title: Reproductibility of cardiac monitoring in men using impedance cardiography during Müeller maneuver.
abstract: Obstructive sleep apnea hypopnea syndrome (OSAHS) is a form of sleep-disordered breathing highlighted by recurrent episodes of upper airway collapse during sleep. OSAHS contributes to an increased risk of cardiac arrhythmias, cardiovascular disease, and altered immune function. Measuring cardiac function in OSAHS patients can provide information that can help delineate clinical treatment efficacy. Cardiac function has been widely tested using electrical bioimpedance.
  
  
  OBJECTIVE
  The aim of this study was to determine the reproducibility of cardiac functional parameters in subjects performing Müeller maneuver.
  
  
  METHODS
  Fifteen apparently healthy males were tested on three different days in a protocol requiring their performance of forced and sustained inspiratory efforts against a closed epiglottis (Müeller maneuver-MM). On each day, the protocol included performance of two simulated apneas of 30 seconds, with at least 3 minutes of normal breathing in between.
  
  
  RESULTS
  Changes from a normal breathing baseline for cardiac output, heart rate and stroke volume were comparable during both MM in all three days. The coefficient of variation was similar on all three trials.
  
  
  CONCLUSIONS
  This new contemporary bioimpedance cardiography device provided reliable measures of dynamic cardiac responses during a simulated apnea event.
authors.affiliation: Department of Human Nutrition, Food and Exercise, Virginia Tech, Blacksburg, VA, USA. aaron@radford.edu
authors.forename: Adrian
authors.initials: A
authors.lastname: Aron
authors.forename: Donald
authors.initials: D
authors.lastname: Zedalis
authors.forename: William G
authors.initials: WG
authors.lastname: Herbert
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging; D002302:Cardiac Output; D002307:Cardiography, Impedance / Q000379:methods; D015150:Echocardiography, Doppler; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D017286:Polysomnography; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013318:Stroke Volume