Reasons for Repeat Sleep Study After Years on CPAP
A repeat sleep study should be performed if a patient on CPAP therapy experiences deterioration in respiratory function or sleep quality, as this may indicate a need to reassess treatment efficacy and adjust therapy accordingly. 1
Common Indications for Repeat Sleep Studies
Treatment Efficacy Assessment: When symptoms return despite initial good response to CPAP therapy, a follow-up polysomnography (PSG) or attended cardiorespiratory sleep study is routinely indicated to assess treatment results 1
Significant Weight Changes: Follow-up PSG is routinely indicated after substantial weight loss (e.g., 10% of body weight) or substantial weight gain with return of symptoms 1
Persistent or Recurrent Symptoms: When clinical response is insufficient or symptoms return despite a good initial response to CPAP, a repeat sleep study is warranted 1
Deterioration in Sleep Quality: A repeat NPPV (non-invasive positive pressure ventilation) titration study should be considered if the sleep quality of a patient on chronic treatment deteriorates 1
Inadequate Initial Titration: If the initial titration did not achieve a grade of optimal, good, or adequate (based on respiratory disturbance index, oxygen saturation, and other parameters), a repeat study may be needed 1
Specific Clinical Scenarios Requiring Reassessment
Changes in Comorbid Conditions: Patients with significant cardiac disease such as congestive heart failure (CHF) who continue to have nocturnal symptoms despite optimal medical management should undergo testing 1
Development of New Symptoms: New onset of excessive sleepiness during major wake periods, accidents associated with drowsiness, or falling asleep while performing safety-sensitive duties may necessitate reassessment 1
Treatment Non-adherence: Patients who are found to be non-adherent with treatment recommendations or follow-up, especially those with AHI ≥ 20 events/h, may need reassessment 1
Medication Changes: Introduction of medications that can affect upper airway tone (e.g., opiates, sedative-hypnotics) may worsen OSA syndrome and require reassessment 1
Technical Considerations for Repeat Studies
Assessment Parameters: The repeat study should record EEG, EOG, chin EMG, airflow, oxygen saturation, respiratory effort, and ECG or heart rate to properly evaluate OSA 1
Quality Metrics: An optimal titration should meet treatment goals (RDI < 5/hour, absence of snoring, minimum SpO2 > 90%) for at least a 15-minute period that includes REM sleep in the supine position 1
Duration Requirements: If less than 3 hours of sleep was recorded during the initial titration, a repeat study should be considered 1
Clinical Implications and Management
Treatment Adjustments: The repeat study may indicate a need to adjust CPAP pressure settings, as settings determined during initial titration may not remain adequate if patient characteristics change 1
Alternative Treatments: For patients who cannot tolerate or are not appropriate candidates for CPAP, evaluation for alternative treatments may be necessary, such as mandibular advancement devices or surgical options 1
Monitoring Adherence: Close follow-up after any treatment adjustments is indicated to establish effective utilization patterns, using objective adherence data when possible 1
Addressing Barriers: Problems including side effects and interface issues should be remediated to ensure equipment is maintained in good repair 1
Pitfalls and Caveats
Avoiding Unnecessary Testing: Routine follow-up PSG is not indicated in patients treated with CPAP whose symptoms continue to be resolved with treatment 1
Considering Night-to-Night Variability: There can be significant night-to-night variability in AHI scores, which may affect diagnostic accuracy 1
Balancing Benefits and Harms: The benefits of a repeat sleep study must be weighed against the inconvenience to the patient, resource utilization, healthcare costs, and potential delays in care for other patients 1