title: Clinical state transitions during advanced life support (ALS) in in-hospital cardiac arrest.
abstract: BACKGROUND
  When providing advanced life support (ALS) in cardiac arrest, the patient may alternate between four clinical states: ventricular fibrillation/tachycardia (VF/VT), pulseless electrical activity (PEA), asystole, and return of spontaneous circulation (ROSC). At the end of the resuscitation efforts, either death has been declared or sustained ROSC has been obtained. The aim of this study was to describe and analyze the clinical state transitions during ALS among patients experiencing in-hospital cardiac arrest.
  
  
  RESULTS
  The defibrillator files from 311 in-hospital cardiac arrests at the University of Chicago Hospital (IL, USA) and St. Olav University Hospital (Trondheim, Norway) were analyzed (clinicaltrials.gov: NCT00920244). The transitions between clinical states were annotated along the time axis and visualized as plots of the state prevalence according to time. The cumulative intensity of the state transitions was estimated by the Nelson-Aalen estimator for each type of state transition, and for the intensities of overall state transitions. Between 70% and 90% of patients who eventually obtained sustained ROSC had progressed to ROSC by approximately 15-20 min of ALS, depending on the initial rhythm. Patients behaving unstably after this time period, i.e., alternating between ROSC, VF/VT and PEA, had a high risk of ultimately being declared dead.
  
  
  CONCLUSIONS
  We provide an overall picture of the intensities and patterns of clinical state transitions during in-hospital ALS. The majority of patients who obtained sustained ROSC obtained this state and stabilized within the first 15-20 min of ALS. Those who continued to behave unstably after this time point had a high risk of ultimately being declared dead.
authors.affiliation: Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway. trond.nordseth@ntnu.no
authors.forename: Trond
authors.initials: T
authors.lastname: Nordseth
authors.forename: Daniel
authors.initials: D
authors.lastname: Bergum
authors.forename: Dana P
authors.initials: DP
authors.lastname: Edelson
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Olasveengen
authors.forename: Trygve
authors.initials: T
authors.lastname: Eftestøl
authors.forename: Rune
authors.initials: R
authors.lastname: Wiseth
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Abella
authors.forename: Eirik
authors.initials: E
authors.lastname: Skogvoll
mesh_terms: D022561:Advanced Cardiac Life Support / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000503:physiopathology / Q000628:therapy; D053840:Brugada Syndrome; D000075224:Cardiac Conduction System Disease; D016887:Cardiopulmonary Resuscitation / Q000379:methods* / Q000401:mortality; D015331:Cohort Studies; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006323:Heart Arrest / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy*; D006329:Heart Conduction System / Q000002:abnormalities / Q000503:physiopathology; D006339:Heart Rate; D006439:Hemodynamics / Q000502:physiology*; D006785:Hospitals, University; D006801:Humans; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D009664:Norway; D020127:Recovery of Function; D018570:Risk Assessment; D012720:Severity of Illness Index; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000503:physiopathology / Q000628:therapy; D016896:Treatment Outcome; D014481:United States; D014693:Ventricular Fibrillation / Q000503:physiopathology / Q000628:therapy
keywords: Cardiac arrest; Cardiopulmonary resuscitation; Dynamics; Statistics