Rationale, timeline, study design, and protocol overview of the therapeutic hypothermia after pediatric cardiac arrest trials

Extracorporeal Cardiopulmonary Resuscitation: One-Year Survival and Neurobehavioral Outcome Among Infants and Children With In-Hospital Cardiac Arrest

OBJECTIVE

To describe neurobehavioral outcomes and investigate factors associated with survival and survival with good neurobehavioral outcome 1 year after in-hospital cardiac arrest for children who received extracorporeal cardiopulmonary resuscitation.

DESIGN

Secondary analysis of the Therapeutic Hypothermia after Pediatric Cardiac Arrest In-Hospital trial.

SETTING

Thirty-seven PICUs in the United States, Canada, and the United Kingdom.

PATIENTS

Children (n = 147) resuscitated with extracorporeal cardiopulmonary resuscitation following in-hospital cardiac arrest.

INTERVENTIONS

Neurobehavioral status was assessed using the Vineland Adaptive Behavior Scales, Second Edition, at prearrest baseline and 12 months postarrest. Norms for Vineland Adaptive Behavior Scales, Second Edition, are 100 (mean) ± 15 (SD). Higher scores indicate better functioning. Outcomes included 12-month survival, 12-month survival with Vineland Adaptive Behavior Scales, Second Edition, decreased by less than or equal to 15 points from baseline, and 12-month survival with Vineland Adaptive Behavior Scales, Second Edition, greater than or equal to 70.

MEASUREMENTS AND MAIN RESULTS

Of 147 children receiving extracorporeal cardiopulmonary resuscitation, 125 (85.0%) had a preexisting cardiac condition, 75 (51.0%) were postcardiac surgery, and 84 (57.1%) were less than 1 year old. Duration of chest compressions was greater than 30 minutes for 114 (77.5%). Sixty-one (41.5%) survived to 12 months, 32 (22.1%) survived to 12 months with Vineland Adaptive Behavior Scales, Second Edition, decreased by less than or equal to 15 points from baseline, and 39 (30.5%) survived to 12 months with Vineland Adaptive Behavior Scales, Second Edition, greater than or equal to 70. On multivariable analyses, open-chest cardiac massage was independently associated with greater 12-month survival with Vineland Adaptive Behavior Scales, Second Edition, decreased by less than or equal to 15 points and greater 12-month survival with Vineland Adaptive Behavior Scales, Second Edition, greater than or equal to 70. Higher minimum postarrest lactate and preexisting gastrointestinal conditions were independently associated with lower 12-month survival with Vineland Adaptive Behavior Scales, Second Edition, decreased by less than or equal to 15 points and lower 12-month survival with Vineland Adaptive Behavior Scales, Second Edition, greater than or equal to 70.

CONCLUSIONS

About one third of children survived with good neurobehavioral outcome 1 year after receiving extracorporeal cardiopulmonary resuscitation for in-hospital arrest. Open-chest cardiac massage and minimum postarrest lactate were associated with survival with good neurobehavioral outcome at 1 year.

The association of early post-resuscitation hypotension with discharge survival following targeted temperature management for pediatric in-hospital cardiac arrest

AIM

Approximately 40% of children who have an in-hospital cardiac arrest (IHCA) in the US survive to discharge. We aimed to evaluate the impact of post-cardiac arrest hypotension during targeted temperature management following IHCA on survival to discharge.

METHODS

This is a secondary analysis of the therapeutic hypothermia after pediatric cardiac arrest in-hospital (THAPCA-IH) trial. "Early hypotension" was defined as a systolic blood pressure less than the fifth percentile for age and sex for patients not treated with extracorporeal membrane oxygenation (ECMO) or a mean arterial pressure less than fifth percentile for age and sex for patients treated with ECMO during the first 6 h of temperature intervention. The primary outcome was survival to hospital discharge.

RESULTS

Of 299 children, 142 (47%) patients did not receive ECMO and 157 (53%) received ECMO. Forty-two of 142 (29.6%) non-ECMO patients had systolic hypotension. Twenty-three of 157 (14.7%) ECMO patients had mean arterial hypotension. After controlling for confounders of interest, non-ECMO patients who had early systolic hypotension were less likely to survive to hospital discharge (40.5% vs. 72%; adjusted OR [aOR] 0.34; 95%CI, 0.12-0.93). There was no difference in survival to discharge by blood pressure groups for children treated with ECMO (30.4% vs. 49.3%; aOR = 0.60; 95%CI, 0.22-1.63).

CONCLUSIONS

In this secondary analysis of the THAPCA-IH trial, in patients not treated with ECMO, systolic hypotension within 6 h of temperature intervention was associated with lower odds of discharge survival. Blood pressure groups in patients treated with ECMO were not associated with survival to discharge.

One-year cognitive and neurologic outcomes in survivors of paediatric extracorporeal cardiopulmonary resuscitation

OBJECTIVE

To describe one-year cognitive and neurologic outcomes among extracorporeal cardiopulmonary resuscitation (ECPR) survivors enrolled in the Therapeutic Hypothermia after Paediatric Cardiac Arrest In-Hospital (THAPCA-IH) trial; and compare outcomes between survivors who received ECPR, later extracorporeal membrane oxygenation (ECMO), or no ECMO.

METHODS

All children recruited to THAPCA-IH were comatose post-arrest. Neurobehavioral function was assessed by caregivers using the Vineland Adaptive Behaviour Scales, 2nd edition (VABS-II) at pre-arrest baseline and 12 months post-arrest. Age-appropriate cognitive performance measures (Mullen Scales of Early Learning or Wechsler Abbreviated Scale of Intelligence) and neurologic examinations were obtained 12 months post-arrest. VABS-II and cognitive performance measures were transformed to standard scores (mean = 100, SD = 15) with higher scores representing better performance. Only children with broadly normal pre-arrest function (VABS-II ≥70) were included in this analysis.

RESULTS

One-year follow-up was attained for 127 survivors with pre-arrest VABS-II ≥70. Of these, 57 received ECPR, 14 received ECMO later in their course, and 56 did not receive ECMO. VABS-II assessments were completed at 12 months for 55 (96.5%) ECPR survivors, cognitive testing for 44 (77.2%) and neurologic examination for 47 (82.5%). At 12 months, 39 (70.9%) ECPR survivors had VABS-II scores ≥70. On cognitive testing, 24 (54.6%) had scores ≥70, and on neurologic examination, 28 (59.5%) had no/minimal to mild impairment. Cognitive and neurologic score distributions were similar between ECPR, later ECMO and no ECMO groups.

CONCLUSIONS

Many ECPR survivors had favourable outcomes although impairments were common. ECPR survivors had similar outcomes to other survivors who were initially comatose post-arrest.

Pediatric out-of-hospital cardiac arrest: Time to goal target temperature and outcomes

AIM

Although recent out-of-hospital cardiac arrest (CA) trials found no benefits of hypothermia versus normothermia targeted temperature management, preclinical models suggest earlier timing of hypothermia improves neuroprotective efficacy. This study investigated whether shorter time to goal temperature was associated with better one-year outcomes in the Therapeutic Hypothermia After Pediatric Cardiac Arrest Out-of-Hospital Trial.

METHODS

Patients were classified by tertiles of time to attain assigned goal temperature range (32-34°C or 36-37.5°C) following ROSC. Outcomes in the first tertile ("earlier") Group 1 were compared with second and third tertiles ("later") Group 2. Separate analyses were, additionally, completed for hypothermia and normothermia intervention groups. Three one-year outcomes were examined: survival; Vineland Adaptive Behavior Scale (VABS-II) score≥70; and decrease in VABS-II≤15 points from baseline.

RESULTS

In the entire cohort (n=281), median time from ROSC to goal temperature was 7.4 [IQR 6.2-9.7] hours: Group 1, 5.8 [IQR 5.2, 6.2] and Group 2, 8.8 [IQR 7.4, 10.4] h. Outcomes did not differ between these groups. For hypothermia subgroup, survival was lower in Group 1 than 2, [10/49(20%) versus 47/99(47%), p<0.002], with a trend toward fewer with VABS-II scores≥70 and change in VABS-II≤15 points (p=0.07-0.08). For normothermia subgroup, there was a trend toward higher survival in Group 1 than 2 [18/42(43%) versus 21/83(25%), p=0.065], but no differences in VABS-II-related measures. In multivariable logistic regression models, no difference in earlier and later groups or temperature intervention was observed.

CONCLUSION

We found no evidence that earlier time to goal temperature was associated with better outcomes.

One-Year Survival and Neurologic Outcomes After Pediatric Open-Chest Cardiopulmonary Resuscitation

BACKGROUND

Limited data exist about neurobehavioral outcomes of children treated with open-chest cardiopulmonary resuscitation (CPR). Our objective was to describe neurobehavioral outcomes 1 year after arrest among children who received open-chest CPR during in-hospital cardiac arrest and to explore factors associated with 1-year survival and survival with good neurobehavioral outcome.

METHODS

The study is a secondary analysis of the Therapeutic Hypothermia after Pediatric Cardiac Arrest In-Hospital Trial. Fifty-six children who received open-chest CPR for in-hospital cardiac arrest were included. Neurobehavioral status was assessed using the Vineland Adaptive Behavior Scales, Second Edition (VABS-II) at baseline before arrest and 12 months after arrest. Norms for VABS-II are 100 ± 15 points. Outcomes included 12-month survival, 12-month survival with VABS-II decreased by no more than 15 points from baseline, and 12-month survival with VABS-II of 70 or more points.

RESULTS

Of 56 children receiving open-chest CPR, 49 (88%) were after cardiac surgery and 43 (77%) were younger than 1 year. Forty-four children (79%) were cannulated for extracorporeal membrane oxygenation (ECMO) during CPR or within 6 hours of return of spontaneous circulation. Thirty-three children (59%) survived to 12 months, 22 (41%) survived to 12 months with VABS-II decreased by no more than 15 points from baseline, and of the children with baseline VABS-II of 70 or more points 23 (51%) survived to 12 months with VABS-II of 70 or more points. On multivariable analyses, use of ECMO, renal replacement therapy, and higher maximum international normalized ratio were independently associated with lower 12-month survival with VABS-II of 70 or more points.

CONCLUSIONS

Approximately one-half of children survived with good neurobehavioral outcome 1 year after open-chest CPR for in-hospital cardiac arrest. Use of ECMO and postarrest renal or hepatic dysfunction may be associated with worse neurobehavioral outcomes.

Therapeutic hypothermia after paediatric cardiac arrest: Pooled randomized controlled trials

BACKGROUND

Separate trials to evaluate therapeutic hypothermia after paediatric cardiac arrest for out-of-hospital and in-hospital settings reported no statistically significant differences in survival with favourable neurobehavioral outcome or safety compared to therapeutic normothermia. However, larger sample sizes might detect smaller clinical effects. Our aim was to pool data from identically conducted trials to approximately double the sample size of the individual trials yielding greater statistical power to compare outcomes.

METHODS

Combine individual patient data from two clinical trials set in forty-one paediatric intensive care units in USA, Canada and UK. Children aged at least 48 h up to 18 years old, who remained comatose after resuscitation, were randomized within 6 h of return of circulation to hypothermia or normothermia (target 33.0 °C or 36.8 °C). The primary outcome, survival 12 months post-arrest with Vineland Adaptive Behaviour Scales, Second Edition (VABS-II) score at least 70 (scored from 20 to 160, higher scores reflecting better function, population mean = 100, SD = 15), was evaluated among patients with pre-arrest scores ≥70.

RESULTS

624 patients were randomized. Among 517 with pre-arrest VABS-II scores ≥70, the primary outcome did not significantly differ between hypothermia and normothermia groups (28% [75/271] and 26% [63/246], respectively; relative risk, 1.08; 95% confidence interval [CI], 0.81 to 1.42; p = 0.61). Among 602 evaluable patients, the change in VABS-II score from baseline to 12 months did not differ significantly between groups (p = 0.20), nor did, proportion of cases with declines no more than 15 points or improvement from baseline [22% (hypothermia) and 21% (normothermia)]. One-year survival did not differ significantly between hypothermia and normothermia groups (44% [138/317] and 38% [113/ 297], respectively; relative risk, 1.15; 95% CI, 0.95 to 1.38; p = 0.15). Incidences of blood-product use, infection, and serious cardiac arrhythmia adverse events, and 28-day mortality, did not differ between groups.

CONCLUSIONS

Analysis of combined data from two paediatric cardiac arrest targeted temperature management trials including both in-hospital and out-of-hospital cases revealed that hypothermia, as compared with normothermia, did not confer a significant benefit in survival with favourable functional outcome at one year.

Burden of caregiving after a child's in-hospital cardiac arrest

OBJECTIVE

To describe caregiver burden among those whose children survive in-hospital cardiac arrest and have high risk of neurologic disability, and explore factors associated with burden during the first year post-arrest.

METHODS

The study is a secondary analysis of the Therapeutic Hypothermia after Paediatric Cardiac Arrest In-Hospital (THAPCA-IH) trial. 329 children who had an in-hospital cardiac arrest, chest compressions for >2 min, and mechanical ventilation after return of circulation were recruited to THAPCA-IH. Of these, 155 survived to one year, and caregivers of 138 were assessed for burden. Caregiver burden was assessed at baseline, and 3 and 12 months post-arrest using the Infant Toddler Quality of Life Questionnaire for children <5 years old and the Child Health Questionnaire for children >5 years. Child functioning was assessed using the Vineland Adaptive Behaviour Scales Second Edition (VABS-II), the Paediatric Overall Performance Category (POPC) and Paediatric Cerebral Performance Category (PCPC) scales, and caregiver perception of global functioning.

RESULTS

Of 138 children, 77 (55.8%) were male, 77 (55.8%) were white, and 109 (79.0%) were <5 years old at the time of arrest. Caregiver burden was greater than reference norms at all time points. Worse POPC, PCPC and VABS-II scores at 3 months post-arrest were associated with greater caregiver burden at 12 months. Worse global functioning at 3 months was associated with greater burden at 12 months for children <5 years.

CONCLUSIONS

Caregiver burden is substantial during the first year after paediatric in-hospital cardiac arrest, and associated with the extent of the child's neurobehavioural dysfunction.

Paediatric in-hospital cardiac arrest: Factors associated with survival and neurobehavioural outcome one year later

OBJECTIVE

To investigate clinical characteristics associated with 12-month survival and neurobehavioural function among children recruited to the Therapeutic Hypothermia after Paediatric Cardiac Arrest In-Hospital trial.

METHODS

Children (n = 329) with in-hospital cardiac arrest who received chest compressions for ≥2 min, were comatose, and required mechanical ventilation after return of circulation were included. Neurobehavioural function was assessed using the Vineland Adaptive Behaviour Scales, second edition (VABS-II) at baseline (reflecting pre-arrest status) and 12 months post-arrest. Norms for VABS-II are 100 (mean) ±15 (SD). Higher scores indicate better functioning. Outcomes included 12-month survival, 12-month survival with VABS-II decreased by ≤15 points from baseline, and 12-month survival with VABS-II ≥70.

RESULTS

Asystole as the initial arrest rhythm, administration of >4 adrenaline doses, and higher post-arrest blood lactate concentration were independently associated with lower 12-month survival; an adrenaline dosing interval of 3-<5 min and open chest compressions were independently associated with greater 12-month survival. Use of extracorporeal membrane oxygenation (ECMO) and higher blood lactate were independently associated with lower 12-month survival with VABS-II decreased by ≤15 points from baseline; open chest compressions was independently associated with greater 12-month survival with VABS-II decreased by ≤15 points. Asystole as the initial rhythm, use of ECMO, and higher blood lactate were independently associated with lower 12-month survival with VABS-II ≥70; open chest compressions was independently associated with greater 12-month survival with VABS-II ≥70.

CONCLUSIONS

Cardiac arrest and resuscitation factors are associated with long-term survival and neurobehavioural function among children who are comatose after in-hospital arrest.

Association of Early Postresuscitation Hypotension With Survival to Discharge After Targeted Temperature Management for Pediatric Out-of-Hospital Cardiac Arrest: Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

Out-of-hospital cardiac arrest (OHCA) occurs in more than 6000 children each year in the United States, with survival rates of less than 10% and severe neurologic morbidity in many survivors. Post-cardiac arrest hypotension can occur, but its frequency and association with survival have not been well described during targeted temperature management.

OBJECTIVE

To determine whether hypotension is associated with survival to discharge in children and adolescents after resuscitation from OHCA.

DESIGN, SETTING, AND PARTICIPANTS

This post hoc secondary analysis of the Therapeutic Hypothermia After Pediatric Cardiac Arrest (THAPCA) trial included 292 pediatric patients older than 48 hours and younger than 18 years treated in 36 pediatric intensive care units from September 1, 2009, through December 31, 2012. Participants underwent therapeutic hypothermia (33.0°C) vs therapeutic normothermia (36.8°C) for 48 hours. All participants had hourly systolic blood pressure measurements documented during the initial 6 hours of temperature intervention. Hourly blood pressures beginning at the time of temperature intervention (time 0) were normalized for age, sex, and height. Early hypotension was defined as a systolic blood pressure less than the fifth percentile during the first 6 hours after temperature intervention. With use of forward stepwise logistic regression, covariates of interest (age, sex, initial cardiac rhythm, any preexisting condition, estimated duration of cardiopulmonary resuscitation [CPR], primary cause of cardiac arrest, temperature intervention group, night or weekend cardiac arrest, witnessed status, and bystander CPR) were evaluated in the final model. Data were analyzed from February 5, 2016, through June 13, 2017.

EXPOSURES

Hypotension.

MAIN OUTCOMES AND MEASURE

Survival to hospital discharge.

RESULTS

Of 292 children (194 boys [66.4%] and 98 girls [33.6%]; median age, 23.0 months [interquartile range, 5.0-105.0 months]), 78 (26.7%) had at least 1 episode of early hypotension. No difference was observed between the therapeutic hypothermia and therapeutic normothermia groups in the prevalence of hypotension during induction and maintenance (73 of 153 [47.7%] vs 72 of 139 [51.8%]; P = .50) or rewarming (35 of 118 [29.7%] vs 19 of 95 [20.0%]; P = .10) during the first 72 hours. Participants who had early hypotension were less likely to survive to hospital discharge (20 of 78 [25.6%] vs 93 of 214 [43.5%]; adjusted odds ratio, 0.39; 95% CI, 0.20-0.74).

CONCLUSIONS AND RELEVANCE

In this post hoc secondary analysis of the THAPCA trial, 26.7% of participants had hypotension within 6 hours after temperature intervention. Early post-cardiac arrest hypotension was associated with lower odds of discharge survival, even after adjusting for covariates of interest.

Targeted temperature management in neurological intensive care unit

Targeted temperature management (TTM) shows the most promising neuroprotective therapy against hypoxic/ischemic encephalopathy (HIE). In addition, TTM is also useful for treatment of elevated intracranial pressure (ICP). HIE and elevated ICP are common catastrophic conditions in patients admitted in Neurologic intensive care unit (ICU). The most common cause of HIE is cardiac arrest. Randomized control trials demonstrate clinical benefits of TTM in patients with post-cardiac arrest. Although clinical benefit of ICP control by TTM in some specific critical condition, for an example in traumatic brain injury, is still controversial, efficacy of ICP control by TTM is confirmed by both in vivo and in vitro studies. Several methods of TTM have been reported in the literature. TTM can apply to various clinical conditions associated with hypoxic/ischemic brain injury and elevated ICP in Neurologic ICU.

Functional Outcome Trajectories After Out-of-Hospital Pediatric Cardiac Arrest

OBJECTIVES

To analyze functional performance measures collected prospectively during the conduct of a clinical trial that enrolled children (up to age 18 yr old), resuscitated after out-of-hospital cardiac arrest, who were at high risk of poor outcomes.

DESIGN

Children with Glasgow Motor Scale score less than 5, within 6 hours of resuscitation, were enrolled in a clinical trial that compared two targeted temperature management interventions (THAPCA-OH, NCT00878644). The primary outcome, 12-month survival with Vineland Adaptive Behavior Scale, second edition, score greater or equal to 70, did not differ between groups.

SETTING

Thirty-eight North American PICUs.

PARTICIPANTS

Two hundred ninety-five children were enrolled; 270 of 295 had baseline Vineland Adaptive Behavior Scale, second edition, scores greater or equal to 70; 87 of 270 survived 1 year.

INTERVENTIONS

Targeted temperatures were 33.0°C and 36.8°C for hypothermia and normothermia groups.

MEASUREMENTS AND MAIN RESULTS

Baseline measures included Vineland Adaptive Behavior Scale, second edition, Pediatric Cerebral Performance Category, and Pediatric Overall Performance Category. Pediatric Cerebral Performance Category and Pediatric Overall Performance Category were rescored at hospital discharges; all three were scored at 3 and 12 months. In survivors with baseline Vineland Adaptive Behavior Scale, second edition scores greater or equal to 70, we evaluated relationships of hospital discharge Pediatric Cerebral Performance Category with 3- and 12-month scores and between 3- and 12-month Vineland Adaptive Behavior Scale, second edition, scores. Hospital discharge Pediatric Cerebral Performance Category scores strongly predicted 3- and 12-month Pediatric Cerebral Performance Category (r = 0.82 and 0.79; p < 0.0001) and Vineland Adaptive Behavior Scale, second edition, scores (r = -0.81 and -0.77; p < 0.0001). Three-month Vineland Adaptive Behavior Scale, second edition, scores strongly predicted 12-month performance (r = 0.95; p < 0.0001). Hypothermia treatment did not alter these relationships.

CONCLUSIONS

In comatose children, with Glasgow Motor Scale score less than 5 in the initial hours after out-of-hospital cardiac arrest resuscitation, function scores at hospital discharge and at 3 months predicted 12-month performance well in the majority of survivors.

Pediatric cardiac arrest due to drowning and other respiratory etiologies: Neurobehavioral outcomes in initially comatose children

AIM

To describe the 1-year neurobehavioral outcome of survivors of cardiac arrest secondary to drowning, compared with other respiratory etiologies, in children enrolled in the Therapeutic Hypothermia after Pediatric Cardiac Arrest Out-of-Hospital (THAPCA-OH) trial.

METHODS

Exploratory analysis of survivors (ages 1-18 years) who received chest compressions for ≥2min, were comatose, and required mechanical ventilation after return of circulation (ROC). Participants recruited from 27 pediatric intensive care units in North America received targeted temperature management [therapeutic hypothermia (33°C) or therapeutic normothermia (36.8°C)] within 6h of ROC. Neurobehavioral outcomes included 1-year Vineland Adaptive Behavior Scales, Second Edition (VABS-II) total and domain scores and age-appropriate cognitive performance measures (Mullen Scales of Early Learning or Wechsler Abbreviated Scale of Intelligence).

RESULTS

Sixty-six children with a respiratory etiology of cardiac arrest survived for 1-year; 60/66 had broadly normal premorbid functioning (VABS-II≥70). Follow up was obtained on 59/60 (30 with drowning etiology). VABS-II composite and domain scores declined significantly from premorbid scores in drowning and non-drowning groups (p<0.001), although declines were less pronounced for the drowning group. Seventy-two percent of children had well below average cognitive functioning at 1-year. Younger age, fewer doses of epinephrine, and drowning etiology were associated with better VABS-II composite scores. Demographic variables and treatment with hypothermia did not influence neurobehavioral outcomes.

CONCLUSIONS

Risks for poor neurobehavioral outcomes were high for children who were comatose after out-of-hospital cardiac arrest due to respiratory etiologies; survivors of drowning had better outcomes than those with other respiratory etiologies.

Therapeutic Hypothermia after In-Hospital Cardiac Arrest in Children

BACKGROUND

Targeted temperature management is recommended for comatose adults and children after out-of-hospital cardiac arrest; however, data on temperature management after in-hospital cardiac arrest are limited.

METHODS

In a trial conducted at 37 children's hospitals, we compared two temperature interventions in children who had had in-hospital cardiac arrest. Within 6 hours after the return of circulation, comatose children older than 48 hours and younger than 18 years of age were randomly assigned to therapeutic hypothermia (target temperature, 33.0°C) or therapeutic normothermia (target temperature, 36.8°C). The primary efficacy outcome, survival at 12 months after cardiac arrest with a score of 70 or higher on the Vineland Adaptive Behavior Scales, second edition (VABS-II, on which scores range from 20 to 160, with higher scores indicating better function), was evaluated among patients who had had a VABS-II score of at least 70 before the cardiac arrest.

RESULTS

The trial was terminated because of futility after 329 patients had undergone randomization. Among the 257 patients who had a VABS-II score of at least 70 before cardiac arrest and who could be evaluated, the rate of the primary efficacy outcome did not differ significantly between the hypothermia group and the normothermia group (36% [48 of 133 patients] and 39% [48 of 124 patients], respectively; relative risk, 0.92; 95% confidence interval [CI], 0.67 to 1.27; P=0.63). Among 317 patients who could be evaluated for change in neurobehavioral function, the change in VABS-II score from baseline to 12 months did not differ significantly between the groups (P=0.70). Among 327 patients who could be evaluated for 1-year survival, the rate of 1-year survival did not differ significantly between the hypothermia group and the normothermia group (49% [81 of 166 patients] and 46% [74 of 161 patients], respectively; relative risk, 1.07; 95% CI, 0.85 to 1.34; P=0.56). The incidences of blood-product use, infection, and serious adverse events, as well as 28-day mortality, did not differ significantly between groups.

CONCLUSIONS

Among comatose children who survived in-hospital cardiac arrest, therapeutic hypothermia, as compared with therapeutic normothermia, did not confer a significant benefit in survival with a favorable functional outcome at 1 year. (Funded by the National Heart, Lung, and Blood Institute; THAPCA-IH ClinicalTrials.gov number, NCT00880087 .).

Exploring the safety and efficacy of targeted temperature management amongst infants with out-of-hospital cardiac arrest due to apparent life threatening events

OBJECTIVE

To explore the safety and efficacy of targeted temperature management amongst infants with out-of-hospital cardiac arrest due to an apparent life threatening event (ALTE) recruited to the Therapeutic Hypothermia after Paediatric Cardiac Arrest Out-of-Hospital trial.

METHODS

Fifty-four infants (48h to <1year of age) with ALTE who received chest compressions for ≥2min, were comatose, and required mechanical ventilation after return of circulation were included. Infants were randomised to therapeutic hypothermia (33°C) (n=26) or therapeutic normothermia (36.8°C) (n=28) within six hours of return of circulation. Outcomes included 12-month survival with Vineland Adaptive Behaviour Scales, Second Edition (VABS-II) score ≥70, 12-month survival, change in VABS-II score from pre-arrest to 12 months post-arrest, and select safety measures.

RESULTS

Amongst infants with pre-arrest VABS-II ≥70 (n=52), there was no difference in 12-month survival with VABS-II ≥70 between therapeutic hypothermia and therapeutic normothermia groups (2/25 (8.0%) vs. 1/27 (3.7%); relative risk 2.16; 95% confidence interval 0.21-22.38, p=0.60). Amongst all evaluable infants (n=53), the change in VABS-II score from pre-arrest to 12 months post-arrest did not differ (p=0.078) between therapeutic hypothermia and therapeutic normothermia groups, nor did 12-month survival (5/26 (19.2%) vs. 1/27 (3.7%); relative risk 5.19; 95% confidence interval 0.65-41.50, p=0.10).

CONCLUSIONS

Mortality was high amongst infants that were comatose after out-of-hospital cardiac arrest due to ALTE in both therapeutic hypothermia and therapeutic normothermia treated groups. Functional status was markedly reduced among survivors. (ClinicalTrials.gov, NCT00878644).

Pediatric Out-of-Hospital Cardiac Arrest Characteristics and Their Association With Survival and Neurobehavioral Outcome

OBJECTIVE

To investigate relationships between cardiac arrest characteristics and survival and neurobehavioral outcome among children recruited to the Therapeutic Hypothermia after Pediatric Cardiac Arrest Out-of-Hospital trial.

DESIGN

Secondary analysis of Therapeutic Hypothermia after Pediatric Cardiac Arrest Out-of-Hospital trial data.

SETTING

Thirty-six PICUs in the United States and Canada.

PATIENTS

All children (n = 295) had chest compressions for greater than or equal to 2 minutes, were comatose, and required mechanical ventilation after return of circulation.

INTERVENTIONS

Neurobehavioral function was assessed using the Vineland Adaptive Behavior Scales, Second Edition at baseline (reflecting prearrest status) and 12 months postarrest. U.S. norms for Vineland Adaptive Behavior Scales, Second Edition scores are 100 (mean) ± 15 (SD). Higher scores indicate better functioning. Outcomes included 12-month survival and 12-month survival with Vineland Adaptive Behavior Scales, Second Edition greater than or equal to 70.

MEASUREMENT AND MAIN RESULTS

Cardiac etiology of arrest, initial arrest rhythm of ventricular fibrillation/tachycardia, shorter duration of chest compressions, compressions not required at hospital arrival, fewer epinephrine doses, and witnessed arrest were associated with greater 12-month survival and 12-month survival with Vineland Adaptive Behavior Scales, Second Edition greater than or equal to 70. Weekend arrest was associated with lower 12-month survival. Body habitus was associated with 12-month survival with Vineland Adaptive Behavior Scales, Second Edition greater than or equal to 70; underweight children had better outcomes, and obese children had worse outcomes. On multivariate analysis, acute life threatening event/sudden unexpected infant death, chest compressions more than 30 minutes, and weekend arrest were associated with lower 12-month survival; witnessed arrest was associated with greater 12-month survival. Acute life threatening event/sudden unexpected infant death, other respiratory causes of arrest except drowning, other/unknown causes of arrest, and compressions more than 30 minutes were associated with lower 12-month survival with Vineland Adaptive Behavior Scales, Second Edition greater than or equal to 70.

CONCLUSIONS

Many factors are associated with survival and neurobehavioral outcome among children who are comatose and require mechanical ventilation after out-of-hospital cardiac arrest. These factors may be useful for identifying children at risk for poor outcomes, and for improving prevention and resuscitation strategies.

Emergency Neurological Life Support: Resuscitation Following Cardiac Arrest

Cardiac arrest is the most common cause of death in North America. Neurocritical care interventions, including targeted temperature management (TTM), have significantly improved neurological outcomes in patients successfully resuscitated from cardiac arrest. Therefore, resuscitation following cardiac arrest was chosen as an emergency neurological life support protocol. Patients remaining comatose following resuscitation from cardiac arrest should be considered for TTM. This protocol will review induction, maintenance, and re-warming phases of TTM, along with management of TTM side effects. Aggressive shivering suppression is necessary with this treatment to ensure the maintenance of a target temperature. Ancillary testing, including electrocardiography, computed tomography and/or magnetic resonance imaging of the brain, continuous electroencephalography monitoring, and correction of electrolyte, blood gas, and hematocrit changes, are also necessary to optimize outcomes.

Incidence and Outcomes of Cardiopulmonary Resuscitation in PICUs

OBJECTIVES

To determine the incidence of cardiopulmonary resuscitation in PICUs and subsequent outcomes.

DESIGN, SETTING, AND PATIENTS

Multicenter prospective observational study of children younger than 18 years old randomly selected and intensively followed from PICU admission to hospital discharge in the Collaborative Pediatric Critical Care Research Network December 2011 to April 2013.

RESULTS

Among 10,078 children enrolled, 139 (1.4%) received cardiopulmonary resuscitation for more than or equal to 1 minute and/or defibrillation. Of these children, 78% attained return of circulation, 45% survived to hospital discharge, and 89% of survivors had favorable neurologic outcomes. The relative incidence of cardiopulmonary resuscitation events was higher for cardiac patients compared with non-cardiac patients (3.4% vs 0.8%, p <0.001), but survival rate to hospital discharge with favorable neurologic outcome was not statistically different (41% vs 39%, respectively). Shorter duration of cardiopulmonary resuscitation was associated with higher survival rates: 66% (29/44) survived to hospital discharge after 1-3 minutes of cardiopulmonary resuscitation versus 28% (9/32) after more than 30 minutes (p < 0.001). Among survivors, 90% (26/29) had a favorable neurologic outcome after 1-3 minutes versus 89% (8/9) after more than 30 minutes of cardiopulmonary resuscitation.

CONCLUSIONS

These data establish that contemporary PICU cardiopulmonary resuscitation, including long durations of cardiopulmonary resuscitation, results in high rates of survival-to-hospital discharge (45%) and favorable neurologic outcomes among survivors (89%). Rates of survival with favorable neurologic outcomes were similar among cardiac and noncardiac patients. The rigorous prospective, observational study design avoided the limitations of missing data and potential selection biases inherent in registry and administrative data.

Targeted Temperature Management After Pediatric Cardiac Arrest Due To Drowning: Outcomes and Complications

OBJECTIVE

To describe outcomes and complications in the drowning subgroup from the Therapeutic Hypothermia After Pediatric Cardiac Arrest Out-of-Hospital trial.

DESIGN

Exploratory post hoc cohort analysis.

SETTING

Twenty-four PICUs.

PATIENTS

Pediatric drowning cases.

INTERVENTIONS

Therapeutic hypothermia versus therapeutic normothermia.

MEASUREMENTS AND MAIN RESULTS

An exploratory study of pediatric drowning from the Therapeutic Hypothermia After Pediatric Cardiac Arrest Out-of-Hospital trial was conducted. Comatose patients aged more than 2 days and less than 18 years were randomized up to 6 hours following return-of-circulation to hypothermia (n = 46) or normothermia (n = 28). Outcomes assessed included 12-month survival with a Vineland Adaptive Behavior Scale score of greater than or equal to 70, 1-year survival rate, change in Vineland Adaptive Behavior Scale-II score from prearrest to 12 months, and select safety measures. Seventy-four drowning cases were randomized. In patients with prearrest Vineland Adaptive Behavior Scale-II greater than or equal to 70 (n = 65), there was no difference in 12-month survival with Vineland Adaptive Behavior Scale-II score of greater than or equal to 70 between hypothermia and normothermia groups (29% vs 17%; relative risk, 1.74; 95% CI, 0.61-4.95; p = 0.27). Among all evaluable patients (n = 68), the Vineland Adaptive Behavior Scale-II score change from baseline to 12 months did not differ (p = 0.46), and 1-year survival was similar (49% hypothermia vs 42%, normothermia; relative risk, 1.16; 95% CI, 0.68-1.99; p = 0.58). Hypothermia was associated with a higher prevalence of positive bacterial culture (any blood, urine, or respiratory sample; 67% vs 43%; p = 0.04); however, the rate per 100 days at risk did not differ (11.1 vs 8.4; p = 0.46). Cumulative incidence of blood product use, serious arrhythmias, and 28-day mortality were not different. Among patients with cardiopulmonary resuscitation durations more than 30 minutes or epinephrine doses greater than 4, none had favorable Pediatric Cerebral Performance Category outcomes (≤ 3).

CONCLUSIONS

In comatose survivors of out-of-hospital pediatric cardiac arrest due to drowning, hypothermia did not result in a statistically significant benefit in survival with good functional outcome or mortality at 1 year, as compared with normothermia. High risk of culture-proven bacterial infection was observed in both groups.

Family Burden After Out-of-Hospital Cardiac Arrest in Children

OBJECTIVES

To describe family burden among caregivers of children who survived out-of-hospital cardiac arrest and who were at high risk for neurologic disability and examine relationships between family burden, child functioning, and other factors during the first year post arrest.

DESIGN

Secondary analysis of data from the Therapeutic Hypothermia after Pediatric Cardiac Arrest Out-of-Hospital trial.

SETTING

Thirty-six PICUs in the United States and Canada.

PATIENTS

Seventy-seven children recruited to the Therapeutic Hypothermia after Pediatric Cardiac Arrest Out-of-Hospital trial who had normal prearrest neurologic functioning and were alive 1 year post arrest.

INTERVENTIONS

Family burden was assessed using the Infant Toddler Quality of Life Questionnaire for children less than 5 years old and the Child Health Questionnaire for children 5 years old or older at baseline (reflecting prearrest status), 3 months, and 12 months post arrest. Child functioning was assessed using the Vineland Adaptive Behavior Scale II, the Pediatric Overall Performance Category, and Pediatric Cerebral Performance Category scales and caregiver perception of global functioning.

MEASUREMENTS AND MAIN RESULTS

Fifty-six children (72.7%) were boys, 48 (62.3%) were whites, and 50 (64.9%) were less than 5 years old prior to out-of-hospital cardiac arrest. Family burden at baseline was not significantly different from reference values. Family burden was increased at 3 and 12 months post arrest compared with reference values (p < 0.001). Worse Pediatric Overall Performance Category and Pediatric Cerebral Performance Category, lower adaptive behavior, lower global functioning, and higher family burden all measured 3 months post arrest were associated with higher family burden 12 months post arrest (p < 0.05). Sociodemographics and prearrest child functioning were not associated with family burden 12 months post arrest.

CONCLUSIONS

Families of children who survive out-of-hospital cardiac arrest and have high risk for neurologic disability often experience substantial burden during the first year post arrest. The extent of child dysfunction 3 months post arrest is associated with family burden at 12 months.

Nurses' Attitudes Toward Clinical Research: Experience of the Therapeutic Hypothermia After Pediatric Cardiac Arrest Trials

OBJECTIVES

To understand factors affecting nurses' attitudes toward the Therapeutic Hypothermia After Pediatric Cardiac Arrest trials and association with approach/consent rates.

DESIGN

Cross-sectional survey of pediatric/cardiac intensive care nurses' perceptions of the trials.

SETTING

Study was conducted at 16 of 38 self-selected study sites.

SUBJECTS

Pediatric and cardiac intensive care nurses.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the proportion of nurses with positive perceptions, as defined by agree or strongly agree with the statement "I am happy to take care of a Therapeutic Hypothermia after Pediatric Cardiac Arrest patient". Associations between perceptions and study approach/consent rates were also explored. Of 2,241 nurses invited, 1,387 (62%) completed the survey and 77% reported positive perceptions of the trials. Nurses, who felt positively about the scientific question, the study team, and training received, were more likely to have positive perceptions of the trials (p < 0.001). Nurses who had previously cared for a research patient had significantly more positive perceptions of Therapeutic Hypothermia After Pediatric Cardiac Arrest compared with those who had not (79% vs 54%; p < 0.001). Of the 754 nurses who cared for a Therapeutic Hypothermia After Pediatric Cardiac Arrest patient, 82% had positive perceptions, despite 86% reporting it required more work. Sixty-nine percent believed that hypothermia reduces brain injury and mortality; sites had lower consent rates when their nurses believed that hypothermia was beneficial. Institution-specific approach rates were positively correlated with nurses' perceptions of institutional support for the trial (r = 0.54; p = 0.04), ICU support (r = 0.61; p = 0.02), and the importance of conducting the trial in children (r = 0.61; p = 0.01).

CONCLUSIONS

The majority of nurses had positive perceptions of the Therapeutic Hypothermia After Pediatric Cardiac Arrest trials. Institutional, colleague, and study team support and training were contributing factors. Despite increased work, nurses remained enthusiastic demonstrating that studies with intensive bedside nursing procedures are feasible. Institutions whose nurses believed hypothermia was beneficial had lower consent rates, suggesting that educating nurses on study rationale and equipoise may enhance study participation.

Trends in PICU Admission and Survival Rates in Children in Australia and New Zealand Following Cardiac Arrest

OBJECTIVES

To describe the temporal trends in rates of PICU admissions and mortality for out-of-hospital cardiac arrests and in-hospital cardiac arrests admitted to PICU over the last decade.

DESIGN

Multicenter, retrospective analysis of prospectively collected binational data of the Australian and New Zealand Paediatric Intensive Care Registry. All nine specialist PICUs in Australia and New Zealand were included.

PATIENTS

All children admitted between 2003 and 2012 to PICU who were less than 16 years old at the time of admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were a total of 71,425 PICU admissions between 2003 and 2012. Overall, cardiac arrest accounted for 1.86% of all admissions (1,329 cases), including 677 cases of in-hospital cardiac arrest (51.0%) and 652 cases of out-of-hospital cardiac arrest (49.0%). Over the last decade, there has been a 29.6% increase in the odds of PICU survival for all pediatric admissions (odds ratio, 1.30; 95% CI, 1.09-1.54). By contrast, there was no significant improvement in the risk-adjusted odds of survival for out-of-hospital cardiac arrest admissions (odds ratio, 1.03; 95% CI, 0.50-2.10; p = 0.94) or in-hospital cardiac arrest admissions (odds ratio, 1.03; 95% CI, 0.54-1.98; p = 0.92).

CONCLUSIONS

Despite improvements in overall outcomes in children admitted to Australian and New Zealand PICUs, survival of children admitted with out-of-hospital cardiac arrest or in-hospital cardiac arrest did not change significantly over the past decade.

Therapeutic hypothermia after out-of-hospital cardiac arrest in children

BACKGROUND

Therapeutic hypothermia is recommended for comatose adults after witnessed out-of-hospital cardiac arrest, but data about this intervention in children are limited.

METHODS

We conducted this trial of two targeted temperature interventions at 38 children's hospitals involving children who remained unconscious after out-of-hospital cardiac arrest. Within 6 hours after the return of circulation, comatose patients who were older than 2 days and younger than 18 years of age were randomly assigned to therapeutic hypothermia (target temperature, 33.0°C) or therapeutic normothermia (target temperature, 36.8°C). The primary efficacy outcome, survival at 12 months after cardiac arrest with a Vineland Adaptive Behavior Scales, second edition (VABS-II), score of 70 or higher (on a scale from 20 to 160, with higher scores indicating better function), was evaluated among patients with a VABS-II score of at least 70 before cardiac arrest.

RESULTS

A total of 295 patients underwent randomization. Among the 260 patients with data that could be evaluated and who had a VABS-II score of at least 70 before cardiac arrest, there was no significant difference in the primary outcome between the hypothermia group and the normothermia group (20% vs. 12%; relative likelihood, 1.54; 95% confidence interval [CI], 0.86 to 2.76; P=0.14). Among all the patients with data that could be evaluated, the change in the VABS-II score from baseline to 12 months was not significantly different (P=0.13) and 1-year survival was similar (38% in the hypothermia group vs. 29% in the normothermia group; relative likelihood, 1.29; 95% CI, 0.93 to 1.79; P=0.13). The groups had similar incidences of infection and serious arrhythmias, as well as similar use of blood products and 28-day mortality.

CONCLUSIONS

In comatose children who survived out-of-hospital cardiac arrest, therapeutic hypothermia, as compared with therapeutic normothermia, did not confer a significant benefit in survival with a good functional outcome at 1 year. (Funded by the National Heart, Lung, and Blood Institute and others; THAPCA-OH ClinicalTrials.gov number, NCT00878644.).

Evolution, safety and efficacy of targeted temperature management after pediatric cardiac arrest

BACKGROUND

It is unknown whether targeted temperature management (TTM) improves survival after pediatric out-of-hospital cardiac arrest (OHCA). The aim of this study was to assess the evolution, safety and efficacy of TTM (32-34 °C) compared to standard temperature management (STM) (<38 °C).

METHODS

Retrospective, single center cohort study. Patients aged >one day up to 16 years, admitted to a UK Paediatric Intensive Care Unit (PICU) after OHCA (January 2004-December 2010). Primary outcome was survival to hospital discharge; efficacy and safety outcomes included: application of TTM, physiological, hematological and biochemical side effects.

RESULTS

Seventy-three patients were included. Thirty-eight patients (52%) received TTM (32-34 °C). Prior to ILCOR guidance adoption in January 2007, TTM was used infrequently (4/25; 16%). Following adoption, TTM (32-34 °C) use increased significantly (34/48; 71% Chi(2); p < 0.0001). TTM (32-34 °C) and STM (<38 °C) groups were similar at baseline. TTM (32-34 °C) was associated with bradycardia and hypotension compared to STM (<38 °C). TTM (32-34 °C) reduced episodes of hyperthermia (>38 °C) in the 1st 24h; however, excessive hypothermia (<32 °C) and hyperthermia (>38 °C) occurred in both groups up to 72 h, and all patients (n = 11) experiencing temperature <32 °C died. The study was underpowered to determine a difference in hospital survival (34% (TTM (32-34 °C)) versus 23% (STM (<38 °C)); p = 0.284). However, the TTM (32-34 °C) group had a significantly longer PICU length of stay.

CONCLUSIONS

TTM (32-34 °C) was feasible but associated with bradycardia, hypotension, and increased length of stay in PICU. Temperature <32 °C had a universally grave prognosis. Larger studies are required to assess effect on survival.

Additive Neuroprotection of a 20-HETE Inhibitor with Delayed Therapeutic Hypothermia after Hypoxia-Ischemia in Neonatal Piglets

The severity of perinatal hypoxia-ischemia and the delay in initiating therapeutic hypothermia limit the efficacy of hypothermia. After hypoxia-ischemia in neonatal piglets, the arachidonic acid metabolite 20-hydroxyeicosatetraenoic acid (20-HETE) has been found to contribute to oxidative stress at 3 h of reoxygenation and to eventual neurodegeneration. We tested whether early administration of a 20-HETE synthesis inhibitor after reoxygenation augments neuroprotection with 3-hour delayed hypothermia. In two hypothermic groups, whole body cooling from 38.5 to 34°C was initiated 3 h after hypoxia-ischemia. Rewarming occurred from 20 to 24 h; then anesthesia was discontinued. One hypothermic group received a 20-HETE inhibitor at 5 min after reoxygenation. A sham-operated group and another hypoxia-ischemia group remained normothermic. At 10 days of recovery, resuscitated piglets with delayed hypothermia alone had significantly greater viable neuronal density in the putamen, caudate nucleus, sensorimotor cortex, CA3 hippocampus, and thalamus than did piglets with normothermic recovery, but the values remained less than those in the sham-operated group. In piglets administered the 20-HETE inhibitor before hypothermia, the density of viable neurons in the putamen, cortex and thalamus was significantly greater than in the group with hypothermia alone. Cytochrome P450 4A, which can synthesize 20-HETE, was expressed in piglet neurons in these regions. We conclude that early treatment with a 20-HETE inhibitor enhances the therapeutic benefit of delayed hypothermia in protecting neurons in brain regions known to be particularly vulnerable to hypoxia-ischemia in term newborns.

Efficacy outcome selection in the therapeutic hypothermia after pediatric cardiac arrest trials

OBJECTIVES

The Therapeutic Hypothermia After Pediatric Cardiac Arrest trials will determine whether therapeutic hypothermia improves survival with good neurobehavioral outcome, as assessed by the Vineland Adaptive Behavior Scales Second Edition, in children resuscitated after cardiac arrest in the in-hospital and out-of-hospital settings. We describe the innovative efficacy outcome selection process during Therapeutic Hypothermia After Pediatric Cardiac Arrest protocol development.

DESIGN/SETTING

Consensus assessment of potential outcomes and evaluation timepoints.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We evaluated practical and technical advantages of several follow-up timepoints and continuous/categorical outcome variants. Simulations estimated power assuming varying hypothermia benefit on mortality and on neurobehavioral function among survivors. Twelve months after arrest was selected as the optimal assessment timepoint for pragmatic and clinical reasons. Change in Vineland Adaptive Behavior Scales Second Edition from prearrest level, measured as quasicontinuous with death and vegetative status being worst-possible levels, yielded optimal statistical power. However, clinicians preferred simpler multicategorical or binary outcomes because of easier interpretability and favored outcomes based solely on postarrest status because of concerns about accurate parental assessment of prearrest status and differing clinical impact of a given Vineland Adaptive Behavior Scales Second Edition change depending on prearrest status. Simulations found only modest power loss from categorizing or dichotomizing quasicontinuous outcomes because of high expected mortality. The primary outcome selected was survival with 12-month Vineland Adaptive Behavior Scales Second Edition no less than two SD below a reference population mean (70 points), necessarily evaluated only among children with prearrest Vineland Adaptive Behavior Scales Second Edition greater than or equal to 70. Two secondary efficacy outcomes, 12-month survival and quasicontinuous Vineland Adaptive Behavior Scales Second Edition change from prearrest level, will be evaluated among all randomized children, including those with compromised function prearrest.

CONCLUSIONS

Extensive discussion of optimal efficacy assessment timing, and of the advantages versus drawbacks of incorporating prearrest status and using quasicontinuous versus simpler outcomes, was highly beneficial to the final Therapeutic Hypothermia After Pediatric Cardiac Arrest design. A relatively simple, binary primary outcome evaluated at 12 months was selected, with two secondary outcomes that address the potential disadvantages of primary outcome.

The Pediatric Emergency Care Applied Research Network: a history of multicenter collaboration in the United States

In this article, we review the history and progress of a large multicenter research network pertaining to emergency medical services for children. We describe the history, organization, infrastructure, and research agenda of the Pediatric Emergency Care Applied Research Network and highlight some of the important accomplishments since its inception. We also describe the network's strategy to grow its research portfolio, train new investigators, and study how to translate new evidence into practice. This strategy ensures not only the sustainability of the network in the future but the growth of research in emergency medical services for children in general.

The Pediatric Emergency Care Applied Research Network: a history of multicenter collaboration in the United States

In this article, we review the history and progress of a large multicenter research network pertaining to emergency medical services for children. We describe the history, organization, infrastructure, and research agenda of the Pediatric Emergency Care Applied Research Network (PECARN), and highlight some of the important accomplishments since its inception. We also describe the network’s strategy to grow its research portfolio, train new investigators, and study how to translate new evidence into practice. This strategy ensures not only the sustainability of the network in the future, but the growth of research in emergency medical services for children in general.

Mechanisms of hypothermia-induced cell protection in the brain

Therapeutic hypothermia is an effective cytoprotectant and promising intervention shown to improve outcome in patients following cardiac arrest and neonatal hypoxia-ischemia. However, despite our clinical and experimental experiences, the protective molecular mechanisms of therapeutic hypothermia remain to be elucidated. Therefore, in this brief overview we discuss both the clinical evidence and molecular mechanisms of therapeutic hypothermia in order to provide further insights into this promising intervention.

Dilemmas in undertaking research in paediatric intensive care

Providing evidence-based interventions for infants and children is important in paediatric intensive care, where decision making impacts most acutely on morbidity and mortality. However, despite the major progress of medicine in the 21st century, we still lack this evidence for majority of the decisions we make. In this article, we explore and suggest possible solutions for several dilemmas faced by paediatric intensive care researchers. These include ethical dilemmas such as validity of informed consent, use of deferred consent, balancing risk versus benefit and methodological dilemmas such as how to generate high-quality evidence with low-patient volume, choice of valid outcome measures and how best to use research and researchers' networks.

Therapeutic hypothermia after in-hospital cardiac arrest: a critique

More than 210,000 in-hospital cardiac arrests occur annually in the United States. Use of moderate therapeutic hypothermia (TH) in comatose survivors after return of spontaneous circulation following out-of-hospital cardiac arrest (OOH-CA) caused by ventricular fibrillation or pulseless ventricular tachycardia is recommended strongly by many professional organizations and societies. The use of TH after cardiac arrest associated with nonshockable rhythms and after in-hospital cardiac arrest (IH-CA) is recommended to be considered by these same organizations and is being applied widely. The use in these latter circumstances is based on an extrapolation of the data supporting its use after out-of-hospital cardiac arrest associated with shockable rhythms. The purpose of this article is to review the limitations of existing data supporting these extended application of TH after cardiac arrest and to suggest approaches to this dilemma. The data supporting its use for OOH-CA appear to this author, and to some others, to be rather weak, and the data supporting the use of TH for IH-CA appear to be even weaker and to include no randomized controlled trials (RCTs) or supportive observational studies. The many reasons why TH might be expected to be less effective following IH-CA are reviewed. The degree of neurologic injury may be more severe in many of these cases and, thus, may not be responsive to TH as currently practiced following OOH-CA. The potential adverse consequences of the routine use of TH for IH-CA are listed and include complications associated with TH, interference with diagnostic and interventional therapy, and use of scarce personnel and financial resources. Most importantly, it inhibits the ability of researchers to conduct needed RCTs. The author believes that the proper method of providing TH in these cases needs to be better defined. Based on this analysis the author concludes that TH should not be used indiscriminantly following most cases of IH-CA, and instead clinicians should concentrate their efforts in conducting high-quality large RCTs or large-scale, well-designed prospective observation studies to determine its benefits and identify appropriate candidates.

Neuroinflammation and neuroimmune dysregulation after acute hypoxic-ischemic injury of developing brain

Hypoxic-ischemic (HI) injury to developing brain results from birth asphyxia in neonates and from cardiac arrest in infants and children. It is associated with varying degrees of neurologic sequelae, depending upon the severity and length of HI. Global HI triggers a series of cellular and biochemical pathways that lead to neuronal injury. One of the key cellular pathways of neuronal injury is inflammation. The inflammatory cascade comprises activation and migration of microglia - the so-called "brain macrophages," infiltration of peripheral macrophages into the brain, and release of cytotoxic and proinflammatory cytokines. In this article, we review the inflammatory and immune mechanisms of secondary neuronal injury after global HI injury to developing brain. Specifically, we highlight the current literature on microglial activation in relation to neuronal injury, proinflammatory and anti-inflammatory/restorative pathways, the role of peripheral immune cells, and the potential use of immunomodulators as neuroprotective compounds.