Pressure Support during Sleep in Chronic Respiratory Failure : Cooperative Clinical and Basic Science Investigations.

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There have been several reports that nasal pressure support is a useful treatment for patients with respiratory failure. However, there have been no research on the respiratory muscle during sleep or the effect of pressure support therapy in terms of respiratory muscle control. Combining basic research and clinical research, we investigated control of respiratory muscle to suggest safe and correct usage of the nasal pressure support during sleep for patients with chronic respiratory failure. We did basic animal research in University of Calgary, using unique experimental system with chronically instrumented dogs, which Dr.Easton created for the research of the respiratory muscle control during sleep. Each mongrel dog had pairs of sonomicrometry transducers and bipolar fine-wire EMG electrodes implanted in left costal and crural diaphragm segments, transversus abdominis, and parasternal intercostal muscles. Animals were studied after diaphragm segmental shortening had recovered fully. W … More e did basic research on humans and clinical research in Kitasato University, using another unique system for the research of the human respiratory muscle control. Fine wire electrodes were inserted into four abdominal muscles ; rectus abdominis, externaloblique, internal oblique, and transversus abdominis with real-time, high resolution ultrasound. N-BiPAP was applied to the patients with hypercapnia. In humans, transversus abdominis showed significant expiratory activity during resting supine breathing. To increasing CO2 stimulation or increasing nasal continuous positive airway pressure (n-CPAP), transversus abdominis was activated first, followed by internal oblique, then external oblique, and finally rectus abdominis. In patients with respiratory failure with hypercapnia, significant amelioration of PaCO2 and pH was observed by nasal bilevel positive airway pressure (n-BiPAP), although PaO2 was not significantly improoved. In chronically instrumented dogs, followings were suggested ; 1) Respiratory muscle activity depends on sleep stage, 2) Respiratory muscle control is very different during REM sleep from during non-REM sleep, 3) Differential activity of respiratory muscles occurs during REM sleep. Less