***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background —Recent clinical studies have demonstrated that hypothermia to 32 ° to 34 ° C provides significant clinical benefit when induced after resuscitation from cardiac arrest . However , cooling during the postresuscitation period was slow , requiring 4 to 8 hours to achieve target temperatures after return of spontaneous circulation ( ROSC ) . Whether more rapid cooling would further improve survival remains unclear . We sought to determine whether cooling during cardiac arrest before ROSC ( ie , “ intra-arrest ” hypothermia ) has survival benefit over more delayed post-ROSC cooling , using a murine cardiac arrest model . Methods and Results —A model of potassium-induced cardiac arrest was established in C57BL/6 mice . After 8 minutes of untreated cardiac arrest , resuscitation was attempted with chest compression , ventilation , and intravenous fluid .  Mice were r and omized to 3 treatment groups ( n=10 each ) : an intra-arrest hypothermia group , in which mice were cooled to 30 ° C just before attempted resuscitation , and then rewarmed after 1 hour ; a post-ROSC hypothermia group , in which mice were kept at 37 ° C for 20 minutes after successful ROSC and then were cooled to 30 ° C for 1 hour ; and a normothermic control group , in which mice were kept at 37 ° C . The intra-arrest hypothermia group demonstrated better 72-hour survival than delayed hypothermia and normothermia groups ( 6/10 versus 1/10 and 1/10 survivors , respectively , P < 0.05 ) , with similar differences seen at 6-hour survival and on neurological scoring . Conclusions —Timing of hypothermia is a crucial determinant of survival in the murine arrest model . Early intra-arrest cooling appears to be significantly better than delayed post-ROSC cooling or normothermic resuscitation Background — Therapeutic hypothermia is recommended for the treatment of neurological injury after resuscitation from out-of-hospital cardiac arrest . Laboratory studies have suggested that earlier cooling may be associated with improved neurological outcomes . We hypothesized that induction of therapeutic hypothermia by paramedics before hospital arrival would improve outcome . Methods and Results — In a prospect i ve , r and omized controlled trial , we assigned adults who had been resuscitated from out-of-hospital cardiac arrest with an initial cardiac rhythm of ventricular fibrillation to either prehospital cooling with a rapid infusion of 2 L of ice-cold lactated Ringer 's solution or cooling after hospital admission . The primary outcome measure was functional status at hospital discharge , with a favorable outcome defined as discharge either to home or to a rehabilitation facility . A total of 234 patients were r and omly assigned to either paramedic cooling ( 118 patients ) or hospital cooling ( 116 patients ) . Patients allocated to paramedic cooling received a median of 1900 mL ( first quartile 1000 mL , third quartile 2000 mL ) of ice-cold fluid . This result ed in a mean decrease in core temperature of 0.8 ° C ( P=0.01 ) . In the paramedic-cooled group , 47.5 % patients had a favorable outcome at hospital discharge compared with 52.6 % in the hospital-cooled group ( risk ratio 0.90 , 95 % confidence interval 0.70 to 1.17 , P=0.43 ) . Conclusions — In adults who have been resuscitated from out-of-hospital cardiac arrest with an initial cardiac rhythm of ventricular fibrillation , paramedic cooling with a rapid infusion of large-volume , ice-cold intravenous fluid decreased core temperature at hospital arrival but was not shown to improve outcome at hospital discharge compared with cooling commenced in the hospital . Clinical Trial Registration — URL : http://www.anzctr.org.au . Unique identifier : ACTRN12605000179639 Background — Although delayed hospital cooling has been demonstrated to improve outcome after cardiac arrest , in-field cooling started immediately after the return of spontaneous circulation may be more beneficial . The aims of the present pilot study were to assess the feasibility , safety , and effectiveness of in-field cooling . Methods and Results — We determined the effect on esophageal temperature , before hospital arrival , of infusing up to 2 L of 4 ° C normal saline as soon as possible after resuscitation from out-of-hospital cardiac arrest . A total of 125 such patients were r and omized to receive st and ard care with or without intravenous cooling .  Of the 63 patients r and omized to cooling , 49 ( 78 % ) received an infusion of 500 to 2000 mL of 4 ° C normal saline before hospital arrival . These 63 patients experienced a mean temperature decrease of 1.24±1 ° C with a hospital arrival temperature of 34.7 ° C , whereas the 62 patients not r and omized to cooling experienced a mean temperature increase of 0.10±0.94 ° C ( P<0.0001 ) with a hospital arrival temperature of 35.7 ° C . In-field cooling was not associated with adverse consequences in terms of blood pressure , heart rate , arterial oxygenation , evidence for pulmonary edema on initial chest x-ray , or rearrest . Secondary end points of awakening and discharged alive from hospital trended toward improvement in ventricular fibrillation patients r and omized to in-field cooling . Conclusions — These pilot data suggest that infusion of up to 2 L of 4 ° C normal saline in the field is feasible , safe , and effective in lowering temperature . We propose that the effect of this cooling method on neurological outcome after cardiac arrest be studied in larger numbers of patients , especially those whose initial rhythm is ventricular fibrillation Background The International Liaison Committee on Resuscitation ( ILCOR ) now recommends therapeutic hypothermia ( TH ) ( 33 ° C for 12 - 24 hours ) as soon as possible for patients who remain comatose after resuscitation from shockable rhythm in out-of-hospital cardiac arrest and that it be considered for non shockable rhythms . The optimal timing of TH is still uncertain . Laboratory data have suggested that there is significantly decreased neurological injury if cooling is initiated during CPR . In addition , peri-arrest cooling may increase the rate of successful defibrillation . This study aims to determine whether paramedic cooling during CPR improves outcome compared st and ard treatment in patients who are being resuscitated from out-of-hospital cardiac arrest . Methods / Design This paper describes the methodology for a definitive multi-centre , r and omised , controlled trial of paramedic cooling during CPR compared with st and ard treatment . Paramedic cooling during CPR will be achieved using a rapid infusion of large volume ( 20 - 40 mL/kg to a maximum of 2 litres ) ice-cold ( 4 ° C ) normal saline . The primary outcome measure is survival at hospital discharge . Secondary outcome measures are rates of return of spontaneous circulation , rate of survival to hospital admission , temperature on arrival at hospital , and 12 month quality of life of survivors . Discussion This trial will test the effect of the administration of ice cold saline during CPR on survival outcomes . If this simple treatment is found to improve outcomes , it will have generalisability to prehospital services globally . Trial Registration Clinical Trials.gov : Objective : Accurate measurement of temperature is vital in the intensive care setting . A prospect i ve trial was performed to compare the accuracy of tympanic , urinary , and axillary temperatures with that of pulmonary artery ( PA ) core temperature measurements . Design : A total of 110 patients were enrolled in a prospect i ve observational cohort study . Setting : Multidisciplinary intensive care unit of a university teaching hospital . Patients : The cohort was ( mean ± sd ) 65 ± 16 yrs of age , Acute Physiology and Chronic Health Evaluation ( APACHE ) II score was 25 ± 9 , 58 % of the patients were men , and 76 % were mechanically ventilated . The accuracy of tympanic ( averaged over both ears ) , axillary ( averaged over both sides ) , and urinary temperatures was referenced ( as mean difference , & Dgr ; degrees centi grade ) to PA temperatures as st and ard in 6,703 recordings . Lin concordance correlation ( pc ) and Bl and –Altman 95 % limits of agreement ( degrees centi grade ) described the relationship between paired measurements . Regression analysis ( linear mixed model ) assessed covariate confounding with respect to temperature modes and reliability formulated as an intraclass correlation coefficient . Measurements and Main Results : Concordance of PA temperatures with tympanic , urinary , and axillary was 0.77 , 0.92 , and 0.83 , respectively . Compared with PA temperatures , & Dgr ; ( limits of agreement ) were 0.36 ° C ( −0.56 ° C , 1.28 ° C ) , −0.05 ° C ( −0.69 ° C , 0.59 ° C ) , and 0.30 ° C ( −0.42 ° C , 1.01 ° C ) for tympanic , urinary , and axillary temperatures , respectively . Temperature measurement mode effect , estimated via regression analysis , was consistent with concordance and & Dgr ; ( PA vs. urinary , p = .98 ) . Patient age ( p = .03 ) , sedation score ( p = .0001 ) , and dialysis ( p = .0001 ) had modest negative relations with temperature ; quadratic relationships were identified with adrenaline and dobutamine . No interactions with particular temperature modes were identified ( p ≥ .12 for all comparisons ) and no relationship was identified with either mean arterial pressure or APACHE II score ( p ≥ .64 ) . The average temperature mode intraclass correlation coefficient for test – retest reliability was 0.72 . Conclusion : Agreement of tympanic with pulmonary temperature was inferior to that of urinary temperature , which , on overall assessment , seemed more likely to reflect PA core temperature Background — Transnasal evaporative cooling has sufficient heat transfer capacity for effective intra-arrest cooling and improves survival in swine . The aim of this study was to determine the safety , feasibility , and cooling efficacy of prehospital transnasal cooling in humans and to explore its effects on neurologically intact survival to hospital discharge . Methods and Results — Witnessed cardiac arrest patients with a treatment interval ≤20 minutes were r and omized to intra-arrest cooling with a RhinoChill device ( treatment group , n=96 ) versus st and ard care ( control group , n=104 ) . The final analysis included 93 versus 101 patients , respectively . Both groups were cooled after hospital arrival . The patients had similar demographics , initial rhythms , rates of byst and er cardiopulmonary resuscitation , and intervals to cardiopulmonary resuscitation and arrival of advanced life support personnel . Eighteen device-related adverse events ( 1 periorbital emphysema , 3 epistaxis , 1 perioral bleed , and 13 nasal discolorations ) were reported . Time to target temperature of 34 ° C was shorter in the treatment group for both tympanic ( 102 versus 282 minutes , P=0.03 ) and core ( 155 versus 284 minutes , P=0.13 ) temperature . There were no significant differences in rates of return of spontaneous circulation between the groups ( 38 % in treated subjects versus 43 % in control subjects , P=0.48 ) , in overall survival of those admitted alive ( 44 % versus 31 % , respectively , P=0.26 ) , or in neurologically intact survival to discharge ( Pittsburgh cerebral performance category scale 1 to 2 , 34 % versus 21 % , P=0.21 ) , although the study was not adequately powered to detect changes in these outcomes . Conclusions — Prehospital intra-arrest transnasal cooling is safe and feasible and is associated with a significant improvement in the time intervals required to cool patients . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00808236 BACKGROUND Therapeutic hypothermia ( TH ) represents an important method to attenuate post-resuscitation injury after cardiac arrest . Laboratory investigations have suggested that induction of hypothermia before return of spontaneous circulation ( ROSC ) may confer the greatest benefit . We hypothesized that a short delay in resuscitation to induce hypothermia before ROSC , even at the expense of more prolonged ischemia , may yield both physiological and survival advantages . METHODS Cardiac arrest was induced in C57BL/6 mice using intravenous potassium chloride ; resuscitation was attempted with CPR and fluid administration .  Animals were r and omized into three groups ( n=15 each ) : a normothermic control group , in which 8 min of arrest at 37 degrees C was followed by resuscitation ; an early intra-arrest hypothermia group , in which 6.5 min of 37 degrees C arrest were followed by 90s of cooling , with resuscitation attempted at 30 degrees C ( 8 min total ischemia ) ; and a delayed intra-arrest hypothermia group , with 90s cooling begun after 8 min of 37 degrees C ischemia , so that animals underwent resuscitation at 9.5 min . RESULTS Animals treated with TH demonstrated improved hemodynamic variables and survival compared to normothermic controls . This was the case even when comparing the delayed intra-arrest hypothermia group with prolonged ischemia time against normothermic controls with shorter ischemia time ( 7-day survival , 4/15 vs. 0/15 , p<0.001 ) . CONCLUSIONS Short res 
    Output:
    
However , no significant differences were observed in the survival to the hospital discharge , favorable neurological outcome at hospital discharge , and rearrest .
This review demonstrates that prehospital therapeutic hypothermia after cardiac arrest can decrease temperature on hospital admission .
On the other h and , regarding the survival to hospital discharge , favorable neurological outcome at hospital discharge , and rearrest , our meta- analysis and review produces non-significant results .