Clinical Full-Time Equivalent in PICUs: Survey of the U.S. Pediatric Critical Care Chiefs Network, 2020-2022.

OBJECTIVES: To inform workforce planning for pediatric critical care (PCC) physicians, it is important to understand current staffing models and the spectrum of clinical responsibilities of physicians. Our objective was to describe the expected workload associated with a clinical full-time equivalent (cFTE) in PICUs across the U.S. Pediatric Critical Care Chiefs Network (PC3N). DESIGN: Cross-sectional survey. SETTING: PICUs participating in the PC3N. SUBJECTS: PICU division chiefs or designees participating in the PC3N from 2020 to 2022. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A series of three surveys were used to capture unit characteristics and clinical responsibilities for an estimated 1.0 cFTE intensivist. Out of a total of 156 PICUs in the PC3N, the response rate was 46 (30%) to all three distributed surveys. Respondents used one of four models to describe the construction of a cFTE-total clinical hours, total clinical shifts, total weeks of service, or % full-time equivalent. Results were stratified by unit size. The model used for construction of a cFTE did not vary significantly by the total number of faculty nor the total number of beds. The median (interquartile range) of clinical responsibilities annually for a 1.0 cFTE were: total clinical hours 1750 (1483-1858), total clinical shifts 142 (129-177); total weeks of service 13.0 (11.3-16.0); and total night shifts 52 (36-60). When stratified by unit size, larger units had fewer nights or overnight hours, but covered more beds per shift. CONCLUSIONS: This survey of the PC3N (2020-2022) provides the most contemporary description of clinical responsibilities associated with a cFTE physician in PCC. A 1.0 cFTE varies depending on unit size. There is no correlation between the model used to construct a cFTE and the associated clinical responsibilities.

Multi-center retrospective study of children with sickle cell disease admitted to pediatric intensive care units in the United States.

Data on outcomes and interventions for children with sickle cell disease (SCD) admitted to a pediatric intensive care units (PICU) are unknown. We provide the first comprehensive multi-center report on PICU interventions associated with death, the need for invasive respiratory support or stroke among critically ill children with SCD. We collected retrospective multi-center cohort data from January 1, 2012 to December 31, 2019 utilizing the Virtual Pediatric Systems, LLC database. We identified 3388 unique children with SCD, accounting for a total of 5264 PICU admissions from 138 PICUs. The overall mortality rate for the PICU admissions cohort was 1.8% (95/5264 PICU admissions, 95/3388 [2.8%] of all unique patients), the rate of needing of needing Invasive Respiratory Support (IRS, a composite category of exposure) was 21.3% (872/4093 PICU admissions with complete data) and the overall rate of stroke (ischemic or hemorrhagic) was 12.5% (657/5264 PICU admissions). In multivariable analysis adjusting for admission age category, sex, race/ethnicity, PRISM-3 score at admission, exposure to IRS, quartile of unit volume of patients with SCD, and patient origin, admitted children who needed invasive respiratory support (IRS) had higher adjusted odds ratios for mortality (adjusted odds ratio [aOR], 19.72; 95% confidence interval [CI] 8.98-43.29; p < 0.001), although admitted children > 2 years old had decreased aOR for needing IRS (aOR 0.25-0.62; 95% CI 0.16-0.94; p < 0.001-0.025). By contrast, admitted children > 2 years old had a strikingly increased aOR for stroke (aOR 7.57-16.32; 95% CI 2.25-52.15; p < 0.001). These groups may represent PICU-specific subsets of patients with SCD who are at higher risk for more serious illness and should deserve early consideration for referral to a pediatric institution providing comprehensive care for patients with SCD.

Retrospective observational study of chloral hydrate use in mechanically-ventilated pediatric intensive care unit (PICU) patients 2012-2017.

Introduction: Chloral hydrate (CH) has long been utilized as a pediatric procedural sedation agent. However, very little is published describing CH use in a pediatric intensive care unit (PICU) setting. The aim of this retrospective observational cohort study was to investigate and describe the use of CH in mechanically-ventilated, critically ill children at a large pediatric tertiary referral hospital. Methods: Data were extracted from the hospital electronic medical record and a locally maintained registry of all children admitted to the PICU between 2012 and 2017. Patients admitted to the cardiovascular ICU were not included in this review. The clinical and pharmacy data for 3806 consecutive PICU admissions of mechanically-ventilated, critically ill children were examined. Results: 283 admissions received CH during their first ICU stay. CH-exposed children were younger (16 months vs. 35 months, p < 0.001), the median total dose of CH (indexed to duration of ventilation) was 11 mg/kg/day, the median time to first CH dose was 3 days and more CH doses were administered at night (1112 vs. 958, p < 0.001). We constructed a propensity score to adjust for the differences in patients with and without CH exposure using logistic regression including variables of age, sex, diagnosis, and PRISM3 score. After adjustment, the median length of mechanical ventilation was 5 days longer in the CH-exposed group (95% Confidence Interval [CI] 4-6) compared to unexposed CH patients. Similarly, the median length of ICU duration was 9.4 days longer (95% CI 7.1-11.6) and median length of hospital admission duration was 13.2 days longer (95% CI 7.8-18.6) in CH-exposed patients compared to CH-non-exposed. After adjustment, CH-exposed patients had a 9% higher median exposure to HFOV (95% CI 3.9-14.6), but did not have higher median exposures to new tracheostomy (95% CI -0.4-2.2) or ECMO (95% CI -0.2-5.0). Discussion: As part of an extended sedation regimen in mechanically-ventilated and critically ill children, CH is associated with somewhat higher complexity of illness and longer ICU durations.

Guidance for Structuring a Pediatric Intermediate Care Unit.

The purpose of this policy statement is to update the 2004 American Academy of Pediatrics clinical report and provide enhanced guidance for institutions, administrators, and providers in the development and operation of a pediatric intermediate care unit (IMCU). Since 2004, there have been significant advances in pediatric medical, surgical, and critical care that have resulted in an evolution in the acuity and complexity of children potentially requiring IMCU admission. A group of 9 clinical experts in pediatric critical care, hospital medicine, intermediate care, and surgery developed a consensus on priority topics requiring updates, reviewed the relevant evidence, and, through a series of virtual meetings, developed the document. The intended audience of this policy statement is broad and includes pediatric critical care professionals, pediatric hospitalists, pediatric surgeons, other pediatric medical and surgical subspecialists, general pediatricians, nurses, social workers, care coordinators, hospital administrators, health care funders, and policymakers, primarily in resource-rich settings. Key priority topics were delineation of core principles for an IMCU, clarification of target populations, staffing recommendations, and payment.

Variations in analgesic, sedation, and delirium management between trauma and non-trauma critically ill children.

INTRODUCTION: Studies have shown the benefit of intensive care unit (ICU) bundled protocols; however, they are primarily derived from medical patients. We hypothesized that patients and their medication profiles are different between critically ill medical, surgical, and trauma patients. METHODS: The Pediatric Health Information System 2017 dataset was used to perform a retrospective cohort study of critically ill children. The pediatric medical, surgical, and trauma cohorts were separated based on ICD-10 codes. Data collected included demographics, secondary diagnoses, outcomes, and medication data. Medications were grouped as opiates, GABA-agonists, alpha-2 agonists, anti-psychotics, paralytics, and "other" sedatives. A non-parametric Kolmogorov-Smirnov test (KS test) and odds ratios (reference group: medical cohort) were calculated to compare medication administration between the study cohorts for the first 30 ICU days. RESULTS: A total of 4488 critically ill children (medical 2078, surgical 1650, and trauma 760) were identified. The trauma cohort had increased incidence of delirium (medical 10.8%, surgical 11.5%, trauma 13.8%; p < 0.01) and mortality (medical 5.4%, surgical 2.4%, trauma 11.7%; p < 0.01). For all study cohorts, > 50% received GABA-agonists on ICU days 0-30. With the KS test, there was a significant difference in administration of opiates, GABA-agonists, alpha-2 agonists, anti-psychotics, and "other" sedatives over the first 30 days in the ICU. Relative to medical patients, trauma patients had significantly higher odds of receiving anti-psychotics on ICU days 10-20 and 22-24. CONCLUSION: Critically ill pediatric trauma, medical, and surgical patients are distinctly different patient populations with differing pharmacologic profiles for analgesia, sedation, and delirium. LEVEL OF EVIDENCE: Level III (Retrospective Comparative Study).

Testing positive pressure delivered from commercial and WHO-style pediatric bubble CPAP devices.

BACKGROUND/AIM: Low-cost commercial bCPAP devices have been deployed in resource-limited settings to treat neonatal respiratory failure. The use of these devices has increased access to pediatric respiratory support for infants. However, constrained resources may result in substitution of recommended consumables and/or use in older age groups. We hypothesized that commercially available bCPAP devices, the standard WHO-style device and various improvised adaptations would all generate effective, safe positive pressure at the patient interface. METHODS: Performance of 2 commercially available bCPAP devices was tested against the standard WHO-style bCPAP device, as well as several improvised modifications of these devices, by measuring positive pressure delivered at the patient interface. Variables tested included different flow rates, patient interfaces and respiratory circuit tubing. RESULTS: Both commercial devices utilized according to manufacturer recommendations generated the expected positive pressure at the patient interface. When testing the recommended WHO-style bCPAP device with recommended materials as well as other improvised modifications, we found variable and potentially unpredictable generation of positive pressure at the patient interface. CONCLUSIONS: Modified or improvised bCPAP devices should be used with extreme caution as the support provided may be more or less than expected depending on respiratory tubing and flow rates employed. Our data support the effectiveness of bCPAP in newborns and young infants. But, to our knowledge, there are no bCPAP patient interfaces for older children effective with low liter flow devices. Therefore, based on these results, we recommend against using WHO-style bCPAP devices for non-infant patients with respiratory failure and instead recommend using standard oxygen therapy with nasal cannulae or face-masks, as well as early consideration of transfer to a higher level of care.

Derangement of Arginine and Related Amino Acids in Children Undergoing Surgery for Congenital Heart Disease With Cardiopulmonary Bypass.

Arginine is a conditionally essential amino acid, the precursor for nitric oxide and a key factor in cell proliferation, protein synthesis, and energy metabolism. When there is increased demand in the setting of inflammation, ischemia-reperfusion injury, and organ dysfunction, endogenous arginine production falls short, and external supplementation may be necessary. The goal of this study was to assess changes in concentrations of plasma arginine, citrulline, ornithine, glutamine, and plasma arginase in infants and children undergoing surgery for congenital heart disease with cardiopulmonary bypass. DESIGN: Prospective observational study. SETTING: The study was conducted in the Heart Center at Texas Children's Hospital. SUBJECTS: Children undergoing surgery for congenital heart disease with cardiopulmonary bypass. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Serial perioperative blood samples were collected for quantification of amino acids, arginase, nitric oxide metabolites, and markers of organ function (lactate, Pao2/Fio2 ratio, and creatinine clearance). Thirty children (18 males) were included in the study; median (interquartile range) age 0.5 years (0.3-0.9 yr). The mean ± sd for plasma amino acid concentrations before cardiopulmonary bypass: arginine 62 ± 20 µmol/L, citrulline 24 ± 6 µmol/L, ornithine 53 ± 32 µmol/L, and glutamine 591 ± 126 µmol/L. Arginine concentration was decreased within the first 24 hours (43 ± 15 µmol/L; p = 0.004), citrulline and glutamine concentrations decreased over the first 48 hours (11 ± 4 µmol/L; p < 0.001 and 493 ± 131 µmol/L; p = 0.019, respectively) and were associated with an increase in arginase (3.8 ± 3 µg/mL; p < 0.05). There was an increase in Vasoactive-Inotropic Score (5.9 ± 19 vs 0.5 ± 2; p < 0.001), decrease in creatinine clearance (76 ± 24 vs 93 ± 31; p = 0.002), and Pao2/Fio2 ratio (243 ± 138 vs 374 ± 200; p = 0.007) comparing to baseline. CONCLUSIONS: A widely variable degree of arginine, citrulline, and glutamine depletion occurs in children after surgery for congenital heart disease. These findings were associated with increased arginase and coincide with some of the markers of organ perfusion.

Early Suppression of Macrophage Gene Expression by Leishmania braziliensis.

Leishmania braziliensis is an intracellular parasite that resides mostly in macrophages. Both the parasite genome and the clinical disease manifestations show considerable polymorphism. Clinical syndromes caused by L. braziliensis include localized cutaneous (CL), mucosal (ML), and disseminated leishmaniasis (DL). Our prior studies showed that genetically distinct L. braziliensis clades associate with different clinical types. Herein, we hypothesized that: (1) L. braziliensis induces changes in macrophage gene expression that facilitates infection; (2) infection of macrophages with strains associated with CL (clade B), ML (clade C), or DL (clade A) will differentially affect host cell gene expression, reflecting their different pathogenic mechanisms; and (3) differences between the strains will be reflected by differences in macrophage gene expression after initial exposure to the parasite. Human monocyte derived macrophages were infected with L. braziliensis isolates from clades A, B, or C. Patterns of gene expression were compared using Affymetrix DNA microarrays. Many transcripts were significantly decreased by infection with all isolates. The most dramatically decreased transcripts encoded proteins involved in signaling pathways, apoptosis, or mitochondrial oxidative phosphorylation. Some transcripts encoding stress response proteins were up-regulated. Differences between L. braziliensis clades were observed in the magnitude of change, rather than the identity of transcripts. Isolates from subjects with metastatic disease (ML and DL) induced a greater magnitude of change than isolates from CL. We conclude that L. braziliensis enhances its intracellular survival by inhibiting macrophage pathways leading to microbicidal activity. Parasite strains destined for dissemination may exert a more profound suppression than less invasive L. braziliensis strains that remain near the cutaneous site of inoculation.

Human macrophage response to L. (Viannia) panamensis: microarray evidence for an early inflammatory response.

BACKGROUND: Previous findings indicate that susceptibility to Leishmania (Viannia) panamensis infection of monocyte-derived macrophages from patients and asymptomatically infected individuals were associated with the adaptive immune response and clinical outcome. METHODOLOGY/PRINCIPAL FINDINGS: To understand the basis for this difference we examined differential gene expression of human monocyte-derived macrophages following exposure to L. (V.) panamensis. Gene activation profiles were determined using macrophages from healthy volunteers cultured with or without stationary phase promastigotes of L. (V.) panamensis. Significant changes in expression (>1.5-fold change; p<0.05; up- or down-regulated) were identified at 0.5, 4 and 24 hours. mRNA abundance profiles varied over time, with the highest level of activation occurring at earlier time points (0.5 and 4 hrs). In contrast to observations for other Leishmania species, most significantly changed mRNAs were up- rather than down-regulated, especially at early time points. Up-regulated transcripts over the first 24 hours belonged to pathways involving eicosanoid metabolism, oxidative stress, activation of PKC through G protein coupled receptors, or mechanism of gene regulation by peroxisome proliferators via PPARα. Additionally, a marked activation of Toll-receptor mediated pathways was observed. Comparison with published microarray data from macrophages infected with L. (Leishmania) chagasi indicate differences in the regulation of genes involved in signaling, motility and the immune response. CONCLUSIONS: Results show that the early (0.5 to 24 hours) human monocyte-derived macrophage response to L. (Viannia) panamensis is not quiescent, in contrast to published reports examining later response times (48-96 hours). Early macrophage responses are important for the developing cellular response at the site of infection. The kinetics and the mRNA abundance profiles induced by L. (Viannia) panamensis illustrate the dynamics of these interactions and the distinct biologic responses to different Leishmania species from the outset of infection within their primary host cell.

Genetic admixture in Brazilians exposed to infection with Leishmania chagasi.

Visceral leishmaniasis (VL) in northeast Brazil is a disease caused by infection with the protozoan Leishmania chagasi. Infection leads to variable clinical outcomes ranging from asymptomatic infection to potentially fatal disease. Prior studies suggest the genetic background of the host contributes to the development of different outcomes after infection, although it is not known if ancestral background itself influences outcomes. VL is endemic in peri-urban areas around the city of Natal in northeast Brazil. The population of northeast Brazil is a mixture of distinct racial and ethnic groups. We hypothesized that some sub-populations may be more susceptible than others to develop different clinical outcomes after L. chagasi infection. Using microsatellite markers, we examined whether admixture of the population as a whole, or markers likely inherited from a distinct ethnic background, differed between individuals with VL, individuals with an asymptomatic infection, or individuals with no infection. There was no apparent significant difference in overall population admixture proportions among the three clinical phenotype groups. However, one marker on Chr. 22 displayed evidence of excess ancestry from putative ancestral populations among different clinical phenotypes, suggesting this region may contain genes determining the course of L. chagasi infection.

Macrophage and T-cell gene expression in a model of early infection with the protozoan Leishmania chagasi.

Visceral leishmaniasis is a potentially fatal infectious disease caused by the protozoan parasite Leishmania infantum/chagasi in the New World, or by L. donovani or L. infantum/chagasi in the Old World. Infection leads to a variety of outcomes ranging from asymptomatic infection to active disease, characterized by fevers, cachexia, hepatosplenomegaly and suppressed immune responses. We reasoned that events occurring during the initial few hours when the parasite encounters cells of the innate and adaptive immune systems are likely to influence the eventual immune response that develops. Therefore, we performed gene expression analysis using Affymetrix U133Plus2 microarray chips to investigate a model of early infection with human monocyte-derived macrophages (MDMs) challenged with wild-type L. chagasi parasites, with or without subsequent co-culture with Leishmania-naïve, autologous T-cells. Microarray data generated from total RNA were analyzed with software from the Bioconductor Project and functional clustering and pathway analysis were performed with DAVID and Gene Set Enrichment Analysis (GSEA), respectively. Many transcripts were down-regulated by infection in cultures containing macrophages alone, and the pattern indicated a lack of a classically activated phenotype. By contrast, the addition of autologous Leishmania-naïve T cells to infected macrophages resulted in a pattern of gene expression including many markers of type 1 immune cytokine activation (IFN-gamma, IL-6, IL-1alpha, IL-1beta). There was simultaneous up-regulation of a few markers of immune modulation (IL-10 cytokine accumulation; TGF-beta Signaling Pathway). We suggest that the initial encounter between L. chagasi and cells of the innate and adaptive immune system stimulates primarily type 1 immune cytokine responses, despite a lack of classical macrophage activation. This local microenvironment at the site of parasite inoculation may determine the initial course of immune T-cell development.

Genetic predisposition to self-curing infection with the protozoan Leishmania chagasi: a genomewide scan.

The protozoan Leishmania chagasi can cause disseminated, fatal visceral leishmaniasis (VL) or asymptomatic infection in humans. We hypothesized that host genetic factors contribute to this variable response to infection. A family study was performed in neighborhoods of endemicity for L. chagasi near Natal in northeastern Brazil. Study subjects were assessed for the presence of VL or asymptomatic infection, which was defined by a positive delayed-type hypersensitivity (DTH) skin test response to Leishmania antigen without disease symptoms. A genomewide panel of 385 autosomal microsatellite markers in 1254 subjects from 191 families was analyzed to identify regions of linkage. Regions with potential linkage to the DTH response on chromosomes 15 and 19, as well as a novel region on chromosome 9 with potential linkage to VL, were identified. Understanding the genetic factors that determine whether an individual will develop symptomatic or asymptomatic infection with L. chagasi may identify proteins essential for immune protection against this parasitic disease and reveal strategies for immunotherapy or prevention.