Diaphragm Paralysis and Other Indications
What is Diaphragm Paralysis?
Diaphragm Paralysis is the loss of control of one or both hemidiaphragms caused by a traumatic injury or disease process which decreases or terminates the impulse of respiratory stimuli originating in the brain. Causes of diaphragm paralysis include, but are not limited to:
• Central neurological disorders such as a brain or brainstem stroke,
• Spinal cord disorders such as syringomyelia or poliomyelitis,
• Direct trauma to the phrenic nerve from surgery, radiation, or tumor,
• Autoimmune diseases such as multiple sclerosis,
• Demyelinating disease processes such as Guillan-Barré syndrome and ALS (Lou Gehrig's Disease),
• Phrenic nerve neuropathy, viral or bacterial infections, and unknown (ie, idiopathic) etiologies.
Breathing Pacemakers for Diaphragm Paralysis
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Breathing pacemakers are indicated for patients with diaphragm paralysis who would otherwise be completely or partially dependent on mechanical ventilation so long as the phrenic nerve(s) and diaphragm(s) are intact. Patients with diseases in which there is progressive demyelination of the phrenic nerves (such as ALS) or weakening of the diaphragm muscle (such as muscular dystrophy) are generally poor candidates for diaphragm pacing.
Careful preoperative evaluation (phrenic nerve conduction studies, pulmonary function tests, etc.) would be indicated in all cases. Benefits of diaphragm pacing for either unilateral or bilateral diaphragm paralysis include:
• Improved respiratory function 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.
• Lower infection rates due to the reduction in suctioning, elimination of external humidifier and ventilator circuits, and the potential removal of the tracheostomy tube.
• Improved mobility, normalized breathing and speech patterns, ease of eating and drinking.
For patients with unilateral diaphragm paralysis and non-functioning phrenic nerves, a diaphragm plication may be considered. Following a plication procedure, the paralyzed diaphragm resists upward movement and generates negative pleural pressure which improves ventilation and gas exchange on the functioning side.