cm H2O, respectively 1.

From the Research

CPAP Settings

• The best starting settings for CPAP, including expiratory positive airway pressure (EPAP) and fraction of inspired oxygen (FIO2), are not explicitly stated in the provided studies.
• However, a study from 1990 2 suggests that treatment of obstructive sleep apnea with nasal continuous positive airway pressure mandates simultaneous increases of both inspiratory and expiratory positive airway pressures to eliminate apneas as well as nonapneic oxyhemoglobin desaturation events.
• The same study 2 also found that obstructive sleep-disordered breathing can be eliminated at lower levels of expiratory airway pressure compared with conventional nasal CPAP therapy by using a device that permits independent adjustment of EPAP and IPAP.

Expiratory Positive Airway Pressure (EPAP)

• A review of EPAP nasal device therapy for obstructive sleep apnea syndrome from 2015 3 states that EPAP provides a new therapeutic option for obstructive sleep apnea (OSA) and has been shown to reduce the apnea/hypopnea index (AHI) and daytime sleepiness.
• Patients generally prefer EPAP to continuous positive airway pressure (CPAP), and there are no serious adverse effects from its use 3.
• However, more studies are needed to assess the efficacy of and compliance with EPAP nasal devices, to define which patients will benefit from EPAP therapy, and to compare EPAP to other alternative OSA therapies 3.

Fraction of Inspired Oxygen (FIO2)

• A study from 2017 4 examined the impact of continuous positive airway pressure and oxygen on health status in patients with coronary heart disease, cardiovascular risk factors, and obstructive sleep apnea.
• The study found that CPAP treatment improved vitality, sleepiness, mental health, social functioning, and depressive symptoms in patients with OSA and established CHD or risk factors 4.
• Nocturnal supplemental oxygen may have beneficial effects on perceived physical functioning 4.

CPAP Treatment

• A meta-analysis from 2013 5 found that CPAP treatment improves the left ventricular ejection fraction (LVEF) among patients with OSA, with a significant improvement in LVEF observed after CPAP treatment.
• Subgroup analysis revealed that patients with OSA and heart failure had a significant improvement in the LVEF after CPAP treatment 5.