title: Fully automatic rhythm analysis during chest compression pauses.
abstract: OBJECTIVE
  Chest compression artefacts impede a reliable rhythm analysis during cardiopulmonary resuscitation (CPR). These artefacts are not present during ventilations in 30:2 CPR. The aim of this study is to prove that a fully automatic method for rhythm analysis during ventilation pauses in 30:2 CPR is reliable an accurate.
  
  
  METHODS
  For this study 1414min of 30:2 CPR from 135 out-of-hospital cardiac arrest cases were analysed. The data contained 1942 pauses in compressions longer than 3.5s. An automatic pause detector identified the pauses using the transthoracic impedance, and a shock advice algorithm (SAA) diagnosed the rhythm during the detected pauses. The SAA analysed 3-s of the ECG during each pause for an accurate shock/no-shock decision.
  
  
  RESULTS
  The sensitivity and PPV of the pause detector were 93.5% and 97.3%, respectively. The sensitivity and specificity of the SAA in the detected pauses were 93.8% (90% low CI, 90.0%) and 95.9% (90% low CI, 94.7%), respectively. Using the method, shocks would have been advanced in 97% of occasions. For patients in nonshockable rhythms, rhythm reassessment pauses would be avoided in 95.2% (95% CI, 91.6-98.8) of occasions, thus increasing the overall chest compression fraction (CCF).
  
  
  CONCLUSIONS
  An automatic method could be used to safely analyse the rhythm during ventilation pauses. This would contribute to an early detection of refibrillation, and to increase CCF in patients with nonshockable rhythms.
authors.affiliation: Communications Engineering Department, University of the Basque Country UPV/EHU, Alameda Urquijo S/N, 48013 Bilbao, Spain. Electronic address: unai.ayala@ehu.es.
authors.forename: U
authors.initials: U
authors.lastname: Ayala
authors.affiliation: Communications Engineering Department, University of the Basque Country UPV/EHU, Alameda Urquijo S/N, 48013 Bilbao, Spain.
authors.forename: U
authors.initials: U
authors.lastname: Irusta
authors.affiliation: Communications Engineering Department, University of the Basque Country UPV/EHU, Alameda Urquijo S/N, 48013 Bilbao, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Ruiz
authors.affiliation: Communications Engineering Department, University of the Basque Country UPV/EHU, Alameda Urquijo S/N, 48013 Bilbao, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Ruiz de Gauna
authors.affiliation: Communications Engineering Department, University of the Basque Country UPV/EHU, Alameda Urquijo S/N, 48013 Bilbao, Spain.
authors.forename: D
authors.initials: D
authors.lastname: González-Otero
authors.affiliation: Communications Engineering Department, University of the Basque Country UPV/EHU, Alameda Urquijo S/N, 48013 Bilbao, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Alonso
authors.affiliation: National Advisory Unit for Prehospital Emergency Medicine (NAKOS) and Department of Anaesthesiology, Oslo University Hospital and University of Oslo, P.O. Box 4956 Nydalen, N-0424 Oslo, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Kramer-Johansen
authors.affiliation: National Advisory Unit for Prehospital Emergency Medicine (NAKOS) and Department of Anaesthesiology, Oslo University Hospital and University of Oslo, P.O. Box 4956 Nydalen, N-0424 Oslo, Norway.
authors.forename: H
authors.initials: H
authors.lastname: Naas
authors.affiliation: Department of Electrical Engineering and Computer Science, Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Eftestøl
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D002307:Cardiography, Impedance; D016887:Cardiopulmonary Resuscitation; D004554:Electric Countershock; D004562:Electrocardiography; D006801:Humans; D009664:Norway; D058687:Out-of-Hospital Cardiac Arrest / Q000175:diagnosis* / Q000628:therapy*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results
keywords: Automated external defibrillator (AED); Cardiac arrest; Cardiopulmonary resuscitation (CPR); Chest compression; Transthoracic impedance