The Effect of Acute Exposure to Morphine on Breathing Variability and Cardiopulmonary Coupling in Men with Obstructive Sleep Apnea: A Randomized Controlled Trial

This study aimed to detect and quantify opioid-induced cardiorespiratory pattern changes during sleep in OSA patients using novel automated methods and to correlate these with conventional polysomnography (PSG) measures. Under a randomized double-blind placebo-controlled crossover design, 60 male OSA patients attended two one-night visits to the sleep laboratory, at least a week apart receiving either 40-mg controlled-release oral morphine dose or placebo. The authors analyzed the inter-breath interval (IBI) from the PSG flow channel to quantify breathing irregularity while cardiopulmonary coupling (CPC) was analyzed using the PSG electrocardiogram (ECG) channel. After morphine use, OSA patients had fewer breaths, a longer inter-breath interval and more irregular breathing compared to the placebo night. Consumption of 40 mg controlled-release morphine resulted in a longer breathing cycle and increased breathing irregularity but generally more stable sleep in OSA patients. The significant links between respiratory, cardiopulmonary and sleep-disordered breathing parameters may suggest a practical value in surrogate overnight cardiorespiratory measurements, because both respiratory flow and ECG can be detected by small portable devices.