Adaptive servoventilation (ASV) in patients with sleep disordered breathing associated with chronic opioid medications for non-malignant pain

Abstract

Background: Adaptive servoventilation (ASV) can be effective therapy for specific types of central apnea such as Cheyne-Stokes respiration (CSR). Patients treated chronically with opioids develop central apneas and ataxic breathing patterns (Biot's respiration), but therapy with CPAP is usually unsuccessful. There are no published studies of ASV in patients with sleep apnea complicated by chronic opioid therapy.

Methods: Retrospective analysis of 22 consecutive patients referred for evaluation and treatment of sleep apnea who had been using opioid medications for at least 6 months, had an apnea-hypopnea index (AHI) > or = 20/h, and had been tested with ASV. Baseline polysomnography was compared with CPAP and ASV.

Outcome variables: AHI, central apnea index (CAI), obstructive apnea index (OAI), hypopnea index (HI), desaturation index, mean SpO2, lowest SpO2, time SpO2 < 90%, and degree of Biot's respiration.

Results: Mean (SD) AHI measured 66.6/h (37.3) at baseline, 70.1/h (32.6) on CPAP, and 54.2/h (33.0) on ASV. With ASV, the mean OAI was significantly decreased to 2.4/h (p < 0.0001), and the mean HI increased significantly to 35.7/h (p < 0.0001). The decrease of CAI from 26.4/h to 15.6/h was not significant (p = 0.127). Biot's breathing persisted, and oxygenation parameters were unimproved with ASV.

Conclusions: Due to residual respiratory events and hypoxemia, ASV was considered insufficient therapy in these patients. Persistence of obstructive events could be due to suboptimal pressure settings (end expiratory and/or maximal inspiratory). Residual central events could be related to fundamental differences in the pathophysiology of CSR compared to opioid induced breathing disturbances.

Figure 1

Variations of “Biot's Breathing”. Air flow patterns obtained from PTAF signals showing varying degrees of ataxic or irregular breathing (mild, moderate and severe) plus an example of “cluster breathing” obtained from patients in this series who were chronically receiving opioid medications. Note the marked variability of V_T and frequency in the moderate and severe categories.

Figure 2

Comparison of various respiratory parameters obtained at baseline, CPAP, and ASV.

Figure 3

Severity of ataxic breathing (Biot's respiration). See text for definitions. Markedly irregular breathing was seen in the majority of patients across all conditions.

Figure 4

Case Illustration. See text for details. The scored graphic results of polysomnography at baseline (4A), CPAP (4B), and ASV (4C) are shown. The respiratory and sleep data refer only to the room air portions of the studies. With each study is shown a representative 120-sec sample of raw data.

Figure 5

Ataxic breathing (Biot's respiration) during 120-sec epoch while breathing supplemental oxygen on the baseline study. Typical category 4 ataxic breathing pattern.

Figure 6

Central apnea during 120-sec epoch with ASV support. This 120-sec sample of raw data obtained with EEP of 9.0 cm H₂O shows respiratory events that are indicated by desaturation and the absence of thoracic and abdominal motion in spite of the air flow signals by PTAF corresponding with the backup rate of 15/h and the evidence of increasing pressure by the ASV. Increasing inspiratory pressure is associated with an increasing airflow signal without a corresponding increase in chest volume reflected by the thoracic abdominal signal. These events were scored as central apneas. It is conceivable that airway obstruction is present but this can only be inferred.