title: An observational study of surface versus endovascular cooling techniques in cardiac arrest patients: a propensity-matched analysis.
abstract: BACKGROUND
  Various methods and devices have been described for cooling after cardiac arrest, but the ideal cooling method remains unclear. The aim of this study was to compare the neurological outcomes, efficacies and adverse events of surface and endovascular cooling techniques in cardiac arrest patients.
  
  
  METHODS
  We performed a multicenter, retrospective, registry-based study of adult cardiac arrest patients treated with therapeutic hypothermia presenting to 24 hospitals across South Korea from 2007 to 2012. We included patients who received therapeutic hypothermia using overall surface or endovascular cooling devices and compared the neurological outcomes, efficacies and adverse events of both cooling techniques. To adjust for differences in the baseline characteristics of each cooling method, we performed one-to-one matching by the propensity score.
  
  
  RESULTS
  In total, 803 patients were included in the analysis. Of these patients, 559 underwent surface cooling, and the remaining 244 patients underwent endovascular cooling. In the unmatched cohort, a greater number of adverse events occurred in the surface cooling group. Surface cooling was significantly associated with a poor neurological outcome (cerebral performance category 3-5) at hospital discharge (p = 0.01). After propensity score matching, surface cooling was not associated with poor neurological outcome and hospital mortality [odds ratio (OR): 1.26, 95% confidence interval (CI): 0.81-1.96, p = 0.31 and OR: 0.85, 95% CI: 0.55-1.30, p = 0.44, respectively]. Although surface cooling was associated with an increased incidence of adverse events (such as overcooling, rebound hyperthermia, rewarming related hypoglycemia and hypotension) compared with endovascular cooling, these complications were not associated with surface cooling using hydrogel pads.
  
  
  CONCLUSIONS
  In the overall matched cohort, no significant difference in neurological outcomes and hospital morality was observed between the surface and endovascular cooling methods.
authors.affiliation: Department of Emergency Medicine, College of Medicine, The Catholic University of Korea, 222, Banpodaero, Seocho-gu, Seoul, Korea, 137-701. ohmytweety@catholic.ac.kr.
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Oh
authors.affiliation: Department of Emergency Medicine, College of Medicine, The Catholic University of Korea, 222, Banpodaero, Seocho-gu, Seoul, Korea, 137-701. ohjoosuk@gmail.com.
authors.forename: Joo Suk
authors.initials: JS
authors.lastname: Oh
authors.affiliation: Department of Emergency Medicine, College of Medicine, The Catholic University of Korea, 222, Banpodaero, Seocho-gu, Seoul, Korea, 137-701. emart@catholic.ac.kr.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, College of Medicine, The Catholic University of Korea, 222, Banpodaero, Seocho-gu, Seoul, Korea, 137-701. emsky@catholic.ac.kr.
authors.forename: Kyu Nam
authors.initials: KN
authors.lastname: Park
authors.affiliation: Department of Emergency Medicine, College of Medicine, The Catholic University of Korea, 222, Banpodaero, Seocho-gu, Seoul, Korea, 137-701. emvic98@catholic.ac.kr.
authors.forename: Seung Pill
authors.initials: SP
authors.lastname: Choi
authors.affiliation: Department of Emergency Medicine, College of Medicine, Ajou University, 164, World cup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, Korea, 443-380. flyingguy@ajou.ac.kr.
authors.forename: Gi Woon
authors.initials: GW
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, College of Medicine, Chonnam National University, 42, Jebong-ro, Dong-gu, Gwangju, South Korea, 501-757. neoneti@hanmail.net.
authors.forename: Kyung Woon
authors.initials: KW
authors.lastname: Jeung
authors.affiliation: Department of Emergency Medicine, College of Medicine, Catholic University of Daegu, 33, Duryugongwonro 17-gil, Nam-gu, Daegu, Korea, 705-718. bizkit96@naver.com.
authors.forename: Tae Chang
authors.initials: TC
authors.lastname: Jang
authors.affiliation: Department of Emergency Medicine, College of Medicine, Yonsei University, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, Korea, 120-752. pys0905@yuhs.ac.
authors.forename: Yoo Seok
authors.initials: YS
authors.lastname: Park
authors.affiliation: Department of Emergency Medicine, College of Medicine, The Catholic University of Korea, 222, Banpodaero, Seocho-gu, Seoul, Korea, 137-701. primebee@catholic.ac.kr.
authors.forename: Yeon Young
authors.initials: YY
authors.lastname: Kyong
mesh_terms: D000328:Adult; D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D005260:Female; D006323:Heart Arrest / Q000401:mortality / Q000628:therapy*; D017052:Hospital Mortality; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects / Q000379:methods*; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D012042:Registries; D056910:Republic of Korea; D012189:Retrospective Studies; D017694:Rewarming / Q000009:adverse effects; D016896:Treatment Outcome