Control of breathing in patients with brainstem lesions

In order to analyze the impact of brainstem strokes at different sites on the control of respiration in human beings, we correlated MRT-located ischemic brainstem lesions with sleep-related breathing disorders, measured by whole-night polysomnography, and the hypercapnic ventilatory drive during wakefulness, using a steady-state test, in 18 patients (17 men, mean age: 57yrs, range 44–72yrs), suffering from medullary/cerebellar lesions (group M, n=5), isolated pontine lesions (group P, n=7) and combined lesions of the pons and other midbrain regions (group P+, n=6). Patients were examined 6.5 (median, IqR 5.8) weeks after the incident. The HCVR slopes significantly differed between P (1.9±0.5l/min/Torr) and P+ (0.7±0.5l/min/Torr, p<0.005, ANOVA), with M at 1.2±0.7l/min/Torr (n.s.). P tended to lower apnea-hypopnea indices (AHI; P: 7.6±6.5/h; P+: 23.3±25.6/h; M: 25.0±19.5/h; n.s.). M, P and P+ had comparable BMI values, but 3/5 patients of group M, 3/6 of group P+, but only 1/7 of group P had an AHI above 15/h. We conclude that in contrast to isolated pontine lesions, combined pontine/midbrain lesions coincide with a reduced hypercapnic ventilatory response and a tendency towards sleep-related breathing disorders.