Introduction: Subjects on methadone maintenance for drug addiction have been reported to have central sleep apnea (CSA). However, there are few reports of disordered breathing in patients receiving opioids for chronic pain.
Materials and methods: We report on six patients (ages 41-68, two females, body mass index 27-34, morphine equivalent doses 120-420 mg/day, Epworth Scales 7-21) referred to our sleep center receiving sustained release opioids for more than 6 months with excessive daytime sleepiness. CSA was defined as apnea-hypopnea index (AHI) more than 5 per hour with > or =50% central events. Bilevel (BLV) titration was done to determine settings and all patients were followed for at least 6 months on nocturnal BLV. AHI ranged 28.4-106 per hour. Time less than 90% O(2) saturation ranged 1.8 min to 6.4 h. Four of the patients were treated with chronic BLV ventilation with settings ranging 12-16 cm H(2)O (inspiratory positive airway pressure)/4-8 cm H(2)O (expiratory positive airway pressure) with backup rate of 12-16. Among the four patients who used BLV treatment for at least 6 months, Epworth scores improved (by 4, 12, 5, and 9, respectively).
Conclusion: Treatment of opioid-associated CSA with BLV corrected nocturnal hypoxemia and reduced sleep fragmentation. Randomized controlled trials, with objective measures of daytime function, are recommended in opioid-induced CSA patients.