Central Sleep Apnea
What is Central Sleep Apnea?
Central Sleep Apnea is a sleep disorder characterized by pauses in breathing during sleep. It can be a congenital or acquired condition, and can also affect a patient's respiratory effort while awake.
Central Sleep Apnea differs from Obstructive Sleep Apnea which is characterized by a physical disruption of airflow in spite of respiratory effort. A Complex or Mixed sleep apnea exhibits characteristics of both central and obstructive sleep apnea.
When present from birth, central sleep apnea is called Congenital Central Hypoventilation Syndrome, CCHS, or historically, Ondine's Curse. Studies have it to be caused by a mutation of the PHOX2b gene.
CCHS is characterized by adequate ventilation while the patient is awake and by hypoventilation with shallow breathing during sleep. More severely affected patients hypoventilate when both awake and asleep. Both of these phenotypes present in the newborn period. Children with CCHS often have physiologic and anatomic manifestations of a generalized autonomic nervous system dysfunction, altered development of neural-crest-derived structures (i.e., Hirschsprung disease), and tumors.
Acquired central sleep apnea is usually the result of a brain stem stroke, tumor or other trauma which affects the ability of the brain to properly regulate respiratory drive.
Breathing Pacemakers for Central Sleep Apnea
The phrenic nerves originate at C3 through C5 and are the neurological pathways between the brain and each hemidiaphragm. Unlike a spinal cord injury which can damage these pathways, central sleep apnea is a condition in which the brain does not utilize these pathways consistently, if at all. Once a sleep study confirms that the patients apneic events are of central origin, a breathing pacemaker should be considered.
A breathing pacemaker is a phrenic nerve stimulator which delivers electrical impulses to the hemidiaphragms and restores breathing function. Pacing has many advantages over mechanical ventilation, including:
Breathing pacemakers provide respiratory function superior to mechanical ventilators since the inhaled air is drawn into the lungs by the diaphragm under negative pressure, rather than being forced into the chest under positive pressure.
Pacing patients experience lower infection rates due to the reduction in suctioning, elimination of external humidifier and ventilator circuits and the potential removal of the tracheostomy tube.
Most patients prefer pacing over mechanical ventilation for a variety of reasons including normal breathing and speech patterns, ease of eating and drinking and its silent operation.