What is Treatment-Emergent Central Sleep Apnea (TE-CSA)?
Treatment-emergent central sleep apnea (TE-CSA or TECSA) is a specific sleep-disordered breathing pattern characterized by the new emergence or persistence of central apneas (central apnea-hypopnea index ≥5 events/hour) during positive airway pressure therapy for obstructive sleep apnea, which cannot be explained by other causes. 1, 2
Definition and Diagnostic Criteria
- TE-CSA occurs when patients with obstructive sleep apnea develop central sleep apnea during treatment with CPAP or other PAP modalities 1
- The diagnosis requires a central AHI ≥5/h that emerges during PAP therapy and is not attributable to other underlying conditions (such as heart failure, neurologic disease, or medication effects) 2
- This phenomenon has been documented not only with CPAP but also with mandibular advancement devices 3
Epidemiology and Natural History
- The prevalence of TE-CSA varies widely across studies, ranging from 1.8% to 20% of OSA patients treated with CPAP 1, 2
- Approximately 60-80% of TE-CSA cases are self-limiting and resolve spontaneously with continued CPAP therapy over time 1, 2, 4
- In about two-thirds of cases, the condition resolves during the course of ongoing positive pressure therapy 2
Pathophysiology
The mechanisms underlying TE-CSA are incompletely understood but involve several key factors:
- Ventilatory control instability appears central to TE-CSA development, with PaCO2 and the associated apnea threshold playing critical roles 1, 2
- Low arousal threshold contributes to the instability of breathing patterns 1
- Activation of lung stretch receptors during PAP therapy may trigger central apneas 1
- Prolonged circulation time can contribute to ventilatory control instability 1
- Increasing tidal volume through higher inspiratory positive airway pressure (IPAP) may contribute to TE-CSA onset through ventilatory overshoot 5
Clinical Management Approach
Initial Management: Watchful Waiting
- For most patients with TE-CSA, continuation of CPAP therapy with close monitoring is appropriate, given the high spontaneous resolution rate 1, 2, 4
- Follow-up polysomnography should be performed to assess whether central apneas persist or resolve 3
When to Intervene
If TE-CSA persists beyond the initial treatment period or develops later during established PAP therapy, further evaluation is indicated:
- Perform echocardiography to exclude heart failure 2
- Conduct neurologic examination to rule out central nervous system pathology 2
- Review medication history, particularly for opiates which can cause central apneas 2
Treatment Options for Persistent TE-CSA
When central apneas persist despite regular CPAP therapy and cause significant symptoms or high central apnea index, several treatment modifications can be considered:
- Reducing inspiratory positive airway pressure can effectively eliminate central apneas - one study showed complete resolution of TE-CSA in all patients by reducing IPAP (central AHI decreased from 17.3 to 1.5 events/hour) 5
- Adaptive servo-ventilation (ASV) may be necessary for patients with persistent symptomatic TE-CSA 1, 2
- Bilevel positive airway pressure with backup respiratory rate can be effective 2
- Acetazolamide as adjunct to CPAP has shown efficacy in resolving TE-CSA, particularly in patients where CPAP adherence is imperative 4
- Supplemental nocturnal oxygen can be added to CPAP therapy 2
Important Clinical Pitfalls
- Do not immediately discontinue CPAP or switch to advanced ventilation modes when TE-CSA is first detected - most cases resolve spontaneously 1, 2
- Ensure adequate follow-up with objective monitoring of efficacy and usage data, as recommended for all PAP therapy 6
- Carefully evaluate baseline demographic and polysomnographic data before attributing central apneas to TE-CSA - rule out pre-existing central sleep apnea or other causes 1
- Consider potential association between TE-CSA and atrial fibrillation, which may increase susceptibility to periodic ventilation 3