title: Increasing survival after admission to UK critical care units following cardiopulmonary resuscitation.
abstract: BACKGROUND
  In recent years there have been many developments in post-resuscitation care. We have investigated trends in patient characteristics and outcome following admission to UK critical care units following cardiopulmonary resuscitation (CPR) for the period 2004-2014. Our hypothesis is that there has been a reduction in risk-adjusted mortality during this period.
  
  
  METHODS
  We undertook a prospectively defined, retrospective analysis of the Intensive Care National Audit & Research Centre (ICNARC) Case Mix Programme Database (CMPD) for the period 1 January 2004 to 31 December 2014. Admissions, mechanically ventilated in the first 24 hours in the critical care unit and admitted following CPR, defined as the delivery of chest compressions in the 24 hours before admission, were identified. Case mix, withdrawal, outcome and activity were described annually for all admissions identified as post-cardiac arrest admissions, and separately for out-of-hospital cardiac arrest and in-hospital cardiac arrest. To assess whether in-hospital mortality had improved over time, hierarchical multivariate logistic regression models were constructed, with in-hospital mortality as the dependent variable, year of admission as the main exposure variable and intensive care unit (ICU) as a random effect. All analyses were repeated using only the data from those ICUs contributing data throughout the study period.
  
  
  RESULTS
  During the period 2004-2014 survivors of cardiac arrest accounted for an increasing proportion of mechanically ventilated admissions to ICUs in the ICNARC CMPD (9.0 % in 2004 increasing to 12.2 % in 2014). Risk-adjusted hospital mortality following admission to ICU after cardiac arrest has decreased significantly during this period (OR 0.96 per year). Over this time, the ICU length of stay and time to treatment withdrawal has increased significantly. Re-analysis including only those 116 ICUs contributing data throughout the study period confirmed all the results of the primary analysis.
  
  
  CONCLUSIONS
  Risk-adjusted hospital mortality following admission to ICU after cardiac arrest has decreased significantly during the period 2004-2014. Over the same period the ICU length of stay and time to treatment withdrawal has increased significantly.
authors.affiliation: School of Clinical Sciences, University of Bristol, 69 St. Michael's Hill, Bristol, BS2 8DZ, UK. jerry.nolan@nhs.net.|Anaesthesia and Intensive Care Medicine, Royal United Hospital, Combe Park, Bath, BA1 3NG, UK. jerry.nolan@nhs.net.
authors.forename: J P
authors.initials: JP
authors.lastname: Nolan
authors.affiliation: Intensive Care National Audit & Research Centre (ICNARC), Napier House, 24 High Holborn, London, WC1V 6AZ, UK.
authors.forename: P
authors.initials: P
authors.lastname: Ferrando
authors.affiliation: Anaesthesia and Intensive Care Medicine, Southmead Hospital, North Bristol NHS Trust, Bristol, BS10 5NB, UK.
authors.forename: J
authors.initials: J
authors.lastname: Soar
authors.affiliation: Faculty of Health and Applied Sciences, Glenside Campus, Blackberry Hill, University of the West of England, Bristol, BS16 1DD, UK.
authors.forename: J
authors.initials: J
authors.lastname: Benger
authors.affiliation: Intensive Care Medicine, University Hospitals, Bristol, BS2 8HW, UK.
authors.forename: M
authors.initials: M
authors.lastname: Thomas
authors.affiliation: Intensive Care National Audit & Research Centre (ICNARC), Napier House, 24 High Holborn, London, WC1V 6AZ, UK.
authors.forename: D A
authors.initials: DA
authors.lastname: Harrison
authors.affiliation: Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.|Intensive Care Medicine, Heart of England NHS Foundation Trust, Coventry, CV4 7AL, UK.
authors.forename: G D
authors.initials: GD
authors.lastname: Perkins
mesh_terms: D016887:Cardiopulmonary Resuscitation / Q000401:mortality*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007362:Intensive Care Units / Q000458:organization & administration / Q000706:statistics & numerical data*; D058687:Out-of-Hospital Cardiac Arrest / Q000453:epidemiology / Q000401:mortality; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000706:statistics & numerical data; D012189:Retrospective Studies; D016019:Survival Analysis; D006113:United Kingdom / Q000453:epidemiology