Acute Respiratory Failure in Pediatric Hematopoietic Cell Transplantation: A Multicenter Study

Timing of intubation of pediatric hematopoietic cell transplant patients: an international survey

Introduction

Retrospective data suggest that pediatric hematopoietic cell transplant (HCT) patients placed on non-invasive ventilation (NIV) prior to intubation have increased risk of mortality compared to patients who are intubated earlier in their course. The HCT-CI subgroup of the PALISI Network set out to gain a better understanding of factors that influence clinician's decisions surrounding timing of intubation of pediatric HCT patients.

Methods

We validated and distributed a brief survey exploring potential factors that may influence clinician's decisions around timing of intubation of pediatric HCT patients with acute lung injury (ALI).

Results

One hundred and four of the 869 PALISI Network's members responded to the survey; 97 of these respondents acknowledged caring for HCT patients and were offered the remainder of the survey. The majority of respondents were PICU physicians (96%), with a small number of Advanced Practice Providers and HCT physicians. As expected, poor prognosis categories were perceived as a factors that delay timing to intubation whereas need for invasive procedures was perceived as a factor shortening timing to intubation. Concerns for oxygen toxicity or NIV-associated lung injury were not believed to influence timing of intubation.

Discussion

Our survey indicates increased risk of ALI from prolonged NIV and oxygen toxicity in HCT patients are not a concern for most clinicians. Further education of pediatric ICU clinicians around these risk factors could lead to improvement in outcomes and demands further study. Additionally, clinicians identified concerns for the patient's poor prognosis as a common reason for delayed intubation.

Risk factors predicting need for the pediatric intensive care unit (PICU) post-hematopoietic cell transplant, PICU utilization, and outcomes following HCT: a single center retrospective analysis

Hematopoietic cell transplant (HCT) is a curative treatment for multiple malignant and non-malignant disorders. While morbidity and mortality have decreased significantly over the years, some patients still require management in the pediatric intensive care unit (PICU) during their HCT course for additional respiratory, cardiovascular, and/or renal support. We retrospectively reviewed pediatric patients (0-18 years) who underwent HCT from January 2015-December 2020 at our institution to determine risk factors for PICU care and evaluate PICU utilization and outcomes. We also assessed pulmonary function testing (PFT) data to determine if differences were noted between PICU and non-PICU patients as well as potential evolution of pulmonary dysfunction over time. Risk factors of needing PICU care were lower age, lower weight, having an underlying inborn error of metabolism, and receiving busulfan-based conditioning. Nearly half of PICU encounters involved use of each of respiratory support types including high-flow nasal cannula, non-invasive positive pressure ventilation, and mechanical ventilation. Approximately one-fifth of PICU encounters involved renal replacement therapy. Pulmonary function test results largely did not differ between PICU and non-PICU patients at any timepoint aside from individuals who required PICU care having lower DLCO scores at one-year post-HCT. Future directions include consideration of combining our data with other centers for a multi-center retrospective analysis with the goal of gathering and reporting additional multi-center data to work toward continuing to decrease morbidity and mortality for patients undergoing HCT.

Immunocompromised-Associated Pediatric Acute Respiratory Distress Syndrome: Experience From the 2016/2017 Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology Prospective Cohort Study

OBJECTIVES

To characterize immunocompromised-associated pediatric acute respiratory distress syndrome (I-PARDS) and contrast it to PARDS.

DESIGN

This is a secondary analysis of the 2016-2017 PARDS incidence and epidemiology (PARDIE) study, a prospective observational, cross-sectional study of children with PARDS.

SETTING

Dataset of 145 PICUs across 27 countries.

PATIENTS

During 10 nonconsecutive weeks (from May 2016 to June 2017), data about immunocompromising conditions (ICCs, defined as malignancy, congenital/acquired immunodeficiency, posttransplantation, or diseases requiring immunosuppression) were collected.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 708 subjects, 105 (14.8%) had ICC. Before the development of I-PARDS, those with ICC were more likely to be hospitalized (70% vs. 35%, p < 0.001), have more at-risk for PARDS ( p = 0.046), and spent more hours at-risk (20 [interquartile range, IQR: 8-46] vs. 11 [IQR: 4-33], [ p = 0.002]). Noninvasive ventilation (NIV) use was more common in those with ICC ( p < 0.001). Of those diagnosed with PARDS on NIV ( n = 161), children with ICC were more likely to be subsequently intubated ( n = 28/40 [70%] vs n = 53/121 [44%], p = 0.004). Severe PARDS was more common (32% vs 23%, p < 0.001) in I-PARDS. Oxygenation indices were higher at diagnosis and had less improvement over the first 3 days of PARDS ( p < 0.001). Children with I-PARDS had greater nonpulmonary organ dysfunction. Adjusting for Pediatric Risk of Mortality IV and oxygenation index, children with I-PARDS had a higher severity of illness-adjusted PICU mortality (adjusted hazard ratio: 3.0 [95% CI, 1.9-4.7] p < 0.001) and were less likely to be extubated alive within 28 days (subdistribution hazard ratio: 0.47 [95% CI, 0.31-0.71] p < 0.001).

CONCLUSIONS

I-PARDS is a unique subtype of PARDS associated with hospitalization before diagnosis and increased: time at-risk for PARDS, NIV use, hypoxia, nonpulmonary organ dysfunction, and mortality. The opportunity for early detection and intervention seems to exist. Dedicated study in these patients is imperative to determine if targeted interventions will benefit these unique patients with the ultimate goal of improving outcomes.

Intensive care risk and long-term outcomes in pediatric allogeneic hematopoietic cell transplant recipients

ABSTRACT

Allogeneic hematopoietic cell transplantation (HCT) can be complicated by life-threatening organ toxicity and infection necessitating intensive care. Epidemiologic data have been limited by single-center studies, poor database granularity, and a lack of long-term survivors. To identify contemporary trends in intensive care unit (ICU) use and long-term outcomes, we merged data from the Center for International Blood and Marrow Transplant Research and the Virtual Pediatric Systems databases. We identified 6995 pediatric patients with HCT aged ≤21 years who underwent first allogeneic HCT between 2008 and 2014 across 69 centers in the United States or Canada and followed patients until the year 2020. ICU admission was required for 1067 patients (8.3% by day +100, 12.8% by 1 year, and 15.3% by 5 years after HCT), and was linked to demographic background, pretransplant organ toxicity, allograft type and HLA-match, and the development of graft-versus-host disease or malignancy relapse. Survival to ICU discharge was 85.7%, but more than half of ICU survivors required ICU readmission, leading to 52.5% and 42.6% survival at 1- and 5-years post-ICU transfer, respectively. ICU survival was worse among patients with malignant disease, poor pretransplant organ function, and alloreactivity risk factors. Among 1-year HCT survivors, those who required ICU in the first year had 10% lower survival at 5 years and developed new dialysis-dependent renal failure at a greater rate (P<.001). Thus, although ICU management is common and survival to ICU discharge is high, ongoing complications necessitate recurrent ICU admission and lead to a poor 1-year outcome in select patients who are at high risk.

Mortality Risk Factors in Pediatric Onco-Critical Care Patients and Machine Learning Derived Early Onco-Critical Care Phenotypes in a Retrospective Cohort

OBJECTIVES

To use supervised and unsupervised statistical methodology to determine risk factors associated with mortality in critically ill pediatric oncology patients to identify patient phenotypes of interest for future prospective study.

DESIGN

This retrospective cohort study included nonsurgical pediatric critical care admissions from January 2017 to December 2018. We determined the prevalence of multiple organ failure (MOF), ICU mortality, and associated factors. Consensus k-means clustering analysis was performed using 35 bedside admission variables for early, onco-critical care phenotype development.

SETTING

Single critical care unit in a subspeciality pediatric hospital.

INTERVENTION

None.

PATIENTS

There were 364 critical care admissions in 324 patients with underlying malignancy, hematopoietic cell transplant, or immunodeficiency reviewed.

MEASUREMENTS

Prevalence of multiple organ failure, ICU mortality, determination of early onco-critical care phenotypes.

MAIN RESULTS

ICU mortality was 5.2% and was increased in those with MOF (18.4% MOF, 1.7% single organ failure [SOF], 0.6% no organ failure; p ≤ 0.0001). Prevalence of MOF was 23.9%. Significantly increased ICU mortality risk was associated with day 1 MOF (hazards ratio [HR] 2.27; 95% CI, 1.10-6.82; p = 0.03), MOF during ICU admission (HR 4.16; 95% CI, 1.09-15.86; p = 0.037), and with invasive mechanical ventilation requirement (IMV; HR 5.12; 95% CI, 1.31-19.94; p = 0.018). Four phenotypes were derived (PedOnc1-4). PedOnc1 and 2 represented patient groups with low mortality and SOF. PedOnc3 was enriched in patients with sepsis and MOF with mortality associated with liver and renal dysfunction. PedOnc4 had the highest frequency of ICU mortality and MOF characterized by acute respiratory failure requiring invasive mechanical ventilation at admission with neurologic dysfunction and/or severe sepsis. Notably, most of the mortality in PedOnc4 was early (i.e., within 72 hr of ICU admission).

CONCLUSIONS

Mortality was lower than previously reported in critically ill pediatric oncology patients and was associated with MOF and IMV. These findings were further validated and expanded by the four derived nonsynonymous computable phenotypes. Of particular interest for future prospective validation and correlative biological study was the PedOnc4 phenotype, which was composed of patients with hypoxic respiratory failure requiring IMV with sepsis and/or neurologic dysfunction at ICU admission.

The Determining Factors for Outcome of Pediatric Intensive Care Admitted Children After Stem Cell Transplantation

INTRODUCTION

Requiring pediatric intensive care unit (PICU) admission relates to high mortality and morbidity in patients who received hematopoietic stem cell transplantation (HSCT). In this study, we aimed to evaluate the indications for PICU admission, treatments, and the determining risk factors for morbidity and mortality in patients who had allogeneic HSCT from various donors.

MATERIALS AND METHODS

In this retrospective study, we enrolled to patients who required the PICU after receiving allogeneic HSCT at our Pediatric Bone Marrow Transplantation Unit between 2005 and 2020. We evaluated to indication to PICU admission, applications, mortality rate, and the determining factors to outcomes.

RESULTS

Thirty-three (7%) patients had 47 PICU admissions and 471 patients underwent bone marrow transplantation during 16-year study period. Also, 14 repeated episodes were registered in 9 different patients. The median age of PICU admitted patients was 4 (0.3 to 18) years and 29 (62%) were male. The main reasons for PICU admission were a respiratory failure, sepsis, and neurological event in 20, 8, and 7 patients, respectively. The average length of PICU stay was 14.5 (1 to 80) days, 14 (43%) of patients survived and the mortality rate was 57%. Multiple organ failure ( P =0.001), need for respiratory support ( P =0.007), inotrope agents ( P =0.001), and renal replacement therapy ( P =0.013) were found as significant risk factors for mortality.

CONCLUSIONS

Allogeneic HSCT recipients need PICU admission because of its related different life-threatening complications. But there is a good chance of survival with quality PICU care and different advanced organ support methods.

Peri-Intubation Adverse Events in the Critically Ill Child After Hematopoietic Cell Transplant

OBJECTIVES

Mechanically ventilated children post-hematopoietic cell transplant (HCT) have increased morbidity and mortality compared with other mechanically ventilated critically ill children. Tracheal intubation-associated adverse events (TIAEs) and peri-intubation hypoxemia universally portend worse outcomes. We investigated whether adverse peri-intubation associated events occur at increased frequency in patients with HCT compared with non-HCT oncologic or other PICU patients and therefore might contribute to increased mortality.

DESIGN

Retrospective cohort between 2014 and 2019.

SETTING

Single-center academic noncardiac PICU.

PATIENTS

Critically ill children who underwent tracheal intubation (TI).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data from the local airway management quality improvement databases and Virtual Pediatric Systems were merged. These data were supplemented with a retrospective chart review for HCT-related data, including HCT indication, transplant-related comorbidity status, and patient condition at the time of TI procedure. The primary outcome was defined as the composite of hemodynamic TIAE (hypo/hypertension, arrhythmia, cardiac arrest) and/or peri-intubation hypoxemia (oxygen saturation < 80%) events. One thousand nine hundred thirty-one encounters underwent TI, of which 92 (4.8%) were post-HCT, while 319 (16.5%) had history of malignancy without HCT, and 1,520 (78.7%) had neither HCT nor malignancy. Children post-HCT were older more often had respiratory failure as an indication for intubation, use of catecholamine infusions peri-intubation, and use of noninvasive ventilation prior to intubation. Hemodynamic TIAE or peri-intubation hypoxemia were not different across three groups (HCT 16%, non-HCT with malignancy 10%, other 15). After adjusting for age, difficult airway feature, provider type, device, apneic oxygenation use, and indication for intubation, we did not identify an association between HCT status and the adverse TI outcome (odds ratio, 1.32 for HCT status vs other; 95% CI, 0.72-2.41; p = 0.37).

CONCLUSIONS

In this single-center study, we did not identify an association between HCT status and hemodynamic TIAE or peri-intubation hypoxemia during TI.

Pathobiology, Severity, and Risk Stratification of Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

To review the literature for studies published in children on the pathobiology, severity, and risk stratification of pediatric acute respiratory distress syndrome (PARDS) with the intent of guiding current medical practice and identifying important areas for future research related to severity and risk stratification.

DATA SOURCES

Electronic searches of PubMed and Embase were conducted from 2013 to March 2022 by using a combination of medical subject heading terms and text words to capture the pathobiology, severity, and comorbidities of PARDS.

STUDY SELECTION

We included studies of critically ill patients with PARDS that related to the severity and risk stratification of PARDS using characteristics other than the oxygenation defect. Studies using animal models, adult only, and studies with 10 or fewer children were excluded from our review.

DATA EXTRACTION

Title/abstract review, full-text review, and data extraction using a standardized data collection form.

DATA SYNTHESIS

The Grading of Recommendations Assessment, Development, and Evaluation approach was used to identify and summarize relevant evidence and develop recommendations for clinical practice. There were 192 studies identified for full-text extraction to address the relevant Patient/Intervention/Comparator/Outcome questions. One clinical recommendation was generated related to the use of dead space fraction for risk stratification. In addition, six research statements were generated about the impact of age on acute respiratory distress syndrome pathobiology and outcomes, addressing PARDS heterogeneity using biomarkers to identify subphenotypes and endotypes, and use of standardized ventilator, physiologic, and nonpulmonary organ failure measurements for future research.

CONCLUSIONS

Based on an extensive literature review, we propose clinical management and research recommendations related to characterization and risk stratification of PARDS severity.

Pediatric Acute Lung Injury and Sepsis Investigators (PALISI): Evolution of an Investigator-Initiated Research Network

The Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network originated over 20 years ago to foster research to optimize the care of critically ill infants and children. Over this period, PALISI has seen two major evolutions: formalization of our network infrastructure and a broadening of our clinical research focus. First, the network is unique in that its activities and meetings are funded by subscriptions from members who now comprise a multidisciplinary group of investigators from over 90 PICUs all over the United States (US) and Canada, with collaborations across the globe. In 2020, the network converted into a standalone, nonprofit organizational structure (501c3), making the PALISI Network formally independent of academic and clinical institutions or professional societies. Such an approach allows us to invest in infrastructure and future initiatives with broader opportunities for fund raising. Second, our research investigations have expanded beyond the original focus on sepsis and acute lung injury, to incorporate the whole field of pediatric critical care, for example, efficient liberation from mechanical ventilator support, prudent use of blood products, improved safety of intubation practices, optimal sedation practices and glucose control, and pandemic research on influenza and COVID-19. Our network approach in each field follows, where necessary, the full spectrum of clinical and translational research, including: immunobiology studies for understanding basic pathologic mechanisms; surveys to explore contemporary clinical practice; consensus conferences to establish agreement about literature evidence; observational prevalence and incidence studies to measure scale of a clinical issue or question; case control studies as preliminary best evidence for design of definitive prospective studies; and, randomized controlled trials for informing clinical care. As a research network, PALISI and its related subgroups have published over 350 peer-reviewed publications from 2002 through September 2022.

Fluid Overload in Pediatric Acute Respiratory Distress Syndrome after Allogeneic Hematopoietic Cell Transplantation

The aim of the study is to examine the relationship between fluid overload (FO) and severity of respiratory dysfunction in children post-hematopoietic cell transplantation (HCT) with pediatric acute respiratory distress syndrome (PARDS). This investigation was a secondary analysis of a multicenter retrospective cohort of children (1month to 21 years) post-allogeneic HCT with PARDS receiving invasive mechanical ventilation (IMV) from 2009 to 2014. Daily FO % (FO%) and daily oxygenation index (OI) were calculated for each patient up to the first week of IMV (day 0 = intubation). Linear mixed-effect regression was employed to examine whether FO% and OI were associated on any day during the study period. In total, 158 patients were included. Severe PARDS represented 63% of the cohort and had higher mortality (78 vs. 42%, p <0.001), fewer ventilator free days at 28 (0 [IQR 0–0] vs. 14 [IQR 0–23], p <0.001), and 60 days (0 [IQR 0–27] v. 45 [IQR 0–55], p <0.001) relative to non-severe PARDS. Increasing FO% was strongly associated with higher OI (p <0.001). For children with 10% FO, OI was higher by nearly 5 points (adjusted β 4.6, 95% CI [2.9, 6.3]). In subgroup analyses, the association between FO% and OI was strongest among severe PARDS (p <0.001) and during the first 3 days elapsed from intubation (p <0.001). FO% was associated with lower PaO2/FiO2 (adjusted β −1.92, 95% CI [−3.11, −0.73], p = 0.002), but not mean airway pressure (p = 0.746). In a multicenter cohort of children post-HCT with PARDS, FO was independently associated with oxygenation impairment. The associations were strongest among children with severe PARDS and early in the course of IMV.

A biomarker panel for risk of early respiratory failure following hematopoietic cell transplantation

This study identified and validated ST2, WFDC2, IL-6, and TNFR1 as risk biomarkers for RF and related mortality post-HCT.

Plasma biomarkers associated with respiratory failure (RF) following hematopoietic cell transplantation (HCT) have not been identified. Therefore, we aimed to validate early (7 and 14 days post-HCT) risk biomarkers for RF. Using tandem mass spectrometry, we compared plasma obtained at day 14 post-HCT from 15 patients with RF and 15 patients without RF. Six candidate proteins, from this discovery cohort or identified in the literature, were measured by enzyme-linked immunosorbent assay in day-7 and day-14 post-HCT samples from the training (n = 213) and validation (n = 119) cohorts. Cox proportional-hazard analyses with biomarkers dichotomized by Youden’s index, as well as landmark analyses to determine the association between biomarkers and RF, were performed. Of the 6 markers, Stimulation-2 (ST2), WAP 4-disulfide core domain protein 2 (WFDC2), interleukin-6 (IL-6), and tumor necrosis factor receptor 1 (TNFR1), measured at day 14 post-HCT, had the most significant association with an increased risk for RF in the training cohort (ST2: hazard ratio [HR], 4.5, P = .004; WFDC2: HR, 4.2, P = .010; IL-6: HR, 6.9, P < .001; and TFNR1: HR, 6.1, P < .001) and in the validation cohort (ST2: HR, 23.2, P = .013; WFDC2: HR, 18.2, P = .019; IL-6: HR, 12.2, P = .014; and TFNR1: HR, 16.1, P = .001) after adjusting for the conditioning regimen. Using cause-specific landmark analyses, including days 7 and 14, high plasma levels of ST2, WFDC2, IL-6, and TNFR1 were associated with an increased HR for RF in the training and validation cohorts. These biomarkers were also predictive of mortality from RF. ST2, WFDC2, IL-6 and TNFR1 levels measured early posttransplantation improve risk stratification for RF and its related mortality.

The pulmonary metatranscriptome prior to pediatric HCT identifies post-HCT lung injury

Lung injury after pediatric allogeneic hematopoietic cell transplantation (HCT) is a common and disastrous complication that threatens long-term survival. To develop strategies to prevent lung injury, novel tools are needed to comprehensively assess lung health in HCT candidates. Therefore, this study analyzed biospecimens from 181 pediatric HCT candidates who underwent routine pre-HCT bronchoalveolar lavage (BAL) at the University Medical Center Utrecht between 2005 and 2016. BAL fluid underwent metatranscriptomic sequencing of microbial and human RNA, and unsupervised clustering and generalized linear models were used to associate microbiome gene expression data with the development of post-HCT lung injury. Microbe-gene correlations were validated using a geographically distinct cohort of 18 pediatric HCT candidates. The cumulative incidence of post-HCT lung injury varied significantly according to 4 pre-HCT pulmonary metatranscriptome clusters, with the highest incidence observed in children with pre-HCT viral enrichment and innate immune activation, as well as in children with profound microbial depletion and concomitant natural killer/T-cell activation (P < .001). In contrast, children with pre-HCT pulmonary metatranscriptomes containing diverse oropharyngeal taxa and lacking inflammation rarely developed post-HCT lung injury. In addition, activation of epithelial-epidermal differentiation, mucus production, and cellular adhesion were associated with fatal post-HCT lung injury. In a separate validation cohort, associations among pulmonary respiratory viral load, oropharyngeal taxa, and pulmonary gene expression were recapitulated; the association with post-HCT lung injury needs to be validated in an independent cohort. This analysis suggests that assessment of the pre-HCT BAL fluid may identify high-risk pediatric HCT candidates who may benefit from pathobiology-targeted interventions.

Beginning Restorative Activities Very Early: Implementation of an Early Mobility Initiative in a Pediatric Onco-Critical Care Unit

Introduction

Children with underlying oncologic and hematologic diseases who require critical care services have unique risk factors for developing functional impairments from pediatric post-intensive care syndrome (PICS-p). Early mobilization and rehabilitation programs offer a promising approach for mitigating the effects of PICS-p in oncology patients but have not yet been studied in this high-risk population.

Methods

We describe the development and feasibility of implementing an early mobility quality improvement initiative in a dedicated pediatric onco-critical care unit. Our primary outcomes include the percentage of patients with consults for rehabilitation services within 72 h of admission, the percentage of patients who are mobilized within 72 h of admission, and the percentage of patients with a positive delirium screen after 48 h of admission.

Results

Between January 2019 and June 2020, we significantly increased the proportion of patients with consults ordered for rehabilitation services within 72 h of admission from 25 to 56% (p<0.001), increased the percentage of patients who were mobilized within 72 h of admission to the intensive care unit from 21 to 30% (p=0.02), and observed a decrease in patients with positive delirium screens from 43 to 37% (p=0.46). The early mobility initiative was not associated with an increase in unplanned extubations, unintentional removal of central venous catheters, or injury to patient or staff.

Conclusions

Our experience supports the safety and feasibility of early mobility initiatives in pediatric onco-critical care. Additional evaluation is needed to determine the effects of early mobilization on patient outcomes.

Continuous Renal Replacement Therapy: A Review of Use and Application in Pediatric Hematopoietic Stem Cell Transplant Recipients

Hematopoietic stem cell transplant (HSCT) is a curative therapy for malignant and non-malignant conditions. However, complications post-HSCT contribute to significant morbidity and mortality in this population. Acute kidney injury (AKI) is common in the post-allogeneic transplant phase and contributes to morbidity in this population. Continuous renal replacement therapy (CRRT) is used often in the setting of AKI or multiorgan dysfunction in critically ill children. In addition, CRRT can be useful in many disease processes related to transplant and can potentially improve outcomes in this population. This review will focus on the use of CRRT in critically ill children in the post-HSCT setting outside the realm of acute renal failure and highlight the benefits and applications of this modality in this high-risk population.

Perspective: A Framework to Screen Pediatric and Adolescent Hematopoietic Cellular Therapy Patients for Organ Dysfunction: Time for a Multi-Disciplinary and Longitudinal Approach

Hematopoietic Cell Transplantation (HCT) is a potentially curative therapy for children and adolescent/young adults (AYA) with high-risk malignancies as well as some non-malignant genetic diseases. However, HCT may be associated with endotheliopathies and/or organ dysfunction that may progress to pediatric multi-organ dysfunction syndrome (pMODS) and require critical care intervention. Discipline specific scoring systems may be used to characterize individual organ dysfunction, but the extent to which they are used to prospectively monitor HCT patients with mild dysfunction is unknown. Further, separate scoring systems may be used to define risk of mortality and inform prognostication among those who require critical care support. Our understanding of the epidemiology, risk factors, morbidity, mortality, required monitoring, optimal prevention strategies and appropriate management of children undergoing HCT who develop organ dysfunction, endotheliopathies and/or progress to pMODS is poor. Discipline-specific registries and clinical studies have described improving outcomes for children undergoing HCT, including those who require critical care support; however, longitudinal studies/prospective registries that capture common data elements among HCT patients with and without organ dysfunction, endotheliopathies and pMODS are needed to facilitate inter-disciplinary collaboration and optimally characterize the risk profiles, define screening and prophylaxis regimens and mitigate toxicity.

Pulmonary Manifestations of Hematologic and Oncologic Diseases in Children

Pulmonary complications are common in children with hematologic or oncologic diseases, and many experience long-term effects even after the primary disease has been cured. This article reviews pulmonary complications in children with cancer, after hematopoietic stem cell transplant, and caused by sickle cell disease and discusses their management.

Outcome of Acute Respiratory Failure Secondary to Engraftment in Children After Hematopoietic Stem Cell Transplant

Introduction: Respiratory complications due to engraftment syndrome (ES) in the post-hematopoietic stem cell transplant (HSCT) setting can lead to acute respiratory failure (ARF). Outcomes of children developing ARF due to engraftment are unknown.

Methods: We conducted a retrospective analysis of 1,527 pediatric HSCT recipients and identified children who developed ARF due to ES over a 17-year period. Thirty patients that developed ARF and required invasive mechanical ventilation (IMV) due to ES were included in this study.

Results: The survival rate for our cohort was 80% [alive at intensive care unit (ICU) discharge]. The most common underlying primary disease was hematologic malignancy, and 67% of children underwent allogeneic HSCT. Further, 73% required vasopressor drips and 23% underwent dialysis. Survivors had a shorter median ICU length of stay than did non-survivors (15 vs. 40 days, respectively, p = 0.01). Survivors had a significantly lower median cumulative fluid overload % on days 4 and 5 after initiation of IMV than did non-survivors (2.8 vs. 14.0 ml/kg, p = 0.038 on day 4, and 1.8 vs. 14.9 ml/kg, p = 0.044 on day 5, respectively).

Conclusion: Our results suggest that children who develop ARF during engraftment have better ICU survival rates than do those with other etiologies of ARF post-HSCT. Furthermore, fluid overload contributes to mortality in these children; therefore, strategies to prevent and address fluid overload should be considered.

Treatment of Children With Cancer and/or Hematopoietic Stem Cell Transplantation in the Intensive Care Unit: Experience at a Large European Pediatric Cancer Center

Pediatric cancer treatment and hematopoietic stem cell transplantation (HSCT) carry considerable risks of morbidity. We conducted a single-center retrospective analysis of intensive care unit (ICU) admissions in unselected children and adolescents treated for cancer or undergoing HSCT. In a 10-year time period, 140 patients had 188 ICU admissions for a life-threatening condition. Main reasons for ICU admission were respiratory or cardiovascular insufficiency and sepsis. Mortality in the ICU was 19.1% and related to organ failure or acute complications in 77.8% and progress of the underlying malignancy in 22.2%. Mortality rates at 30, 100, and 365 days after discharge from the ICU were 24.5%, 30.9%, and 39.9%. Kaplan-Meier survival probabilities at 5 and 10 years were 46.4% and 39.8%, respectively. Multivariable analysis revealed the number of failed organ systems, the number of prior ICU stays, and days spent in the ICU as parameters independently associated with death. Taken together, the outcome of pediatric cancer and/or HSCT patients admitted to the ICU for life-threatening conditions was not as dismal as reported elsewhere. Most patients benefitted from ICU care, and survival was predominantly compromised by the evolution of complications.

How We Treat Fever and Hypotension in Pediatric Hematopoietic Cell Transplant Patients

Pediatric allogeneic hematopoietic cell transplant (HCT) survival is limited by the development of post-transplant infections. In this overview, we discuss a clinical approach to the prompt recognition and treatment of fever and hypotension in pediatric HCT patients. Special attention is paid to individualized hemodynamic resuscitation, thorough diagnostic testing, novel anti-pathogen therapies, and the multimodal support required for recovery. We present three case vignettes that illustrate the complexities of post-HCT sepsis and highlight best practices that contribute to optimal transplant survival in children.

Factors affecting survival in children requiring intensive care after hematopoietic stem cell transplantation. A retrospective single-center study

Allo-HSCT is associated with life-threatening complications. Therefore, a considerable number of patients require admission to a PICU. We evaluated the incidence and outcome of PICU admissions after allo-HSCT in children, along with the potential factors influencing PICU survival. A retrospective chart review of 668 children who underwent first allo-HSCT in the Department of Pediatric Hematology/Oncology and BMT in Wrocław during years 2005-2017, particularly focusing on patients admitted to the PICU within 1-year post-HSCT. Fifty-eight (8.7%) patients required 64 admissions to the PICU. Twenty-four (41.5%) were discharged, and 34 (58.6%) patients died. Among the discharged patients, 6-month survival was 66.7%. Compared with survivors, death cases were more likely to have required MV (31/34; 91.2% vs. 16/24; 66.7% P = .049), received more aggressive cardiac support (17/34; 50% vs. 2/24; 8.3% P = .002), and had a lower ANC on the last day of their PICU stay (P = .004). Five patients were successfully treated with NIV and survived longer than 6 months post-discharge. The intensity of cardiac support and ANC on the last day of PICU treatment was independent factors influencing PICU survival. Children admitted to the PICU after allo-HSCT have a high mortality rate. Mainly those who needed a more aggressive approach and had a lower ANC on the last day of treatment had a greater risk of death. While requiring MV is associated with decreased PICU survival, early implementation of NIV might be considered.

Ventilator-induced lung injury in children: a reality?

Mechanical ventilation (MV) is inextricably linked to the care of critically ill patients admitted to the paediatric intensive care unit (PICU). Even today, little evidence supports best MV practices for life-threatening acute respiratory failure in children. However, careful attention must be paid because this life-saving technique induces pulmonary inflammation that aggravates pre-existing lung injury, a concept that is known as ventilator-induced lung injury (VILI). The delivery of too large tidal volumes (Vt) (i.e., volutrauma) and repetitive opening and closure of alveoli (i.e., atelectrauma) are two key mechanisms underlying VILI. Despite the knowledge of these mechanisms, the clinical relevance of VILI in critically ill children is poorly understood as almost all of our knowledge has been obtained from studies in adults or experimental studies mimicking the adult critical care situation. This leaves the question if VILI is relevant in the paediatric context. In fact, limited paediatric experimental data showed that the use of large, supraphysiologic Vt resulted in less inflammation and injury in paediatric animal models compared to adult models. Furthermore, the association between large Vt and adverse outcome has not been confirmed and the issue of setting positive end-expiratory pressure (PEEP) to prevent atelectrauma has hardly been studied in paediatric clinical studies. Hence, even today, the question whether or not there VILI is relevant in pediatric critical remains to be answered. Consequently, how MV is used remains thus based on institutional preferences, personal beliefs and clinical data extrapolated from adults. This signifies the need for clinical and experimental studies in order to better understand the use and effects of MV in paediatric patients with or without lung injury.

Comprehensive Prognostication in Critically Ill Pediatric Hematopoietic Cell Transplant Patients: Results from Merging the Center for International Blood and Marrow Transplant Research (CIBMTR) and Virtual Pediatric Systems (VPS) Registries

Critically ill pediatric allogeneic hematopoietic cell transplant (HCT) patients may benefit from early and aggressive interventions aimed at reversing the progression of multiorgan dysfunction. Therefore, we evaluated 25 early risk factors for pediatric intensive care unit (PICU) mortality to improve mortality prognostication. We merged the Virtual Pediatric Systems and Center for International Blood and Marrow Transplant Research databases and analyzed 936 critically ill patients ≤21 years of age who had undergone allogeneic HCT and subsequently required PICU admission between January 1, 2009, and December 31, 2014. Of 1532 PICU admissions, the overall PICU mortality rate was 17.4% (95% confidence interval [CI], 15.6% to 19.4%) but was significantly higher for patients requiring mechanical ventilation (44.0%), renal replacement therapy (56.1%), or extracorporeal life support (77.8%). Mortality estimates increased significantly the longer that patients remained in the PICU. Of 25 HCT- and PICU-specific characteristics available at or near the time of PICU admission, moderate/severe pre-HCT renal injury, pre-HCT recipient cytomegalovirus seropositivity, <100-day interval between HCT and PICU admission, HCT for underlying acute myeloid leukemia, and greater admission organ dysfunction as approximated by the Pediatric Risk of Mortality 3 score were each independently associated with PICU mortality. A multivariable model using these components identified that patients in the top quartile of risk had 3 times greater mortality than other patients (35.1% versus 11.5%, P < .001, classification accuracy 75.2%; 95% CI, 73.0% to 77.4%). These data improve our working knowledge of the factors influencing the progression of critical illness in pediatric allogeneic HCT patients. Future investigation aimed at mitigating the effect of these risk factors is warranted.