Muscle atrophy in mechanically-ventilated critically ill children

Association between protein intake and muscle wasting in critically ill children: A prospective cohort study

BACKGROUND

Survival from pediatric critical illness in high-income countries is high, and the focus now must be on optimizing the recovery of survivors. Muscle mass wasting during critical illness is problematic, so identifying factors that may reduce this is important. Therefore, the aim of this study was to examine the relationship between quadricep muscle mass wasting (assessed by ultrasound), with protein and energy intake during and after pediatric critical illness.

METHODS

A prospective cohort study in a mixed cardiac and general pediatric intensive care unit in England, United Kingdom. Serial ultrasound measurements were undertaken at day 1, 3, 5, 7, and 10.

RESULTS

Thirty-four children (median age 6.65 [0.47-57.5] months) were included, and all showed a reduction in quadricep muscle thickness during critical care admission, with a mean muscle wasting of 7.75%. The 11 children followed-up had all recovered their baseline muscle thickness by 3 months after intensive care discharge. This muscle mass wasting was not related to protein (P = 0.53, ρ = 0.019) (95% CI: -0.011 to 0.049) or energy intake (P = 0.138, ρ = 0.375 95% CI: -0.144 to 0.732) by 72 h after admission, nor with severity of illness, highest C-reactive protein, or exposure to intravenous steroids. Children exposed to neuromuscular blocking drugs exhibited 7.2% (95% CI: -0.13% to 14.54%) worse muscle mass wasting, but this was not statistically significant (P = 0.063).

CONCLUSION

Our study did not find any association between protein or energy intake at 72 h and quadricep muscle mass wasting.

Relationship among low baseline muscle mass, skeletal muscle quality, and mortality in critically ill children

BACKGROUND

Studies in adults have shown that low baseline muscle mass at intensive care unit (ICU) admission was associated with poor clinical outcomes. However, no information on the relationship between baseline muscle quality or mass and clinical outcomes in critically ill children was found.

METHODS

3775 children were admitted to the pediatric ICU (PICU), 262 were eligible for inclusion. Abdominal computed tomography was performed to assess baseline skeletal muscle mass and quality. Patients were categorized to normal or low group based on the cutoff value for predicting hospital mortality of the skeletal muscle index (SMI; 30.96 cm2/m2) and skeletal muscle density (SMD; 41.21 Hounsfield units).

RESULTS

Body mass index (BMI) (18.07 ± 4.44 vs 15.99 ± 4.51) and BMI-for-age z score (0.46 [-0.66 to 1.74] vs -0.87 [-1.69 to 0.05]) were greater in the normal-SMI group, the length of PICU stay was longer in the low-SMI group (16.00 days [8.50-32.50] vs 13.00 days [7.50-20.00]), and the in-PICU mortality rate in the normal-SMI group (10.00%) was lower than the low-SMI group (22.6%). Children with low SMD had a higher in-PICU mortality rate (25.6% vs 7.7%), were younger (36.00 months [12.00-120.00] vs 84.00 months [47.50-147.50]) and weighed less (16.40 kg [10.93-37.25] vs 23.00 kg [16.00-45.00]). Mortality was greater in patients with lower SMD and prolonged hospital stay (log-rank, P = 0.007). SMD was an independent predictor for length of PICU stay and in-PICU mortality.

CONCLUSIONS

Low baseline skeletal muscle quality in critically ill children is closely tied with a higher in-PICU mortality and longer PICU stay and is an independent risk factor for unfavorable clinical outcomes.

Recovery Trajectories in Children Requiring 3 or More Days of Invasive Ventilation

OBJECTIVES

To characterize health-related quality of life (HRQL) and functional recovery trajectories and risk factors for prolonged impairments among critically ill children receiving greater than or equal to 3 days of invasive ventilation.

DESIGN

Prospective cohort study.

SETTING

Quaternary children's hospital PICU.

PATIENTS

Children without a preexisting tracheostomy who received greater than or equal to 3 days of invasive ventilation, survived hospitalization, and completed greater than or equal to 1 postdischarge data collection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We evaluated 144 children measuring HRQL using proxy-report Pediatric Quality of Life Inventory and functional status using the Functional Status Scale (FSS) reflecting preillness baseline, PICU and hospital discharge, and 1, 3, 6, and 12 months after hospital discharge. They had a median age of 5.3 years (interquartile range, 1.1-13.0 yr), 58 (40%) were female, 45 (31%) had a complex chronic condition, and 110 (76%) had normal preillness FSS scores. Respiratory failure etiologies included lung disease ( n = 49; 34%), neurologic failure ( n = 23; 16%), and septic shock ( n = 22; 15%). At 1-month postdischarge, 68 of 122 (56%) reported worsened HRQL and 35 (29%) had a new functional impairment compared with preillness baseline. This improved at 3 months to 54 (46%) and 24 (20%), respectively, and remained stable through the remaining 9 months of follow-up. We used interaction forests to evaluate relative variable importance including pairwise interactions and found that therapy consultation within 3 days of intubation was associated with better HRQL recovery in older patients and those with better preillness physical HRQL. During the postdischarge year, 76 patients (53%) had an emergency department visit or hospitalization, and 62 (43%) newly received physical, occupational, or speech therapy.

CONCLUSIONS

Impairments in HRQL and functional status as well as health resource use were common among children with acute respiratory failure. Early therapy consultation was a modifiable characteristic associated with shorter duration of worsened HRQL in older patients.

Pediatric Intensive Care Unit Early Mobility Program: Impact on Patient Functional Status

INTRODUCTION

Patients admitted to the pediatric Intensive Care Unit (PICU) are frequently sedated, restrained, and placed on bed rest. These practices have known negative impacts including prolonged hospital stay and diminished functional status after discharge. The authors' objective was to investigate the impact of a PICU early mobility protocol on the frequency of orders for physical, occupational, and speech therapy (PT, OT, ST) and improvement in patient functional status.

METHODS

Patients admitted in 2019 prior to the development of the PICU early mobility protocol were compared to those admitted in 2020 who underwent the protocol. Differences in clinical characteristics; PICU length of stay; rates of PT, OT, and ST orders; rates of bedside mobility activities; and functional status scores (FSSs) were assessed in bivariate and multivariate analyses. The protocol included early PT, OT, and ST order placement and frequent in-room mobility activities.

RESULTS

Of the 384 patients included in the study, 216 (56%) were preprotocol patients, and 168 (44%) underwent the protocol. Patients in 2020 were more likely to receive a physical therapy order compared to their 2019 counterparts (79% vs 47%, p < 0.001). Patients in 2020 had a higher daily incidence of mobility activities compared to those in 2019 (4.88 activities vs 4.1 activities, p < 0.001). Changes in functional status scores were similar between the 2 groups.

CONCLUSION

PICU early mobility was associated with increased physical, occupational, and speech therapy orders and daily mobility activities but was not associated with a reduction in functional morbidity at discharge or 3 months post-discharge.

Thigh ultrasound monitoring identifies muscle atrophy in mechanically ventilated pediatric patients

Over the last decade, ultrasonography has taken on an increasingly important role in the daily management of critically patients and has recently been proposed as a means of measuring muscle volume and architecture. This study had two main aims: to monitor for the onset of muscle atrophy in mechanically ventilated pediatric patients during stays in a pediatric intensive care unit based on quadriceps femoris muscle thickness measurements and to study whether demographic and clinical variables have an impact on muscle loss in critically children. The study followed a prospective, observational, single-center design. The sample included all children admitted to our pediatric intensive care unit (PICU) who required mechanical ventilation for more than 48 h. Two trained clinicians measured the thickness of the quadriceps using a 12-MHz linear ultrasound transducer within 24 h of initiating invasive mechanical ventilation and again at 72 h, 1 week, and weekly thereafter until extubation. For the entire cohort, quadriceps femoris muscle thickness decreased by 4.67% on average (IQR = -13.4 to -0.59) between the first two assessments and 13% by the time of the final measurement (IQR = -24 to -0.5%) or 1.57%/day (p < 0.001). Approximately half of all the children (23/41; 56%) experienced muscle atrophy (defined a priori as a decrease in thickness of 10% or more). Bivariate analyses revealed that increasing age, being a child (vs. infant), cumulative energy and protein deficit, highest C-reactive protein value, exposure to neuromuscular blockers, and a longer stay in the PICU were all predictive of a greater decrease in thickness. In a multivariate model, exposure to neuromuscular blockers was linked with greater muscle loss.       Conclusion: In mechanically ventilated children, point-of-care ultrasonography can identify skeletal muscle atrophy. Muscle atrophy of limbs is strongly associated with the use of neuromuscular blockers. Ultrasound-based monitoring of the quadriceps femoris is a clinically useful tool for assessing muscle mass that can provide information on nutritional status and guide rehabilitation. What is Known: • ICU-acquired muscle atrophy is common and has a deleterious effect on adult outcomes. The prevalence and severity of muscular atrophy in critically ill children, however, are poorly understood. • Point-of-care ultrasonography has been put forward as an accurate, reliable method for monitoring variations in muscle mass.. What is New: • The quadriceps femoris muscle tends to suffer an intense loss of thickness early on in most critically ill children. • Quadriceps femoris ultrasound monitoring is a helpful tool for measuring muscle thickness and could lead to the development of novel therapies for critically ill children.

Nutritional management of children with acute kidney injury-clinical practice recommendations from the Pediatric Renal Nutrition Taskforce

The nutritional management of children with acute kidney injury (AKI) is complex. The dynamic nature of AKI necessitates frequent nutritional assessments and adjustments in management. Dietitians providing medical nutrition therapies to this patient population must consider the interaction of medical treatments and AKI status to effectively support both the nutrition status of patients with AKI as well as limit adverse metabolic derangements associated with inappropriately prescribed nutrition support. The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric renal dietitians and pediatric nephrologists, has developed clinical practice recommendations (CPR) for the nutritional management of children with AKI. We address the need for intensive collaboration between dietitians and physicians so that nutritional management is optimized in line with AKI medical treatments. We focus on key challenges faced by dietitians regarding nutrition assessment. Furthermore, we address how nutrition support should be provided to children with AKI while taking into account the effect of various medical treatment modalities of AKI on nutritional needs. Given the poor quality of evidence available, a Delphi survey was conducted to seek consensus from international experts. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs, based on the clinical judgment of the treating physician and dietitian. Research recommendations are provided. CPRs will be regularly audited and updated by the PRNT.

Nutrition for critically ill children with congenital heart disease

Children with congenital heart disease often require admission to the cardiac intensive care unit at some point in their lives, either after elective surgical or catheter-based procedures or during times of acute critical illness. Meeting both the macronutrient and micronutrient needs of children in the cardiac intensive care unit requires complex decision-making when considering gastrointestinal perfusion, vasoactive support, and fluid balance goals. Although nutrition guidelines exist for critically ill children, these cannot always be extrapolated to children with congenital heart disease. Children with congenital heart disease may also suffer unique circumstances, such as chylothoraces, heart failure, and the need for mechanical circulatory support, which greatly impact nutrition delivery. Guidelines for neonates and children with heart disease continue to be developed. We provide a synthesized narrative review of current literature and considerations for nutrition evaluation and management of critically ill children with congenital heart disease.

Macronutrient and Micronutrient Intake in Children with Lung Disease

This review article aims to summarize the literature findings regarding the role of micronutrients in children with lung disease. The nutritional and respiratory statuses of critically ill children are interrelated, and malnutrition is commonly associated with respiratory failure. The most recent nutrition support guidelines for critically ill children have recommended an adequate macronutrient intake in the first week of admission due to its association with good outcomes. In children with lung disease, it is important not to exceed the proportion of carbohydrates in the diet to avoid increased carbon dioxide production and increased work of breathing, which potentially could delay the weaning of the ventilator. Indirect calorimetry can guide the process of estimating adequate caloric intake and adjusting the proportion of carbohydrates in the diet based on the results of the respiratory quotient. Micronutrients, including vitamins, trace elements, and others, have been shown to play a role in the structure and function of the immune system, antioxidant properties, and the production of antimicrobial proteins supporting the defense mechanisms against infections. Sufficient levels of micronutrients and adequate supplementation have been associated with better outcomes in children with lung diseases, including pneumonia, cystic fibrosis, asthma, bronchiolitis, and acute respiratory failure.

Muscle Ultrasound Changes and Physical Function of Critically Ill Children: A Comparison of Rectus Femoris Cross-Sectional Area and Quadriceps Thickness Measurements

Quadriceps thickness (QT) and rectus femoris cross-sectional area (RF_CSA) are both used to evaluate muscle changes in critically ill children. However, their correlation and association with physical function has not been compared.

OBJECTIVES

To compare QT with RF_CSA changes, and their association with physical function in critically ill children.

DESIGN SETTING AND PARTICIPANTS

Secondary analysis of a prospective cohort study of children 0-18 years old admitted to a tertiary mixed PICU between January 2015 and October 2018 with PICU stay greater than 48 hours and greater than or equal to one organ dysfunction.

MAIN OUTCOMES AND MEASURES

Ultrasound QT and RF_CSA were measured at PICU admission, PICU discharge, hospital discharge, and 6 months post-discharge. QT and RF_CSA changes from baseline were compared with each other and with change in motor function, physical ability, and physical health-related quality of life (HRQOL).

RESULTS

Two hundred thirty-seven images from 66 subjects were analyzed. RF_CSA change was not significantly different from QT change at PICU (-8.07% [interquartile range (IQR), -17.11% to 4.80%] vs -4.55% [IQR, -14.32% to 4.35%]; p = 0.927) or hospital discharge (-5.62% [IQR, -15.00% to 9.42%] vs -8.81% [IQR, -18.67% to 2.39%]; p = 0.238) but was significantly greater than QT change at 6 months (32.7% [IQR, 5.74-109.76%] vs 9.66% [IQR, -8.17% to 25.70%]; p < 0.001). Motor function change at PICU discharge was significantly associated with RF_CSA change (adjusted β coefficient, 0.02 [95% CI, 0.01-0.03]; p = 0.013) but not QT change (adjusted β coefficient, -0.01 [95% CI, -0.02 to 0.01]; p = 0.415). Similar results were observed for physical HRQOL changes at hospital discharge (adjusted β coefficient for RF_CSA change, 0.51 [95% CI, 0.10-0.92]; p = 0.017 and adjusted β coefficient for QT change, -0.21 [-0.76 to 0.35]; p = 0.458). Physical ability was not significantly associated with RFCSA or QT changes at 6 months post-discharge.

CONCLUSIONS AND RELEVANCE

Ultrasound derived RF_CSA is associated with PICU motor function and hospital discharge physical HRQOL changes, unlike QT, and may be more useful for in-hospital muscle monitoring in critically ill children.

Pediatric Ventilator Liberation: One-Hour Versus Two-Hour Spontaneous Breathing Trials in a Single Center

BACKGROUND

The optimal spontaneous breathing trial (SBT) duration is not known for children who are critically ill. The study objective was to evaluate extubation outcomes between cohorts exposed to a 1- or 2-h SBT.

METHODS

This was a retrospective cohort study of a quality improvement project database in a 24-bed pediatric ICU. The intervention was a respiratory therapist-driven SBT clinical pathway across 2 improvement cycles by using a 2- or 1-h SBT. The primary outcomes were extubation failure and rescue noninvasive ventilation in the first 48 h. Secondary outcomes included SBT results and process measures.

RESULTS

There were 218 and 305 encounters in the 2- and 1-h cohorts, respectively. Extubation failure (7.3 vs 8.5%; P = .62) and rescue noninvasive ventilation rates (9.3 vs 8.2%; P = .68) were similar. In logistic regression models, SBT duration was not independently associated with either primary outcome. Extubation after 1-h SBT failure was associated with significantly higher odds of rescue noninvasive ventilation exposure (odds ratio 3.94, 95% CI 1.3-11.9; P = .02). SBT results were not associated with odds of extubation failure. There were 1,072 (2 h) and 1,333 (1 h) SBTs performed. The 1-h SBT pass rate was significantly higher versus the 2-h SBT (71.4 vs 51.1%; P < .001). Among all failed SBTs, the top 3 reported failure modes were tidal volume ≤ 5 mL/kg (23.6%), breathing frequency increase > 30% (21%), and oxygen saturation < 92% (17.3%). When considering all failed SBTs, 75.5% of failures occurred before 45 min.

CONCLUSIONS

A 1-h SBT may be a viable alternative to a 2-h version for the average child who is critically ill. Further, a 1-h SBT may better balance extubation outcomes and duration of invasive ventilation for the general pediatric ICU population.

Reference values of diaphragmatic dimensions in healthy children aged 0-8 years

Diaphragmatic thickness (Tdi) and diaphragm thickening fraction (dTF) are widely used parameters in ultrasound studies of the diaphragm in mechanically ventilated children, but normal values for healthy children are scarce. We determined reference values of Tdi and dTF using ultrasound in healthy children aged 0-8 years old and assessed their reproducibility. In a prospective, observational cohort, Tdi and dTF were measured on ultrasound images across four age groups comprising at least 30 children per group: group 1 (0-6 months), group 2 (7 months-1 year), group 3 (2-4 years) and group 4 (5-8 years). Ultrasound images of 137 healthy children were included. Mean Tdi at inspiration was 2.07 (SD 0.40), 2.09 (SD 0.40), 1.69 (SD 0.30) and 1.72 (SD 0.30) mm for groups 1, 2, 3 and 4, respectively. Mean Tdi at expiration was 1.64 (SD 0.30), 1.67 (SD 0.30), 1.38 (SD 0.20) and 1.42 (SD 0.20) mm for groups 1, 2, 3 and 4, respectively. Mean Tdi at inspiration and mean Tdi at expiration for groups 1 and 2 were significantly greater than those for groups 3 and 4 (both p < 0.001). Mean dTF was 25.4% (SD 10.4), 25.2% (SD 8.3), 22.8% (SD 10.9) and 21.3% (SD 7.1) for group 1, 2, 3 and 4, respectively. The intraclass correlation coefficients (ICC) representing the level of inter-rater reliability between two examiners performing the ultrasounds was 0.996 (95% CI 0.982-0.999). ICC of the inter-rater reliability between the raters in 11 paired assessments was 0.989 (95% CI 0.973-0.995).   Conclusion: Ultrasound measurements of Tdi and dTF were highly reproducible in healthy children aged 0-8 years.    Trial registration: ClinicalTrials.gov identifier (NCT number): NCT04589910. What is Known: • Diaphragmatic thickness and diaphragm thickening fraction are widely used parameters in ultrasound studies of the diaphragm in mechanically ventilated children, but normal values for healthy children to compare these with are scarce. What is New: • We determined normal values of diaphragmatic thickness and diaphragm thickening fraction using ultrasound in 137 healthy children aged 0-8 years old. The diaphragmatic thickness of infants up to 1 year old was significantly greater than that of children from 2 to 8 years old. Diaphragmatic thickness decreased with an increase in body surface area. These normal values in healthy children can be used to assess changes in respiratory muscle thickness in mechanically ventilated children.

Electrical impedance myography combined with quantitative assessment techniques in paretic muscle of stroke survivors: Insights and challenges

Aging is a non-modifiable risk factor for stroke and the global burden of stroke is continuing to increase due to the aging society. Muscle dysfunction, common sequela of stroke, has long been of research interests. Therefore, how to accurately assess muscle function is particularly important. Electrical impedance myography (EIM) has proven to be feasible to assess muscle impairment in patients with stroke in terms of micro structures, such as muscle membrane integrity, extracellular and intracellular fluids. However, EIM alone is not sufficient to assess muscle function comprehensively given the complex contributors to paretic muscle after an insult. This article discusses the potential to combine EIM and other common quantitative methods as ways to improve the assessment of muscle function in stroke survivors. Clinically, these combined assessments provide not only a distinct advantage for greater accuracy of muscle assessment through cross-validation, but also the physiological explanation on muscle dysfunction at the micro level. Different combinations of assessments are discussed with insights for different purposes. The assessments of morphological, mechanical and contractile properties combined with EIM are focused since changes in muscle structures, tone and strength directly reflect the muscle function of stroke survivors. With advances in computational technology, finite element model and machine learning model that incorporate multi-modal evaluation parameters to enable the establishment of predictive or diagnostic model will be the next step forward to assess muscle function for individual with stroke.

Pediatric ventilation liberation: evaluating the role of endotracheal secretions in an extubation readiness bundle

BACKGROUND

An evidence gap exists regarding the role of endotracheal secretions in pediatric extubation decisions. This study aims to evaluate whether endotracheal secretion burden independently correlates with pediatric extubation failure.

METHODS

This is a single-center, prospective cohort study of children aged <19 years requiring intubation. Nurses (RN) and respiratory therapists (RT) independently used a novel secretion assessment score focusing on secretion volume, character, and trend. We hypothesized that the RN and RT secretion scores would not correlate with extubation outcome and inter-rater reliability would be poor.

RESULTS

RN secretion character sub-score (OR 3.3, 95% CI 1.1-11.1, p = 0.048) was independently associated with extubation failure. RN and RT inter-rater reliability was poor (correlation 0.385, 95% CI 0.339-0.429, p < 0.001). A failure prediction model incorporating the RN secretion character sub-score as well as indication for mechanical ventilation and spontaneous breathing trial result demonstrated an area under the receiver operating curve of 0.817 (95% CI 0.730-0.904, p < 0.001).

CONCLUSIONS

In the general pediatric population, the RN assessment of endotracheal secretion character was independently associated with extubation failure. A model incorporating indication for mechanical ventilation, spontaneous breathing result, and RN assessment of endotracheal secretion character demonstrated reasonable accuracy in predicting failure in those clinically selected for extubation.

IMPACT

Development of comprehensive and sensitive extubation readiness bundles are key to balancing the competing risks of prolonged invasive mechanical ventilation duration and extubation failure. Evidence for clinical factors linked to extubation outcomes in children are limited. Endotracheal secretion burden is a common factor considered but has not been studied. This study supports a role for endotracheal secretion burden, as assessed by the bedside nurse, in extubation readiness bundles. Inter-rater reliability with respiratory therapists was poor. A model incorporating other key factors showed good discrimination for extubation outcome and sets the stage for prospective evaluation in the general population and diagnosis-specific subgroups.

Effectiveness of physical rehabilitation interventions in critically ill patients-A protocol for an overview of systematic reviews

INTRODUCTION

Adult and pediatric patients admitted to intensive care units (ICUs) requiring invasive ventilatory support, sedation, and muscle blockade may present neuromusculoskeletal deterioration. Different physical rehabilitation interventions have been studied to evaluate their effectiveness in improving critically ill patients' outcomes. Given that many published systematic reviews (SRs) aims to determine the effectiveness of different types of physical rehabilitation interventions, it is necessary to group them systematically and assess the methodological quality of SRs to help clinicians make better evidence-based decisions. This overview of SRs (OoSRs) aims to map the existing evidence and to determine the effectiveness of physical rehabilitation interventions to improve neuromusculoskeletal function and other clinical outcomes in adult and pediatric critically ill patients.

METHODS

An OoSRs of randomized and non-randomized clinical trials involving critically ill adult and pediatric patients receiving physical rehabilitation intervention will be conducted. A sensitive search of MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCOhost), Cochrane Library, Epistemonikos, and other search resources will be conducted. Two independent reviewers will conduct study selection, data extraction, and methodological quality assessment. Discrepancies will be resolved by consensus or a third reviewer. The degree of overlap of studies will be calculated using the corrected covered area. The methodological quality of the SRs will be measured using the AMSTAR-2 tool. The GRADE framework will report the certainty of evidence by selecting the "best" SR for each physical rehabilitation intervention and outcome.

DISCUSSION

The findings of this overview are expected to determine the effectiveness and safety of physical rehabilitation interventions to improve neuromusculoskeletal function in adult and pediatric critically ill patients based on a wide selection of the best available evidence and to determine the knowledge gaps in this topic by mapping and assessing the methodological quality of published SRs.

REGISTRATION NUMBER

CRD42023389672.

No association between thickening fraction of the diaphragm and extubation success in ventilated children

Introduction

In mechanically ventilated adults, thickening fraction of diaphragm (dTF) measured by ultrasound is used to predict extubation success. Whether dTF can also predict extubation success in children is unclear.

Aim

To investigate the association between dTF and extubation success in children. Second, to assess diaphragm thickness during ventilation and the correlation between dTF, diaphragm thickness (Tdi), age and body surface.

Method

Prospective observational cohort study in children aged 0-18 years old with expected invasive ventilation for >48 h. Ultrasound was performed on day 1 after intubation (baseline), day 4, day 7, day 10, at pre-extubation, and within 24 h after extubation. Primary outcome was the association between dTF pre-extubation and extubation success. Secondary outcome measures were Tdi end-inspiratory and Tdi end-expiratory and atrophy defined as <10% decrease of Tdi end-expiratory versus baseline at pre-extubation. Correlations were calculated with Spearman correlation coefficients. Inter-rater reliability was calculated with intraclass correlation (ICC).

Results

Fifty-three patients, with median age 3.0 months (IQR 0.1-66.0) and median duration of invasive ventilation of 114.0 h (IQR 55.5-193.5), were enrolled. Median dTF before extubation with Pressure Support 10 above 5 cmH₂O was 15.2% (IQR 9.7-19.3). Extubation failure occurred in six children, three of whom were re-intubated and three then received non-invasive ventilation. There was no significant association between dTF and extubation success; OR 0.33 (95% CI; 0.06-1.86). Diaphragmatic atrophy was observed in 17/53 cases, in three of extubation failure occurred. Children in the extubation failure group were younger: 2.0 months (IQR 0.81-183.0) vs. 3.0 months (IQR 0.10-48.0); p = 0.045. At baseline, pre-extubation and post-extubation there was no significant correlation between age and BSA on the one hand and dTF, Tdi- insp and Tdi-exp on the other hand. The ICC representing the level of inter-rater reliability between the two examiners performing the ultrasounds was 0.994 (95% CI 0.970-0.999). The ICC of the inter-rater reliability between the raters in 36 paired assessments was 0.983 (95% CI 0.974-0.990).

Conclusion

There was no significant association between thickening fraction of the diaphragm and extubation success in ventilated children.

Diaphragmatic Thickening Fraction by Ultrasound in Mechanically Ventilated Pediatric Patients: Pilot Observations During Spontaneous Breathing Trials

OBJECTIVES

In critically ill, mechanically ventilated adults, diaphragmatic atrophy and reduced diaphragmatic thickening fraction (DTF) has been associated with poor extubation outcomes. Diaphragmatic ultrasound assessment in critically ill pediatric patients shows similar results, though studies are on-going. We sought to explore the feasibility and utility of using DTF, obtained during a spontaneous breathing trial (SBT) in predicting weaning outcomes.

METHODS

We conducted a prospective, observational study in a single-center tertiary noncardiac pediatric intensive care unit (PICU) in a children's hospital. Mechanically ventilated pediatric patients were included except for those with preexisting conditions of neuromuscular weakness, diaphragm paresis, or chronic respiratory failure requiring non-invasive or invasive mechanical ventilation at baseline. A convenience sample of 38 patients were included in the study.

RESULTS

Weaning failure occurred in 10/38 (26%) instances with 9/38 (24%) occurring due to failed SBT and 1/38 (2%) due to failed extubation requiring reintubation. Median DTF was 24% (IQR: 12-33). DTF was significantly lower in instances of failed SBT, 12% compared to 27% (P < .01). The odds ratio (OR) of SBT failure utilizing: TF < 25% is 12 (CI: 1.33-108.0, Z-score: 2.22, P = .027), TV <5 mL/kg was 10.4 (CI: 1.76-61.67, Z-score: 2.58, P = .01), and combined TV <5 mL/kg and TF < 25% is 17.6 (CI: 1.19-259.61, Z-score: 2.09, P = .04).

CONCLUSIONS

Our preliminary study suggests that ultrasound measurements of diaphragm thickening fraction during spontaneous breaths in mechanically ventilated pediatric patients may be a useful addition in predicting weaning readiness.

Comparing ventilation modes by electrical impedance segmentography in ventilated children

Electrical impedance segmentography offers a new radiation-free possibility of continuous bedside ventilation monitoring. The aim of this study was to evaluate the efficacy and reproducibility of this bedside tool by comparing synchronized intermittent mandatory ventilation (SIMV) with neurally adjusted ventilatory assist (NAVA) in critically-ill children. In this prospective randomized case-control crossover trial in a pediatric intensive care unit of a tertiary center, including eight mechanically-ventilated children, four sequences of two different ventilation modes were consecutively applied. All children were randomized into two groups; starting on NAVA or SIMV. During ventilation, electric impedance segmentography measurements were recorded. The relative difference of vertical impedance between both ventilatory modes was measured (median 0.52, IQR 0-0.87). These differences in left apical lung segments were present during the first (median 0.58, IQR 0-0.89, p = 0.04) and second crossover (median 0.50, IQR 0-0.88, p = 0.05) as well as across total impedance (0.52 IQR 0-0.87; p = 0.002). During NAVA children showed a shift of impedance towards caudal lung segments, compared to SIMV. Electrical impedance segmentography enables dynamic monitoring of transthoracic impedance. The immediate benefit of personalized ventilatory strategies can be seen when using this simple-to-apply bedside tool for measuring lung impedance.

Pediatric Ventilation Liberation: Bundled Extubation Readiness and Analgosedation Pathways Decrease Mechanical Ventilation Duration and Benzodiazepine Exposure

BACKGROUND

Recent studies reported that children on mechanical ventilation who were managed with an analgosedation approach and standardized extubation readiness testing experienced better outcomes, including decreased delirium and invasive mechanical ventilation duration.

METHODS

This was a quality improvement project in a 24-bed pediatric ICU within a single center, including subjects ≤ 18 years old who required invasive mechanical ventilation via an oral or nasal endotracheal tube. The aim was to decrease the invasive mechanical ventilation duration for all the subjects by 25% within 9 months through the development and implementation of bundled benzodiazepine-sparing analgosedation and extubation readiness testing clinical pathways.

RESULTS

In the pre-implementation cohort, there were 274 encounters, with 253 (92.3%) that met inclusion for ending in an extubation attempt. In the implementation cohort, there were 367 encounters with 332 (90.5%) that ended in an extubation attempt. The mean invasive mechanical ventilation duration decreased by 23% (Pre 3.95 d vs Post 3.1 d; P = .039) after the implementation without a change in the mean pediatric ICU length of stay (Pre 7.5 d vs Post 6.5 d; P = .42). No difference in unplanned extubation (P > .99) or extubation failure rates (P = .67) were demonstrated. Sedation levels as evaluated by the mean State Behavioral Scale were similar (Pre -1.0 vs Post -1.1; P = .09). The median total benzodiazepine dose administered decreased by 75% (Pre 0.4 vs Post 0.1 mg/kg/ventilated day; P < .001). No difference in narcotic withdrawal (Pre 17.8% vs Post 16.4%; P = .65) or with delirium treatment (Pre 5.5% vs Post 8.7%; P = .14) was demonstrated.

CONCLUSIONS

A multidisciplinary, bundled benzodiazepine-sparing analgosedation and extubation readiness testing approach resulted in a reduction in mechanical ventilation duration and benzodiazepine exposure without impacting key balancing measures. External validity needs to be evaluated in similar centers and consensus on best practices developed.

Ultrasound imaging of diaphragmatic motion

The diaphragm is the key muscle of respiration, especially in infants. Diaphragmatic dysfunction and paralysis can have significant implications for medical management and treatment, and they can be challenging to diagnose by clinical parameters alone. Multiple imaging modalities are useful for assessing the diaphragm, but US - specifically M-mode US - offers several distinct advantages and few limitations compared to fluoroscopy, radiography, CT and MRI. The purpose of this manuscript is to discuss the pathophysiology of the diaphragm, review common indications for dynamic diaphragmatic US, describe optimal imaging technique, and discuss how to avoid imaging pitfalls.

Pediatric Ventilation Liberation: A Survey of International Practice Among 555 Pediatric Intensivists

Pediatric ventilation liberation has limited evidence, likely resulting in wide practice variation. To inform future work, practice patterns must first be described.

Reliability and Validity of an Ultrasound-Based Protocol for Measurement of Quadriceps Muscle Thickness in Children

Introduction and aims: Accurate determination of skeletal muscle size is of great importance in multiple settings including resistance exercise, aging, disease, and disuse. Ultrasound (US) measurement of muscle thickness (MT) is a method of relatively high availability and low cost. The present study aims to evaluate a multisite ultrasonographic protocol for measurement of MT with respect to reproducibility and correlation to gold-standard measurements of muscle volume (MV) with magnetic resonance imaging (MRI) in children.

Material and methods: 15 children completed the study (11 ± 1 year, 41 ± 8 kg, 137 ± 35 cm). Following 20 min supine rest, two investigators performed US MT measurements of all four heads of the m. quadriceps femoris, at pre-determined sites. Subsequently, MRI scanning was performed and MV was estimated by manual contouring of individual muscle heads.

Results: Ultrasound measurement of MT had an intra-rater reliability of ICC = 0.985–0.998 (CI 95% = 0.972–0.998) and inter-rater reliability of ICC = 0.868–0.964 (CI 95% = 0.637–0.983). The US examinations took less than 15 min, per investigator. Muscle thickness of all individual quadriceps muscles correlated significantly with their corresponding MV as measured by MRI (overall r = 0.789, p < 0.001).

Conclusion: The results of this study indicate that US measurement of MT using a multisite protocol is a competitive alternative to MRI scanning, especially with respect to availability and time consumption. Therefore, US MT could allow for wider clinical and scientific implementation.

Evaluation of Changes in Quadriceps Femoris Muscle in Critically III Children Using Ultrasonography

OBJECTIVE

To measure changes in muscle thickness and echogenicity, reflecting muscle bulk and quality, respectively, of quadriceps femoris (QF), in critically ill children.

METHODS

This study was done on 58 children aged 1-18 y requiring mechanical ventilation, admitted in a pediatric intensive care unit (PICU) of a tertiary care hospital from January 2018 to June 2019. QF thickness was measured twice in longitudinal plane and twice in transverse plane, and an average of these four measurements was used. Muscle quality was assessed using ImageJ software to determine the mean echogenicity, and was calculated separately for vastus intermedius and rectus femoris. These observations were repeated on day 3 and day 7 of the ICU stay.

RESULTS

The median muscle thickness of QF was 1.58 cm, and vastus intermedius and rectus femoris echogenicity was 35.5 and 25.88 units, respectively in the present cohort, with median age of 6 y. Only 36 of the 58 patients underwent day 7 ultrasonography, as the remainder were either extubated or died. There was no significant change in the muscle thickness over 7 d. Rectus femoris echogenicity increased significantly over 7 d by 16.1% (p = 0.03). Baseline vastus intermedius echogenicity was significantly higher in patients who subsequently died during the course of their illness (p = 0.026).

CONCLUSION

There was a significant change in rectus femoris echogenicity, but not in QF thickness. Echogenicity rather than muscle thickness may be a more sensitive marker for changes in muscle properties.

Ventilation Liberation Practices Among 380 International PICUs

1) Characterize the prevalence of ventilator liberation protocol use in international PICUs, 2) identify the most commonly used protocol elements, and 3) estimate an international extubation failure rate and use of postextubation noninvasive respiratory support modes.

Nutritional Support for Pediatric Severe Traumatic Brain Injury

In critically ill children with severe traumatic brain injury (sTBI), nutrition may help facilitate optimal recovery. There is ongoing research regarding nutritional practices in the pediatric intensive care unit (PICU). These are focused on identifying a patient's most appropriate energy goal, the mode and timing of nutrient delivery that results in improved outcomes, as well as balancing these goals against inherent risks associated with nutrition therapy. Within the PICU population, children with sTBI experience complex physiologic derangements in the acute post-injury period that may alter metabolic demand, leading to nutritional needs that may differ from those in other critically ill patients. Currently, there are relatively few studies examining nutrition practices in PICU patients, and even fewer studies that focus on pediatric sTBI patients. Available data suggest that contemporary neurocritical care practices may largely blunt the expected hypermetabolic state after sTBI, and that early enteral nutrition may be associated with lower morbidity and mortality. In concordance with these data, the most recent guidelines for the management of pediatric sTBI released by the Brain Trauma Foundation recommend initiation of enteral nutrition within 72 h to improve outcome (Level 3 evidence). In this review, we will summarize available literature on nutrition therapy for children with sTBI and identify gaps for future research.

Diaphragm Ultrasonography to Predict Noninvasive Respiratory Treatment Failure in Infants With Severe Bronchiolitis

BACKGROUND

Noninvasive respiratory support is commonly used in treatment of bronchiolitis. Determinants of failure are needed to prevent delayed intubation.

METHODS

We conducted a prospective observational pilot study in infants admitted to a pediatric ICU. Diaphragmatic excursion (dExc), diaphragmatic inspiratory/expiratory time, and diaphragmatic thickening fraction (dTF) were recorded at admission, 24 h, and 48 h in both hemidiaphragms.

RESULTS

Twenty-six subjects were included (14 on HFNC and 12 on NIV) with a total of 56 ultrasonographic evaluations. Three subjects required invasive ventilation. Sixty-four percent of the subjects on HFNC required NIV as rescue therapy and 2/14 invasive ventilation (14.2%). In the HFNC group there were no differences in dExc between those who required escalation to NIV or invasive ventilation and those who didn't. Left dTF was higher in subjects on HFNC requiring invasive ventilation versus those needing NIV (left dTF 47% vs 22% [13-30]; P = .046, r = 0.7). Diaphragmatic I:E ratios were higher in infants on HFNC requiring invasive ventilation and diaphragmatic expiratory time was shorter (left P = .038; right P = .02). In the NIV group there were no differences in dExc, I:E ratios, or dTF between subjects needing escalation to invasive ventilation and those who didn't. We found no correlation between a clinical work of breathing score and echographic dTF.

CONCLUSIONS

In infants with moderate or severe bronchiolitis receiving HFNC, the use of ultrasonographic left dTF could help predict respiratory treatment failure and need for invasive ventilation. The use of ultrasonographic dExc is of little help to predict both.

Nurse-driven early rehabilitation protocol for critically ill children

BACKGROUND

Physical impairment is a major morbidity in children surviving intensive care. The main objective of this study was to evaluate the effectiveness of a nurse-driven protocol in the early mobilization of critically ill children in terms of reduction of motor dysfunction, pediatric intensive care unit stays, and ventilator days. The secondary objective was to evaluate safety, in terms of injury, dislodgement of medical devices, and cardiorespiratory instability attributable to the intervention.

METHODS

The early rehabilitation intervention was initiated in July 2020. This retrospective interrupted time-series study was divided into the pre-implementation phase (January-June 2020) and the post-implementation phase (July-December 2020). The motor function domain of the Functional Status Scale was used to define the motor dysfunction after pediatric intensive care unit discharge.

RESULTS

Twenty-five children were allocated in each group. The median age of the whole cohort was 11.5 months and approximately 58% of the population was male. The baseline characteristics of both groups were not statistically significant. There was a statistically significant reduction in motor dysfunction after protocol implementation (64.0% vs 36.0%; P = 0.044) with an absolute risk reduction of 28%. The number needed to treat was 3.6 children. There were no statistically significant differences in the median ventilator days, length of stay in the intensive care unit, and hospital length of stay. No complications were found.

CONCLUSIONS

A nurse-driven protocol for the early mobilization of critically ill children was feasible and could be effective in reducing post-intensive care motor dysfunction.

Ultrasound Protocols to Assess Skeletal and Diaphragmatic Muscle in People Who Are Critically Ill: A Systematic Review

This study aims to review published studies that use protocols and ultrasound measurements to evaluate skeletal and diaphragmatic muscles in patients who are critically ill. We searched for references on databases through September 2020 and included in our systematic review studies that used muscular ultrasound to assess skeletal or diaphragm muscles in patients who are critically ill. Seventy-six studies were included, 32 (1720 patients) using skeletal-muscle ultrasound and 44 (2946 patients) using diaphragmatic-muscle ultrasound, with a total of 4666 patients. The population is predominantly adult men. As for designs, most studies (n = 62) were cohort studies. B-mode B was dominant in the evaluations. Medium-to-high frequency bands were used in the analysis of peripheral muscles and medium-to-low frequency bands for diaphragmatic muscles. Evaluation of the echogenicity, muscle thickness and pennation angle of the muscle was also reported. These variables are important in the composition of the diagnosis of muscle loss. Studies demonstrate great variability in their protocols, and sparse description of the important variables that can directly interfere with the quality and validity of these measures. Therefore, a document is needed that standardizes these parameters for ultrasound assessment in patients who are critically ill.

Actigraphy in mechanically ventilated pediatric ICU patients: comparison to PSG and evaluation of behavioral circadian rhythmicity

Sleep disruption is common in pediatric intensive care unit (PICU) patients, but measuring sleep in this population is challenging. We aimed to evaluate the utility of actigraphy for estimating circadian rhythmicity in mechanically ventilated PICU patients and its accuracy for measuring sleep by comparing it to polysomnogram (PSG). We conducted a single-center prospective observational study of children 6 months - 17 years of age receiving mechanical ventilation and standard, protocolized sedation for acute respiratory failure, excluding children with acute or historical neurologic injury. We enrolled 16 children and monitored them with up to 14 days of actigraphy and 24 hours of simultaneous limited (10 channel) PSG. Daily actigraphy-based activity profiles demonstrated that patients had a high level of nighttime activity (30-41% of total activity), suggesting disrupted circadian activity cycles. Among n = 12 patients with sufficient actigraphy and PSG data overlap, actigraphy-based sleep estimation showed poor agreement with PSG-identified sleep states, with good sensitivity (94%) but poor specificity (28%), low accuracy (70%,) and low agreement (Cohen's kappa = 0.2, 95% CI = 0.08-0.31). Using univariate linear regression, we identified that Cornell Assessment of Pediatric Delirium scores were associated with accuracy of actigraphy but that other clinical factors including sedative medication doses, activity levels, and restraint use were not. In this population, actigraphy did not reliably discern between sleep and wake states. However, in select patients, actigraphy was able to distinguish diurnal variation in activity patterns, and therefore may be useful for evaluating patients' response to circadian-oriented interventions.

Ultrasound Assessment of Quadriceps Femoris Muscle Thickness in Critically Ill Children

OBJECTIVES

Evaluate the reliability of ultrasound to measure quadriceps femoris muscle thickness in critically ill children and to describe serial changes in quadriceps femoris muscle thickness in relation to fluid balance and nutritional intake.

DESIGN

Prospective observational study.

SETTING

Tertiary care children's hospital.

PATIENTS

Inpatients age 3 months to 18 years recently admitted to the ICU who were sedated and mechanically ventilated at the time of the first ultrasound scan.

METHODS

Prospective observational study to examine the reliability of averaged ultrasound measurements of quadriceps femoris muscle thickness. Change in average quadriceps femoris muscle thickness over time was correlated with fluid balance and nutritional intake.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Averaged quadriceps femoris muscle thickness demonstrated good to excellent reliability when comparing pediatric critical care providers to pediatric radiologists and when comparing between different pediatric critical care providers. We found no significant association between fluid balance over 1 or 3 days and change in quadriceps femoris muscle thickness over the same time frame. However, there was a significant association between percent of goal calories (p < 0.001) or percent of goal protein (p < 0.001) over 6 days and change in quadriceps femoris muscle thickness over the same time frame.

CONCLUSIONS

Averaged ultrasound measurements of quadriceps femoris muscle thickness demonstrate good to excellent reliability, are not confounded by fluid balance, and are useful for tracking changes in muscle thickness that are associated with nutritional intake. Ultrasound-based assessment of quadriceps femoris is a clinically useful tool for evaluating muscle mass and may be a proxy for nutritional status.

A narrative review of skeletal muscle atrophy in critically ill children: pathogenesis and chronic sequelae

Muscle wasting is now recognized as a growing, debilitating problem in critically ill adults, resulting in long-term deficits in function and an impaired quality of life. Ultrasonography has demonstrated decreases in skeletal muscle size during pediatric critical illness, although variations exist. However, muscle protein turnover patterns during pediatric critical illness are unclear. Understanding muscle protein turnover during critical illness is important in guiding interventions to reduce muscle wasting. The aim of this review was to explore the possible protein synthesis and breakdown patterns in pediatric critical illness. Muscle protein turnover studies in critically ill children are lacking, with the exception of those with burn injuries. Children with burn injuries demonstrate an elevation in both muscle protein breakdown (MPB) and synthesis during critical illness. Extrapolations from animal models and whole-body protein turnover studies in children suggest that children may be more dependent on anabolic factors (e.g., nutrition and growth factors), and may experience greater muscle degradation in response to insults than adults. Yet, children, particularly the younger ones, are more responsive to anabolic agents, suggesting modifiable muscle wasting during critical illness. There is a lack of evidence for muscle wasting in critically ill children and its correlation with outcomes, possibly due to current available methods to study muscle protein turnover in children-most of which are invasive or tedious. In summary, children may experience muscle wasting during critical illness, which may be more reversible by the appropriate anabolic agents than adults. Age appears an important determinant of skeletal muscle turnover. Less invasive methods to study muscle protein turnover and associations with long-term outcome would strengthen the evidence for muscle wasting in critically ill children.

A narrative review of diaphragmatic ultrasound in pediatric critical care

The use of point of care ultrasound (POCUS) at the bedside has increased dramatically within emergency medicine and in critical care. Applications of POCUS have spread to include diaphragmatic assessments in both adults and children. Diaphragm POCUS can be used to assess for diaphragm dysfunction (DD) and atrophy or to guide ventilator titration and weaning. Quantitative, semi-quantitative and qualitative measurements of diaphragm thickness, diaphragm excursion, and diaphragm thickening fraction provide objective data related to DD and atrophy. The potential for quick, noninvasive, and repeatable bedside diaphragm assessments has led to a growing amount of literature on diaphragm POCUS. To date, there are no reviews of the current state of diaphragm POCUS in pediatric critical care. The aims of this narrative review are to summarize the current literature regarding techniques, reference values, applications, and future innovations of diaphragm POCUS in critically ill children. A summary of current practice and future directions will be discussed.

Neurally-Adjusted Ventilatory Assist (NAVA) versus Pneumatically Synchronized Ventilation Modes in Children Admitted to PICU

Traditionally, invasively ventilated children in the paediatric intensive care unit (PICU) are weaned using pneumatically-triggered ventilation modes with a fixed level of assist. The best weaning mode is currently not known. Neurally adjusted ventilatory assist (NAVA), a newer weaning mode, uses the electrical activity of the diaphragm (Edi) to synchronise ventilator support proportionally to the patient’s respiratory drive. We aimed to perform a systematic literature review to assess the effect of NAVA on clinical outcomes in invasively ventilated children with non-neonatal lung disease. Three studies (n = 285) were included for analysis. One randomised controlled trial (RCT) of all comers showed a significant reduction in PICU length of stay and sedative use. A cohort study of acute respiratory distress syndrome (ARDS) patients (n = 30) showed a significantly shorter duration of ventilation and improved sedation with the use of NAVA. A cohort study of children recovering from cardiac surgery (n = 75) showed significantly higher extubation success, shorter duration of ventilation and PICU length of stay, and a reduction in sedative use. Our systematic review presents weak evidence that NAVA may shorten the duration of ventilation and PICU length of stay, and reduce the requirement of sedatives. However, further RCTs are required to more fully assess the effect of NAVA on clinical outcomes and treatment costs in ventilated children.

Sarcopenia in critically ill children: A bedside assessment using point-of-care ultrasound and anthropometry

BACKGROUND & AIMS

Due to the lack of validated methods of muscle assessment, sarcopenia is not well described in critically ill children. The main objectives of this study were to assess muscle wasting using point-of-care ultrasound (POCUS) and anthropometry, as well as its association with nutrition delivery in PICU.

METHODS

This was a single-center, prospective cohort study, including consecutive children admitted to the PICU. Quadriceps femoris muscle thickness (QFMT) and anthropometrics measurements were performed at admission and then weekly until the 14th day of the PICU stay. The three moments of assessment were defined as T0 (baseline), T1 (7th day) and T2 (14th day). For analysis purposes, participants assessed only in T0 and T1 were defined as Subgroup 1, while those assessed in T0, T1 and T2 were defined as Subgroup 2. Actual total daily intake was determined by patient intake records until discharge or during the first 14 full days of PICU admission.

RESULTS

In all, 119 patients were included with a median age of 12.0 months (IQR 4.0-42.5). In Subgroup 1, QFMT significantly decreased between T0 and T1 (-12.93 ± 14.07 %; p < 0.001), and the same was observed in Subgroup 2 (-13.81 ± 13.05 %; p < 0.001). However, no differences in QFMT was observed between T1 and T2 (-2.06 ± 13.80 %; p = 0.936). Triceps skinfold thickness, mid-upper arm circumference, and upper arm muscle area presented a similar pattern of changes between periods in both groups. Decrease of QFMT at T1 was significantly correlated with the cumulative protein deficit in both subgroups, but not with the cumulative energy deficit.

CONCLUSION

Substantial muscle wasting occurs early in critically ill children and may be related to insufficient protein delivery. Anthropometric measurements are valuable in PICU and POCUS has the potential to play a major role in sarcopenia assessment during critical illnesses.

TRIAL REGISTRATION

Brazilian Clinical Trials registry, registration number: RBR-85YYGN.

Evolution of inspiratory muscle function in children during mechanical ventilation

BACKGROUND

There is no universally accepted method to assess the pressure-generating capacity of inspiratory muscles in children on mechanical ventilation (MV), and no study describing its evolution over time in this population.

METHODS

In this prospective observational study, we have assessed the function of the inspiratory muscles in children on various modes of MV. During brief airway occlusion maneuvers, we simultaneously recorded airway pressure depression at the endotracheal tube (ΔPaw, force generation) and electrical activity of the diaphragm (EAdi, central respiratory drive) over five consecutive inspiratory efforts. The neuro-mechanical efficiency ratio (NME, ΔPaw/EAdimax) was also computed. The evolution over time of these indices in a group of children in the pediatric intensive care unit (PICU) was primarily described. As a secondary objective, we compared these values to those measured in a group of children in the operating room (OR).

RESULTS

In the PICU group, although median NMEoccl decreased over time during MV (regression coefficient - 0.016, p = 0.03), maximum ΔPawmax remained unchanged (regression coefficient 0.109, p = 0.50). Median NMEoccl at the first measurement in the PICU group (after 21 h of MV) was significantly lower than at the only measurement in the OR group (1.8 cmH2O/µV, Q1-Q3 1.3-2.4 vs. 3.7 cmH2O/µV, Q1-Q3 3.5-4.2; p = 0.015). Maximum ΔPawmax in the PICU group was, however, not significantly different from the OR group (35.1 cmH2O, Q1-Q3 21-58 vs. 31.3 cmH2O, Q1-Q3 28.5-35.5; p = 0.982).

CONCLUSIONS

The function of inspiratory muscles can be monitored at the bedside of children on MV using brief airway occlusions. Inspiratory muscle efficiency was significantly lower in critically ill children than in children undergoing elective surgery, and it decreased over time during MV in critically ill children. This suggests that both critical illness and MV may have an impact on inspiratory muscle efficiency.

Physical Functioning After Admission to the PICU: A Scoping Review

Supplemental Digital Content is available in the text.

Objectives:

To conduct a scoping review to 1) describe findings and determinants of physical functioning in children during and/or after PICU stay, 2) identify which domains of physical functioning are measured, 3) and synthesize the clinical and research knowledge gaps.

Data Sources:

A systematic search was conducted in PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library databases following the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews guidelines.

Study Selection:

Two investigators independently screened and included studies against predetermined criteria.

Data Extraction:

One investigator extracted data with review by a second investigator. A narrative analyses approach was used.

Data Synthesis:

A total of 2,610 articles were identified, leaving 68 studies for inclusion. Post-PICU/hospital discharge scores show that PICU survivors report difficulties in physical functioning during and years after PICU stay. Although sustained improvements in the long-term have been reported, most of the reported levels were lower compared with the reference and baseline values. Decreased physical functioning was associated with longer hospital stay and presence of comorbidities. A diversity of instruments was used in which mobility and self-care were mostly addressed.

CONCLUSIONS:

The results show that children perceive moderate to severe difficulties in physical functioning during and years after PICU stay. Longitudinal assessments during and after PICU stay should be incorporated, especially for children with a higher risk for poor functional outcomes. There is need for consensus on the most suitable methods to assess physical functioning in children admitted to the PICU.

Muscle atrophy in critically ill patients : a review of its cause, evaluation, and prevention

Critically ill patients exhibit prominent muscle atrophy, which occurs rapidly after ICU admission and leads to poor clinical outcomes. The extent of atrophy differs among muscles as follows: upper limb: 0.7%-2.4% per day, lower limb: 1.2%-3.0% per day, and diaphragm 1.1%-10.9% per day. This atrophy is caused by numerous risk factors such as inflammation, immobilization, nutrition, hyperglycemia, medication, and mechanical ventilation. Muscle atrophy should be monitored noninvasively by ultrasound at the bedside. Ultrasound can assess muscle mass in most patients, although physical assessment is limited to almost half of all critically ill patients due to impaired consciousness. Important strategies to prevent muscle atrophy are physical therapy and electrical muscular stimulation. Electrical muscular stimulation is especially effective for patients with limited physical therapy. Regarding diaphragm atrophy, mechanical ventilation should be adjusted to maintain spontaneous breathing and titrate inspiratory pressure. However, the sufficient timing and amount of nutritional intervention remain unclear. Further investigation is necessary to prevent muscle atrophy and improve long-term outcomes. J. Med. Invest. 67 : 1-10, February, 2020.

Challenging Convention: Daytime Versus Nighttime Extubation in the Pediatric ICU

BACKGROUND

The majority of pediatric extubations occur during day shift hours. There is a time-dependent relationship between mechanical ventilation duration and complications. It is not known if extubation shift (day vs night) correlates with pediatric extubation outcomes. Pediatric ventilation duration may be unnecessarily prolonged if extubation is routinely delayed until day shift hours.

METHODS

We hypothesized that extubation failure would not correlate with shift of extubation and that ventilation duration at first extubation and that length of stay in the pediatric ICU (PICU) would be shorter for children extubated at night. This was a retrospective cohort study within one tertiary care, 24-bed, academic PICU.

RESULTS

582 ventilation encounters were included, representing 517 unique subjects. Status epilepticus was a more common diagnosis among night shift extubations (P = .005), whereas surgical airway conditions were more common among day shift extubations (P = .02). Mechanical ventilation duration at first extubation (37.6 vs 62.5 h, P < .001) and length of stay in the PICU (2.8 vs 4.5 d, P < .001) were shorter for night shift extubations. The extubation failure rate was 10.3% for day shift and 8.1% for night shift (P = .40). Logistic regression modeling at the level of the unique subject indicated that extubation shift was not associated with extubation failure (P = .44). The majority of re-intubation events occurred on the shift opposite of extubation. There was no difference in complications according to shift of re-intubation (P = .72).

CONCLUSIONS

Extubation failure was not independently associated with extubation shift in this single-center study. Ventilation liberation should be considered at the first opportunity dictated by clinical data and patient-specific factors rather than by the time of day at centers with similar resources.

Skeletal Muscle Changes, Function, and Health-Related Quality of Life in Survivors of Pediatric Critical Illness

OBJECTIVES

To describe functional and skeletal muscle changes observed during pediatric critical illness and recovery and their association with health-related quality of life.

DESIGN

Prospective cohort study.

SETTING

Single multidisciplinary PICU.

PATIENTS

Children with greater than or equal to 1 organ dysfunction, expected PICU stay greater than or equal to 48 hours, expected survival to discharge, and without progressive neuromuscular disease or malignancies were followed from admission to approximately 6.7 months postdischarge.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Functional status was measured using the Functional Status Scale score and Pediatric Evaluation of Disability Inventory-Computer Adaptive Test. Patient and parental health-related quality of life were measured using the Pediatric Quality of Life Inventory and Short Form-36 questionnaires, respectively. Quadriceps muscle size, echogenicity, and fat thickness were measured using ultrasonography during PICU stay, at hospital discharge, and follow-up. Factors affecting change in muscle were explored. Associations between functional, muscle, and health-related quality of life changes were compared using regression analysis. Seventy-three survivors were recruited, of which 44 completed follow-ups. Functional impairment persisted in four of 44 (9.1%) at 6.7 months (interquartile range, 6-7.7 mo) after discharge. Muscle size decreased during PICU stay and was associated with inadequate energy intake (adjusted β, 0.15; 95% CI, 0.02-0.28; p = 0.030). No change in echogenicity or fat thickness was observed. Muscle growth postdischarge correlated with mobility function scores (adjusted β, 0.05; 95% CI, 0.01-0.09; p = 0.046). Improvements in mobility scores were associated with improved physical health-related quality of life at follow-up (adjusted β, 1.02; 95% CI, 0.23-1.81; p = 0.013). Child physical health-related quality of life at hospital discharge was associated with parental physical health-related quality of life (adjusted β, 0.09; 95% CI, 0.01-0.17; p = 0.027).

CONCLUSIONS

Muscle decreased in critically ill children, which was associated with energy inadequacy and impaired muscle growth postdischarge. Muscle changes correlated with change in mobility, which was associated with child health-related quality of life. Mobility, child health-related quality of life, and parental health-related quality of life appeared to be interlinked.

Diaphragmatic atrophy and dysfunction in critically ill mechanically ventilated children

RATIONALE

The extent of diaphragmatic atrophy and dysfunction in critically ill children from developing countries is not established.

OBJECTIVES

To estimate changes in ultrasound measurements of diaphragmatic thickness over the first week of mechanical ventilation. To assess magnitude and risk factors of diaphragmatic atrophy.

METHODS

In an observational cohort study, children aged 1-18 years, requiring mechanical ventilation were included. Ultrasound measurements of diaphragmatic thickness at end-expiration (DTe) and end-inspiration (DTi), and diaphragmatic thickening fraction (DTF) were performed daily during the first week of admission, and pre- and post-extubation. Diaphragmatic atrophy (%) and atrophy rate (rate of decline in DTe, % per day) were calculated.

MEASUREMENTS AND MAIN RESULTS

Of 55 children (74.6% boys) enrolled, 20 (36.4%) died. Of 35 children with planned extubation, 5 (14.3%) required reintubation. Baseline median (interquartile range [IQR]) DTe, DTi, and DTF were 1.27 mm (1, 1.6), 1.76 mm (1.35, 2.10), and 33.75% (26.90, 44.60), respectively. There was a significant reduction in DTe over the first week of mechanical ventilation (p < .001), median (IQR) diaphragmatic atrophy and atrophy rate of 9.91% (5.26, 17.35) and 2.01% (1.08, 3.04) per day, respectively. Diaphragmatic atrophy rate was lower in pressure targeted ventilation (n = 44; 1.79% [1.03, 2.87]) than volume targeted ventilation (n = 11; 3.10% [1.31, 5.49]), p = .038. There was no difference in diaphragmatic parameters (atrophy rate, and peri-extubation DTe and DTF) in extubation success versus failure.

CONCLUSIONS

The diaphragm undergoes progressive atrophy during the first week of mechanical ventilation in critically ill children. Future studies should evaluate ventilation strategies to reduce the diaphragmatic atrophy.

Monitoring diaphragm function in the ICU

PURPOSE OF REVIEW

To review the clinical problem of diaphragm function in critically ill patients and describes recent advances in bedside monitoring of diaphragm function.

RECENT FINDINGS

Diaphragm weakness, a consequence of diaphragm dysfunction and atrophy, is common in the ICU and associated with serious clinical consequences. The use of ultrasound to assess diaphragm structure (thickness, thickening) and mobility (caudal displacement) appears to be feasible and reproducible, but no large-scale 'real-life' study is available. Diaphragm ultrasound can also be used to evaluate diaphragm muscle stiffness by means of shear-wave elastography and strain by means of speckle tracking, both of which are correlated with diaphragm function in healthy. Electrical activity of the diaphragm is correlated with diaphragm function during brief airway occlusion, but the repeatability of these measurements exhibits high within-subject variability.

SUMMARY

Mechanical ventilation is involved in the pathogenesis of diaphragm dysfunction, which is associated with severe adverse events. Although ultrasound and diaphragm electrical activity could facilitate monitoring of diaphragm function to deliver diaphragm-protective ventilation, no guidelines concerning the use of these modalities have yet been published. The weaning process, assessment of patient-ventilator synchrony and evaluation of diaphragm function may be the most clinically relevant indications for these techniques.

PREVENTION OF RESPIRATORY MUSCLE DYSFUNCTION DUE TO DIAPHRAGM ATROPHY IN CHILDREN WITH RESPIRATORY FAILURE

The aim of the study was to determine whether diaphragm-protective mechanical ventilation can prevent diaphragm atrophy in children with respiratory failure. Materials and methods. We complete the prospective single-center cohort study. Data analysis included 82 patients 1 month - 18 years old, divided into I group (lung-protective MV) and II group (diaphragm-protective in addition to lung-protective MV). Patients were divided into age subgroups. Stages of the study: 1st day (d1), 3rd (d3), 5th (d5), 7th (d7), 9th (d9), 28th (d28). We studied changes in diaphragm thickness at the end of exhalation and compared them with these indicators at patient`s admission to the study (baseline). Primary endpoint was length of stay in ICU, secondary endpoints were complications (prolonged MV). Results are described as arithmetic mean (X) and standard deviation (σ) with level of significance p. Results. There were significant differences in length of stay in ICU among patients of the 1st and 5th age subgroups: in 1st age subgroup this data was in 1.3 times lower in II group, compared with I group (p <0,05); in 5th age subgroup the situation was the opposite - length of stay in ICU was in 1.4 times higher in II group, compared with I group (p<0.05). There were no patients who required lifelong mechanical ventilation in any of the groups. Changes in the thickness of the diaphragm, which indicate its atrophy, were the most significant among patients of the first, second, third and fourth age subgroups and the severity of atrophy was higher among patients of group I, compared with patients of group II. Conclusions. Diaphragm-protective mechanical ventilation significantly prevents diaphragm atrophy in children with respiratory failure in 2nd, 4th, and 5th age subgroups. Providing goal-directed diaphragm-protective MV might reduce the length of stay in ICU among patients of 1st and 5th age subgroups. There were no observed complications like lifelong mechanical ventilation in both patient`s group.

Sleep Architecture in Mechanically Ventilated Pediatric ICU Patients Receiving Goal-Directed, Dexmedetomidine- and Opioid-based Sedation

This single-center prospective observational study aimed to evaluate sleep architecture in mechanically ventilated pediatric intensive care unit (PICU) patients receiving protocolized light sedation. We enrolled 18 children, 6 months to 17 years of age, receiving mechanical ventilation and standard, protocolized sedation for acute respiratory failure, and monitored them with 24 hours of limited (10 channels) polysomnogram (PSG). The PSG was scored by a sleep technician and reviewed by a pediatric sleep medicine physician. Sixteen children had adequate PSG data for sleep stage scoring. All received continuous opioid infusions, 15 (94%) received dexmedetomidine, and 7 (44%) received intermittent benzodiazepines. Total sleep time was above the age-matched normal reference range (median 867 vs. 641 minutes, p = 0.002), attributable to increased stage N1 and N2 sleep. Diurnal variation was absent, with a median of 47% of sleep occurring during night-time hours. Rapid eye movement (REM) sleep was observed as absent in most patients (n = 12, 75%). Sleep was substantially disrupted, with more awakenings per hour than normal for age (median 2.2 vs. 1.1, p = 0.008), resulting in a median average sleep period duration (sleep before awakening) of only 25 minutes (interquartile range [IQR]: 14–36) versus normal 72 minutes (IQR: 65–86, p = 0.001). Higher ketamine and propofol doses were associated with increased sleep disruption. Children receiving targeted, opioid-, and dexmedetomidine-based sedation to facilitate mechanical ventilation for acute respiratory failure have substantial sleep disruption and abnormal sleep architecture, achieving little to no REM sleep. Dexmedetomidine-based sedation does not ensure quality sleep in this population.

DIAPHRAGMATIC MYOTRAUMA IN CHILDREN WITH ACUTE RESPIRATORY FAILURE

The aim of the study was to establish the prevalence of diaphragmatic dysfunction (DD), depending on the strategy of mechanical ventilation (MV). Materials and methods. We completed the prospective single-center cohort study. Data analysis included 82 patients (1 month – 18 years old), divided into I group (lung-protective MV) and II group (diaphragm-protective in addition to lung-protective MV). Patients were divided into age subgroups. Stages of the study: 1st day (d1), 3rd (d3), 5th (d5), 7th (d7), 9th (d9), 14th (d14), 28th (d28). We studied amplitude of diaphragm movement; thickening fraction, parameters of acid-base balance and MV. Results are described as median [IQR - interquartile range] with level of significance p. Results. In patients of the 1st age subgroup in I group there were episodes with under-assist during MV, while in II group diaphragm overload was registered only on d5. In patients of 2nd subgroup in I group we found over-assist of MV with excessive work of the right hemidiaphragm and low contractions of left dome at all stages of study, while in II group – the only episode of diaphragmatic weakness on d3 due to under-assist of MV. In the 3rd subgroup the proper diaphragmatic activity in I group was restored significantly later than in II group. In 4th subgroup of I group there was episode of high work of diaphragm on d5, whereas in II group – all data were within the recommended parameters for diaphragm-protective strategy of MV. In 5th subgroup of I group excessive work of both right and left domes of diaphragm was significantly more often registered than in II group, however, in II group there were found episodes of both type changes – diaphragmatic weakness and excessive work. Conclusion: The prevalence and variety of manifestations of DD depend on the strategy of MV. Low incidence of DD was associated with lower duration of MV: in 1st age subgroup in 1.5 times; in 2nd age subgroup – in 2.4 times; in 4th age subgroup – in 1.75 times; in 5th age subgroup – in 4.25 times.

A prospective observational study on critically ill children with diaphragmatic dysfunction: clinical outcomes and risk factors

Background

Diaphragmatic dysfunction (DD) has a great negative impact on clinical outcomes, and it is a well-recognized complication in adult patients with critical illness. However, DD is largely unexplored in the critically ill pediatric population. The aim of this study was to identify risk factors associated with DD, and to investigate the effects of DD on clinical outcomes among critically ill children.

Methods

Diaphragmatic function was assessed by diaphragm ultrasound. According to the result of diaphragmatic ultrasound, all enrolled subjects were categorized into the DD group (n = 24) and the non-DD group (n = 46). Collection of sample characteristics in both groups include age, sex, height, weight, primary diagnosis, complications, laboratory findings, medications, ventilatory time and clinical outcomes.

Results

The incidence of DD in this PICU was 34.3%. The level of CRP at discharge (P = 0.003) in the DD group was higher than the non-DD group, and duration of elevated C-reactive protein (CRP) (P < 0.001), sedative days (P = 0.008) and ventilatory treatment time (P < 0.001) in the DD group was significantly longer than the non-DD group. Ventilatory treatment time and duration of elevated CRP were independently risk factors associated with DD. Patients in the DD group had longer PICU length of stay, higher rate of weaning or extubation failure and higher mortality.

Conclusion

DD is associated with poorer clinical outcomes in critically ill childern, which include a longer PICU length of stay, higher rate of weaning or extubation failure and a higher mortality. The ventilatory treatment time and duration of elevated CRP are main risk factors of DD in critically ill children.

Trial registration

Current Controlled Trials ChiCTR1800020196, Registered 01 Dec 2018.

The impact of critical illness on the expiratory muscles and the diaphragm assessed by ultrasound in mechanical ventilated children

Background

Critical illness has detrimental effects on the diaphragm, but the impact of critical illness on other major muscles of the respiratory pump has been largely neglected. This study aimed to determine the impact of critical illness on the most important muscles of the respiratory muscle pump, especially on the expiratory muscles in children during mechanical ventilation. In addition, the correlation between changes in thickness of the expiratory muscles and the diaphragm was assessed.

Methods

This longitudinal observational cohort study performed at a tertiary pediatric intensive care unit included 34 mechanical ventilated children (> 1 month– < 18 years). Thickness of the diaphragm and expiratory muscles (obliquus interna, obliquus externa, transversus abdominis and rectus abdominis) was assessed daily using ultrasound. Contractile activity was estimated from muscle thickening fraction during the respiratory cycle.

Results

Over the first 4 days, both diaphragm and expiratory muscles thickness decreased (> 10%) in 44% of the children. Diaphragm and expiratory muscle thickness increased (> 10%) in 26% and 20% of the children, respectively. No correlation was found between contractile activity of the muscles and the development of atrophy. Furthermore, no correlation was found between changes in thickness of the diaphragm and the expiratory muscles (P = 0.537). Decrease in expiratory muscle thickness was significantly higher in patients failing extubation compared to successful extubation (− 34% vs − 4%, P = 0.014).

Conclusions

Changes in diaphragm and expiratory muscles thickness develop rapidly after the initiation of mechanical ventilation. Changes in thickness of the diaphragm and expiratory muscles were not significantly correlated. These data provide a unique insight in the effects of critical illness on the respiratory muscle pump in children.

Development of muscle ultrasound density in healthy fetuses and infants

Muscle ultrasound density (MUD) is a non-invasive parameter to indicate neuromuscular integrity in both children and adults. In healthy fetuses and infants, physiologic MUD values during development are still lacking. We therefore aimed to determine the physiologic, age-related MUD trend of biceps, quadriceps, tibialis anterior, hamstrings, gluteal and calf muscles, from pre- to the first year of postnatal life. To avoid a bias by pregnancy-related signal disturbances, we expressed fetal MUD as a ratio against bone ultrasound density. We used the full-term prenatal MUD ratio and the newborn postnatal MUD value as reference points, so that MUD development could be quantified from early pre- into postnatal life. Results: During the prenatal period, the total muscle group revealed a developmental MUD trend concerning a fetal increase in MUD-ratio from the 2nd trimester up to the end of the 3rd trimester [median increase: 27% (range 16-45), p < .001]. After birth, MUD-values increased up to the sixth month [median increase: 11% (range -7-27), p = 0.025] and stabilized thereafter. Additionally, there were also individual MUD characteristics per muscle group and developmental stage, such as relatively low MUD values of fetal hamstrings and high values of the paediatric gluteus muscles. These MUD trends are likely to concur with analogous developmentally, maturation-related alterations in the muscle water to peptide content ratios.

Post-Intensive-Care Syndrome for the Pediatric Neurologist

The number of children who survive critical illness has steadily increased. However, lower mortality rates have resulted in a proportional increase in post-intensive-care morbidity. Critical illness in childhood affects a child's development, cognition, and family functioning. The constellation of physical, emotional, cognitive, and psychosocial symptoms that begin in the intensive care unit and continue after discharge has recently been termed post-intensive-care syndrome. A conceptual model of the post-intensive-care syndrome experienced by children who survive critical illness, their siblings, and parents has been coined post-intensive-care syndrome in pediatrics. Owing to their prolonged hospitalizations, the use of sedative medications, and the nature of their illness, children with primary neurological injury are among those at the highest risk for post-intensive-care syndrome in pediatrics. The pediatric neurologist participates in the care of children with acute brain injury throughout their hospitalization and remains involved after the patient leaves the hospital. Hence it is important for pediatric neurologists to become versed in the early recognition and management of post-intensive-care syndrome in pediatrics. In this review, we discuss the current knowledge regarding post-intensive-care syndrome in pediatrics and its risk factors. We also discuss our experience establishing Pediatric Neurocritical Care Recovery Programs at two large academic centers. Last, we provide a battery of validated tests to identify and manage the different aspects of post-intensive-care syndrome in pediatrics, which have been successfully implemented at our institutions. Dissemination of this "road map" may assist others interested in establishing recovery programs, therefore mitigating the burden of post-intensive-care morbidity in children.

Effects of diaphragm thickness on rehabilitation outcomes in post-ICU patients with spinal cord and brain injury

BACKGROUND

Intensive care unit (ICU) complications affect outcomes but it remains unknown if the diaphragm thickness affects rehabilitation outcomes after ICU. We conducted a pilot study to evaluate the effect of diaphragm thickness on rehabilitation outcomes of post-ICU patients with spinal cord injury (SCI) and traumatic brain injury (TBI) and to evaluate factors that may be associated with diaphragm atrophy.

MATERIALS AND METHODS

Fifty-one patients (26 SCI, 25 TBI) who admitted to the rehabilitation clinic from the ICU included in this study. All demographic data were recorded. All participants underwent diaphragmatic ultrasonography evaluation before and after 12 weeks of neurologic rehabilitation program. The diaphragm thickness and outcome parameters were compared in all patient groups and in each patient subgroups. Evaluation parameters of patients before and after treatment were compared in patient subgroups.

RESULTS

Diaphragm atrophy was found in 14 patients (64%) in TBI group and 12 patients (46%) in SCI group. The diaphragm thickness negatively correlated with the ICU length of stay and positively correlated with the before/after rehabilitation functional scores and the change in functional independence measure scores (p < 0.05). According to the regression analysis; the change in functional independence measure scores was found to be affected by the diaphragm thickness (p < 0.05).

CONCLUSIONS

The diaphragm thickness may be an effective factor on the rehabilitation process.

Monitoring of Respiratory Muscle Function in Critically Ill Children

OBJECTIVES

This review discusses the different techniques used at the bedside to assess respiratory muscle function in critically ill children and their clinical applications.

DATA SOURCES

A scoping review of the medical literature on respiratory muscle function assessment in critically ill children was conducted using the PubMed search engine.

STUDY SELECTION

We included all scientific, peer-reviewed studies about respiratory muscle function assessment in critically ill children, as well as some key adult studies.

DATA EXTRACTION

Data extracted included findings or comments about techniques used to assess respiratory muscle function.

DATA SYNTHESIS

Various promising physiologic techniques are available to assess respiratory muscle function at the bedside of critically ill children throughout the disease process. During the acute phase, this assessment allows a better understanding of the pathophysiological mechanisms of the disease and an optimization of the ventilatory support to increase its effectiveness and limit its potential complications. During the weaning process, these physiologic techniques may help predict extubation success and therefore optimize ventilator weaning.

CONCLUSIONS

Physiologic techniques are useful to precisely assess respiratory muscle function and to individualize and optimize the management of mechanical ventilation in children. Among all the available techniques, the measurements of esophageal pressure and electrical activity of the diaphragm appear particularly helpful in the era of individualized ventilatory management.