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Hypocapnia increases cough motor drive and decreases sample entropy of inspiratory and expiratory muscle electromyograms (EMG)
Author(s) -
Vovk Andrea,
Deoghare Harsha,
Rose Melanie J.,
Morris Kendall F.,
Lindsey Bruce G.,
Bolser Donald C.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.653.13
Subject(s) - hypocapnia , medicine , sample entropy , cardiology , anesthesia , respiratory system , entropy (arrow of time) , physics , hypercapnia , thermodynamics
Repetitive coughing produces profound hyperventilation (HV). However, little is known about the effects of hypocapnia on cough. We hypothesized that hypocapnia augments cough motor drive and alters complexity in respiratory muscle EMG signals. Five anesthetized cats were mechanically ventilated from a PETCO 2 of 38±3 to 23±2.6 mmHg for 3 to 4 min. Repetitive tracheobronchial cough was elicited before and after HV. Parasternal (PS) and transversus abdominis (TA) EMG burst amplitudes (Amp) during cough were 50% and 56% greater following HV, indicating an increase in cough motor drive. Hypocapnia did not change cough number. Sample Entropy (SampEn), a metric of signal complexity, significantly decreased for PS and TA EMG during cough following HV (PS: 0.70±0.05 to 0.52±0.04; TA: 0.56±0.06 to 0.38±0.05), consistent with the hypothesis that voltage patterns in the EMGs were more periodic. PS EMG Amp and SampEn were negatively correlated before (r 2 =0.42) and after (r 2 = 0.33) HV. TA EMG Amp and SampEn were moderately correlated before HV (r 2 =0.26) with a negative slope. This correlation was lower following HV (r 2 = 0.12), suggesting that the mechanism(s) responsible for the decrease in SampEn were not directly linked to the increased cough motor drive. These data support novel chemical control of respiratory muscle EMG activity during coughing. Supported by NIH R33 HL89104 & R01 HL 103415.