Modeling of Heart Rate Variability and Respiratory Muscle Activity in Organophosphate Poisoned Patients

Abstract

We propose an extended model of cardiovascular regulation to assess heart rate variability in patients poisoned with organophosphate during their treatment with mechanical ventilation. The model was modified to fit a population of twentyone (21) patients poisoned with organophosphorus compounds and undergoing mechanical ventilation. The extended model incorporated the respiratory muscle activity measured by surface electromyography for quantifying the vagal-sympathetic engagement during spontaneous breathing test. The order and structure of the parasympathetic and the sympathetic transfer function with respect to the original model were modified to a second-order system. In this extended model, the parameters related to the vagal-sympathetic response (corner frequency and constant gain) were correlated with respiratory muscle activity. When the diaphragm's contractions were stronger, the sympathetic corner frequency increased while the parasympathetic corner frequency and gain decreased. Thus the proposed model could be useful to improve the ventilatory support and pharmacological treatment for patients poisoned with organophosphorus compounds considering the vagalsympathetic response inferred from the respiratory muscle activity.

Refined Matrix Completion for Spectrum Estimation of Heart Rate Variability

“…In particular, spectral features of HRV data were found to be reliable markers of sympathetic and/or parasympathetic activity [12]. For example, the low frequency (LF: 0.04 - 0.15 Hz) of HRV spectrum is generally mediated by sympathetic and parasympathetic actions; while the high frequency (HF: 0.15 - 0.4 Hz) is mediated by the parasympathetic nervous system; as a consequence, the LF/HF ratio can be used as an index of sympathovagal balance [13], [14].…”

Spectrum Estimation of Heart Rate Variability Using Low-rank Matrix Completion

“…In particular, HRV indices in frequency domain describe power distributions with different frequency bands, which have been found to be reliable markers for assessing sympathetic (SNS) and parasympathetic nervous system (PNS) activities [1]. For example, the low frequency (LF) (0.04-0.15 Hz) of the HRV spectrum is generally mediated by sympathetic and parasympathetic actions; while the high frequency (HF) band (0.15-0.4 Hz) is mediated by PNS [3].…”