Vagus Nerve Stimulation Electrode Impedance Over Time in Children With Lennox-Gastaut Syndrome.

OBJECTIVE: This manuscript describes the behavior of impedance of vagus nerve stimulation (VNS) electrode over time in a cohort of children with Lennox-Gastaut syndrome. MATERIALS AND METHODS: Nineteen consecutive pediatric patients with Lennox-Gastaut syndrome submitted to VNS were studied. All patients had at least four years of follow-up. Serial impedance measurements were carried out during every out-patient visit. A baseline value was obtained one month after surgery, before generator activation and yearly values were recorded for the next four years. Outcome regarding seizures was obtained through analysis of standardized seizure diaries filled out by the patient, relatives, or caregivers. RESULTS: There were 12 boys. Age ranged from four to 14 years (mean = 7.2). Mean impedance value was 2635 Ω at baseline, 2576 Ω after one year, 2418 Ω after two years, 2340 Ω after three years, and 2241 Ω after four years. There was a mean impedance decrease of 17% after four years. This decrease was statistically significant compared with baseline by the second year of follow-up: p = 0.342 after one year, p = 0.007 after two years, p = 0.001 after three years, and p = 0.001 after four years. There was no significant relationship between impedance values and seizure outcome at any time point. CONCLUSIONS: VNS electrode impedance significantly decreased during long-term follow-up in children with Lennox-Gastaut syndrome. To our knowledge, this is the first report on such findings regarding VNS in the literature. These findings suggest that the electrode/nerve interface is stable during long-term follow-up of VNS therapy and that this preserved anatomical relationship might be related to our ability to safely stimulate and review/explant the system whenever needed.

Vaccination coverage in a cohort of HIV-infected patients receiving care at an AIDS outpatient clinic in Espírito Santo, Brazil.

This cross-sectional study assessed the immunization status of human immune deficiency virus (HIV)-infected patients receiving care at an outpatient clinic in Brazil. The sociodemographic characteristics, CD4 count and HIV viral load of 281 out of 612 adult outpatients were analyzed. A total of 331 patients were excluded because of no availability of vaccination cards. Chi-square or Fisher's exact test were used. Immunization coverage was higher for diphtheria/tetanus (59.79%) and hepatitis B (56.7%), and lowest for hepatitis A (6.8%) and for meningococcal group C (6%). Only 11.74% of the patients had received the influenza virus vaccine yearly since their HIV-infection diagnosis. No vaccination against influenza (p<0.034) or hepatitis B (p<0.029) were associated with CD4 counts <500cells/mL; no vaccination against flu or pneumococcus were associated with detectable HIV viral load (p<0.049 and p<0.002, respectively). Immunization coverage is still very low among HIV-infected adults in this setting despite recommendations and high infection-related mortality.

Vaccination coverage in a cohort of HIV-infected patients receiving care at an AIDS outpatient clinic in Espírito Santo, Brazil

Abstract This cross-sectional study assessed the immunization status of human immune deficiency virus (HIV)-infected patients receiving care at an outpatient clinic in Brazil. The sociodemographic characteristics, CD4 count and HIV viral load of 281 out of 612 adult outpatients were analyzed. A total of 331 patients were excluded because of no availability of vaccination cards. Chi-square or Fisher's exact test were used. Immunization coverage was higher for diphtheria/tetanus (59.79%) and hepatitis B (56.7%), and lowest for hepatitis A (6.8%) and for meningococcal group C (6%). Only 11.74% of the patients had received the influenza virus vaccine yearly since their HIV-infection diagnosis. No vaccination against influenza (p < 0.034) or hepatitis B (p < 0.029) were associated with CD4 counts <500 cells/mL; no vaccination against flu or pneumococcus were associated with detectable HIV viral load (p < 0.049 and p < 0.002, respectively). Immunization coverage is still very low among HIV-infected adults in this setting despite recommendations and high infection-related mortality.