Cerebrovascular Physiology During Pediatric Extracorporeal Membrane Oxygenation: A Multicenter Study Using Transcranial Doppler Ultrasonography.

OBJECTIVES: To explore changes to expected, age-related transcranial Doppler ultrasound variables during pediatric extracorporeal membrane oxygenation. DESIGN: Prospective, observational, multicenter study. SETTING: Tertiary care PICUs. PATIENTS: Children 1 day to 18 years old requiring veno arterial extracorporeal membrane oxygenation. METHODS: Participants underwent daily transcranial Doppler ultrasound measurement of bilateral middle cerebral artery flow velocities. Acute neurologic injury was diagnosed if seizures, cerebral hemorrhage, or diffuse cerebral ischemia was detected. MEASUREMENTS AND MAIN RESULTS: Fifty-two children were enrolled and analyzed. In the 44 children without acute neurologic injury, there was a significant reduction in systolic flow velocity and mean flow velocity compared with predicted values over time (F [8, 434] = 60.44; p ≤ 0.0001, and F [8, 434] = 17.61; p ≤ 0.0001). Middle cerebral artery systolic flow velocity was lower than predicted on extracorporeal membrane oxygenation days 1-5, and mean flow velocity was lower than predicted on extracorporeal membrane oxygenation days 1-3. In the six infants less than 90 days old suffering diffuse cerebral ischemia, middle cerebral artery systolic flow velocity, mean flow velocity, and diastolic flow velocity from extracorporeal membrane oxygenation days 1-9 were not significantly different when compared with children of similar age in the cohort that did not suffer acute neurologic injury (systolic flow velocity F [8, 52] = 0.6659; p = 0.07 and diastolic flow velocity F [8, 52] = 1.4; p = 0.21 and mean flow velocity F [8, 52] = 1.93; p = 0.07). Pulsatility index was higher in these infants over time than children of similar age in the cohort on extracorporeal membrane oxygenation that did not suffer acute neurologic injury (F [8, 52] = 3.1; p = 0.006). No patient in the study experienced cerebral hemorrhage. CONCLUSIONS: Flow velocities in the middle cerebral arteries of children requiring extracorporeal membrane oxygenation are significantly lower than published normative values for critically ill, mechanically ventilated, sedated children. Significant differences in measured systolic flow velocity, diastolic flow velocity, and mean flow velocity were not identified in children suffering ischemic injury compared with those who did not. However, increased pulsatility index may be a marker for ischemic injury in young infants on extracorporeal membrane oxygenation.

Delirium in Critically Ill Children: An International Point Prevalence Study.

OBJECTIVES: To determine prevalence of delirium in critically ill children and explore associated risk factors. DESIGN: Multi-institutional point prevalence study. SETTING: Twenty-five pediatric critical care units in the United States, the Netherlands, New Zealand, Australia, and Saudi Arabia. PATIENTS: All children admitted to the pediatric critical care units on designated study days (n = 994). INTERVENTION: Children were screened for delirium using the Cornell Assessment of Pediatric Delirium by the bedside nurse. Demographic and treatment-related variables were collected. MEASUREMENTS AND MAIN RESULTS: Primary study outcome measure was prevalence of delirium. In 159 children, a final determination of mental status could not be ascertained. Of the 835 remaining subjects, 25% screened positive for delirium, 13% were classified as comatose, and 62% were delirium-free and coma-free. Delirium prevalence rates varied significantly with reason for ICU admission, with highest delirium rates found in children admitted with an infectious or inflammatory disorder. For children who were in the PICU for 6 or more days, delirium prevalence rate was 38%. In a multivariate model, risk factors independently associated with development of delirium included age less than 2 years, mechanical ventilation, benzodiazepines, narcotics, use of physical restraints, and exposure to vasopressors and antiepileptics. CONCLUSIONS: Delirium is a prevalent complication of critical illness in children, with identifiable risk factors. Further multi-institutional, longitudinal studies are required to investigate effect of delirium on long-term outcomes and possible preventive and treatment measures. Universal delirium screening is practical and can be implemented in pediatric critical care units.

Feasibility Study Evaluating Therapeutic Hypothermia for Refractory Status Epilepticus in Children.

Pediatric refractory status epilepticus (RSE) is a neurological emergency with significant morbidity and mortality, which lacks consensus regarding diagnosis and treatment(s). Therapeutic hypothermia (TH) is an effective treatment for RSE in preclinical models and small series. In addition, TH is a standard care for adults after cardiac arrest and neonates with hypoxic-ischemic encephalopathy. The purpose of this study was to identify the feasibility of a study of pediatric RSE within a research group (Pediatric Neurocritical Care Research Group [PNCRG]). Pediatric intensive care unit (PICU) admissions at seven centers were prospectively screened from October 2012 to July 2013 for RSE. Experts within the PNCRG estimated that clinicians would be unwilling to enroll a child, unless the child required at least two different antiepileptic medications and a continuous infusion of another antiepileptic medication with ongoing electrographic seizure activity for ≥2 hours after continuous infusion initiation. Data for children meeting the above inclusion criteria were collected, including the etiology of RSE, history of epilepsy, and maximum dose of continuous antiepileptic infusions. There were 8113 PICU admissions over a cumulative 52 months (October 2012-July 2013) at seven centers. Of these, 69 (0.85%) children met inclusion criteria. Twenty children were excluded due to acute diagnoses affected by TH, contraindications to TH, or lack of commitment to aggressive therapies. Sixteen patients had seizure cessation within 2 hours, resulting in 33 patients who had inadequate seizure control after 2 hours and a continuous antiepileptic infusion. Midazolam (21/33, 64%) and pentobarbital (5/33, 15%) were the most common infusions with a wide maximum dose range. More than one infusion was required for seizure control in four patients. There are substantial numbers of subjects at clinical sites within the PNCRG with RSE that would meet the proposed inclusion criteria for a study of TH. The true feasibility of such a study depends on the sample size necessary to achieve therapeutic effects on justifiable clinical outcomes.

Computed tomography vs magnetic resonance imaging for identifying acute lesions in pediatric traumatic brain injury.

BACKGROUND AND OBJECTIVE: Pediatric traumatic brain injury (TBI) is a leading cause of morbidity and mortality in children. Computed tomography (CT) is the modality of choice to screen for brain injuries. MRI may provide more clinically relevant information. The purpose of this study was to compare lesion detection between CT and MRI after TBI. METHODS: Retrospective cohort of children (0-21 years) with TBI between 2008 and 2010 at a Level 1 pediatric trauma center with a head CT scan on day of injury and a brain MRI scan within 2 weeks of injury. Agreement between CT and MRI was determined by κ statistic and stratified by injury mechanism. RESULTS: One hundred five children were studied. Of these, 78% had mild TBI. The MRI scan was obtained a median of 1 day (interquartile range, 1-2) after CT. Overall, CT and MRI demonstrated poor agreement (κ=-0.083; P=.18). MRI detected a greater number of intraparenchymal lesions (n=36; 34%) compared with CT (n=16; 15%) (P<.001). Among patients with abusive head trauma, MRI detected intraparenchymal lesions in 16 (43%), compared with only 4 (11%) lesions with CT (P=.03). Of 8 subjects with a normal CT scan, 6 out of 8 had abnormal lesions on MRI. CONCLUSIONS: Compared with CT, MRI identified significantly more intraparenchymal lesions in pediatric TBI, particularly in children with abusive head trauma. The prognostic value of identification of intraparenchymal lesions by MRI is unknown but warrants additional inquiry. Risks and benefits from early MRI (including sedation, time, and lack of radiation exposure) compared with CT should be weighed by clinicians.

Multiplex assessment of cytokine and chemokine levels in cerebrospinal fluid following severe pediatric traumatic brain injury: effects of moderate hypothermia.

This study performed a comprehensive analysis of cerebrospinal fluid (CSF) cytokine levels after severe traumatic brain injury (TBI) in children using a multiplex bead array assay and to evaluate the effects of moderate hypothermia on cytokine levels. To this end, samples were collected during two prospective randomized controlled trials of therapeutic moderate hypothermia in pediatric TBI. Thirty-six children with severe TBI (Glasgow Coma Scale [GCS] score of