title: The autonomic effects of cardiopulmonary decompression sickness in swine using principal dynamic mode analysis.
abstract: Methods to predict onset of cardiopulmonary (CP) decompression sickness (DCS) would be of great benefit to clinicians caring for stricken divers. Principal dynamic mode (PDM) analysis of the electrocardiogram has been shown to provide accurate separation of the sympathetic and parasympathetic tone dynamics. Nine swine (Sus scrofa) underwent a 15-h saturation dive at 184 kPa (60 ft. of saltwater) in a hyperbaric chamber followed by dropout decompression, whereas six swine, used as a control, underwent a 15-h saturation dive at 15 kPa (5 ft. of saltwater). Noninvasive electrocardiograms were recorded throughout the experiment and autonomic nervous system dynamics were evaluated by heart rate series analysis using power spectral density (PSD) and PDM methods. We observed a significant increase in the sympathetic and parasympathetic tones using the PDM method on average 20 min before DCS onset following a sudden induction of decompression. Parasympathetic activities remained elevated, but the sympathetic modulation was significantly reduced at onset of cutis and CP DCS signs, as reported by a trained observer. Similar nonsignificant observations occurred during PSD analysis. PDM observations contrast with previous work showing that neurological DCS resulted in a >50% reduction in both sympathetic and parasympathetic tone. Therefore, tracking dynamics of the parasympathetic tones via the PDM method may allow discrimination between CP DCS and neurological DCS, and this significant increase in parasympathetic tone has potential use as a marker for early diagnosis of CP DCS.
authors.affiliation: Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts;
authors.forename: Yan
authors.initials: Y
authors.lastname: Bai
authors.forename: Nandakumar
authors.initials: N
authors.lastname: Selvaraj
authors.forename: Kyle
authors.initials: K
authors.lastname: Petersen
authors.forename: Richard
authors.initials: R
authors.lastname: Mahon
authors.forename: William A
authors.initials: WA
authors.lastname: Cronin
authors.forename: Joseph
authors.initials: J
authors.lastname: White
authors.forename: Peter R
authors.initials: PR
authors.lastname: Brink
authors.forename: Ki H
authors.initials: KH
authors.lastname: Chon
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000503:physiopathology*; D003664:Decompression; D003665:Decompression Sickness / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D004195:Disease Models, Animal; D004242:Diving; D042241:Early Diagnosis; D004562:Electrocardiography; D006321:Heart / Q000294:innervation*; D006339:Heart Rate; D008297:Male; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D011237:Predictive Value of Tests; D012815:Signal Processing, Computer-Assisted; D034421:Sus scrofa; D013564:Sympathetic Nervous System / Q000503:physiopathology; D013997:Time Factors
keywords: autonomic nervous system; cutis marmorata; heart rate variability; parasympathetic; sympathetic