Passive motion of the extremities modifies alveolar ventilation during sleep in patients with congenital central hypoventilation syndrome

Passive motion of lower extremities (PMLE) elicits significant increases in alveolar ventilation (VA) in awake children with congenital central hypove ntilation syndrome (CCHS), who have absent or near absent ventilatory respo nses to hypercapnia. We hypothesized that PMLE would improve VA during non- rapid eye movement (NREM) sleep. To study this, six patients with CCHS (0.2 to 7 yr of age) were disconnected from mechanical ventilatory support duri ng Stage III-IV NREM, and their feet were passively moved at the ankle, eit her manually or with a motorized device strapped to their feet at 40 to 50 strokes/min. Holding of the feet without motion served as control (C). From a total of 74 successful trials not associated with sleep state changes, P ETCO2 decreased from 58.9 +/- 3.5 to 40.9 +/- 2.6 mm Hg with PMLE (n = 58; p < 0.001), whereas end-tidal carbon dioxide (PETCO2) increased in C (n = 1 6; 58.8 +/- 3.1 to 60.3 +/- 3.7 mm Hg; PMLE versus C: p < 0.001). PMLE incr eased respiratory frequency from 10.2 +/- 1.9 to 21.2 +/- 2.7 breaths/min ( p < 0.0001). We conclude that PMLE during NREM increases (V) over dot(A) po ssibly via activation of mechanoreceptor-afferent pathways rather than by r espiratory entrainment. We speculate that such effect may provide future no ninvasive ventilatory support strategies in patients with CCHS and mild phe notypic expression of their disease.