Efficacy of tracheostomy for central alveolar hypoventilation syndrome caused by lateral medullary infarction.

Central alveolar hypoventilation syndrome (CAHS) is a rare and potentially fatal condition. However, respiratory care for patients with CAHS caused by lateral medullary infarction (CAHS-LMI) remains an important unsolved problem. We describe 2 patients with CAHS-LMI and review the case reports for 17 previously described patients. Patient 1 was a 78-year-old man who was referred to our hospital because of dizziness. After admission, Wallenberg syndrome developed. Magnetic resonance imaging showed left LMI. He had hypercapnia and respiratory acidosis the next afternoon and temporarily received mechanical ventilation. A tracheotomy was performed on the 12th hospital day, and the patient was weaned from the ventilator on the 18th hospital day. Patient 2 was 72-year-old man who was referred to our hospital because of dizziness and gait disturbance. Wallenberg syndrome was diagnosed after admission, and magnetic resonance imaging showed right LMI. His consciousness deteriorated, and hypercapnia developed on the ninth hospital day. The patient received ventilatory support, and a tracheotomy was performed on the 12th hospital day. He was weaned from the ventilator by the 16th hospital day. Consistent with our findings, most previously reported cases of CAHS-LMI were initially associated with mild symptoms, which subsequently worsened. Five of the 19 patients (26.3%) died within 1 month after onset, and 7 patients (36.8%) died within 1 year. Tracheotomy was performed in 12 patients, 2 of whom died 1 month after onset (16.7%); another patient died of chronic renal failure after 2 years. Tracheotomy seemed to be an effective procedure in patients with CAHS-LMI. We speculate that tracheotomy assists alveolar ventilation by reducing dead space ventilation. Closure of the tracheotomy should, therefore, be avoided in patients with CAHS-LMI, even if respiratory status is good.