Anticoagulation practices associated with bleeding and thrombosis in pediatric extracorporeal membrane oxygenation; a multi-center secondary analysis.

To determine associations between anticoagulation practices and bleeding and thrombosis during pediatric extracorporeal membrane oxygenation (ECMO), we performed a secondary analysis of prospectively collected data which included 481 children (<19 years), between January 2012 and September 2014. The primary outcome was bleeding or thrombotic events. Bleeding events included a blood product transfusion >80 ml/kg on any day, pulmonary hemorrhage, or intracranial bleeding, Thrombotic events included pulmonary emboli, intracranial clot, limb ischemia, cardiac clot, and arterial cannula or entire circuit change. Bleeding occurred in 42% of patients. Five percent of subjects thrombosed, of which 89% also bled. Daily bleeding odds were independently associated with day prior activated clotting time (ACT) (OR 1.03, 95% CI= 1.00, 1.05, p=0.047) and fibrinogen levels (OR 0.90, 95% CI 0.84, 0.96, p <0.001). Thrombosis odds decreased with increased day prior heparin dose (OR 0.88, 95% CI 0.81, 0.97, p=0.006). Lower ACT values and increased fibrinogen levels may be considered to decrease the odds of bleeding. Use of this single measure, however, may not be sufficient alone to guide optimal anticoagulation practice during ECMO.

Development of the Pediatric Extracorporeal Membrane Oxygenation Prediction Model for Risk-Adjusting Mortality.

OBJECTIVES: To develop a prognostic model for predicting mortality at time of extracorporeal membrane oxygenation initiation for children which is important for determining center-specific risk-adjusted outcomes. DESIGN: Multivariable logistic regression using a large national cohort of pediatric extracorporeal membrane oxygenation patients. SETTING: The ICUs of the eight tertiary care children's hospitals of the Collaborative Pediatric Critical Care Research Network. PATIENTS: Five-hundred fourteen children (< 19 yr old), enrolled with an initial extracorporeal membrane oxygenation run for any indication between January 2012 and September 2014. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 514 first extracorporeal membrane oxygenation runs were analyzed with an overall mortality of 45% (n = 232). Weighted logistic regression was used for model selection and internal validation was performed using cross validation. The variables included in the Pediatric Extracorporeal Membrane Oxygenation Prediction model were age (pre-term neonate, full-term neonate, infant, child, and adolescent), indication for extracorporeal membrane oxygenation (extracorporeal cardiopulmonary resuscitation, cardiac, or respiratory), meconium aspiration, congenital diaphragmatic hernia, documented blood stream infection, arterial blood pH, partial thromboplastin time, and international normalized ratio. The highest risk of mortality was associated with the presence of a documented blood stream infection (odds ratio, 5.26; CI, 1.90-14.57) followed by extracorporeal cardiopulmonary resuscitation (odds ratio, 4.36; CI, 2.23-8.51). The C-statistic was 0.75 (95% CI, 0.70-0.80). CONCLUSIONS: The Pediatric Extracorporeal Membrane Oxygenation Prediction model represents a model for predicting in-hospital mortality among children receiving extracorporeal membrane oxygenation support for any indication. Consequently, it holds promise as the first comprehensive pediatric extracorporeal membrane oxygenation risk stratification model which is important for benchmarking extracorporeal membrane oxygenation outcomes across many centers.

Cognitive Development One Year After Infantile Critical Pertussis.

OBJECTIVES: Pertussis can cause life-threatening illness in infants. Data regarding neurodevelopment after pertussis remain scant. The aim of this study was to assess cognitive development of infants with critical pertussis 1 year after PICU discharge. DESIGN: Prospective cohort study. SETTING: Eight hospitals comprising the Eunice Kennedy Shriver National Institute for Child Health and Human Development Collaborative Pediatric Critical Care Research Network and 18 additional sites across the United States. PATIENTS: Eligible patients had laboratory confirmation of pertussis infection, were less than 1 year old, and were admitted to the PICU for at least 24 hours. INTERVENTIONS: The Mullen Scales of Early Learning was administered at a 1-year follow-up visit. Functional status was determined by examination and parental interview. MEASUREMENTS AND MAIN RESULTS: Of 196 eligible patients, 111 (57%) completed the Mullen Scales of Early Learning. The mean scores for visual reception, receptive language, and expressive language domains were significantly lower than the norms (p < 0.001), but not fine and gross motor domains. Forty-one patients (37%) had abnormal scores in at least one domain and 10 (9%) had an Early Learning Composite score 2 or more SDs below the population norms. Older age (p < 0.003) and Hispanic ethnicity (p < 0.008) were associated with lower mean Early Learning Composite score, but presenting symptoms and PICU course were not. CONCLUSIONS: Infants who survive critical pertussis often have neurodevelopmental deficits. These infants may benefit from routine neurodevelopmental screening.

Factors Associated with Bleeding and Thrombosis in Children Receiving Extracorporeal Membrane Oxygenation.

RATIONALE: Extracorporeal membrane oxygenation (ECMO) is used for respiratory and cardiac failure in children but is complicated by bleeding and thrombosis. OBJECTIVES: (1) To measure the incidence of bleeding (blood loss requiring transfusion or intracranial hemorrhage) and thrombosis during ECMO support; (2) to identify factors associated with these complications; and (3) to determine the impact of these complications on patient outcome. METHODS: This was a prospective, observational cohort study in pediatric, cardiac, and neonatal intensive care units in eight hospitals, carried out from December 2012 to September 2014. MEASUREMENTS AND MAIN RESULTS: ECMO was used on 514 consecutive patients under age 19 years. Demographics, anticoagulation practices, severity of illness, circuitry components, bleeding, thrombotic events, and outcome were recorded. Survival was 54.9%. Bleeding occurred in 70.2%, including intracranial hemorrhage in 16%, and was independently associated with higher daily risk of mortality. Circuit component changes were required in 31.1%, and patient-related clots occurred in 12.8%. Laboratory sampling contributed to transfusion requirement in 56.6%, and was the sole reason for at least one transfusion in 42.2% of patients. Pump type was not associated with bleeding, thrombosis, hemolysis, or mortality. Hemolysis was predictive of subsequent thrombotic events. Neither hemolysis nor thrombotic events increased the risk of mortality. CONCLUSIONS: The incidences of bleeding and thrombosis are high during ECMO support. Laboratory sampling is a major contributor to transfusion during ECMO. Strategies to reduce the daily risk of bleeding and thrombosis, and different thresholds for transfusion, may be appropriate subjects of future trials to improve outcomes of children requiring this supportive therapy.

Variability in Usual Care Mechanical Ventilation for Pediatric Acute Respiratory Distress Syndrome: Time for a Decision Support Protocol?

OBJECTIVES: Although pediatric intensivists philosophically embrace lung protective ventilation for acute lung injury and acute respiratory distress syndrome, we hypothesized that ventilator management varies. We assessed ventilator management by evaluating changes to ventilator settings in response to blood gases, pulse oximetry, or end-tidal CO2. We also assessed the potential impact that a pediatric mechanical ventilation protocol adapted from National Heart Lung and Blood Institute acute respiratory distress syndrome network protocols could have on reducing variability by comparing actual changes in ventilator settings to those recommended by the protocol. DESIGN: Prospective observational study. SETTING: Eight tertiary care U.S. PICUs, October 2011 to April 2012. PATIENTS: One hundred twenty patients (age range 17 d to 18 yr) with acute lung injury/acute respiratory distress syndrome. MEASUREMENTS AND MAIN RESULTS: Two thousand hundred arterial and capillary blood gases, 3,964 oxygen saturation by pulse oximetry, and 2,757 end-tidal CO2 values were associated with 3,983 ventilator settings. Ventilation mode at study onset was pressure control 60%, volume control 19%, pressure-regulated volume control 18%, and high-frequency oscillatory ventilation 3%. Clinicians changed FIO2 by ±5 or ±10% increments every 8 hours. Positive end-expiratory pressure was limited at ~10 cm H2O as oxygenation worsened, lower than would have been recommended by the protocol. In the first 72 hours of mechanical ventilation, maximum tidal volume/kg using predicted versus actual body weight was 10.3 (8.5-12.9) (median [interquartile range]) versus 9.2 mL/kg (7.6-12.0) (p < 0.001). Intensivists made changes similar to protocol recommendations 29% of the time, opposite to the protocol's recommendation 12% of the time and no changes 56% of the time. CONCLUSIONS: Ventilator management varies substantially in children with acute respiratory distress syndrome. Opportunities exist to minimize variability and potentially injurious ventilator settings by using a pediatric mechanical ventilation protocol offering adequately explicit instructions for given clinical situations. An accepted protocol could also reduce confounding by mechanical ventilation management in a clinical trial.

Potential Acceptability of a Pediatric Ventilator Management Computer Protocol.

OBJECTIVES: To examine issues regarding the granularity (size/scale) and potential acceptability of recommendations in a ventilator management protocol for children with pediatric acute respiratory distress syndrome. DESIGN: Survey/questionnaire. SETTING: The eight PICUs in the Collaborative Pediatric Critical Care Research Network. PARTICIPANTS: One hundred twenty-two physicians (attendings and fellows). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We used an online questionnaire to examine attitudes and assessed recommendations with 50 clinical scenarios. Overall 80% of scenario recommendations were accepted. Acceptance did not vary by provider characteristics but did vary by ventilator mode (high-frequency oscillatory ventilation 83%, pressure-regulated volume control 82%, pressure control 75%; p = 0.002) and variable adjusted (ranging from 88% for peak inspiratory pressure and 86% for FIO2 changes to 69% for positive end-expiratory pressure changes). Acceptance did not vary based on child size/age. There was a preference for smaller positive end-expiratory pressure changes but no clear granularity preference for other variables. CONCLUSIONS: Although overall acceptance rate for scenarios was good, there was little consensus regarding the size/scale of ventilator setting changes for children with pediatric acute respiratory distress syndrome. An acceptable protocol could support robust evaluation of ventilator management strategies. Further studies are needed to determine if adherence to an explicit protocol leads to better outcomes.

Research as a Standard of Care in the PICU.

OBJECTIVES: Excellence in clinical care coupled with basic and applied research reflects the maturation of a medical subspecialty, advances that field, and provides objective data for identifying best practices. PICUs are uniquely suited for conducting translational and clinical research. In addition, multiple investigations have reported that a majority of parents are interested in their children's participation in clinical research, even when the research offers no direct benefit to their child. However, such activity may generate ethical conflict with bedside care providers trying to acutely identify the best approach for an individual critically ill child. Ultimately, this conflict may diminish enthusiasm for the generation of scientific evidence that supports the application of evidence-based medicine into PICU clinical standard work. Accordingly this review endeavors to provide an overview of current state PICU clinical research strengths, liabilities, opportunities, and barriers and contrast this with an established pediatric hematology-oncology iterative research model that constitutes a learning healthcare system. DATA SOURCES, DATA EXTRACTION, AND DATA SYNTHESIS: Narrative review of medical literature published in English. CONCLUSIONS: Currently, most PICU therapy is not evidence based. Developing a learning healthcare system in the PICU integrates clinical research into usual practice and fosters a culture of evidence-based learning and continual care improvement. As PICU mortality has significantly decreased, identification and validation of patient-centered, clinically relevant research outcome measures other than mortality is essential for future clinical trial design. Because most pediatric critical illness may be classified as rare diseases, participation in research networks will facilitate iterative, collaborative, multiinstitutional investigations that over time identify the best practices to improve PICU outcomes. Despite real ethical challenges, critically ill children and their families should have the opportunity to participate in translational/clinical research whenever feasible.

Association of bleeding and thrombosis with outcome in extracorporeal life support.

OBJECTIVE: Changes in technology and increased reports of successful extracorporeal life support use in patient populations, such as influenza, cardiac arrest, and adults, are leading to expansion of extracorporeal life support. Major limitations to extracorporeal life support expansion remain bleeding and thrombosis. These complications are the most frequent causes of death and morbidity. As a pilot project to provide baseline data for a detailed evaluation of bleeding and thrombosis in the current era, extracorporeal life support patients were analyzed from eight centers in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Collaborative Pediatric Critical Care Research Network. STUDY DESIGN: Retrospective analysis of patients (< 19 yr) reported to the Extracorporeal Life Support Organization registry from eight Collaborative Pediatric Critical Care Research Network centers between 2005 and 2011. SETTING: Tertiary children's hospitals within the Collaborative Pediatric Critical Care Research Network. SUBJECTS: The study cohort consisted of 2,036 patients (13% with congenital diaphragmatic hernia). INTERVENTIONS: None. MAIN RESULTS: In the cohort of patients without congenital diaphragmatic hernia (n = 1,773), bleeding occurred in 38% of patients, whereas thrombosis was noted in 31%. Bleeding and thrombosis were associated with a decreased survival by 40% (relative risk, 0.59; 95% CI, 0.53-0.66) and 33% (odds ratio, 0.67; 95% CI, 0.60-0.74). Longer duration of extracorporeal life support and use of venoarterial cannulation were also associated with increased risk of bleeding and/or thrombotic complications and lower survival. The most common bleeding events included surgical site bleeding (17%; n = 306), cannulation site bleeding (14%; n = 256), and intracranial hemorrhage (11%; n = 192). Common thrombotic events were clots in the circuit (15%; n = 274) and the oxygenator (12%; n = 212) and hemolysis (plasma-free hemoglobin > 50 mg/dL) (10%; n = 177). Among patients with congenital diaphragmatic hernia, bleeding and thrombosis occurred in, respectively, 45% (n = 118) and 60% (n = 159), Bleeding events were associated with reduced survival (relative risk, 0.62; 95% CI, 0.46-0.86) although thrombotic events were not (relative risk, 0.92; 95% CI, 0.67-1.26). CONCLUSIONS: Bleeding and thrombosis remain common complications in patients undergoing extracorporeal life support. Further research to reduce or eliminate bleeding and thrombosis is indicated to help improve patient outcome.

Feasibility and perceived benefits of a framework for physician-parent follow-up meetings after a child's death in the PICU.

OBJECTIVE: To evaluate the feasibility and perceived benefits of conducting physician-parent follow-up meetings after a child's death in the PICU according to a framework developed by the Collaborative Pediatric Critical Care Research Network. DESIGN: Prospective observational study. SETTING: Seven Collaborative Pediatric Critical Care Research Network-affiliated children's hospitals. SUBJECTS: Critical care attending physicians, bereaved parents, and meeting guests (i.e., parent support persons, other health professionals). INTERVENTIONS: Physician-parent follow-up meetings using the Collaborative Pediatric Critical Care Research Network framework. MEASUREMENTS AND MAIN RESULTS: Forty-six critical care physicians were trained to conduct follow-up meetings using the framework. All meetings were video recorded. Videos were evaluated for the presence or absence of physician behaviors consistent with the framework. Present behaviors were evaluated for performance quality using a 5-point scale (1 = low, 5 = high). Participants completed meeting evaluation surveys. Parents of 194 deceased children were mailed an invitation to a follow-up meeting. Of these, one or both parents from 39 families (20%) agreed to participate, 80 (41%) refused, and 75 (39%) could not be contacted. Of 39 who initially agreed, three meetings were canceled due to conflicting schedules. Thirty-six meetings were conducted including 54 bereaved parents, 17 parent support persons, 23 critical care physicians, and 47 other health professionals. Physician adherence to the framework was high; 79% of behaviors consistent with the framework were rated as present with a quality score of 4.3 ± 0.2. Of 50 evaluation surveys completed by parents, 46 (92%) agreed or strongly agreed the meeting was helpful to them and 40 (89%) to others they brought with them. Of 36 evaluation surveys completed by critical care physicians (i.e., one per meeting), 33 (92%) agreed or strongly agreed the meeting was beneficial to parents and 31 (89%) to them. CONCLUSIONS: Follow-up meetings using the Collaborative Pediatric Critical Care Research Network framework are feasible and viewed as beneficial by meeting participants. Future research should evaluate the effects of follow-up meetings on bereaved parents' health outcomes.

A single nucleotide polymorphism in the corticotropin receptor gene is associated with a blunted cortisol response during pediatric critical illness.

OBJECTIVES: The cortisol response during critical illness varies widely among patients. Our objective was to examine single nucleotide polymorphisms in candidate genes regulating cortisol synthesis, metabolism, and activity to determine if genetic differences were associated with variability in the cortisol response among critically ill children. DESIGN: This was a prospective observational study employing tag single nucleotide polymorphism methodology to examine genetic contributions to the variability of the cortisol response in critical illness. Thirty-one candidate genes and 31 ancestry markers were examined. SETTING: Patients were enrolled from seven pediatric critical care units that constitute the Eunice Kennedy Shriver Collaborative Pediatric Critical Care Research Network. SUBJECTS: Critically ill children (n = 92), age 40 weeks gestation to 18 years old, were enrolled. INTERVENTIONS: Blood samples were obtained from all patients for serum cortisol measurements and DNA isolation. Demographic and illness severity data were collected. MEASUREMENTS AND MAIN RESULTS: Single nucleotide polymorphisms were tested for association with serum free cortisol concentrations in context of higher illness severity as quantified by Pediatric Risk of Mortality III score greater than 7. A single nucleotide polymorphism (rs1941088) in the MC2R gene was strongly associated (p = 0.0005) with a low free cortisol response to critical illness. Patients with the AA genotype were over seven times more likely to have a low free cortisol response to critical illness than those with a GG genotype. Patients with the GA genotype exhibited an intermediate free cortisol response to critical illness. CONCLUSIONS: The A allele at rs1941088 in the MC2R gene, which encodes the adrenocorticotropic hormone (corticotropin, ACTH) receptor, is associated with a low cortisol response in critically ill children. These data provide evidence for a genetic basis for a portion of the variability in cortisol production during critical illness. Independent replication of these findings will be important and could facilitate development of personalized treatment for patients with a low cortisol response to severe illness.

Ratio of PICU versus ward cardiopulmonary resuscitation events is increasing.

OBJECTIVES: The aim of this study was to evaluate the relative frequency of pediatric in-hospital cardiopulmonary resuscitation events occurring in ICUs compared to general wards. We hypothesized that the proportion of pediatric cardiopulmonary resuscitation provided in ICUs versus general wards has increased over the past decade, and this shift is associated with improved resuscitation outcomes. DESIGN: Prospective and observational study. SETTING: Total of 315 hospitals in the American Heart Association's Get With The Guidelines-Resuscitation database. PATIENTS: Total of 5,870 pediatric cardiopulmonary resuscitation events between January 1, 2000 and September 14, 2010. Cardiopulmonary resuscitation events were defined as external chest compressions longer than 1 minute. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was proportion of total ICU versus general ward cardiopulmonary resuscitation events over time evaluated by chi-square test for trend. Secondary outcome included return of spontaneous circulation following the cardiopulmonary resuscitation event. Among 5,870 pediatric cardiopulmonary resuscitation events, 5,477 (93.3%) occurred in ICUs compared to 393 (6.7%) in inpatient wards. Over time, significantly more of these cardiopulmonary resuscitation events occurred in the ICU compared to the wards (test for trend: p<0.01), with a prominent shift noted between 2003 and 2004 (2000-2003: 87-91% vs 2004-2010: 94-96%). In a multivariable model controlling for within center variability and other potential confounders, return of spontaneous circulation increased in 2004-2010 compared with 2000-2003 (relative risk, 1.08; 95% CI, 1.03-1.13). CONCLUSIONS: In-hospital pediatric cardiopulmonary resuscitation is much more commonly provided in ICUs than in wards, and the proportion has increased significantly over the past decade, with concomitant increases in return of spontaneous circulation.

Baseline serum concentrations of zinc, selenium, and prolactin in critically ill children.

OBJECTIVES: To describe serum concentrations of zinc, selenium, and prolactin in critically ill children within 72 hours of PICU admission, and to investigate relationships between these immunomodulators and lymphopenia. DESIGN: An analysis of baseline data collected as part of the multicenter Critical Illness Stress Induced Immune Suppression (CRISIS) Prevention Trial. SETTING: PICUs affiliated with the Collaborative Pediatric Critical Care Research Network. PATIENTS: All children enrolled in the CRISIS Prevention Trial that had baseline serum samples available for analysis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 293 critically ill children enrolled in the CRISIS Prevention Trial, 284 had baseline serum samples analyzed for prolactin concentration, 280 for zinc concentration, and 278 for selenium concentration within 72 hours of PICU admission. Lymphocyte counts were available for 235 children. Zinc levels ranged from nondetectable (< 0.1 µg/mL) to 2.87 µg/mL (mean 0.46 µg/mL and median 0.44 µg/mL) and were below the normal reference range for 235 (83.9%) children. Selenium levels ranged from 26 to 145 ng/mL (mean 75.4 ng/mL and median 74.5 ng/mL) and were below the normal range for 156 (56.1%) children. Prolactin levels ranged from nondetectable (< 1 ng/mL) to 88 ng/mL (mean 12.2 ng/mL and median 10 ng/mL). Hypoprolactinemia was present in 68 (23.9%) children. Lymphopenia was more likely in children with zinc levels below normal than those with zinc levels within or above the normal range (82 of 193 [42.5%] vs. 10 of 39 [25.6%], p = 0.0498). Neither selenium nor prolactin concentrations were associated with lymphopenia (p = 1.0 and p = 0.72, respectively). CONCLUSIONS: Serum concentrations of zinc, selenium, and prolactin are often low in critically ill children early after PICU admission. Low serum zinc levels are associated with lymphopenia, whereas low selenium and prolactin levels are not. The implications of these findings and the mechanisms by which they occur merit further study.

The role of the Data and Safety Monitoring Board in a clinical trial: the CRISIS study.

OBJECTIVES: Randomized clinical trials are commonly overseen by a Data and Safety Monitoring Board comprised of experts in medicine, ethics, and biostatistics. Data and Safety Monitoring Board responsibilities include protocol approval, interim review of study enrollment, protocol compliance, safety, and efficacy data. Data and Safety Monitoring Board decisions can affect study design and conduct, as well as reported findings. Researchers must incorporate Data and Safety Monitoring Board oversight into the design, monitoring, and reporting of randomized trials. DESIGN: Case study, narrative review. METHODS: The Data and Safety Monitoring Board's role during the comparative pediatric Critical Illness Stress-Induced Immune Suppression (CRISIS) Prevention Trial is described. FINDINGS: The National Institutes of Health-appointed CRISIS Data and Safety Monitoring Board was charged with monitoring sample size adequacy and feasibility, safety with respect to adverse events and 28-day mortality, and efficacy with respect to the primary nosocomial infection/sepsis outcome. The Federal Drug Administration also requested Data and Safety Monitoring Board interim review before opening CRISIS to children below 1 yr of age. The first interim analysis found higher 28-day mortality in one treatment arm. The Data and Safety Monitoring Board maintained trial closure to younger children and requested a second interim data review 6 months later. At this second meeting, mortality was no longer of concern, whereas a weak efficacy trend of lower infection/sepsis rates in one study arm emerged. As over 40% of total patients had been enrolled, the Data and Safety Monitoring Board elected to examine conditional power and unmask treatment arm identities. On finding somewhat greater efficacy in the placebo arm, the Data and Safety Monitoring Board recommended stopping CRISIS due to futility. CONCLUSIONS: The design and operating procedures of a multicenter randomized trial must consider a pivotal Data and Safety Monitoring Board role. Maximum study design flexibility must be allowed, and investigators must be prepared for protocol modifications due to interim findings. The Data and Safety Monitoring Board must have sufficient clinical and statistical expertise to assess potential importance of interim treatment differences in the setting of multiple looks at accumulating data with numerous outcomes and subgroups.

Opioid analgesia in mechanically ventilated children: results from the multicenter Measuring Opioid Tolerance Induced by Fentanyl study.

OBJECTIVE: To examine the clinical factors associated with increased opioid dose among mechanically ventilated children in the pediatric intensive care unit. DESIGN: Prospective, observational study with 100% accrual of eligible patients. SETTING: Seven pediatric intensive care units from tertiary-care children's hospitals in the Collaborative Pediatric Critical Care Research Network. PATIENTS: Four hundred nineteen children treated with morphine or fentanyl infusions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data on opioid use, concomitant therapy, demographic and explanatory variables were collected. Significant variability occurred in clinical practices, with up to 100-fold differences in baseline opioid doses, average daily or total doses, or peak infusion rates. Opioid exposure for 7 or 14 days required doubling of the daily opioid dose in 16% patients (95% confidence interval 12%-19%) and 20% patients (95% confidence interval 16%-24%), respectively. Among patients receiving opioids for longer than 3 days (n = 225), this occurred in 28% (95% confidence interval 22%-33%) and 35% (95% confidence interval 29%-41%) by 7 or 14 days, respectively. Doubling of the opioid dose was more likely to occur following opioid infusions for 7 days or longer (odds ratio 7.9, 95% confidence interval 4.3-14.3; p < 0.001) or co-therapy with midazolam (odds ratio 5.6, 95% confidence interval 2.4-12.9; p < 0.001), and it was less likely to occur if morphine was used as the primary opioid (vs. fentanyl) (odds ratio 0.48, 95% confidence interval 0.25-0.92; p = 0.03), for patients receiving higher initial doses (odds ratio 0.96, 95% confidence interval 0.95-0.98; p < 0.001), or if patients had prior pediatric intensive care unit admissions (odds ratio 0.37, 95% confidence interval 0.15-0.89; p = 0.03). CONCLUSIONS: Mechanically ventilated children require increasing opioid doses, often associated with prolonged opioid exposure or the need for additional sedation. Efforts to reduce prolonged opioid exposure and clinical practice variation may prevent the complications of opioid therapy.

The ideal time interval for critical care severity-of-illness assessment.

OBJECTIVE: Determine if the shortest sampling interval for laboratory variables used to estimate baseline severity of illness in pediatric critical care is equivalently sensitive across multiple sites without site-specific bias, while accounting for the vast majority of dysfunction compared with the standard 0- to 12-hour Pediatric Risk of Mortality III score. DESIGN: Prospective random patient selection. SETTING: General/medical and cardiac/cardiovascular PICUs in eight hospitals. PATIENTS: Patients younger than 18 years admitted to the PICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 376 patients were included. Measurements for Pediatric Risk of Mortality III laboratory variables (pH, PCO2, total CO2, PaO2, glucose, potassium, blood urea nitrogen, creatinine, total WBC count, platelet count, and prothrombin time/partial thromboplastin time) were recorded from 2 hours prior to PICU admission through 12 hours of PICU care except for data in the operating room. Decreasing the observation period from 0 to 12 hours post-PICU admission resulted in progressive decreases in the Pediatric Risk of Mortality III laboratory variables measured. However, allowing the observation period to start 2 hours prior to PICU admission to 4 hours reduced this loss to only 3.4%. Similar trends existed for each of the individual laboratory Pediatric Risk of Mortality III variables. There was a nearly identical distribution of laboratory Pediatric Risk of Mortality III points within the -2- to 4-hour period compared with the standard period. We did not detect any institutional bias using the -2- to 4-hour time period compared with the baseline. CONCLUSIONS: Prognostically important laboratory physiologic data collected within the interval from 2 hours prior to PICU to admission through 4 hours after admission account for the vast majority of dysfunction that these variables would contribute to Pediatric Risk of Mortality III scores. There was no institutional bias associated with this sampling period.

Critical pertussis illness in children: a multicenter prospective cohort study.

OBJECTIVE: Pertussis persists in the United States despite high immunization rates. This report characterizes the presentation and acute course of critical pertussis by quantifying demographic data, laboratory findings, clinical complications, and critical care therapies among children requiring admission to the PICU. DESIGN: Prospective cohort study. SETTING: Eight PICUs comprising the Eunice Kennedy Shriver National Institute for Child Health and Human Development Collaborative Pediatric Critical Care Research Network and 17 additional PICUs across the United States. PATIENTS: Eligible patients had laboratory confirmation of pertussis infection, were younger than 18 years old, and died in the PICU or were admitted to the PICU for at least 24 hours between June 2008 and August 2011. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 127 patients were identified. Median age was 49 days, and 105 (83%) patients were less than 3 months old. Fifty-five (43%) patients required mechanical ventilation and 12 patients (9.4%) died during initial hospitalization. Pulmonary hypertension was found in 16 patients (12.5%) and was present in 75% of patients who died, compared with 6% of survivors (p < 0.001). Median WBC was significantly higher in those requiring mechanical ventilation (p < 0.001), those with pulmonary hypertension (p < 0.001), and nonsurvivors (p < 0.001). Age, sex, and immunization status did not differ between survivors and nonsurvivors. Fourteen patients received leukoreduction therapy (exchange transfusion [12], leukopheresis [1], or both [1]). Survival benefit was not apparent. CONCLUSIONS: Pulmonary hypertension may be associated with mortality in pertussis critical illness. Elevated WBC is associated with the need for mechanical ventilation, pulmonary hypertension, and mortality risk. Research is indicated to elucidate how pulmonary hypertension, immune responsiveness, and elevated WBC contribute to morbidity and mortality and whether leukoreduction might be efficacious.

Fatal and near-fatal asthma in children: the critical care perspective.

OBJECTIVE: To characterize the clinical course, therapies, and outcomes of children with fatal and near-fatal asthma admitted to pediatric intensive care units (PICUs). STUDY DESIGN: This was a retrospective chart abstraction across the 8 tertiary care PICUs of the Collaborative Pediatric Critical Care Research Network (CPCCRN). Inclusion criteria were children (aged 1-18 years) admitted between 2005 and 2009 (inclusive) for asthma who received ventilation (near-fatal) or died (fatal). Data collected included medications, ventilator strategies, concomitant therapies, demographic information, and risk variables. RESULTS: Of the 261 eligible children, 33 (13%) had no previous history of asthma, 218 (84%) survived with no known complications, and 32 (12%) had complications. Eleven (4%) died, 10 of whom had experienced cardiac arrest before admission. Patients intubated outside the PICU had a shorter duration of ventilation (median, 25 hours vs 84 hours; P < .001). African-Americans were disproportionately represented among the intubated children and had a shorter duration of intubation. Barotrauma occurred in 15 children (6%) before admission. Pharmacologic therapy was highly variable, with similar outcomes. CONCLUSION: Of the children ventilated in the CPCCRN PICUs, 96% survived to hospital discharge. Most of the children who died experienced cardiac arrest before admission. Intubation outside the PICU was correlated with shorter duration of ventilation. Complications of barotrauma and neuromyopathy were uncommon. Practice patterns varied widely among the CPCCRN sites.

The randomized comparative pediatric critical illness stress-induced immune suppression (CRISIS) prevention trial.

OBJECTIVES: Nosocomial infection/sepsis occurs in up to 40% of children requiring long-term intensive care. Zinc, selenium, glutamine, metoclopramide (a prolactin secretalogue), and/or whey protein supplementation have been effective in reducing infection and sepsis in other populations. We evaluated whether daily nutriceutical supplementation with zinc, selenium, glutamine, and metoclopramide, compared to whey protein, would reduce the occurrence of nosocomial infection/sepsis in this at-risk population. DESIGN: Randomized, double-blinded, comparative effectiveness trial. SETTING: Eight pediatric intensive care units in the National Institutes of Child Health and Human Development Collaborative Pediatric Critical Care Research Network. PATIENTS: Two hundred ninety-three long-term intensive care patients (age 1-17 yrs) expected to require >72 hrs of invasive care. INTERVENTIONS: Patients were stratified according to immunocompromised status and center and then were randomly assigned to receive daily enteral zinc, selenium, glutamine, and intravenous metoclopramide (n = 149), or daily enteral whey protein (n = 144) and intravenous saline for up to 28 days of intensive care unit stay. The primary end point was time to development of nosocomial sepsis/infection. The analysis was intention to treat. MEASUREMENTS AND MAIN RESULTS: There were no differences by assigned treatment in the overall population with respect to time until the first episode of nosocomial infection/sepsis (median whey protein 13.2 days vs. zinc, selenium, glutamine, and intravenous metoclopramide 12.1 days; p = .29 by log-rank test) or the rate of nosocomial infection/sepsis (4.83/100 days whey protein vs. 4.99/100 days zinc, selenium, glutamine, and intravenous metoclopramide; p = .81). Only 9% of the 293 subjects were immunocompromised and there was a reduction in rate of nosocomial infection/sepsis with zinc, selenium, glutamine, and intravenous metoclopramide in this immunocompromised group (6.09/100 days whey protein vs. 1.57/100 days zinc, selenium, glutamine, and intravenous metoclopramide; p = .011). CONCLUSION: Compared with whey protein supplementation, zinc, selenium, glutamine, and intravenous metoclopramide conferred no advantage in the immune-competent population. Further evaluation of zinc, selenium, glutamine, and intravenous metoclopramide supplementation is warranted in the immunocompromised long-term pediatric intensive care unit patient.

Critical care for pediatric asthma: wide care variability and challenges for study.

OBJECTIVES: To describe pediatric severe asthma care, complications, and outcomes to plan for future prospective studies by the Collaborative Pediatric Critical Care Research Network. DESIGN: Retrospective cohort study. SETTING: : Pediatric intensive care units in the United States that submit administrative data to the Pediatric Health Information System. PATIENTS: Children 1-18 yrs old treated in a Pediatric Health Information System pediatric intensive care unit for asthma during 2004-2008. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirteen-thousand five-hundred fifty-two children were studied; 2,812 (21%) were treated in a Collaborative Pediatric Critical Care Research Network and 10,740 (79%) were treated in a non-Collaborative Pediatric Critical Care Research Network pediatric intensive care unit. Medication use in individual Collaborative Pediatric Critical Care Research Network centers differed widely: ipratropium bromide (41%-84%), terbutaline (11%-74%), magnesium sulfate (23%-64%), and methylxanthines (0%-46%). Complications including pneumothorax (0%-0.6%), cardiac arrest (0.2%-2%), and aspiration (0.2%-2%) were rare. Overall use of medical therapies and complications at Collaborative Pediatric Critical Care Research Network centers were representative of pediatric asthma care at non-Collaborative Pediatric Critical Care Research Network pediatric intensive care units. Median length of pediatric intensive care unit stay at Collaborative Pediatric Critical Care Research Network centers was 1 to 2 days and death was rare (0.1%-3%). Ten percent of children treated at Collaborative Pediatric Critical Care Research Network centers received invasive mechanical ventilation compared to 12% at non-Collaborative Pediatric Critical Care Research Network centers. Overall 44% of patients who received invasive mechanical ventilation were intubated in the pediatric intensive care unit. Children intubated outside the pediatric intensive care unit had significantly shorter median ventilation days (1 vs. 3), pediatric intensive care unit days (2 vs. 4), and hospital days (4 vs. 7) compared to those intubated in the pediatric intensive care unit. Among children who received mechanical respiratory support, significantly more (41% vs. 25%) were treated with noninvasive ventilation and significantly fewer (41% vs. 58%) were intubated before pediatric intensive care unit care when treated in a Pediatric Health Information System hospital emergency department. CONCLUSIONS: Marked variations in medication therapies and mechanical support exist. Death and other complications were rare. More than half of patients treated with mechanical ventilation were intubated before pediatric intensive care unit care. Site of respiratory mechanical support initiation was associated with length of stay.

Physicians' experiences and perspectives regarding follow-up meetings with parents after a child's death in the pediatric intensive care unit.

OBJECTIVE: To investigate critical care physicians' experiences and perspectives regarding follow-up meetings with parents after a child's death in the pediatric intensive care unit. Parents of children who die in the pediatric intensive care unit often desire a follow-up meeting with the physicians who cared for their child. DESIGN: Semistructured, audio-recorded telephone interviews. SETTING: Six clinical centers affiliated with the Eunice Kennedy Shriver National Institute of Child Health and Human Development Collaborative Pediatric Critical Care Research Network. PARTICIPANTS: Seventy critical care physicians (i.e., attendings and fellows) practicing or training at a Child Health and Human Development Collaborative Pediatric Critical Care Research Network clinical center between February 1, 2008 and June 30, 2008. MEASUREMENTS AND MAIN RESULTS: Twenty-three (33%) physicians reported never participating in a follow-up meeting with bereaved parents; 22 (31%) participated in one to five meetings; and 25 (36%) participated in more than five meetings. Of those with prior experience, 44 (94%) met with parents at the hospital and 40 (85%) met within 3 months of the death. Meeting content included discussing autopsy, parent questions, hospital course, cause of death, genetic risk, bereavement services, and legal or administrative issues; providing emotional support; and receiving parent feedback. Forty (85%) physicians perceived the meetings to be beneficial to families, and 35 (74%) to physicians. Barriers included time and scheduling, family and physician unwillingness, distance and transportation, language and cultural issues, parent anger, and lack of a system for meeting initiation and planning. CONCLUSIONS: Critical care physicians have a wide range of experience conducting follow-up meetings with bereaved parents. Although physicians perceive benefits to follow-up meetings, barriers exist that interfere with their implementation in clinical practice.