Neural respiratory drive during maximal voluntary ventilation in individuals with hypertension: A case-control study

Abstract

Neural respiratory drive (NRD) is measured using a non-invasive recording of respiratory electromyographic signal. The parasternal intercostal muscle can assess the imbalance between the load and capacity of respiratory muscles and presents a similar pattern to diaphragmatic activity. We aimed to analyze the neural respiratory drive in seventeen individuals with hypertension during quite breathing and maximal voluntary ventilation (MVV) (103.9 ± 5.89 vs. 122.6 ± 5 l/min) in comparison with seventeen healthy subjects (46.5 ± 2.5 vs. 46.4 ± 2.4 years), respectively. The study protocol was composed of quite breathing during five minutes, maximum inspiratory pressure followed by maximal ventilatory ventilation (MVV) was recorded once for 15 seconds. Anthropometric measurements were collected, weight, height, waist, hip, and calf circumferences, waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), BMI, and conicity index (CI). Differences between groups were analyzed using the unpaired t-test or Mann-Whitney test to determine the difference between groups and moments. A significance level of 5% (p<0,05) was adopted for all statistical analyses. The group of individuals with hypertension presented higher values when compared to the healthy group for neural respiratory drive (EMGpara% 17.9±1.3 vs. 13.1±0.8, p = 0.0006) and neural respiratory drive index (NRDi (AU) 320±25 vs. 205.7±15,p = 0.0004) during quiet breathing and maximal ventilatory ventilation (EMGpara% 29.3±2.7 vs. 18.3±0.8, p = 0.000, NRDi (AU) 3140±259.4 vs. 1886±73.1,p<0.0001), respectively. In conclusion, individuals with hypertension presented higher NRD during quiet breathing and maximal ventilatory ventilation when compared to healthy individuals.