[Control of breathing in the central alveolar hypoventilation syndrome with and without a phrenic pacemaker]

Primary central alveolar hypoventilation (CAHV) is a rare disorder described in newborns, children, and adults. We report a 2 9/12 year old child with CAHV of unknown etiology. The evaluation of her ventilatory control system showed abnormalities awake and in the different sleep states. Hypoventilation was found to be more severe during non-REM sleep than during REM sleep and awake state. She had central apnea, an irregular respiratory rhythm in the non-REM sleep too, and diminished ventilatory response to inhaled 5%-6% CO2 in both REM and non-REM sleep. Her ventilation decreased when she was breathing 50% and 100% oxygen. During breathing 15% oxygen she did not arouse in spite a transcutaneous pO2 of 10 mmHg. She was first treated with mechanical ventilation during sleep and has now received bilateral simultaneous phrenic pacemaker support during quiet sleep for about one year. With the phrenic pacemaker she has normal minute volume and transcutaneous blood gases during sleep. During a respiratory infection she needed again mechanical ventilation via her tracheostoma 24 hours a day for one week. This case of a CAHV demonstrates a dysfunction of the central and partially also of the peripheral chemoreceptors. The abnormalities of the ventilation were demonstrable not only in the non-REM sleep but also in the REM sleep and awake state.