Diaphragm Pacing with a Quadripolar Phrenic Nerve Electrode: An International Study

We sought to determine the international experience with the quadripolar diaphragm pacer system and to test two hypotheses: the incidence of pacer complications would be (1) increased among pediatric as compared to adult patients; and (2) highest among active pediatric patients with idiopathic congenital central hypoventilation syndrome (CCHS). Data were collected via a questionnaire coupled with the Atrotech Registry data for a total of 64 patients (35 children and 29 adults) from 14 countries. Thoracic implantation of electrodes and bilateral pacer use each occurred in 94% of all subjects. Tetraplegic (vs pediatric CCHS) patients were more typically paced 24 hours/day (P = 0.001). Pacing duration averaged 2.0 ± 1.0 years among children and 2.2 ± 1.1 years among adults. Infections occurred among 2.9% of surgical procedures, all in pediatric CCHS patients (vs pediatric tetraplegic patients, P = 0.01). The incidence of mechanical trauma was 3.8%, without significant differences among patient groups. The incidence of presumed electrode and receiver failure were 3.1% and 5.9%, respectively, with internal component failure greater among pediatric CCHS than pediatric tetraplegic patients (P < 0.01). Intermittent or absent function of 0–4 electrode combinations occurred among 19% of all patients, with increased frequency among pediatric CCHS than pediatric tetraplegic patients (P < 0.03). Complication- free successful pacing occurred in 60% of pediatric and 52% of adult patients. In all, 94 % of the pediatric and 86% of the adult patients paced successfully after the necessary intervention. Although pacer complications were not increased among pediatric as compared to adult patients, the incidence of complications was highest among the active pediatric patients with CCHS. Longitudinal study of these patients will provide invaluable information for modification and improvement of the quadripolar system.     

Plasma catecholamine concentrations in essential hyperhidrosis and effects of thoracoscopic D2–D3 sympathicolysis

Essential hyperhidrosis (EH) is caused by a poorly understood overactivity of the sympathetic fibres passing through the upper dorsal sympathetic ganglia D₂ and D₃. These ganglia are also in the pathway of the sympathetic innervation of the heart and lungs. Therefore, although the predominant sympathetic neurotransmitter at the eccrine sweat glands is acetylcholine, the plasma concentration of noradrenaline (NA) (which is the main sympathetic neurotransmitter at the end organs including the heart and the lungs) may be elevated. Furthermore, as there are some indications for generalized sympathetic overactivity in EH, the plasma concentration of adrenaline (A) may also be elevated. Plasma levels of NA and A were therefore determined in 13 EH patients before and after thoracoscopic D₂–D₃ sympathicolysis (TS). Preoperative NA and A plasma levels were all within the normal limits used in our laboratory. After TS, mean NA plasma levels are significantly decreased, whereas mean A are unchanged. We conclude that sympathetic overactivity in EH is limited to the upper dorsal sympathetic ganglia and that some of the cardiovascular and pulmonary effects that are observed after TS may be associated with the decrease in NA.