title: Activation of respiratory muscles during weaning from mechanical ventilation.
abstract: Respiratory muscle dysfunction is a key component of weaning failure. Balancing respiratory muscle loading and unloading by applying different ventilation modes along with spontaneous breathing episodes are established weaning strategies. However, the effects of body positioning on the respiratory muscles during weaning remains unclear.
  
  
  
  This study aimed at assessing respiratory drive by surface electromyography (EMG) of the diaphragm (EMGdia) and parasternal muscles (EMGpara) in tracheotomized patients during prolonged weaning in 3 randomized body positions-supine, 30° semirecumbent, and 80° sitting-during mechanical ventilation and spontaneous breathing.
  
  
  
  Nine patients were included for analysis. Cardiorespiratory parameters (heart rate, blood pressure, arterial oxygen saturation, dyspnea) did not change under each condition (all P>.05). EMGparaand EMGdiadid not change under mechanical ventilation (both P>.05). EMGdiachanged under spontaneous breathing from supine to sitting (0.45±0.26 vs 0.32±0.19; P=.012) and between semirecumbent to sitting (0.41±0.23 vs 0.32±0.19; P=.039), whereas EMGparadid not change.
  
  
  
  This is the first study to show that body positioning influences respiratory drive to the diaphragm in tracheotomized patients with prolonged weaning from mechanical ventilation during unassisted breathing. Sitting position reduces respiratory drive compared with semirecumbent and supine positioning and might therefore be favored during spontaneous breathing trials.
authors.affiliation: Department of Pneumology, Cardiology and Intensive Care Medicine, Klinikum Konstanz, Luisenstr. 7, 78464 Konstanz, Germany; Department of Pneumology and Internal Medicine, University Witten-Herdecke, Alfred-Herrhausen-Straße 50, 58448 Witten, Germany. Electronic address: stephan.walterspacher@glkn.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Walterspacher
authors.affiliation: Department of Internal Medicine, Clinic for Pneumology, University Hospital Freiburg, Killianstr. 5, 79106 Freiburg, Germany. Electronic address: julia.gueckler@gmx.net.
authors.forename: Julia
authors.initials: J
authors.lastname: Gückler
authors.affiliation: Department of Internal Medicine, Clinic for Pneumology, University Hospital Freiburg, Killianstr. 5, 79106 Freiburg, Germany. Electronic address: fabian.pietsch@gmx.de.
authors.forename: Fabian
authors.initials: F
authors.lastname: Pietsch
authors.affiliation: Department of Pneumology, Cardiology and Intensive Care Medicine, Klinikum Konstanz, Luisenstr. 7, 78464 Konstanz, Germany; Department of Pneumology and Internal Medicine, University Witten-Herdecke, Alfred-Herrhausen-Straße 50, 58448 Witten, Germany. Electronic address: david.walker@glkn.de.
authors.forename: David Johannes
authors.initials: DJ
authors.lastname: Walker
authors.affiliation: Department of Pneumology, Cardiology and Intensive Care Medicine, Klinikum Konstanz, Luisenstr. 7, 78464 Konstanz, Germany; Department of Internal Medicine, Clinic for Pneumology, University Hospital Freiburg, Killianstr. 5, 79106 Freiburg, Germany. Electronic address: hans-joachim.kabitz@glkn.de.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Kabitz
authors.affiliation: Division of Pneumology, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany. Electronic address: mdreher@ukaachen.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Dreher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003964:Diaphragm / Q000502:physiology*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D056888:Patient Positioning; D011659:Pulmonary Gas Exchange; D012121:Respiration, Artificial; D012132:Respiratory Muscles / Q000502:physiology*; D016896:Treatment Outcome; D015300:Ventilator Weaning
keywords: Diaphragm; Mechanical ventilation; Neural respiratory drive; Parasternal muscles; Weaning