Volume Assured Pressure Support in Central Sleep Apnea Treatment

Mechanism and Effectiveness

The American Academy of Sleep Medicine recommends VAPS as it automatically adjusts inspiratory positive airway pressure (IPAP) between set minimum and maximum limits to deliver a targeted tidal volume, helping prevent the hypoventilation that characterizes central sleep apnea 1
VAPS can be used in spontaneous, spontaneous-timed (ST), or timed modes, with ST mode recommended for patients with central apneas due to the importance of a backup rate 1, 2

Initial recommended settings for VAPS include EPAP = 4 cm H₂O, IPAP min = EPAP + 4 cm H₂O, IPAP max = 25-30 cm H₂O, and target tidal volume = approximately 8 mL/kg ideal body weight 1
A backup rate should always be used (ST mode) in patients with central hypoventilation, central apneas, or inappropriately low respiratory rates 2
Starting backup rate should equal or be slightly less than the spontaneous sleeping respiratory rate (minimum 10 breaths/minute) 2
IPAP time should be set to provide an inspiratory time between 30-40% of the cycle time 2

Standard pressure support ventilation (PSV) can worsen sleep quality and induce central apneas in patients due to hyperventilation and hypocapnia, as reported by the Intensive Care Medicine journal 3
The backup rate in ST mode prevents central apneas that might occur with fixed pressure support 2

Caution is warranted in heart failure patients with reduced ejection fraction, as adaptive servoventilation (a similar but distinct technology) has been associated with increased mortality in this population, according to the American College of Cardiology 5

VAPS titration with polysomnography is the recommended method to determine effective settings, as suggested by the American Academy of Sleep Medicine 2
EPAP should be adjusted first to eliminate obstructive events 1
Pressure support should be increased if tidal volume is low, arterial PCO₂ remains elevated, or SpO₂ remains below 90% 2
Backup rate should be increased in 1-2 breaths per minute increments every 10 minutes if goals are not met 2

Sleep architecture, AHI, oxygen saturation, and PCO₂ levels should be monitored during titration, as recommended by the American Academy of Sleep Medicine 2
Transcutaneous or end-tidal PCO₂ may be used to adjust settings if properly calibrated 2
Patient comfort and mask fit are essential for adherence 2

Patient-ventilator asynchrony can occur and should be minimized through careful titration, as reported by the Intensive Care Medicine journal 6