Childhood opportunity and appropriate use of child safety restraints in motor vehicle collisions.

Objectives: Safety restraints reduce injuries from motor vehicle collisions (MVCs) but are often improperly applied or not used. The Childhood Opportunity Index (COI) reflects social determinants of health and its study in pediatric trauma is limited. We hypothesized that MVC patients from low-opportunity neighborhoods are less likely to be appropriately restrained. Methods: A retrospective cross-sectional study was performed on children/adolescents ≤18 years old in MVCs between January 1, 2011 and December 31, 2021. Patients were identified from the Children's Hospital Los Angeles trauma registry. The outcome was safety restraint use (appropriately restrained, not appropriately restrained). COI levels by home zip codes were stratified as very low, low, moderate, high, and very high. Multivariable regression controlling for age identified factors associated with safety restraint use. Results: Of 337 patients, 73.9% were appropriately restrained and 26.1% were not appropriately restrained. Compared with appropriately restrained patients, more not appropriately restrained patients were from low-COI (26.1% vs 20.9%), high-COI (14.8% vs 10.8%) and very high-COI (10.2% vs 3.6%) neighborhoods. Multivariable analysis demonstrated no significant associations in appropriate restraint use and COI. There was a non-significant trend that children/adolescents from moderate-COI neighborhoods were more likely than those from very low-COI neighborhoods to be appropriately restrained (OR=1.82, 95% CI 0.78, 4.28). Conclusion: Injury prevention initiatives focused on safety restraints should target families of children from all neighborhood types. Level of evidence: III.

Centiles for the shock index among injured children in the prehospital setting.

OBJECTIVE: The shock index (SI), the ratio of heart rate to systolic blood pressure, is a clinical tool for assessing injury severity. Age-adjusted SI models may improve predictive value for injured children in the out-of-hospital setting. We sought to characterize the proportion of children in the prehospital setting with an abnormal SI using established criteria, describe the age-based distribution of SI among injured children, and determine prehospital interventions by SI. METHODS: We performed a multi-agency retrospective cross-sectional study of children (<18 years) in the prehospital setting with a scene encounter for suspected trauma and transported to the hospital between 2018 and 2022 using the National Emergency Medical Services (EMS) Information System datasets. Our exposure of interest was the first calculated SI. We identified the proportion of children with an abnormal SI when using the SI, pediatric age-adjusted (SIPA); and the pediatric SI (PSI) criteria. We developed and internally validated an age-based distributional model for the SI using generalized additive models for location, scale, and shape to describe the age-based distribution of the SI as a centile or Z-score. We evaluated EMS interventions (basic airway interventions, advanced airway interventions, cardiac interventions, vascular access, intravenous fluids, and vasopressor use) in relation to both the SIPA, PSI, and distributional SI values. RESULTS: We analyzed 1,007,863 pediatric EMS trauma encounters (55.0% male, median age 13 years [IQR, 8-16 years]). The most common dispatch complaint was for traffic/transport related injury (32.9%). When using the PSI and SIPA, 13.1% and 16.3% were classified as having an abnormal SI, respectively. There were broad differences in the percentage of encounters classified as having an abnormal SI across the age range, varying from 5.1 to 22.8% for SIPA and 3.7-20.1% for PSI. The SIPA values ranged from the 75th to 95th centiles, while the PSI corresponded to an SI greater than the 90th centile, except in older children. The centile distribution for SI declined during early childhood and stabilized during adolescence and demonstrated a difference of <0.1% at cutoff values. An abnormal PSI, SIPA and higher SI centiles (>90th centile and >95th centiles) were associated with interventions related to basic and advanced airway management, cardiac procedures, vascular access, and provision of intravenous fluids occurred with greater frequency at higher SI centiles. Some procedures, including airway management and vascular access, had a smaller peak at lower (<10th) centiles. DISCUSSION: We describe the empiric distribution of the pediatric SI across the age range, which may overcome limitations of extant criteria in identifying patients with shock in the prehospital setting. Both high and low SI values were associated with important, potentially lifesaving EMS interventions. Future work may allow for more precise identification of children with significant injury using cutpoint analysis paired to outcome-based criteria. These may additionally be combined with other physiologic and mechanistic criteria to assist in triage decisions.

The Sensitivity of Limited-Sequence MRI in Identifying Pediatric Cervical Spine Injury: A Western Pediatric Surgery Research Consortium Multicenter Retrospective Cohort Study.

INTRODUCTION: Clinical clearance of a child's cervical spine after trauma is often challenging due to impaired mental status or an unreliable neurologic examination. Magnetic resonance imaging (MRI) is the gold standard for excluding ligamentous injury in children but is constrained by long image acquisition times and frequent need for anesthesia. Limited-sequence MRI (LSMRI) is used in evaluating the evolution of traumatic brain injury and may also be useful for cervical spine clearance while potentially avoiding the need for anesthesia. The purpose of this study was to assess the sensitivity and negative predictive value of LSMRI as compared to gold standard full-sequence MRI as a screening tool to rule out clinically significant ligamentous cervical spine injury. METHODS: We conducted a ten-center, five-year retrospective cohort study (2017-2021) of all children (0-18y) with a cervical spine MRI after blunt trauma. MRI images were re-reviewed by a study pediatric radiologist at each site to determine if the presence of an injury could be identified on limited sequences alone. Unstable cervical spine injury was determined by study neurosurgeon review at each site. RESULTS: We identified 2,663 children less than 18 years of age who underwent an MRI of the cervical spine with 1,008 injuries detected on full-sequence studies. The sensitivity and negative predictive value of LSMRI were both >99% for detecting any injury and 100% for detecting any unstable injury. Young children (age < 5 years) were more likely to be electively intubated or sedated for cervical spine MRI. CONCLUSION: LSMRI is reliably detects clinically significant ligamentous injury in children after blunt trauma. To decrease anesthesia use and minimize MRI time, trauma centers should develop LSMRI screening protocols for children without a reliable neurologic exam. LEVEL OF EVIDENCE: 2 (Diagnostic Tests or Criteria).

Prevalence and Outcomes of High versus Low Ratio Plasma to Red Blood Cell Resuscitation in a Multi-Institutional Cohort of Severely Injured Children.

BACKGROUND: The benefit of targeting high ratio fresh frozen plasma (FFP):red blood cell (RBC) transfusion in pediatric trauma resuscitation is unclear as existing studies are limited to patients who retrospectively met criteria for massive transfusion. The purpose of this study is to evaluate the use of high ratio FFP:RBC transfusion and the association with outcomes in children presenting in shock. METHODS: A post-hoc analysis of a 24-institution prospective observational study (4/2018-9/2019) of injured children <18 years with elevated age-adjusted shock index was performed. Patients transfused within 24 hours were stratified into cohorts of low (<1:2) or high (>1:2) ratio FFP:RBC. Nonparametric Kruskal-Wallis and chi-square were used to compare characteristics and mortality. Competing risks analysis was used to compare extended (≥75th percentile) ventilator, intensive care, and hospital days while accounting for early deaths. RESULTS: Of 135 children with median (IQR) age 10 (5,14) years and weight 40 (20,64) kg, 85 (63%) received low ratio transfusion and 50 (37%) high ratio despite similar activation of institutional massive transfusion protocols (MTP; low-38%, high-46%, p = .34). Most patients sustained blunt injuries (70%). Median injury severity score was greater in high ratio patients (low-25, high-33, p = .01); however, hospital mortality was similar (low-24%, high-20%, p = .65) as was the risk of extended ventilator, ICU, and hospital days (all p > .05). CONCLUSION: Despite increased injury severity, patients who received a high ratio of FFP:RBC had comparable rates of mortality. These data suggest high ratio FFP:RBC resuscitation is not associated with worst outcomes in children who present in shock. MTP activation was not associated with receipt of high ratio transfusion, suggesting variability in MTP between centers. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

Comparison of Vital Sign Cutoffs to Identify Children With Major Trauma.

Importance: Vital signs are essential components in the triage of injured children. The Advanced Trauma Life Support (ATLS) and Pediatric Advanced Life Support (PALS) physiologic criteria are frequently used for trauma assessments. Objective: To evaluate the performance of ATLS and PALS criteria vs empirically derived criteria for identifying major trauma in children. Design, Setting, and Participants: This retrospective cohort study used 2021 American College of Surgeons Trauma Quality Improvement Program (TQIP) data contributed by US trauma centers. Included encounters involved pediatric patients (aged <18 years) with severe injury, excluding those who experienced out-of-hospital cardiac arrest, were receiving mechanical ventilation, or were transferred from another facility. Data were analyzed between April 9 and December 21, 2023. Exposure: Initial hospital vital signs, including heart rate, respiratory rate, and systolic blood pressure (SBP). Main Outcome and Measures: Major trauma, determined by the Standard Triage Assessment Tool, a composite measure of injury severity and interventions performed. Multivariable models developed from PALS and ATLS vital sign criteria were compared with models developed from the empirically derived criteria using the area under the receiver operating characteristic curve. Validation of the findings was performed using the 2019 TQIP dataset. Results: A total of 70 748 patients (median [IQR] age, 11 [5-15] years; 63.4% male) were included, of whom 3223 (4.6%) had major trauma. The PALS criteria classified 31.0% of heart rates, 25.7% of respiratory rates, and 57.4% of SBPs as abnormal. The ATLS criteria classified 25.3% of heart rates, 4.3% of respiratory rates, and 1.1% of SBPs as abnormal. Among children with all 3 vital signs documented (64 326 [90.9%]), PALS had a sensitivity of 88.4% (95% CI, 87.1%-89.3%) and specificity of 25.1% (95% CI, 24.7%-25.4%) for identifying major trauma, and ATLS had a sensitivity of 54.5% (95% CI, 52.7%-56.2%) and specificity of 72.9% (95% CI, 72.6%-73.3%). The empirically derived cutoff vital sign z scores had a sensitivity of 80.0% (95% CI, 78.5%-81.3%) and specificity of 48.7% (95% CI, 48.3%-49.1%) and area under the receiver operating characteristic curve of 70.9% (95% CI, 69.9%-71.8%), which was similar to PALS criteria (69.6%; 95% CI, 68.6%-70.6%) and greater than ATLS criteria (65.4%; 95% CI, 64.4%-66.3%). Validation using the 2019 TQIP database showed similar performance to the derivation sample. Conclusions and Relevance: These findings suggest that empirically derived vital sign criteria strike a balance between the sensitivity of PALS criteria and the specificity of ATLS criteria in identifying major trauma in children. These criteria may help to identify children at greatest risk of trauma-related morbidity and mortality.

Outcomes of pediatric pilonidal disease treatment: excision with off-midline flap reconstruction versus endoscopic pilonidal sinus treatment.

PURPOSE: Pilonidal disease (PD) is marked by chronic inflammation and frequent recurrence which can decrease quality of life. However, debate remains regarding the optimal treatment for PD in the pediatric population. This study compares two recommended treatment approaches-excision with off-midline flap reconstruction (OMF: Bascom cleft lift flap, modified Limberg flap) and minimally invasive endoscopic pilonidal sinus treatment (EPSiT). METHODS: Single-center retrospective evaluation of patients 1-21 years of age with PD who underwent either excision with OMF reconstruction or EPSiT between 10/1/2011 and 10/31/2021. Outcomes included were disease recurrence, reoperation, and wound complication rates. Comparisons were performed using Chi-square and Mann-Whitney U tests. RESULTS: 18 patients underwent excision/OMF reconstruction and 45 patients underwent EPSiT. The excision/OMF reconstruction cohort was predominantly male (44.4% vs 17.8% p = 0.028), with history of prior pilonidal infection (33.3% vs 6.7%; p = 0.006), and longer median operative time (60 min vs 17 min; p < 0.001). The excision/OMF reconstruction cohort had a higher rate of wound complications (22.2% vs 0%; p = 0.001), but lower rates of disease recurrence (5.6% vs 33.3%; p = 0.022) and reoperation (5.6% vs 31.1%; p = 0.031). CONCLUSION: In pediatric patients with PD, excision with OMF reconstruction may decrease recurrence and reoperation rates with increased operative times and wound complication rates, compared to EPSiT.

Trends and Variation in Cervical Spine Imaging Utilization Across Children's Hospitals for Pediatric Trauma.

BACKGROUND: Cervical spine evaluation is a critical component in trauma evaluation, and though several pediatric cervical spine evaluation algorithms have been developed, none has been widely implemented. Here, we assess rates of cervical spine imaging use across children's hospitals, specifically temporal trends in imaging use, variation across hospitals in imaging used, and timing of magnetic resonance imaging in admitted patients. METHODS: Data from the Children's Hospital Associations Pediatric Health Information System was abstracted from 2015 to 2020. Patients less than 18 years of age seen in the emergency department with an International Classification of Diseases (ICD)-10 code indicative of trauma and cervical spine plain radiograph or computed tomography in the emergency department were included. Data visualization and descriptive statistics were used to assess rates of imaging use by age, year, hospital, injury severity, and day of service. Changes in rates of imaging use over time were evaluated via Chi-square test. RESULTS: Across 25,238 patient encounters at 35 children's hospitals, there was an increase in use of cervical spine computed tomography from 2015 to 2020 (28.5 to 36.5%). There was substantial inter-institutional variation in rates of use of plain radiographs versus computed tomography for initial evaluation of the cervical spine across all age groups and regardless of rates of severe injury across institutions. Magnetic resonance imaging was obtained more than three days after admission in 31.5% of intensive care patients who received this imaging. CONCLUSIONS: Increasing use of computed tomography, substantial inter-institutional variation in rates of use of plain radiographs versus computed tomography, and heterogenous timing of magnetic resonance imaging for evaluation of the pediatric cervical spine demonstrate the growing need for development and implementation of an age-specific cervical spine evaluation algorithm to guide judicious use of diagnostic resources. LEVEL OF EVIDENCE: Level III, Epidemiologic.

Cervical Collar-Associated Pressure Injury in Pediatric Trauma Patients: A Western Pediatric Surgery Research Consortium Study.

BACKGROUND: Healthcare-associated pressure injuries (HAPI) are known to be associated with medical devices and are preventable. Cervical spine immobilization is commonly utilized in injured children prior to clinical clearance or for treatment of an unstable cervical spinal injury. The frequency of HAPI has been quantified in adults with cervical spine immobilization but has not been well-described in children. The aim of this study was to describe characteristics of children who developed HAPI associated with cervical immobilization. METHODS: We analyzed a retrospective cohort of children (0-18 years) who developed a stage two or greater cervical HAPI. This cohort was drawn from an overall sample of 49,218 registry patients treated over a five-year period (2017-2021) at ten pediatric trauma centers. Patient demographics, injury characteristics, and cervical immobilization were tabulated to describe the population. RESULTS: The cohort included 32 children with stage two or greater cervical HAPI. The median age was 5 years (IQR 2-13) and 78% (n = 25) were admitted to the intensive care unit. The median (IQR) time to diagnosis of HAPI was 11 (7-21) days post-injury. The majority of cervical HAPI (78%, 25/32) occurred in children requiring immobilization for cervical injuries, with only four children developing HAPI after wearing a prophylactic cervical collar in the absence of a cervical spine injury. CONCLUSION: Advanced-stage HAPI associated with cervical collar use in pediatric trauma patients is rare and usually occurs in patients with cervical spine injuries requiring immobilization for treatment. More expedient cervical spine clearance with MRI is unlikely to substantially reduce cervical HAPI in injured children. LEVEL OF EVIDENCE: Level III (Epidemiologic and Prognostic).

Neighborhood deprivation and childhood opportunity indices are associated with violent injury among children in Los Angeles County.

BACKGROUND: Previous research has demonstrated mixed relationships between individual neighborhood socioeconomic factors and incidences of violence, such as poverty level, population density, and income inequality. We used the Childhood Opportunity Index and Area Disadvantage Index to evaluate the relationship between neighborhood characteristics and the number of incidents of violence among children across the zip codes of Los Angeles (LA) County. METHODS: We performed a retrospective cross-sectional study of children younger than 18 years from 2017 to 2019 who were entered in the LA County Trauma and Emergency Medicine Information System registry with violent mechanisms of injury, including gunshot, stabbing, or assault. Mechanisms classified as self-inflicted injuries were excluded from the study. The number of incidences of violent mechanism per 100,000 persons younger than 18 years for each zip code was calculated using population data from the US Census American Community Survey 5-Year estimates from 2019. The incidences of violence per capita younger than 18 years for each zip code was compared with the zip code Area Deprivation Index and Childhood Opportunity Index using logistic regression models. RESULTS: There were 6,791 trauma activations in LA County over the study period, 12.8% (n = 866) of which were due to violence. The mean prevalence of pediatric violent mechanism of injury per zip code was 4 cases per 100,000 persons younger than 18 years. Most injuries were the result of firearms (n = 345 [60.4%]) and occurred among Hispanic/Latino children (n = 362 [57.1%]). There were significantly greater rates of violent injury among children from highest disadvantage (odds ratio, 8.84) and lowest opportunity (odds ratio, 42.48) zip codes. CONCLUSION: Children living in high disadvantage or low opportunity zip codes had greater rates of violent injury. Further study of neighborhood factors is needed to develop targeted effective interventions to reduce violent injuries among children living in low opportunity areas. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Screening for Child Abuse in Children With Isolated Skull Fractures.

OBJECTIVE: Head trauma is the most common cause of death from child abuse, and each encounter for recurrent abuse is associated with greater morbidity. Isolated skull fractures (ISF) are often treated conservatively in the emergency department (ED). We determined patterns of physical abuse screening in a children's hospital ED for children with ISF. METHODS: A retrospective review was performed for children aged 3 years and younger who presented to the ED with ISF from January 1, 2015 to December 31, 2019. Children were stratified by age (<12 mo, ≥12 mo) and witnessed versus unwitnessed injury. Primary outcome was social work (SW) assessment to prescreen for abuse. Secondary outcomes were suspicion for abuse based on Child Protective Services (CPS) referral and subsequent ED encounters within 1 year. RESULTS: Sixty-six ISF patients were identified. Of unwitnessed injury patients aged younger than 12 months (n = 17/22), 88.2% (n = 15/17) underwent SW assessment and 47.1% (n = 8/17) required CPS referral. Of witnessed injury patients aged younger than 12 months (n = 23/44), 60.9% (n = 14/23) underwent SW assessment, with no CPS referrals. Overall, 18.2% (n = 4/22) unwitnessed and 20.5% (n = 9/44) witnessed injury patients returned to our ED: 2 were aged younger than 12 months and had recurrent trauma. CONCLUSIONS: To decrease risk of missed physical abuse, SW consultation should be considered for all ISF patients.

Advances in Pediatric Surgery Simulation-Based Training.

Pediatric surgery is the diagnostic, operative, and postoperative surgical care of children with congenital and acquired anomalies and diseases. The early history of the specialty followed the classic "see one, do one, teach one" philosophy of training but has since evolved to modern methods including simulation-based training (SBT). Current trainees in pediatric surgery face numerous challenges, such as the decreasing incidence of congenital disease and reduced work hours. SBT consists of several modalities that together assist in the acquisition of technical skills and improve performance in the operating room. SBT has evolved to incorporate simulator models and video gaming technology, in parallel with the development of simulation in other surgical and non-surgical pediatric fields. SBT has advanced to a level of sophistication that means that it can improve the skills of not only pediatric surgery trainees but also practicing attending surgeons. In this review, we will discuss the history of pediatric surgery, simulation in pediatric surgery training, and the potential direction of pediatric surgical simulation training in the future.

Epidemiology and management of abdominal injuries in children.

BACKGROUND: Although more guideline-adherent care has been described in pediatric compared to adult trauma centers, we aimed to provide a more detailed characterization of management and resource utilization of children with intra-abdominal injury (IAI) within pediatric centers. Our primary objective was to describe the epidemiology, diagnostic evaluation, and management of children with IAI across U.S. children's hospitals. Our secondary objective was to describe the interhospital variation in surgical management of children with IAI. METHODS: We conducted a cross-sectional study of 33 hospitals in the Pediatric Health Information System. We included children aged <18 years evaluated in the emergency department from 2010 to 2019 with IAI, as defined by ICD coding, and who underwent an abdominal computed tomography (CT). Our primary outcome was abdominal surgery. We categorized IAI by organ system and described resource utilization data. We used generalized linear regression to calculate adjusted hospital-level proportions of abdominal surgery, with a random effect for hospital. RESULTS: We studied 9265 children with IAI. Median (IQR) age was 9.0 (6.0-13.0) years. Abdominal surgery was performed in 16% (n = 1479) of children, with the lowest proportion of abdominal surgery observed in children aged <5 years. Liver (38.6%) and spleen (32.1%) were the most common organs injured. A total of 3.1% of children with liver injuries and 2.8% with splenic injuries underwent abdominal surgery. Although there was variation in rates of surgery across hospitals (p < 0.001), only three of 33 hospitals had rates that were statistically different from the aggregate mean of 16%. CONCLUSIONS: Most children with IAI are managed nonoperatively, and most children's hospitals manage children with IAI similarly. These data can be used to inform future benchmarking efforts across hospitals to assess concordance with guidelines for the management of children with IAI.

Timing and volume of crystalloid and blood products in pediatric trauma: An Eastern Association for the Surgery of Trauma multicenter prospective observational study.

BACKGROUND: The purpose of this study was to determine the relationship between timing and volume of crystalloid before blood products and mortality, hypothesizing that earlier transfusion and decreased crystalloid before transfusion would be associated with improved outcomes. METHODS: A multi-institutional prospective observational study of pediatric trauma patients younger than 18 years, transported from the scene of injury with elevated age-adjusted shock index on arrival, was performed from April 2018 to September 2019. Volume and timing of prehospital, emergency department, and initial admission resuscitation were assessed including calculation of 20 ± 10 mL/kg crystalloid boluses overall and before transfusion. Multivariable Cox proportional hazards and logistic regression models identified factors associated with mortality and extended intensive care, ventilator, and hospital days. RESULTS: In 712 children at 24 trauma centers, mean age was 7.6 years, median (interquartile range) Injury Severity Score was 9 (2-20), and in-hospital mortality was 5.3% (n = 38). There were 311 patients(43.7%) who received at least one crystalloid bolus and 149 (20.9%) who received blood including 65 (9.6%) with massive transfusion activation. Half (53.3%) of patients who received greater than one crystalloid bolus required transfusion. Patients who received blood first (n = 41) had shorter median time to transfusion (19.8 vs. 78.0 minutes, p = 0.005) and less total fluid volume (50.4 vs. 86.6 mL/kg, p = 0.033) than those who received crystalloid first despite similar Injury Severity Score (median, 22 vs. 27, p = 0.40). On multivariable analysis, there was no association with mortality (p = 0.51); however, each crystalloid bolus after the first was incrementally associated with increased odds of extended ventilator, intensive care unit, and hospital days (all p < 0.05). Longer time to transfusion was associated with extended ventilator duration (odds ratio, 1.11; p = 0.04). CONCLUSION: Resuscitation with greater than one crystalloid bolus was associated with increased need for transfusion and worse outcomes including extended duration of mechanical ventilation and hospitalization in this prospective study. These data support a crystalloid-sparing, early transfusion approach for resuscitation of injured children. LEVEL OF EVIDENCE: Therapeutic, level IV.

Post-Operative Superior Mesenteric Artery Syndrome Following Retroperitoneal Sarcoma Resection.

Superior mesenteric artery (SMA) syndrome is an uncommon phenomenon caused by the compression of the third portion of the duodenum between the aorta and the SMA. Here, we present a previously healthy 15-year-old male who presented with early satiety and 20 kg weight loss. Computed tomography (CT) demonstrated a massive retroperitoneal liposarcoma displacing the entire small intestine into the right upper quadrant. Following resection of the large mass, the patient was intolerant of oral intake despite evidence of bowel function. Abdominal CT revealed a narrowing of the duodenum at the location of the SMA. A nasojejunal feeding tube was placed past this area, and enteral nutrition was initiated before slowly resuming oral intake. Post-operative SMA syndrome is an uncommon complication but should be considered in patients intolerant of oral intake following resection of large abdominal tumors associated with extensive retroperitoneal fat loss, even in the absence of concomitant major visceral resection.

The pediatric intestinal mucosal microbiome remains altered after clinical resolution of inflammatory and ischemic disease.

BACKGROUND: The pediatric intestinal microbiome is impacted by many factors, including age, diet, antibiotics, and environment. We hypothesized that in operative patients, alterations to antibiotics and mechanoluminal stimulation would demonstrate measurable changes in the intestinal microbiome and that microbial diversity would be reduced without normal mechanoluminal stimulation and with prolonged antibiotic treatment. METHODS: Bacterial 16s rRNA was extracted from swabbed samples of 43 intestines from 29 patients, aged 5 days to 13 years old. Swabs were obtained during initial resection or later stoma closure. Samples were compared using phylogenetic diversity whole tree alpha diversity and unweighted UniFrac distance beta diversity and by comparing significantly different taxonomic groups. RESULTS: Microbial community structure varied significantly between obstructive and inflammatory diseases (P = .001), with an effect size of 0.99 (0.97, 1.00). This difference persisted even 6 weeks after return to health. Family Enterobacter and Clostridiaceae predominated in patients with necrotizing enterocolitis or focal intestinal perforation; patients with an obstructive pathology had an abundance of Bacteroides. Comparison of UniFrac distance between paired proximal and distal intestines demonstrated that paired samples were significantly closer than any other comparison. CONCLUSION: In infants, inflammatory and ischemic intestinal pathologies treated with prolonged courses of antibiotics durably alter the intestinal mucosal microbiome. Diversion of mechanoluminal stimulation, however, does not.

Sequestration of Vascular Endothelial Growth Factor (VEGF) Induces Late Restrictive Lung Disease.

RATIONALE: Neonatal respiratory distress syndrome is a restrictive lung disease characterized by surfactant deficiency. Decreased vascular endothelial growth factor (VEGF), which demonstrates important roles in angiogenesis and vasculogenesis, has been implicated in the pathogenesis of restrictive lung diseases. Current animal models investigating VEGF in the etiology and outcomes of RDS require premature delivery, hypoxia, anatomically or temporally limited inhibition, or other supplemental interventions. Consequently, little is known about the isolated effects of chronic VEGF inhibition, started at birth, on subsequent developing lung structure and function. OBJECTIVES: To determine whether inducible, mesenchyme-specific VEGF inhibition in the neonatal mouse lung results in long-term modulation of AECII and whole lung function. METHODS: Triple transgenic mice expressing the soluble VEGF receptor sFlt-1 specifically in the mesenchyme (Dermo-1/rtTA/sFlt-1) were generated and compared to littermate controls at 3 months to determine the impact of neonatal downregulation of mesenchymal VEGF expression on lung structure, cell composition and function. Reduced tissue VEGF bioavailability has previously been demonstrated with this model. MEASUREMENTS AND MAIN RESULTS: Triple transgenic mice demonstrated restrictive lung pathology. No differences in gross vascular development or protein levels of vascular endothelial markers was noted, but there was a significant decrease in perivascular smooth muscle and type I collagen. Mutants had decreased expression levels of surfactant protein C and hypoxia inducible factor 1-alpha without a difference in number of type II pneumocytes. CONCLUSIONS: These data show that mesenchyme-specific inhibition of VEGF in neonatal mice results in late restrictive disease, making this transgenic mouse a novel model for future investigations on the consequences of neonatal RDS and potential interventions.

Human and Murine Tissue-Engineered Colon Exhibit Diverse Neuronal Subtypes and Can Be Populated by Enteric Nervous System Progenitor Cells When Donor Colon Is Aganglionic.

PURPOSE: Tissue-engineered colon (TEC) might potentially replace absent or injured large intestine, but the enteric nervous system (ENS), a key component, has not been investigated. In various enteric neuropathic diseases in which the TEC is derived from aganglionic donor colon, the resulting construct might also be aganglionic, limiting tissue engineering applications in conditions such as Hirschsprung disease (HD). We hypothesized that TEC might contain a diverse population of enteric neuronal subtypes, and that aganglionic TEC can be populated by neurons and glia when supplemented with ENS progenitor cells in the form of neurospheres. MATERIALS AND METHODS: Human and murine organoid units (OU) and multicellular clusters containing epithelium and mesenchyme were isolated from both mouse and human donor tissues, including from normally innervated and aganglionic colon. The OU were seeded onto a biodegradable scaffold and implanted within a host mouse, resulting in the growth of TEC. Aganglionic murine and human OU were supplemented with cultured neurospheres to populate the absent ENS not provided by the OU to rescue the HD phenotype. RESULTS: TEC demonstrated abundant smooth muscle and clusters of neurons and glia beneath the epithelium and deeper within the mesenchyme. Motor and afferent neuronal subtypes were identified in TEC. Aganglionic OU formed TEC with absent neural elements, but neurons and glia were abundant when aganglionic OU were supplemented with ENS progenitor cells. CONCLUSION: Murine and human TEC contain key components of the ENS that were not previously identified, including glia, neurons, and fundamental neuronal subtypes. TEC derived from aganglionic colon can be populated with neurons and glia when supplemented with neurospheres. Combining tissue engineering and cellular replacement therapies represents a new strategy for treating enteric neuropathies, particularly HD.

Assessing medical care availability for student athletes of a large urban high school district.

BACKGROUND: The need for medical care for student athletes is mounting, as participation in high school athletics is continuing to rise. This study assessed medical care available to high school student athletes in a large, urban school district in California that has not been studied since 2002. By surveying athletic directors and coaches, we expected to find inadequate availability of medical care in the studied district and predicted that care would be more widely available for student athletes at larger high schools. METHODS: We developed and validated a questionnaire assessing practice and game coverage, emergency preparedness, treatment, and injury prevention measures. The survey was administered to athletic directors and coaches at a school district athletic directors' meeting. RESULTS: Forty-three (57%) of 75 distributed surveys were completed. We found that 70% of schools did not staff a healthcare provider for practices, 28% did not staff home games, and 30% did not staff away games, for any sports. We found no significant differences between school sizes with respect to physician referrals after a student was injured, provision of health education, or implementation of emergency action plans. CONCLUSIONS: Although these data do not support our hypothesis of larger schools providing better medical care, it suggests that there are multiple areas of inadequate healthcare regardless of school size. We identified numerous gaps; thus, future work will examine the impact of these gaps.

Vitrification preserves murine and human donor cells for generation of tissue-engineered intestine.

BACKGROUND: Short bowel syndrome causes significant morbidity and mortality. Tissue-engineered intestine may serve as a viable replacement. Tissue-engineered small intestine (TESI) has previously been generated in the mouse model from donor cells that were harvested and immediately reimplanted; however, this technique may prove impossible in children who are critically ill, hemodynamically unstable, or septic. We hypothesized that organoid units (OU), multicellular clusters containing epithelium and mesenchyme, could be cryopreserved for delayed production of TESI. METHODS: OU were isolated from <3 wk-old mouse or human ileum. OU were then cryopreserved by either standard snap freezing or vitrification. In the snap freezing protocol, OU were suspended in cryoprotectant and transferred directly to -80°C for storage. The vitrification protocol began with a stepwise increase in cryoprotectant concentration followed by liquid supercooling of the OU solution to -13°C and nucleation with a metal rod to induce vitrification. Samples were then cooled to -80°C at a controlled rate of -1°C/min and subsequently plunged into liquid nitrogen for long-term storage. OU from both groups were maintained in cryostorage for at least 72 h and thawed in a 37°C water bath. Cryoprotectant was removed with serial sucrose dilutions and OU were assessed by Trypan blue assay for post-cryopreservation viability. Via techniques previously described by our laboratory, the thawed murine or human OU were either cultured in vitro or implanted on a scaffold into the omentum of a syngeneic or irradiated Nonobese Diabetic/Severe Combined Immunodeficiency, gamma chain deficient adult mouse. The resultant TESI was analyzed by histology and immunofluorescence. RESULTS: After cryopreservation, the viability of murine OU was significantly higher in the vitrification group (93 ± 2%, mean ± standard error of the mean) compared with standard freezing (56 ± 6%) (P < 0.001, unpaired t-test, n = 25). Human OU demonstrated similar viability after vitrification (89 ± 2%). In vitro culture of thawed OU produced expanding epithelial spheres supported by a layer of mesenchyme. TESI was successfully generated from the preserved OU. Hematoxylin and eosin staining demonstrated a mucosa composed of a simple columnar epithelium whereas immunofluorescence staining confirmed the presence of both progenitor and differentiated epithelial cells. Furthermore, beta-2-microglobulin confirmed that the human TESI epithelium originated from human cells. CONCLUSIONS: We demonstrated improved multicellular viability after vitrification over conventional cryopreservation techniques and the first successful vitrification of murine and human OU with subsequent TESI generation. Clinical application of this method may allow for delayed autologous implantation of TESI for children in extremis.