Early Use of Adjunctive Therapies for Pediatric Acute Respiratory Distress Syndrome: A PARDIE Study

Protocol for the Prone and Oscillation Pediatric Clinical Trial (PROSpect)

OBJECTIVES

Respiratory management for pediatric acute respiratory distress syndrome (PARDS) remains largely supportive without data to support one approach over another, including supine versus prone positioning (PP) and conventional mechanical ventilation (CMV) versus high-frequency oscillatory ventilation (HFOV).

DESIGN

We present the research methodology of a global, multicenter, two-by-two factorial, response-adaptive, randomized controlled trial of supine versus PP and CMV versus HFOV in high moderate-severe PARDS, the Prone and Oscillation Pediatric Clinical Trial (PROSpect, www.ClinicalTrials.gov, NCT03896763).

SETTING

Approximately 60 PICUs with on-site extracorporeal membrane oxygenation support in North and South America, Europe, Asia, and Oceania with experience using PP and HFOV in the care of patients with PARDS.

PATIENTS

Eligible pediatric patients (2 wk old or older and younger than 21 yr) are randomized within 48 h of meeting eligibility criteria occurring within 96 h of endotracheal intubation.

INTERVENTIONS

One of four arms, including supine/CMV, prone/CMV, supine/HFOV, or prone/HFOV. We hypothesize that children with high moderate-severe PARDS treated with PP or HFOV will demonstrate greater than or equal to 2 additional ventilator-free days (VFD).

MEASUREMENTS AND MAIN RESULTS

The primary outcome is VFD through day 28; nonsurvivors receive zero VFD. Secondary and exploratory outcomes include nonpulmonary organ failure-free days, interaction effects of PP with HFOV on VFD, 90-day in-hospital mortality, and among survivors, duration of mechanical ventilation, PICU and hospital length of stay, and post-PICU functional status and health-related quality of life. Up to 600 patients will be randomized, stratified by age group and direct/indirect lung injury. Adaptive randomization will first occur 28 days after 300 patients are randomized and every 100 patients thereafter. At these randomization updates, new allocation probabilities will be computed based on intention-to-treat trial results, increasing allocation to well-performing arms and decreasing allocation to poorly performing arms. Data will be analyzed per intention-to-treat for the primary analyses and per-protocol for primary, secondary, and exploratory analyses.

CONCLUSIONS

PROSpect will provide clinicians with data to inform the practice of PP and HFOV in PARDS.

Lung behavior during a staircase high-frequency oscillatory ventilation recruitment maneuver

BACKGROUND

Lung volume optimization maneuvers (LVOM) are necessary to make physiologic use of high-frequency oscillatory ventilation (HFOV), but lung behavior during such maneuvers has not been studied to determine lung volume changes after initiation of HFOV, to quantify recruitment versus derecruitment during the LVOM and to calculate the time to stabilization after a pressure change.

METHODS

We performed a secondary analysis of prospectively collected data in subjects < 18 years on HFOV. Uncalibrated respiratory inductance plethysmography (RIP) tracings were used to quantify lung recruitment and derecruitment during the LVOM inflation and deflation. The time constant was calculated according to the Niemann model.

RESULTS

RIP data of 51 subjects (median age 3.5 [1.7-13.3] months) with moderate-to-severe pediatric acute respiratory distress syndrome (PARDS) in 85.4% were analyzed. Lung recruitment and derecruitment occurred during the LVOM inflation phase upon start of HFOV and between and within pressure changes. At 90% of maximum inflation pressure, lung derecruitment already started during the deflation phase. Time to stable lung volume (time constant) could only be calculated in 26.2% of all pressure changes during the inflation and in 21.4% during the deflation phase, independent of continuous distending pressure (CDP). Inability to calculate the time constant was due to lack of stabilization of the RIP signal or no change in any direction.

CONCLUSIONS

Significant heterogeneity in lung behavior during a staircase incremental-decremental LVOM occurred, underscoring the need for higher initial inflation pressures when transitioning from conventional mechanical ventilation (CMV) and a longer time between pressure changes to allow for equilibration.

Association between Age and Mortality in Pediatric and Adult Acute Respiratory Distress Syndrome

Rationale: The epidemiology, management, and outcomes of acute respiratory distress syndrome (ARDS) differ between children and adults, with lower mortality rates in children despite comparable severity of hypoxemia. However, the relationship between age and mortality is unclear.Objective: We aimed to define the association between age and mortality in ARDS, hypothesizing that it would be nonlinear.Methods: We performed a retrospective cohort study using data from two pediatric ARDS observational cohorts (n = 1,236), multiple adult ARDS trials (n = 5,547), and an adult observational ARDS cohort (n = 1,079). We aligned all datasets to meet Berlin criteria. We performed unadjusted and adjusted logistic regression using fractional polynomials to assess the potentially nonlinear relationship between age and 90-day mortality, adjusting for sex, PaO2/FiO2, immunosuppressed status, year of study, and observational versus randomized controlled trial, treating each individual study as a fixed effect.Measurements and Main Results: There were 7,862 subjects with median ages of 4 years in the pediatric cohorts, 52 years in the adult trials, and 61 years in the adult observational cohort. Most subjects (43%) had moderate ARDS by Berlin criteria. Ninety-day mortality was 19% in the pediatric cohorts, 33% in the adult trials, and 67% in the adult observational cohort. We found a nonlinear relationship between age and mortality, with mortality risk increasing at an accelerating rate between 11 and 65 years of age, after which mortality risk increased more slowly.Conclusions: There was a nonlinear relationship between age and mortality in pediatric and adult ARDS.

Prone position in the mechanical ventilation of acute respiratory distress syndrome children: a systematic review and meta-analysis

Background

Prone position has been well recognized for the treatment of adult acute respiratory distress syndrome (ARDS). We aimed to evaluate the role of prone position in the mechanical ventilation in children with ARDS, to provide evidence to the treatment and care of children with ARDS.

Methods

We searched the Pubmed et al. databases by computer until January 23, 2024 for randomized controlled trials (RCTs) on the role of prone position in the mechanical ventilation in children with ARDS. We evaluated the quality of included studies according to the quality evaluation criteria recommended by the Cochrane library. RevMan 5.3 software was used for meta-analysis.

Results

7 RCTs involving 433 children with ARDS were included. Meta-analysis indicated that prone position is beneficial to improve the arterial oxygenation pressure [MD = 4.27 mmHg, 95% CI (3.49, 5.06)], PaO2/FiO2 [MD = 26.97, 95% CI (19.17, 34.77)], reduced the oxygenation index [MD = -3.52, 95% CI (-5.41, -1.64)], mean airway pressure [MD = -1.91 cmH2O, 95% CI (-2.27, -1.55)] and mortality [OR = 0.33, 95% CI (0.15, 0.73), all P < 0.05]. There were no statistical differences in the duration of mechanical ventilation between the prone position group and control group [MD = -17.01, 97.27, 95% CI (-38.28, 4.26), P = 0.12]. Egger test results showed that no significant publication bias was found (all P > 0.05).

Conclusions

Prone position ventilation has obvious advantages in improving oxygenation, but there is no significant improvement in the time of mechanical ventilation in the treatment of children with ARDS. In the future, more large-sample, high-quality RCTs are still needed to further analyze the role of prone position in the mechanical ventilation in children with ARDS.

Mechanical ventilation during pediatric extracorporeal life support

PURPOSE OF REVIEW

To discuss the role of ventilator induced lung injury (VILI) and patient self-inflicted lung injury in ventilated children supported on extracorporeal membrane oxygenation (ECMO).

RECENT FINDINGS

While extracorporeal life support is used routinely used every day around the globe to support neonatal, pediatric, and adult patients with refractory cardiac and/or respiratory failure, the optimal approach to mechanical ventilation, especially for those with acute respiratory distress syndrome (ARDS), remains unknown and controversial. Given the lack of definitive data in this population, one must rely on available evidence in those with ARDS not supported with ECMO and extrapolate adult observations. Ventilatory management should include, as a minimum standard, limiting inspiratory and driving pressures, providing a sufficient level of positive end-expiratory pressure, and setting a low rate to reduce mechanical power. Allowing for spontaneous breathing and use of pulmonary specific ancillary treatment modalities must be individualized, while balancing the risk and benefits. Future studies delineating the best strategies for optimizing MV during pediatric extracorporeal life support are much needed.

SUMMARY

Future investigations will hopefully provide the needed evidence and better understanding of the overall goal of reducing mechanical ventilation intensity to decrease risk for VILI and promote lung recovery for those supported with ECMO.

Stratifying Severity of Acute Respiratory Failure Severity in Cyanotic Congenital Heart Disease

Hypoxemia is used to stratify severity in acute respiratory failure (ARF) but is less useful in cyanotic congenital heart disease (CCHD) due to an inability to differentiate hypoxemia from lung injury versus cardiac shunting. Therefore, we aimed to determine whether variables related to respiratory mechanics were associated with outcomes to assist in stratifying ARF severity in pediatric CCHD. We performed a retrospective cohort study from a single cardiac intensive care unit enrolling children with CCHD with ARF requiring mechanical ventilation between 2011 and 2019. Time-averaged ventilator settings and oxygenation data in the first 24 h of ARF were screened for association with the primary outcome of 28-day mortality. Of 344 eligible patients, peak inspiratory pressure (PIP) and driving pressure (ΔP) were selected as candidate variables to stratify ARF severity. PIP (OR 1.10, 95% CI 1.02-1.19) and ΔP (1.11, 95% CI 1.01-1.24) were associated with higher mortality and fewer ventilator-free days (VFDs) at 28 days after adjusting for age, severity of cardiac history, and FiO₂. A three-level (mild, moderate, severe) severity stratification was established for both PIP (≤ 20, 21-29, ≥ 30) and ΔP (≤ 16, 17-24, ≥ 25), showing increasing mortality (both P < 0.01), decreasing VFDs and increasing ventilator days in survivors (all P < 0.05) across increasing pressures. Overall, we found that higher PIP and ΔP were associated with mortality and duration of ventilation across a three-level severity stratification system in pediatric CCHD with ARF, providing a practical method to prognosticate in subjects with multifactorial etiologies for hypoxemia.

Understanding clinical and biological heterogeneity to advance precision medicine in paediatric acute respiratory distress syndrome

Paediatric acute respiratory distress syndrome (PARDS) is a heterogeneous clinical syndrome that is associated with high rates of mortality and long-term morbidity. Factors that distinguish PARDS from adult acute respiratory distress syndrome (ARDS) include changes in developmental stage and lung maturation with age, precipitating factors, and comorbidities. No specific treatment is available for PARDS and management is largely supportive, but methods to identify patients who would benefit from specific ventilation strategies or ancillary treatments, such as prone positioning, are needed. Understanding of the clinical and biological heterogeneity of PARDS, and of differences in clinical features and clinical course, pathobiology, response to treatment, and outcomes between PARDS and adult ARDS, will be key to the development of novel preventive and therapeutic strategies and a precision medicine approach to care. Studies in which clinical, biomarker, and transcriptomic data, as well as informatics, are used to unpack the biological and phenotypic heterogeneity of PARDS, and implementation of methods to better identify patients with PARDS, including methods to rapidly identify subphenotypes and endotypes at the point of care, will drive progress on the path to precision medicine.

Pulmonary Specific Ancillary Treatment for Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

We conducted an updated review of the literature on pulmonary-specific ancillary therapies for pediatric acute respiratory distress syndrome (PARDS) to provide an update to the Pediatric Acute Lung Injury Consensus Conference recommendations and statements about clinical practice and research.

DATA SOURCES

MEDLINE (Ovid), Embase (Elsevier), and CINAHL Complete (EBSCOhost).

STUDY SELECTION

Searches were limited to children, PARDS or hypoxic respiratory failure and overlap with pulmonary-specific ancillary therapies.

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 evidence and develop recommendations. Twenty-six studies were identified for full-text extraction. Four clinical recommendations were generated, related to use of inhaled nitric oxide, surfactant, prone positioning, and corticosteroids. Two good practice statements were generated on the use of routine endotracheal suctioning and installation of isotonic saline prior to endotracheal suctioning. Three research statements were generated related to: the use of open versus closed suctioning, specific methods of airway clearance, and various other ancillary therapies.

CONCLUSIONS

The evidence to support or refute any of the specific ancillary therapies in children with PARDS remains low. Further investigation, including a focus on specific subpopulations, is needed to better understand the role, if any, of these various ancillary therapies in PARDS.

Nonpulmonary Treatments for Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

To provide an updated review of the literature on nonpulmonary treatments for pediatric acute respiratory distress syndrome (PARDS) from the Second Pediatric Acute Lung Injury Consensus Conference.

DATA SOURCES

MEDLINE (Ovid), Embase (Elsevier), and CINAHL Complete (EBSCOhost).

STUDY SELECTION

Searches were limited to children with PARDS or hypoxic respiratory failure focused on nonpulmonary adjunctive therapies (sedation, delirium management, neuromuscular blockade, nutrition, fluid management, transfusion, sleep management, and rehabilitation).

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 evidence and develop recommendations. Twenty-five studies were identified for full-text extraction. Five clinical practice recommendations were generated, related to neuromuscular blockade, nutrition, fluid management, and transfusion. Thirteen good practice statements were generated on the use of sedation, iatrogenic withdrawal syndrome, delirium, sleep management, rehabilitation, and additional information on neuromuscular blockade and nutrition. Three research statements were generated to promote further investigation in nonpulmonary therapies for PARDS.

CONCLUSIONS

These recommendations and statements about nonpulmonary treatments in PARDS are intended to promote optimization and consistency of care for patients with PARDS and identify areas of uncertainty requiring further investigation.

Executive Summary of the Second International Guidelines for the Diagnosis and Management of Pediatric Acute Respiratory Distress Syndrome (PALICC-2)

OBJECTIVES

We sought to update our 2015 work in the Second Pediatric Acute Lung Injury Consensus Conference (PALICC-2) guidelines for the diagnosis and management of pediatric acute respiratory distress syndrome (PARDS), considering new evidence and topic areas that were not previously addressed.

DESIGN

International consensus conference series involving 52 multidisciplinary international content experts in PARDS and four methodology experts from 15 countries, using consensus conference methodology, and implementation science.

SETTING

Not applicable.

PATIENTS

Patients with or at risk for PARDS.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eleven subgroups conducted systematic or scoping reviews addressing 11 topic areas: 1) definition, incidence, and epidemiology; 2) pathobiology, severity, and risk stratification; 3) ventilatory support; 4) pulmonary-specific ancillary treatment; 5) nonpulmonary treatment; 6) monitoring; 7) noninvasive respiratory support; 8) extracorporeal support; 9) morbidity and long-term outcomes; 10) clinical informatics and data science; and 11) resource-limited settings. The search included MEDLINE, EMBASE, and CINAHL Complete (EBSCOhost) and was updated in March 2022. Grading of Recommendations, Assessment, Development, and Evaluation methodology was used to summarize evidence and develop the recommendations, which were discussed and voted on by all PALICC-2 experts. There were 146 recommendations and statements, including: 34 recommendations for clinical practice; 112 consensus-based statements with 18 on PARDS definition, 55 on good practice, seven on policy, and 32 on research. All recommendations and statements had agreement greater than 80%.

CONCLUSIONS

PALICC-2 recommendations and consensus-based statements should facilitate the implementation and adherence to the best clinical practice in patients with PARDS. These results will also inform the development of future programs of research that are crucially needed to provide stronger evidence to guide the pediatric critical care teams managing these patients.

A single-center PICU present status survey of pediatric sepsis-related acute respiratory distress syndrome

BACKGROUND

To describe the incidence, clinical features, outcomes, and mortality risk factors of sepsis associated with acute respiratory distress syndrome (ARDS) in pediatric patients.

METHODS

Patients were included in the study if they met the 2005 version of the International Pediatric Sepsis Consensus Conference and met the Pediatric Acute Lung Injury Consensus Conference (PALICC) definition within 48 h of sepsis diagnosis. Patients were classified as mild, moderate, and severe by the worst oxygenation index (OI) within 72 h of sepsis-related ARDS diagnosis.

RESULTS

Between January 1, 2015 and March 13, 2020, 9836 patients were admitted to the pediatric intensive care unit (PICU) of the Children's Hospital of Chongqing Medical University and 828 (8.4%) were identified with sepsis and 203 (24.5%) met the PALICC definition with a PICU mortality rate of 24.6% (50/203) and a 90-day mortality rate of 40.9% (83/203). After adjusting for septic shock, the pediatric logistic organ dysfunction 2 (PELOD-2), high-frequency oscillation ventilation (HFOV), and continuous renal replacement therapy (CRRT), the variables that retained an independent association with increased 90-day mortality in pediatric sepsis-related ARDS included ARDS severity, the pediatric risk of mortality III (PRISM III), number of organ dysfunctions and use of vasoactive drug types during PICU stay.

CONCLUSIONS

PICU mortality in pediatric sepsis-related ARDS was high (24.6%) and severity of hypoxemia based on the worst OI value 72 h after meeting the PALICC definition accurately stratified the patient outcomes. ARDS severity, PRISM III score, comorbid multiorgan dysfunction, and use of multiple vasoactive drugs during PICU stay were independent risk factors for 90-day mortality in pediatric sepsis-related ARDS.

Paediatric acute respiratory distress syndrome: consider the role of lymphatics

We present a case of a 7-day-old male infant with severe respiratory disease requiring venoarterial extracorporeal membrane oxygenation therapy with evidence of lymphangiectasia on lung biopsy. Differentiating primary versus secondary lymphangiectasis in this patient remains a riddle despite extensive investigations including an infective screen, lung biopsy and whole-genome sequencing. In addition to the standard therapies used in paediatric acute respiratory distress syndrome, such as lung-protective ventilation, permissive hypoxaemia and hypercarbia, nursing in the prone position, early use of muscle relaxants, rescue intravenous corticosteroids and broad-spectrum antibiotics, the patient was also given octreotide despite the absence of a chylothorax based on the theoretical benefit of altering the lymphatic flow. His case raises an interesting discussion around the role of lymphatics in the pathophysiology of paediatric and adult respiratory distress syndrome and prompts the exploration of novel agents which may affect lymphatic vessels used as an adjunctive therapy.

The Physiological Basis of High-Frequency Oscillatory Ventilation and Current Evidence in Adults and Children: A Narrative Review

High-frequency oscillatory ventilation (HFOV) is a type of invasive mechanical ventilation that employs supra-physiologic respiratory rates and low tidal volumes (V_T) that approximate the anatomic deadspace. During HFOV, mean airway pressure is set and gas is then displaced towards and away from the patient through a piston. Carbon dioxide (CO₂) is cleared based on the power (amplitude) setting and frequency, with lower frequencies resulting in higher V_T and CO₂ clearance. Airway pressure amplitude is significantly attenuated throughout the respiratory system and mechanical strain and stress on the alveoli are theoretically minimized. HFOV has been purported as a form of lung protective ventilation that minimizes volutrauma, atelectrauma, and biotrauma. Following two large randomized controlled trials showing no benefit and harm, respectively, HFOV has largely been abandoned in adults with ARDS. A multi-center clinical trial in children is ongoing. This article aims to review the physiologic rationale for the use of HFOV in patients with acute respiratory failure, summarize relevant bench and animal models, and discuss the potential use of HFOV as a primary and rescue mode in adults and children with severe respiratory failure.

Paediatric Acute Respiratory Distress Syndrome Neuromuscular Blockade study (PAN-study): a phase IV randomised controlled trial of early neuromuscular blockade in moderate-to-severe paediatric acute respiratory distress syndrome

Background

Paediatric acute respiratory distress syndrome (PARDS) is a manifestation of severe, life-threatening lung injury necessitating mechanical ventilation with mortality rates ranging up to 40–50%. Neuromuscular blockade agents (NMBAs) may be considered to prevent patient self-inflicted lung injury in PARDS patients, but two trials in adults with severe ARDS yielded conflicting results. To date, randomised controlled trials (RCT) examining the effectiveness and efficacy of NMBAs for PARDS are lacking. We hypothesise that using NMBAs for 48 h in paediatric patients younger than 5 years of age with early moderate-to-severe PARDS will lead to at least a 20% reduction in cumulative respiratory morbidity score 12 months after discharge from the paediatric intensive care unit (PICU).

Methods

This is a phase IV, multicentre, randomised, double-blind, placebo-controlled trial performed in level-3 PICUs in the Netherlands. Eligible for inclusion are children younger than 5 years of age requiring invasive mechanical ventilation with positive end-expiratory pressure (PEEP) ≥ 5 cm H₂O for moderate-to-severe PARDS occurring within the first 96 h of PICU admission. Patients are randomised to continuous infusion of rocuronium bromide or placebo for 48 h. The primary endpoint is the cumulative respiratory morbidity score 12 months after PICU discharge, adjusted for confounding by age, gestational age, family history of asthma and/or allergy, season in which questionnaire was filled out, day-care and parental smoking. Secondary outcomes include respiratory mechanics, oxygenation and ventilation metrics, pulmonary and systemic inflammation markers, prevalence of critical illness polyneuropathy and myopathy and metrics for patient outcome including ventilator free days at day 28, length of PICU and hospital stay, and mortality

Discussion

This is the first paediatric trial evaluating the effects of muscular paralysis in moderate-to-severe PARDS. The proposed study addresses a huge research gap identified by the Paediatric Acute Lung Injury Consensus Collaborative by evaluating practical needs regarding the treatment of PARDS. Paediatric critical care practitioners are inclined to use interventions such as NMBAs in the most critically ill. This liberal use must be weighed against potential side effects. The proposed study will provide much needed scientific support in the decision-making to start NMBAs in moderate-to-severe PARDS.

Trial registration

ClinicalTrials.govNCT02902055. Registered on September 15, 2016.

Early Neuromuscular Blockade in Moderate-to-Severe Pediatric Acute Respiratory Distress Syndrome

Objectives

The use of neuromuscular blocking agents (NMBAs) in pediatric acute respiratory distress syndrome (PARDS) is common but unsupported by efficacy data. We sought to compare the outcomes between patients with moderate-to-severe PARDS receiving continuous NMBA during the first 48 hours of endotracheal intubation (early NMBA) and those without.

Design

Secondary analysis of data from the Randomized Evaluation of Sedation Titration for Respiratory Failure (RESTORE) clinical trial, a pediatric multicenter cluster randomized trial of sedation.

Setting

Thirty-one PICUs in the United States.

Patients

Children 2 weeks to 17 years receiving invasive mechanical ventilation (MV) for moderate-to-severe PARDS (i.e., oxygenation index >= 8 and bilateral infiltrates on chest radiograph on days 0-1 of endotracheal intubation).

Interventions

NMBA for the entire duration of days 1 and 2 after intubation.

Measurements and Main Results

Among 1,182 RESTORE patients with moderate-to-severe PARDS, 196 (17%) received early NMBA for a median of 50.0% ventilator days (interquartile range, 33.3-60.7%). The propensity score model predicting the probability of receiving early NMBA included high-frequency oscillatory ventilation on days 0-2 (odds ratio [OR], 7.61; 95% CI, 4.75-12.21) and severe PARDS on days 0-1 (OR, 2.16; 95% CI, 1.50-3.12). After adjusting for risk category, early use of NMBA was associated with a longer duration of MV (hazard ratio, 0.57; 95% CI, 0.48-0.68; p < 0.0001), but not with mortality (OR, 1.62; 95% CI, 0.92-2.85; p = 0.096) compared with no early use of NMBA. Other outcomes including cognitive, functional, and physical impairment at 6 months post-PICU discharge were similar. Outcomes did not differ when comparing high versus low NMBA usage sites or when patients were stratified by baseline PaO2/FIO2 less than 150.

Conclusions

Early NMBA use was associated with a longer duration of MV. This propensity score analysis underscores the need for a randomized controlled trial in pediatrics.

Mechanical power in pediatric acute respiratory distress syndrome: a PARDIE study

BACKGROUND

Mechanical power is a composite variable for energy transmitted to the respiratory system over time that may better capture risk for ventilator-induced lung injury than individual ventilator management components. We sought to evaluate if mechanical ventilation management with a high mechanical power is associated with fewer ventilator-free days (VFD) in children with pediatric acute respiratory distress syndrome (PARDS).

METHODS

Retrospective analysis of a prospective observational international cohort study.

RESULTS

There were 306 children from 55 pediatric intensive care units included. High mechanical power was associated with younger age, higher oxygenation index, a comorbid condition of bronchopulmonary dysplasia, higher tidal volume, higher delta pressure (peak inspiratory pressure-positive end-expiratory pressure), and higher respiratory rate. Higher mechanical power was associated with fewer 28-day VFD after controlling for confounding variables (per 0.1 J·min-1·Kg-1 Subdistribution Hazard Ratio (SHR) 0.93 (0.87, 0.98), p = 0.013). Higher mechanical power was not associated with higher intensive care unit mortality in multivariable analysis in the entire cohort (per 0.1 J·min-1·Kg-1 OR 1.12 [0.94, 1.32], p = 0.20). But was associated with higher mortality when excluding children who died due to neurologic reasons (per 0.1 J·min-1·Kg-1 OR 1.22 [1.01, 1.46], p = 0.036). In subgroup analyses by age, the association between higher mechanical power and fewer 28-day VFD remained only in children < 2-years-old (per 0.1 J·min-1·Kg-1 SHR 0.89 (0.82, 0.96), p = 0.005). Younger children were managed with lower tidal volume, higher delta pressure, higher respiratory rate, lower positive end-expiratory pressure, and higher PCO2 than older children. No individual ventilator management component mediated the effect of mechanical power on 28-day VFD.

CONCLUSIONS

Higher mechanical power is associated with fewer 28-day VFDs in children with PARDS. This association is strongest in children < 2-years-old in whom there are notable differences in mechanical ventilation management. While further validation is needed, these data highlight that ventilator management is associated with outcome in children with PARDS, and there may be subgroups of children with higher potential benefit from strategies to improve lung-protective ventilation.

TAKE HOME MESSAGE

Higher mechanical power is associated with fewer 28-day ventilator-free days in children with pediatric acute respiratory distress syndrome. This association is strongest in children <2-years-old in whom there are notable differences in mechanical ventilation management.

Lung Ultrasound in Pediatric Acute Respiratory Distress Syndrome Received Extracorporeal Membrane Oxygenation: A Prospective Cohort Study

OBJECTIVE

The aim of this study was to assess the prognostic value of the lung ultrasound (LUS) score in patients with pediatric acute respiratory distress syndrome (pARDS) who received extracorporeal membrane oxygenation (ECMO).

METHODS

A prospective cohort study was conducted in a pediatric intensive care unit (PICU) of a tertiary hospital from January 2016 to June 2021. The severe pARDS patients who received ECMO were enrolled in this study. LUS score was measured at initiation of ECMO (LUS-0 h), then at 24 h (LUS-24 h), 48 h (LUS-48 h), and 72 h (LUS-72 h) during ECMO, and when weaned from ECMO (LUS-wean). The value of LUS scores at the first 3 days of ECMO as a prognostic predictor was analyzed.

RESULTS

Twenty-nine children with severe pARDS who received ECMO were enrolled with a median age of 26 (IQR 9, 79) months. The median duration of ECMO support was 162 (IQR 86, 273) h and the PICU mortality was 31.0% (9/29). The values of LUS-72 h and LUS-wean were significantly lower in survivors than that in non-survivors (both P < 0.001). Daily fluid balance volume during the first 3 days of ECMO support were strongly correlated with LUS score [1st day: r = 0.460, P = 0.014; 2nd day: r = 0.540, P = 0.003; 3rd day: r = 0.589, P = 0.001]. The AUC of LUS-72 h for predicting PICU mortality in these patients was 1.000, and the cutoff value of LUS-72 h was 24 with a sensitivity of 100.0% and a specificity of 100.0%. Furthermore, patients were stratified in two groups of LUS-72 h ≥ 24 and LUS-72 h < 24. Consistently, PICU mortality, length of PICU stay, ratio of shock, vasoactive index score value, and the need for continuous renal replacement therapy were significantly higher in the group of LUS-72 h ≥ 24 than in the group of LUS-72 h < 24 (all P < 0.05).

CONCLUSION

Lung ultrasound score is a promising tool for predicting the prognosis in patients with ARDS under ECMO support. Moreover, LUS-72 h ≥ 24 is associated with high risk of PICU mortality in patients with pARDS who received ECMO.

Respiratory Dysfunction Criteria in Critically Ill Children: The PODIUM Consensus Conference

CONTEXT

Respiratory dysfunction is a component of every organ failure scoring system developed, reflecting the significance of the lung in multiple organ dysfunction syndrome. However, existing systems do not reflect current practice and are not consistently evidence based.

OBJECTIVE

We aimed to review the literature to identify the components of respiratory failure associated with outcomes in children, with the purpose of developing an operational and evidence-based definition of respiratory dysfunction.

DATA SOURCES

Electronic searches of PubMed and Embase were conducted from 1992 to January 2020 by using a combination of medical subject heading terms and text words to define respiratory dysfunction, critical illness, and outcomes.

STUDY SELECTION

We included studies of critically ill children with respiratory dysfunction that evaluated the performance of metrics of respiratory dysfunction and their association with patient-centered outcomes. Studies in adults, studies in premature infants (≤36 weeks' gestational age), animal studies, reviews and commentaries, case series with sample sizes ≤10, and studies not published in English in which we were unable to determine eligibility criteria were excluded.

DATA EXTRACTION

Data were abstracted into a standard data extraction form.

RESULTS

We provided binary (no or yes) and graded (no, nonsevere, or severe) definitions of respiratory dysfunction, prioritizing oxygenation and respiratory support. The proposed criteria were approved by 82% of members in the first round, with a score of 8 of 9 (interquartile range 7-8).

LIMITATIONS

Exclusion of non-English publications, heterogeneity across the pediatric age range, small sample sizes, and incomplete handling of confounders are limitations.

CONCLUSIONS

We propose definitions for respiratory dysfunction in critically ill children after an exhaustive literature review.

Advances in the Pharmacological Management of Pediatric Acute Respiratory Distress Syndrome

INTRODUCTION

Noninvasive mechanical ventilation is the main supportive measure used in patients with pediatric ARDS (PARDS), but adjunctive pharmacological therapies (corticosteroids, inhaled nitric oxide [iNO], surfactant replacement therapy and neuromuscular blocking drugs) are also used, although limited data exists to inform of this practice.

AREAS COVERED

The authors review the current challenges in the pharmacological management of PARDS and highlight the few certainties currently available.

EXPERT OPINION

Children with PARDS must not be treated as young adults with ARDS, essentially because children's lungs differ substantially from those of adults and PARDS occurs in children differently than ARDS in adults. Pharmacological treatments available for PARDS are relatively few and, since there is great uncertainty about their effectiveness also because of the extreme heterogeneity of this syndrome, it is necessary to conduct large clinical trials using currently available definitions and considering recent pathobiological knowledge. The aim is to identify homogeneous subgroups or phenotypes of children with PARDS that may benefit from the specific pharmaceutical approach examined. It will be then necessary to link endotypes and outcomes to appropriately target therapies in future trials, but this will be possible only after it will be possible to identify the different PARDS endotypes.

Feasibility and effectiveness of prone position ventilation technique for postoperative acute lung injury in infants with congenital heart disease: study protocol for a prospective randomized study

Background

Prone position ventilation is a widely used lung protection ventilation strategy. The strategy is more convenient to implement in children compared to adults. Due to the precise mechanism of improving oxygenation function, development of pediatric prone ventilation technology has been largely focused on children with acute respiratory distress syndrome. There is a paucity of high-quality studies investigating the effects of prone position ventilation after pediatric cardiac surgery. The purpose of this study is to evaluate the feasibility and effectiveness of prone position ventilation in infants who develop postoperative acute lung injury after surgery for congenital heart disease.

Methods

A single-center, randomized controlled trial of pediatric patients with acute lung injury after surgery for congenital heart disease who will receive prone position ventilation or usual care (control group). A total of 68 children will be enrolled according to the inclusion criteria. The main outcome measures will be lung compliance and oxygenation index. The secondary outcomes will be duration of mechanical ventilation, length of stay in cardiac intensive care unit, reintubation rate, and complication rate.

Discussion

This study will investigate the feasibility and effectiveness of prone position ventilation techniques in children who develop postoperative acute lung injury after surgery for congenital heart disease. The results may help inform strategies to improve airway management after surgery for congenital heart disease.

Trial registration

ClinicalTrials.gov NCT04607993. Initially registered on 29 October 2020.

Potential therapeutics in pediatric acute respiratory distress syndrome: what does the immune system have to offer? A narrative review

Since first described, acute respiratory distress syndrome (ARDS) has been understood to be an inflammatory disease with a dysregulated hyperinflammatory response. While fewer investigations have studied these phenomena in pediatric ARDS (PARDS), similar pathways are believed to be involved. Significant attention has been paid to the innate immune system, particularly neutrophils and neutrophil-related signaling, more recent studies have provided additional nuance regarding the role of upstream damage-associated molecular patterns (DAMPs) and subsequent neutrophil-mediated inflammation, lung permeability, and alveolar epithelial damage. For example, neutrophil extracellular traps (NETs) and inflammasome signaling have been identified as critical mediators existing at the junction of DAMPs and downstream inflammation. We demonstrate how the conclusions obtained from pre-clinical studies of lung injury are highly dependent upon the model chosen, and how this can lead us astray when developing therapies. More recently the adaptive immune system, specifically select T cell subpopulations, have also been implicated in ARDS. This raises the possibility of antigen-specific immunomodulation as a potential therapeutic avenue in ARDS. Finally, we briefly review randomized controlled trials attempting to manipulate the immune dysregulation in ARDS, including pleiotropic immunomodulators like corticosteroids and interferon-β, and what these studies can teach us about the design of novel therapeutics and the design of future trials.

Adherence to Lung-Protective Ventilation Principles in Pediatric Acute Respiratory Distress Syndrome: A Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology Study

OBJECTIVES

To describe mechanical ventilation management and factors associated with nonadherence to lung-protective ventilation principles in pediatric acute respiratory distress syndrome.

DESIGN

A planned ancillary study to a prospective international observational study. Mechanical ventilation management (every 6 hr measurements) during pediatric acute respiratory distress syndrome days 0-3 was described and compared with Pediatric Acute Lung Injury Consensus Conference tidal volume recommendations (< 7 mL/kg in children with impaired respiratory system compliance, < 9 mL/kg in all other children) and the Acute Respiratory Distress Syndrome Network lower positive end-expiratory pressure/higher Fio2 grid recommendations.

SETTING

Seventy-one international PICUs.

PATIENTS

Children with pediatric acute respiratory distress syndrome.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Analyses included 422 children. On pediatric acute respiratory distress syndrome day 0, median tidal volume was 7.6 mL/kg (interquartile range, 6.3-8.9 mL/kg) and did not differ by pediatric acute respiratory distress syndrome severity. Plateau pressure was not recorded in 97% of measurements. Using delta pressure (peak inspiratory pressure - positive end-expiratory pressure), median tidal volume increased over quartiles of median delta pressure (p = 0.007). Median delta pressure was greater than or equal to 18 cm H2O for all pediatric acute respiratory distress syndrome severity levels. In severe pediatric acute respiratory distress syndrome, tidal volume was greater than or equal to 7 mL/kg 62% of the time, and positive end-expiratory pressure was lower than recommended by the positive end-expiratory pressure/Fio2 grid 70% of the time. In multivariable analysis, tidal volume nonadherence was more common with severe pediatric acute respiratory distress syndrome, fewer PICU admissions/yr, non-European PICUs, higher delta pressure, corticosteroid use, and pressure control mode. Adherence was associated with underweight stature and cuffed endotracheal tubes. In multivariable analysis, positive end-expiratory pressure/Fio2 grid nonadherence was more common with higher pediatric acute respiratory distress syndrome severity, ventilator decisions made primarily by the attending physician, pre-ICU cardiopulmonary resuscitation, underweight stature, and age less than 2 years. Adherence was associated with respiratory therapist involvement in ventilator management and longer time from pediatric acute respiratory distress syndrome diagnosis. Higher nonadherence to tidal volume and positive end-expiratory pressure recommendations were independently associated with higher mortality and longer duration of ventilation after adjustment for confounding variables. In stratified analyses, these associations were primarily influenced by children with severe pediatric acute respiratory distress syndrome.

CONCLUSIONS

Nonadherence to lung-protective ventilation principles is common in pediatric acute respiratory distress syndrome and may impact outcome. Modifiable factors exist that may improve adherence.

Paediatrics: how to manage acute respiratory distress syndrome

Background

Acute respiratory distress syndrome (ARDS) is a significant cause of mortality and morbidity amongst critically ill children. The purpose of this narrative review is to provide an up-to-date review on the evaluation and management of paediatric ARDS (PARDS).

Methods

A PubMed search was performed with Clinical Queries using the key term "acute respiratory distress syndrome". The search strategy included clinical trials, meta-analyses, randomized controlled trials, observational studies and reviews. Google, Wikipedia and UpToDate were also searched to enrich the review. The search was restricted to the English literature and children.

Discussion

Non-invasive positive pressure ventilation, lung-protective ventilation strategies, conservative fluid management and adequate nutritional support all have proven efficacy in the management of PARDS. The Pediatric Acute Lung Injury Consensus Conference recommends the use of corticosteroids, high-frequency oscillation ventilation and inhaled nitric oxide in selected scenarios. Partial liquid ventilation and surfactant are not considered efficacious based on evidence from clinical trials.

Conclusion

PARDS is a serious but relatively rare cause of admission into the paediatric intensive care unit and is associated with high mortality. Non-invasive positive pressure ventilation, lung-protective ventilation strategies, conservative fluid management and adequate nutrition are advocated. As there has been a lack of progress in the management of PARDS in recent years, further well-designed, large-scale, randomized controlled trials in this field are urgently needed.

Prone positioning in children with respiratory failure because of coronavirus disease 2019

PURPOSE OF REVIEW

Acute respiratory distress syndrome (ARDS) is a common manifestation of severe COVID-19. Prone positioning has been used successfully in adult patients with ARDS and has been shown to decrease mortality. The efficacy of prone positioning in pediatric ARDS is less clear. In this review, we discuss the physiologic principles and literature on prone positioning in adults and children relative to COVID-19.

RECENT FINDINGS

There are limited published data on prone positioning in respiratory failure because of COVID-19. The use of proning in nonintubated patients with COVID-19 may improve oxygenation and dyspnea but has not been associated with improved outcomes. Initial adult cohort studies of intubated patients undergoing prone positioning in severe ARDS related to COVID-19 have shown an improvement in mortality. Although the use of proning in children with severe COVID-19 is recommended, data supporting its use is scarce.

SUMMARY

Additional studies to evaluate the efficacy of prone positioning in pediatric ARDS are needed to provide evidence for or against this treatment strategy in children. Given the unknown evolution of this pandemic, collaborative research efforts across pediatric centers provides the greatest opportunity to develop a data driven-approach to make use of this potential therapy.

Plasma Nucleosomes Are Associated With Mortality in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

Circulating nucleosomes and their component histones have been implicated as pathogenic in sepsis and acute respiratory distress syndrome in adults. However, their role in pediatric acute respiratory distress syndrome is unknown.

DESIGN

We performed a prospective cohort study in children with acute respiratory distress syndrome, with plasma collection within 24 hours of acute respiratory distress syndrome onset. We associated nucleosome levels with severity of acute respiratory distress syndrome and with nonpulmonary organ failures and tested for association of nucleosomes with PICU mortality and ventilator-free days at 28 days in univariate and multivariable analyses. We also performed proteomics of DNA-bound plasma proteins in a matched case-control study of septic children with and without acute respiratory distress syndrome in order to identify specific histone proteins elevated in acute respiratory distress syndrome.

SETTING

Large academic tertiary-care PICU.

PATIENTS

Intubated children meeting Berlin criteria for acute respiratory distress syndrome.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We enrolled 333 children with acute respiratory distress syndrome, with 69 nonsurvivors (21%). Plasma nucleosomes were correlated with acute respiratory distress syndrome severity and with the number of nonpulmonary organ failures at acute respiratory distress syndrome onset. Nucleosomes were higher (p < 0.001) in nonsurvivors (0.40 [interquartile range, 0.20-0.71] arbitrary units) relative to survivors (0.10 [interquartile range, 0.04-0.25] arbitrary units). Nucleosomes were associated with PICU mortality in multivariable analysis (adjusted odds ratio 1.84 per 1 sd increase; 95% CI, 1.38-2.45; p < 0.001). Nucleosomes were also associated with a lower probability of being extubated alive by day 28 after multivariable adjustment (adjusted subdistribution hazard ratio, 0.74; 95% CI, 0.63-0.88; p = 0.001). Proteomic analysis demonstrated higher levels of the core nucleosome histones H2A, H2B, H3, and H4 in septic children with acute respiratory distress syndrome, relative to septic children without acute respiratory distress syndrome.

CONCLUSIONS

Plasma nucleosomes are associated with acute respiratory distress syndrome severity, nonpulmonary organ failures, and worse outcomes in pediatric acute respiratory distress syndrome.

High frequency percussive ventilation in pediatric acute respiratory failure

OBJECTIVE

High frequency percussive ventilation (HFPV) is used in acute respiratory failure, but is poorly described in pediatrics. We aimed to describe the clinical characteristics, ventilator settings, and outcomes of a large pediatric cohort, and to determine predictors of who would benefit from HFPV.

HYPOTHESIS

Gas exchange 2 h after HFPV initiation predicts success.

DESIGN

Single center retrospective cohort study testing association between gas exchange 2 h after HFPV initiation with success, defined a priori.

PATIENTS

Intubated children on HFPV for ≥2 h from 2012 to 2018.

METHODS

We described indications, ventilator settings, and gas exchange immediately before, 2 h after, and at termination of HFPV. Univariate and multivariate regression tested association of oxygenation and ventilation after HFPV initiation with success. Areas under the receiver operating characteristic (AUROC) curve and adjusted odds ratios (aORs) were computed.

RESULTS

We performed 237 courses of HFPV in 193 children (22% non-survivors), of which 162 (68%) were successful. In univariate analysis, pH (AUROC, 0.65) and PCO₂ (AUROC, 0.66) 2 h after HFPV predicted success. In multivariate analysis, pH (aOR: 1.67 per 1 SD; 95% confidence interval [CI]: 1.19-2.35), PCO₂ (aOR: 0.49 per 1 SD; 95% CI: 0.31-0.79), and oxygenation index (aOR: 0.66 per 1 SD; 95% CI: 0.44-0.97) 2 h after HFPV initiation were associated with success.

CONCLUSION

We describe the largest cohort of HFPV to date, with detailed description of indications and settings. Gas exchange after 2 h of HFPV was independently associated with success.

The Use of a Kinetic Therapy Rotational Bed in Pediatric Acute Respiratory Distress Syndrome: A Case Series

Patients with acute respiratory distress syndrome (ARDS) commonly have dependent atelectasis and heterogeneous lung disease. Due to the heterogenous lung volumes seen, the application of positive end expiratory pressure (PEEP) can have both beneficial and deleterious effects. Alternating supine and prone positioning may be beneficial in ARDS by providing more homogenous distribution of PEEP and decreasing intrapulmonary shunt. In pediatrics, the pediatric acute lung injury and consensus conference (PALICC) recommended to consider it in severe pediatric ARDS (PARDS). Manually prone positioning patients can be burdensome in larger patients. In adults, the use of rotational beds has eased care of these patients. There is little published data about rotational bed therapy in children. Therefore, we sought to describe the use of a rotational bed in children with PARDS. We performed a retrospective case series of children who utilized a rotational bed as an adjunctive therapy for their PARDS. Patient data were collected and analyzed. Descriptive statistical analyses were performed and reported. Oxygenation indices (OI) pre- and post-prone positioning were analyzed. Twelve patients with PARDS were treated with a rotational bed with minimal adverse events. There were no complications noted. Three patients had malfunctioning of their arterial line while on the rotational bed. Oxygenation indices improved over time in 11 of the 12 patients included in the study while on the rotational bed. Rotational beds can be safely utilized in pediatric patients. In larger children with PARDS, where it may be more difficult to perform a manual prone position, use of a rotational bed can be considered a safe alternative.

Awake proning of a 2-year-old extubated child with severe COVID-19 pneumonitis

With the progress of the coronavirus disease 2019 (COVID‐19) pandemic, available data suggest lower complications and disease severity in children and young patients. Despite most paediatric cases being mild in severity, some children require intensive care and mechanical ventilation due to the development of paediatric severe acute respiratory distress. The use of adjuvant therapies in severely ill paediatric patients has not been reported widely in the literature. Prone positioning in spontaneously breathing children has, to our knowledge, not yet been described. In our report, the trachea of a 2‐year‐old child was intubated, and he was mechanically ventilated for severe bilateral pneumonia. The infant and his mother tested positive for severe acute respiratory syndrome coronavirus disease‐2 (SARS‐CoV‐2) infection with reverse transcription‐polymerase chain reaction testing from nasopharyngeal swabs. Immediately after tracheal extubation, the child developed severe respiratory distress and refractory hypoxia. Awake prone position was employed as a rescue therapy for the management of post‐extubation hypoxia, resulting in a dramatic improvement in oxygenation. Prone positioning in the paediatric patient may improve oxygenation and can be a useful adjuvant for respiratory therapy either before, during or after invasive mechanical ventilation. Awake prone position may be considered as an option for the management of COVID‐19 in paediatric patients, but it requires patient cooperation.