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

Positive end-expiratory pressure in the pediatric intensive care unit

Application of positive end-expiratory pressure (PEEP) targeted towards improving oxygenation is one of the components of the ventilatory management of pediatric acute respiratory distress syndrome (PARDS). Low end-expiratory airway pressures cause repetitive opening and closure of unstable alveoli, leading to surfactant dysfunction and parenchymal shear injury. Consequently, there is less lung volume available for tidal ventilation when there are atelectatic lung regions. This will increase lung strain in aerated lung areas to which the tidal volume is preferentially distributed. Pediatric critical care practitioners tend to use low levels of PEEP and inherently accept higher FiO2, but these practices may negatively affect patient outcome. The Pediatric Acute Lung Injury Consensus Conference (PALICC) suggests that PEEP should be titrated to oxygenation/oxygen delivery, hemodynamics, and compliance measured under static conditions as compared to other clinical parameters or any of these parameters in isolation in patients with PARDS, while limiting plateau pressure and/or driving pressure limits.

Accuracy of tidal volume delivery by paediatric intensive care ventilators: A bench-model study

BACKGROUND

Tidal volume (Vt) delivery during mechanical ventilation is influenced by gas compression, humidity, and temperature.

OBJECTIVES

This bench study aimed at assessing the accuracy of Vt delivery by paediatric intensive care ventilators according to the humidification system. Secondary objectives were to assess the following: (i) the accuracy of Vt delivery in ventilators with an integrated Y-piece pneumotachograph and (ii) the ability of ventilators to deliver and maintain a preset positive end-expiratory pressure.

METHODS

Six latest-generation intensive care ventilators equipped with a paediatric mode were tested on the ASL5000 test lung in four simulated paediatric bench models (full-term neonate, infant, preschool-age chile, and school-age child), under volume-controlled mode with a heated humidifier (HH) or a heat moisture exchanger, with various loading conditions. Three ventilators equipped with a Y-piece pneumotachograph were tested with or without the pneumotachograph in the neonatal and infant models. "Accurate Vt" delivery was defined as a volume error (percentage of the preset Vt under body temperature and pressure and saturated water vapour conditions) being ≤10 % of the absolute preset value.

RESULTS

Vt accuracy varied significantly across ventilators but was acceptable in almost all the ventilators and all the models, except the neonatal model. The humidification system had an impact on Vt delivery in the majority of the tested conditions (p < 0.05). The use of an HH was associated with a better Vt accuracy in four ventilators (V500, V800, R860, and ServoU) and allowed to achieve an acceptable level of volume error in the neonatal model as compared to the use of heat moisture exchanger. The use of an integrated pneumotachograph was associated with lower volume error in only one ventilator (p < 0.01). All the tested ventilators were able to maintain adequate positive end-expiratory pressure levels.

CONCLUSION

The humidification system affects Vt accuracy of paediatric intensive care ventilators, especially in the youngest patients for whom the HH should be preferred.

A prospective study on the precision of height data from electronic medical records in tidal volume calculation for lung-protective ventilation

Lung-protective ventilation is now the norm for all patients, regardless of the presence of acute respiratory distress syndrome (ARDS), owing to the mortality associated with higher tidal volumes (TV). Clinicians calculate TV using recorded height from medical records and predicted body weight (PBW); however, the accuracy remains uncertain. Our study aimed to validate accurate TV settings for lung-protective ventilation by examining the correlation between the charted height and bedside measurements. In a single-center study, we compared PBW-based TV calculated from recorded height to PBW-based TV from measured height and identified factors causing height overestimation during charting. Our team measured patient height within 24 hours of admission using metal tape. TV calculated from recorded height (6-8 mL/kg PBW) was significantly larger (391.55 ± 65.98 to 522.07 ± 87.97) than measured height-based TV (162.62 ± 12.62 to 470.28 ± 89.64) (P < .01). In the height overestimated group, 57.7% were prescribed TV by healthcare provider, which was more than TV of 8 mL/kg of PBW, as determined by measured height. Negative predictors for height overestimation were male sex (OR: 0.45 [95% CI: 0.25-0.82]; P = .008) and presence of driver's license information (OR: 0.45 [95% CI: 0.25-0.80]; P = .007), whereas Asian ethnicity was a positive predictor (OR: 4.34 [95% CI: 1.09-17.27]; P = .04). The height overestimation group had a higher in-patient mortality rate (38.5%) than the matched/underestimation group (20%) (P < .01). In stadiometer-limited hospitals, the PBW-based TV is overestimated using the recorded height instead of the measured height. In the group where heights were overestimated, over half of the patients received TV prescriptions from healthcare providers that surpassed the TV of calculated 8 mL/kg PBW based on their measured height. The risk factors for height overestimation include female sex, Asian ethnicity, and missing driver's license data. Alternative height measurement methods should be explored to ensure precise ventilation settings and patient safety.

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.

Mechanical Power Is Associated With Mortality in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

Mechanical power (MP) transferred from the ventilator to the lungs has been proposed as a summary variable that may impact mortality in children with acute respiratory distress syndrome (ARDS). To date, no study has shown an association between higher MP and mortality in children with ARDS.

DESIGN

Secondary analysis of a prospective observational study.

SETTING

Single-center, tertiary, academic PICU.

PATIENTS

Five hundred forty-six intubated children with ARDS enrolled between January 2013 and December 2019 receiving pressure-controlled ventilation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Higher MP was associated with increased mortality (adjusted hazard ratio [HR] 1.34 per 1 sd increase, 95% CI 1.08-1.65; p = 0.007). When assessing the contribution of individual components of MP, only positive end-expiratory pressure (PEEP) was associated with mortality (HR 1.32; p = 0.007), whereas tidal volume, respiratory rate, and driving pressure (ΔP = [peak inspiratory pressure (PIP)-PEEP]) were not. Finally, we tested whether there remained an association when specific terms were removed from the MP equation by calculating MP from static strain (remove ΔP), MP from dynamic strain (remove PEEP), and mechanical energy (remove respiratory rate). MP from static strain (HR 1.44; p < 0.001), MP from dynamic strain (HR 1.25; p = 0.042), and mechanical energy (HR 1.29; p = 0.009) were all associated with mortality. MP was associated with ventilator-free days only when using MP normalized to predicted body weight, but not when using measured weight.

CONCLUSIONS

Higher MP was associated with mortality in pediatric ARDS, and PEEP appears to be the component most consistently driving this association. As higher PEEP is used in sicker patients, the association between MP and mortality may reflect a marker of illness severity rather than MP itself being causal for mortality. However, our results support future trials testing different levels of PEEP in children with ARDS as a potential means to improve outcome.

Invasive Ventilatory Support in Patients With Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To provide evidence for the Second Pediatric Acute Lung Injury Consensus Conference updated recommendations and consensus statements for clinical practice and future research on invasive mechanical ventilation support of patients with pediatric acute respiratory distress syndrome (PARDS).

DATA SOURCES

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

STUDY SELECTION

We included clinical studies of critically ill patients undergoing invasive mechanical ventilation for PARDS, January 2013 to April 2022. In addition, meta-analyses and systematic reviews focused on the adult acute respiratory distress syndrome population were included to explore new relevant concepts (e.g., mechanical power, driving pressure, etc.) still underrepresented in the contemporary pediatric literature.

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, good practice statements and research statements. We identified 26 pediatric studies for inclusion and 36 meta-analyses or systematic reviews in adults. We generated 12 recommendations, two research statements, and five good practice statements related to modes of ventilation, tidal volume, ventilation pressures, lung-protective ventilation bundles, driving pressure, mechanical power, recruitment maneuvers, prone positioning, and high-frequency ventilation. Only one recommendation, related to use of positive end-expiratory pressure, is classified as strong, with moderate certainty of evidence.

CONCLUSIONS

Limited pediatric data exist to make definitive recommendations for the management of invasive mechanical ventilation for patients with PARDS. Ongoing research is needed to better understand how to guide best practices and improve outcomes for patients with PARDS requiring invasive mechanical ventilation.

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.

Monitoring in Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

Monitoring is essential to assess changes in the lung condition, to identify heart-lung interactions, and to personalize and improve respiratory support and adjuvant therapies in pediatric acute respiratory distress syndrome (PARDS). The objective of this article is to report the rationale of the revised recommendations/statements on monitoring from the Second Pediatric Acute Lung Injury Consensus Conference (PALICC-2).

DATA SOURCES

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

STUDY SELECTION

We included studies focused on respiratory or cardiovascular monitoring of children less than 18 years old with a diagnosis of PARDS. We excluded studies focused on neonates.

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. We identified 342 studies for full-text review. Seventeen good practice statements were generated related to respiratory and cardiovascular monitoring. Four research statements were generated related to respiratory mechanics and imaging monitoring, hemodynamics monitoring, and extubation readiness monitoring.

CONCLUSIONS

PALICC-2 monitoring good practice and research statements were developed to improve the care of patients with PARDS and were based on new knowledge generated in recent years in patients with PARDS, specifically in topics of general monitoring, respiratory system mechanics, gas exchange, weaning considerations, lung imaging, and hemodynamic monitoring.

Pleural and transpulmonary pressures to tailor protective ventilation in children

This review aims to: (1) describe the rationale of pleural (P_PL) and transpulmonary (P_L) pressure measurements in children during mechanical ventilation (MV); (2) discuss its usefulness and limitations as a guide for protective MV; (3) propose future directions for paediatric research. We conducted a scoping review on P_L in critically ill children using PubMed and Embase search engines. We included peer-reviewed studies using oesophageal (P_ES) and P_L measurements in the paediatric intensive care unit (PICU) published until September 2021, and excluded studies in neonates and patients treated with non-invasive ventilation. P_L corresponds to the difference between airway pressure and P_PL Oesophageal manometry allows measurement of P_ES, a good surrogate of P_PL, to estimate P_L directly at the bedside. Lung stress is the P_L, while strain corresponds to the lung deformation induced by the changing volume during insufflation. Lung stress and strain are the main determinants of MV-related injuries with P_L and P_PL being key components. P_L-targeted therapies allow tailoring of MV: (1) Positive end-expiratory pressure (PEEP) titration based on end-expiratory P_L (direct measurement) may be used to avoid lung collapse in the lung surrounding the oesophagus. The clinical benefit of such strategy has not been demonstrated yet. This approach should consider the degree of recruitable lung, and may be limited to patients in which PEEP is set to achieve an end-expiratory P_L value close to zero; (2) Protective ventilation based on end-inspiratory P_L (derived from the ratio of lung and respiratory system elastances), might be used to limit overdistention and volutrauma by targeting lung stress values < 20-25 cmH₂O; (3) P_PL may be set to target a physiological respiratory effort in order to avoid both self-induced lung injury and ventilator-induced diaphragm dysfunction; (4) P_PL or P_L measurements may contribute to a better understanding of cardiopulmonary interactions. The growing cardiorespiratory system makes children theoretically more susceptible to atelectrauma, myotrauma and right ventricle failure. In children with acute respiratory distress, P_PL and P_L measurements may help to characterise how changes in PEEP affect P_PL and potentially haemodynamics. In the PICU, P_PL measurement to estimate respiratory effort is useful during weaning and ventilator liberation. Finally, the use of P_PL tracings may improve the detection of patient ventilator asynchronies, which are frequent in children. Despite these numerous theoritcal benefits in children, P_ES measurement is rarely performed in routine paediatric practice. While the lack of robust clincal data partially explains this observation, important limitations of the existing methods to estimate P_PL in children, such as their invasiveness and technical limitations, associated with the lack of reference values for lung and chest wall elastances may also play a role. P_PL and P_L monitoring have numerous potential clinical applications in the PICU to tailor protective MV, but its usefulness is counterbalanced by technical limitations. Paediatric evidence seems currently too weak to consider oesophageal manometry as a routine respiratory monitoring. The development and validation of a noninvasive estimation of P_L and multimodal respiratory monitoring may be worth to be evaluated in the future.

2021 Year in Review: Pediatric Mechanical Ventilation

Mechanical ventilation is commonly used in the pediatric intensive care unit. This paper reviews studies of pediatric mechanical ventilation published in 2021. Topics include physiology, ventilator modes, alarms, disease states, airway suctioning, ventilator liberation, prolonged ventilation, and others.

Risk factors for air leakage during invasive mechanical ventilation in pediatric intensive care units

Purpose

This study aimed to investigate air leakage during invasive mechanical ventilation (IMV) in a pediatric intensive care unit (PICU) and explore potential risk factors.

Methods

We conducted a retrospective cohort study of children who underwent IMV in a single-center PICU in a tertiary referral hospital. Air leakage risk factors and factors associated with an improved outcome were assessed.

Results

A total of 548 children who underwent IMV were enrolled in this study. Air leakage occurred in 7.5% (41/548) of the cases in the PICU. Air leakage increased the duration of IMV and hospitalization time. Multivariate logistic regression analysis showed a higher risk of air leakage during IMV for PICU patients with acute respiratory dyspnea syndrome (ARDS) (OR = 4.38), a higher pediatric critical illness score (PCIS) (OR = 1.08), or a higher peak inspiratory pressure (PIP) (OR = 1.08), whereas the risk was lower for patients with central respiratory failure (OR = 0.14). The logistic model had excellent predictive power for air leakage, with an area under the curve of 0.883 and tenfold cross-validation. Patients aged between 1 and 6 years who were diagnosed with measles or pneumonia and had a low positive end-expiratory pressure (PEEP) or high PaO2/FiO2 ratio were associated with improved outcomes. Patients diagnosed with central respiratory failure or congenital heart diseases were associated with less desirable outcomes.

Conclusions

Patients with ARDS, a higher PCIS at admission or a higher PIP were at higher risk of air leakage.

Nonadherence to appropriate tidal volume and PEEP in children with pARDS at a single center

BACKGROUND

Low tidal volume and adequate positive end-expiratory pressure (PEEP) are evidence-based approaches for pediatric acute respiratory distress syndrome (pARDS), however, data are limited regarding their use since pARDS guidelines were revised in 2015.

OBJECTIVE

To identify prevalence of, and factors associated with, nonadherence to appropriate tidal volume and PEEP in children with pARDS.

METHODS

Retrospective cohort study of children 1 month to <18 years with pARDS who received invasive mechanical ventilation from 2016 to 2018 in a single pediatric intensive care unit (PICU).

RESULTS

At 24 h after meeting pARDS criteria, 48/86 (56%) patients received tidal volume ≤8 ml/kg of ideal body weight and 45/86 (52%) received appropriate PEEP, with 22/86 (26%) receiving both. Among patients ≥2 years of age, a lower proportion of patients with overweight/obesity (9/25, 36%) had appropriate tidal volume versus those in the normal or underweight category (16/22, 73%, p = 0.02). When FIO2 was ≥50%, PEEP was appropriate in 19/60 (32%) cases versus 26/26 (100%) with FIO2  < 50% (p < 0.0001). pARDS was documented in the progress note in 7/86 (8%) patients at 24 h. Severity of pARDS, documentation in the progress note, and other clinical factors were not significantly associated with use of appropriate tidal volume and PEEP, however pARDS was documented more commonly in patients with severe pARDS.

CONCLUSIONS

In a single PICU in the United States, children with pARDS did not receive appropriate tidal volume for ideal body weight nor PEEP. Targets for improving tidal volume and PEEP adherence may include overweight patients and those receiving FIO2  ≥ 50%, respectively.

The Relevance of Airway Resistance in Children Requiring Mechanical Ventilatory Support

OBJECTIVES

To describe pulmonary resistance in children undergoing invasive mechanical ventilation (MV) for different causes.

DESIGN

A cross-sectional study.

SETTING

Two PICUs in the South region of Brazil.

PATIENTS

Children 1 month to 15 years old undergoing MV for more than 24 hours were included. We recorded ventilator variables and measured pulmonary mechanics (inspiratory and expiratory resistance, auto positive end-expiratory pressure [PEEP], and dynamic and static compliance) in the first 48 hours of MV.

INTERVENTIONS

Measurements of the respiratory mechanics variables during neuromuscular blockade.

MEASUREMENTS AND MAIN RESULTS

A total of 113 children were included, 5 months (median [interquartile range (IQR) [2.0-21.5 mo]) old, and median (IQR) weight 6.5 kg (4.5-11.0 kg), with 60% male. Median (IQR) peak inspiratory pressure (PIP) was 30 cm H 2 O (26-35 cm H 2 O), and median (IQR) PEEP was 5 cm H 2 O (5-7 cm H 2 O). The median (IQR) duration of MV was 7 days (5-9 d), and mortality was nine of 113 (8%). The median (IQR) inspiratory and expiratory resistances were 94.0 cm H 2 O/L/s (52.5-155.5 cm H 2 O/L/s) and 117 cm H 2 O/L/s (71-162 cm H 2 O/L/s), with negative association with weight and age (Spearman -0.850). When we assess weight, in smaller children (&lt; 10 kg) had increased pulmonary resistance, with mean values over 100 mH 2 O/L/s, which were higher than larger children ( p &lt; 0.001).

CONCLUSIONS

Increased pulmonary resistance is prevalent in the pediatric population undergoing invasive MV. Especially in children less than 1 year old, this variable should be considered when defining a ventilatory strategy.

Recognizing Pediatric ARDS: Provider Use of the PALICC Recommendations in a Tertiary Pediatric ICU

BACKGROUND

For almost 50 years, pediatricians used adult guidelines to diagnose ARDS. In 2015, specific criteria for pediatric ARDS were defined. However, it remains unclear how frequently providers recognize pediatric ARDS and whether recognition affects adherence to consensus recommendations.

METHODS

This was a mixed-method, retrospective study of mechanically ventilated pediatric subjects after the release of the pediatric ARDS recommendation statement. Pediatric ARDS cases were identified according to the new criteria. Provider recognition was defined by documentation in the medical record. Pediatric ARDS subjects with and without provider recognition were compared quantitatively according to clinical characteristics, adherence to lung-protective ventilation (LPV), adjunctive therapies, and outcomes. A qualitative document analysis (QDA) was performed to evaluate knowledge and beliefs surrounding the Pediatric Acute Lung Injury Consensus Conference recommendations.

RESULTS

Of 1,983 subject encounters, pediatric ARDS was identified in 321 (16%). Provider recognition was present in 97 (30%) cases and occurred more often in subjects who were older, had worse oxygenation deficits, or were bone marrow transplant recipients. Recognition rates increased each studied year. LPV practices did not differ based on provider recognition; however, subjects who received it were more likely to experience permissive hypoxemia and adherence to extrapulmonary recommendations. Ultimately, there was no differences in outcomes between the provider recognition and non-provider recognition groups. Three themes emerged from the QDA: (1) pediatric ARDS presents within a complex, multidimensional context, with potentially competing organ system failures; (2) similar to historical conceptualizations, pediatric ARDS was often considered a visual diagnosis, with measures of oxygenation unreferenced; and (3) emphasis was placed on non-evidence-based interventions, such as pulmonary clearance techniques, rather than on consensus recommendations.

CONCLUSIONS

Among mechanically ventilated children, pediatric ARDS was common but recognized in a minority of cases. Potential opportunities, such as an opt-out approach to LPV, may exist for improved dissemination and implementation of recommended best practices.

Agreement Between Peak Inspiratory Pressure in Decelerating-Flow Ventilation and Plateau Pressure in Square-Flow Ventilation in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

Acute respiratory distress syndrome guidelines suggest limiting plateau pressures to 28-30 cm H2O. Plateau pressure is most accurately measured in square-flow modes, such as volume control. In children, decelerating-flow modes, such as pressure-regulated volume control and pressure control, are more common. Consequently, plateau pressures are rarely obtained, and pressure limits are instead provided for peak inspiratory pressure. The degree to which peak inspiratory pressure in decelerating-flow overestimates plateau pressure is unknown. Therefore, we assessed the correlation and accuracy of peak inspiratory pressure in decelerating-flow ventilation for approximating plateau pressure during square-flow ventilation.

DESIGN

Prospective, observational study.

SETTING

Tertiary, academic PICU.

PATIENTS

Fifty-two intubated children with acute respiratory distress syndrome enrolled between January 2020 and May 2021.

INTERVENTIONS

Measurement of peak inspiratory pressure in decelerating-flow ventilation and plateau pressure after transition to square-flow ventilation.

MEASUREMENTS AND MAIN RESULTS

Peak inspiratory pressure in decelerating-flow was highly correlated (r2 = 0.99; p < 0.001) with plateau pressure in square-flow. Peak inspiratory pressure was 1.0 ± 0.6 cm H2O higher than plateau pressure, with 96% of values within 2 cm H2O. The single outlier had coexistent asthma and inspiratory flows that did not reach zero.

CONCLUSIONS

Peak inspiratory pressure measured during decelerating-flow ventilation may be an adequate surrogate of plateau pressure in pediatric acute respiratory distress syndrome when inspiratory flow approaches zero. Practitioners should be aware that peak inspiratory pressures in decelerating-flow may not be substantially higher than plateau pressures.

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.