Less Is More?-A Feasibility Study of Fluid Strategy in Critically Ill Children With Acute Respiratory Tract Infection

Relationship between fluid overload and mortality and morbidity in pediatric intensive care unit

OBJECTIVE

The relationship between fluid overload and clinical outcomes was investigated.

DESIGN

This study is an observational and analytic study of a retrospective cohort.

SETTINGS

Pediatric intensive care units.

PATIENTS OR PARTICIPANTS

Between 2019 and 2021 children who needed intensive care were included in the study.

INTERVENTIONS

No intervention.

MAIN VARIABLE OF INTEREST

Early, peak and cumulative fluid overload were evaluated.

RESULTS

The mortality rate was 11.7% (68/513). When fluid overloads were examined in terms of mortality, the percentage of early fluid overload was 1.86 and 3.35, the percent of peak fluid overload was 2.87 and 5.54, and the percent of cumulative fluid overload was 3.40 and 8.16, respectively, in the survivor and the non-survivor groups. After adjustment for age, severity of illness, and other potential confounders, peak (aOR = 1.15; 95%CI 1.05-1.26; p: 0.002) and cumulative (aOR = 1.10; 95%CI 1.04-1.16; p < 0.001) fluid overloads were determined as independent risk factors associated with mortality. When the cumulative fluid overload is 10% or more, a 3.9-fold increase mortality rate was calculated. It is found that the peak and cumulative fluid overload, had significant negative correlation with intensive care unit free days and ventilator free days.

CONCLUSIONS

It is found that peak and cumulative fluid overload in critically ill children were independently associated with intensive care unit mortality and morbidity.

Restricted versus Usual/Liberal Maintenance Fluid Strategy in Mechanically Ventilated Children: An Open-Label Randomized Trial (ReLiSCh Trial)

OBJECTIVES

To assess the impact of restricted vs. usual/liberal maintenance fluid strategy on fluid overload (FO) among mechanically ventilated children.

METHODS

This open-label randomized controlled trial was conducted over a period of 1 y (October 2020-September 2021) in a Pediatric intensive care unit (PICU) in North India. Hemodynamically stable mechanically ventilated children were randomized to 40% (restricted group, n = 50) and 70-80% (usual/liberal group, n = 50) of maintenance fluids. The primary outcome was cumulative fluid overload percentage (FO%) on day 7. Secondary outcomes were FO% >10%; vasoactive inotropic score, sequential organ failure assessment score, pediatric logistic organ dysfunction score and oxygenation index from day 1-7; ventilation free days (VFDs) and PICU free days (PFDs) through day 28; and mortality.

RESULTS

The restricted group had statistically non-significant trend towards lower cumulative FO% at day 7 [7.6 vs. 9.5, p = 0.40]; and proportion of children with FO% >10% (12% vs. 26%, p = 0.21) as compared to usual/liberal group. The increase in FO% from day 1-7 was significant in usual/liberal group as compared to restricted group (p <0.001 and p = 0.134, respectively). Restricted group received significantly lower amount of fluid in the first 5 d; had significantly higher VFDs (23 vs. 17 d, p = 0.008) and PFDs (19 vs. 15 d, p = 0.007); and trend towards lower mortality (8% vs. 16%, p = 0.21).

CONCLUSIONS

Restricted as compared to usual/liberal maintenance fluid strategy among mechanically ventilated children was associated with a trend towards lower rate and severity of FO and mortality; and significantly lower fluid volume received, and higher VFDs and PFDs.

Evaluating fluid overload in critically ill children

PURPOSE OF REVIEW

To review the evaluation and management of fluid overload in critically ill children.

RECENT FINDINGS

Emerging evidence associates fluid overload, i.e. having a positive cumulative fluid balance, with adverse outcome in critically ill children. This is most likely the result of impaired organ function due to increased extravascular water content. The combination of a number of parameters, including physical, laboratory and radiographic markers, may aid the clinician in monitoring and quantifying fluid status, but all have important limitations, in particular to discriminate between intra- and extravascular water volume. Current guidelines advocate a restrictive fluid management, initiated early during the disease course, but are hampered by the lack of high quality evidence.

SUMMARY

Recent advances in early evaluation of fluid status and (tailored) restrictive fluid management in critically ill children may decrease complications of fluid overload, potentially improving outcome. Further clinical trials are necessary to provide the clinician with solid recommendations.

Fluid assessment, fluid balance, and fluid overload in sick children: a report from the Pediatric Acute Disease Quality Initiative (ADQI) conference

BACKGROUND

The impact of disorders of fluid balance, including the pathologic state of fluid overload in sick children has become increasingly apparent. With this understanding, there has been a shift from application of absolute thresholds of fluid accumulation to an appreciation of the intricacies of fluid balance, including the impact of timing, trajectory, and disease pathophysiology.

METHODS

The 26th Acute Disease Quality Initiative was the first to be exclusively dedicated to pediatric and neonatal acute kidney injury (pADQI). As part of the consensus panel, a multidisciplinary working group dedicated to fluid balance, fluid accumulation, and fluid overload was created. Through a search, review, and appraisal of the literature, summative consensus statements, along with identification of knowledge gaps and recommendations for clinical practice and research were developed.

CONCLUSIONS

The 26th pADQI conference proposed harmonized terminology for fluid balance and for describing a pathologic state of fluid overload for clinical practice and research. Recommendations include that the terms daily fluid balance, cumulative fluid balance, and percent cumulative fluid balance be utilized to describe the fluid status of sick children. The term fluid overload is to be preserved for describing a pathologic state of positive fluid balance associated with adverse events. Several recommendations for research were proposed including focused validation of the definition of fluid balance, fluid overload, and proposed methodologic approaches and endpoints for clinical trials.

Association of Fluid Overload with Escalation of Respiratory Support and Endotracheal Intubation in Acute Bronchiolitis Patients

Fluid overload has been associated with increased oxygen requirement, prolonged duration of mechanical ventilation, and longer length of hospital stay in children hospitalized with pulmonary diseases. Critically ill infants with bronchiolitis admitted to the pediatric intensive care unit (PICU) also tend to develop fluid overload and there is limited information of its role on noninvasive respiratory support. Thus, our primary objective was to study the association of fluid overload in patients with bronchiolitis admitted to the PICU with respiratory support escalation (RSE) and need for endotracheal intubation (ETI). Infants ≤24 months of age with bronchiolitis and admitted to the PICU between 9/2009 and 6/2015 were retrospectively studied. Demographic variables, clinical characteristics including type of respiratory support and need for ETI were evaluated. Fluid overload as assessed by net fluid intake and output (net fluid balance), cumulative fluid balance (CFB) (mL/kg), and percentage fluid overload (FO%), was compared between patients requiring and not requiring RSE and among patients requiring ETI and not requiring ETI at 0 (PICU admission), 12, 24, 36, 48, 72, 96, and 120 hours. One-hundred sixty four of 283 patients with bronchiolitis admitted to the PICU qualified for our study. Thirty-four of 164 (21%) patients required escalation of respiratory support within 5 days of PICU admission and of these 34 patients, 11 patients required ETI. Univariate analysis by Kruskal-Wallis test of fluid overload as assessed by net fluid balance, CFB, and FO% between 34 patients requiring and 130 patients not requiring RSE and among 11 patients requiring ETI and 153 patients not requiring ETI, at 0, 12, 24, 36, 48, 72, 96 and 120 hours did not reveal any significant difference ( p >0.05) at any time interval. Multivariable logistic regression analysis revealed higher PRISM score (odds ratio [OR]: 4.95, 95% confidence interval [95% CI]: 1.79-13.66; p  = 0.002), longer hours on high flow nasal cannula (OR: 4.86, 95% CI: 1.68-14.03; p  = 0.003) and longer hours on noninvasive ventilation (OR: 11.16, 95% CI: 3.36-36.98; p  < 0.001) were associated with RSE. Fluid overload as assessed by net fluid balance, CFB, and FO% was not associated with RSE or need for ETI in critically ill bronchiolitis patients admitted to the PICU. Further prospective studies involving larger number of patients with bronchiolitis are needed to corroborate our findings.

Intravenous maintenance fluid therapy in acutely and critically ill children: state of the evidence

Intravenous maintenance fluid therapy (IV-MFT) is one of the most prescribed, yet one of the least studied, interventions in paediatric acute and critical care settings. IV-MFT is not typically treated in the same way as drugs with specific indications, contraindications, compositions, and associated adverse effects. In the last decade, societies in both paediatric and adult medicine have issued evidence-based practice guidelines for the use of intravenous fluids in clinical practice. The main objective of this Viewpoint is to summarise and compare the rationales on which these international expert guidelines were based and how these recommendations affect IV-MFT practices in paediatric acute and critical care. Although these guidelines recommend the use of isotonic fluids as a standard in IV-MFT, some discrepancies and uncertainties remain regarding the systematic use of balanced fluids, glucose and electrolyte requirements, and appropriate fluid volume. IV-MFT should be considered in the same way as any other prescription drug and none of the components of IV-MFT prescription should be overlooked (ie, choice of drug, dosing rate, duration of treatment, and de-escalation). Furthermore, most evidence that was used to inform the guidelines comes from high-income countries. Although some principles of IV-MFT are universal, the direct relevance to and feasibility of implementing the guidelines in low-income and middle-income countries is uncertain.

Variation in Early Pediatric Intensive Care Management Strategies and Duration of Invasive Mechanical Ventilation for Acute Viral Bronchiolitis in the United Kingdom: A Retrospective Multicenter Cohort Study

OBJECTIVES

Management of mechanically ventilated patients with bronchiolitis is not standardized and duration of mechanical ventilation has been shown to vary widely between centers. The aim of this study was to examine practice in a large number of U.K. PICUs with a view to identify if early management choices relating to fluid prescription, sedative agent use, and endotracheal tube (ETT) placement were associated with differences in duration of invasive mechanical ventilation (IMV).

DESIGN

Retrospective multicenter cohort study. Primary outcome was duration of IMV. A hierarchical gamma generalized linear model was used to test for associations between practice variables (sedative and neuromuscular blocking agents, route of endotracheal intubation at 24 hr and fluid balance at 48 hr) and duration of IMV after adjustment for known confounders.

SETTING

Thirteen U.K. PICUs. Duration of 2 months between November and December 2019.

PATIENTS

Three hundred fifty infants receiving IMV for bronchiolitis. Excluded were patients receiving long-term ventilation, extracorporeal life support, or who died before separation from IMV.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After adjustment for confounders, several variables were associated with an increase in the geometric mean duration of IMV (expressed as a percentage) including: nasal ETT use, 16% (95% CI, 1-32%); neuromuscular blockade use, 39% (95% CI, 21-61%); and fluid balance at 48 hr, 13% per 100 mL/kg positive fluid balance (95% CI, -1% to 28%). The association of sedative use varied with class of agent. The use of an alpha-2 agonist alone was associated with a reduction in duration of IMV by 19% in relation to no sedative agent (95% CI, -31 to -5%), whereas benzodiazepine uses alone or with alpha-2 agonist in combination were similar to using neither agent.

CONCLUSIONS

Early management strategies for bronchiolitis were associated with the duration of IMV across U.K. centers after adjustment for confounders. Future work should prospectively assess the impact of fluid restriction, route of endotracheal intubation, and alpha-2 agonist use on duration of IMV in infants with bronchiolitis, with the aim of reducing seasonal bed pressure.

REstrictive versus StandarD FlUid Management in Mechanically Ventilated ChildrEn Admitted to PICU: study protocol for a pilot randomised controlled trial (REDUCE-1)

INTRODUCTION

Intravenous fluid therapy is the most common intervention in critically ill children. There is an increasing body of evidence questioning the safety of high-volume intravenous fluid administration in these patients. To date, the optimal fluid management strategy remains unclear. We aimed to test the feasibility of a pragmatic randomised controlled trial comparing a restrictive with a standard (liberal) fluid management strategy in critically ill children.

METHODS AND ANALYSIS

Multicentre, binational pilot, randomised, controlled, open-label, pragmatic trial. Patients <18 years admitted to paediatric intensive care unit and mechanically ventilated at the time of screening are eligible. Patients with tumour lysis syndrome, diabetic ketoacidosis or postorgan transplant are excluded.

INTERVENTIONS

1:1 random assignment of 154 individual patients into two groups-restrictive versus standard, liberal, fluid strategy-stratified by primary diagnosis (cardiac/non-cardiac). The intervention consists of a restrictive fluid bundle, including lower maintenance fluid allowance, limiting fluid boluses, reducing volumes of drug delivery and initiating diuretics or peritoneal dialysis earlier. The intervention is applied for 48 hours postrandomisation or until discharge (whichever is earlier).

ENDPOINTS

The number of patients recruited per month and proportion of recruited to eligible patients are feasibility endpoints. New-onset acute kidney injury and the incidence of clinically relevant central venous thrombosis are safety endpoints. Fluid balance at 48 hours after randomisation is the efficacy endpoint. Survival free of paediatric intensive care censored at 28 days is the clinical endpoint.

ETHICS AND DISSEMINATION

Ethics approval was gained from the Children's Health Queensland Human Research Ethics Committee (HREC/21/QCHQ/77514, date: 1 September 2021), and University of Zurich (2021-02447, date: 17 March 2023). The trial is registered with the Australia New Zealand Clinical Trials Registry (ACTRN12621001311842). Open-access publication in high impact peer-reviewed journals will be sought. Modern information dissemination strategies will also be used including social media to disseminate the outcomes of the study.

TRIAL REGISTRATION NUMBER

ACTRN12621001311842.

PROTOCOL VERSION/DATE

V5/23 May 2023.

Fluid management strategies and their interaction with mechanical ventilation: from experimental studies to clinical practice

Patients on mechanical ventilation may receive intravenous fluids via restrictive or liberal fluid management. A clear and objective differentiation between restrictive and liberal fluid management strategies is lacking in the literature. The liberal approach has been described as involving fluid rates ranging from 1.2 to 12 times higher than the restrictive approach. A restrictive fluid management may lead to hypoperfusion and distal organ damage, and a liberal fluid strategy may result in endothelial shear stress and glycocalyx damage, cardiovascular complications, lung edema, and distal organ dysfunction. The association between fluid and mechanical ventilation strategies and how they interact toward ventilator-induced lung injury (VILI) could potentiate the damage. For instance, the combination of a liberal fluids and pressure-support ventilation, but not pressure control ventilation, may lead to further lung damage in experimental models of acute lung injury. Moreover, under liberal fluid management, the application of high positive end-expiratory pressure (PEEP) or an abrupt decrease in PEEP yielded higher endothelial cell damage in the lungs. Nevertheless, the translational aspects of these findings are scarce. The aim of this narrative review is to provide better understanding of the interaction between different fluid and ventilation strategies and how these interactions may affect lung and distal organs. The weaning phase of mechanical ventilation and the deresuscitation phase are not explored in this review.

Clinical practice guidelines: management of severe bronchiolitis in infants under 12 months old admitted to a pediatric critical care unit

PURPOSE

We present guidelines for the management of infants under 12 months of age with severe bronchiolitis with the aim of creating a series of pragmatic recommendations for a patient subgroup that is poorly individualized in national and international guidelines.

METHODS

Twenty-five French-speaking experts, all members of the Groupe Francophone de Réanimation et Urgence Pédiatriques (French-speaking group of paediatric intensive and emergency care; GFRUP) (Algeria, Belgium, Canada, France, Switzerland), collaborated from 2021 to 2022 through teleconferences and face-to-face meetings. The guidelines cover five areas: (1) criteria for admission to a pediatric critical care unit, (2) environment and monitoring, (3) feeding and hydration, (4) ventilatory support and (5) adjuvant therapies. The questions were written in the Patient-Intervention-Comparison-Outcome (PICO) format. An extensive Anglophone and Francophone literature search indexed in the MEDLINE database via PubMed, Web of Science, Cochrane and Embase was performed using pre-established keywords. The texts were analyzed and classified according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. When this method did not apply, an expert opinion was given. Each of these recommendations was voted on by all the experts according to the Delphi methodology.

RESULTS

This group proposes 40 recommendations. The GRADE methodology could be applied for 17 of them (3 strong, 14 conditional) and an expert opinion was given for the remaining 23. All received strong approval during the first round of voting.

CONCLUSION

These guidelines cover the different aspects in the management of severe bronchiolitis in infants admitted to pediatric critical care units. Compared to the different ways to manage patients with severe bronchiolitis described in the literature, our original work proposes an overall less invasive approach in terms of monitoring and treatment.

ESPNIC clinical practice guidelines: intravenous maintenance fluid therapy in acute and critically ill children- a systematic review and meta-analysis

PURPOSE

Intravenous maintenance fluid therapy (IV-MFT) prescribing in acute and critically ill children is very variable among pediatric health care professionals. In order to provide up to date IV-MFT guidelines, the European Society of Pediatric and Neonatal Intensive Care (ESPNIC) undertook a systematic review to answer the following five main questions about IV-MFT: (i) the indications for use (ii) the role of isotonic fluid (iii) the role of balanced solutions (iv) IV fluid composition (calcium, magnesium, potassium, glucose and micronutrients) and v) and the optimal amount of fluid.

METHODS

A multidisciplinary expert group within ESPNIC conducted this systematic review using the Scottish Intercollegiate Guidelines Network (SIGN) grading method. Five databases were searched for studies that answered these questions, in acute and critically children (from 37 weeks gestational age to 18 years), published until November 2020. The quality of evidence and risk of bias were assessed, and meta-analyses were undertaken when appropriate. A series of recommendations was derived and voted on by the expert group to achieve consensus through two voting rounds.

RESULTS

56 papers met the inclusion criteria, and 16 recommendations were produced. Outcome reporting was inconsistent among studies. Recommendations generated were based on a heterogeneous level of evidence, but consensus within the expert group was high. "Strong consensus" was reached for 11/16 (69%) and "consensus" for 5/16 (31%) of the recommendations.

CONCLUSIONS

Key recommendations are to use isotonic balanced solutions providing glucose to restrict IV-MFT infusion volumes in most hospitalized children and to regularly monitor plasma electrolyte levels, serum glucose and fluid balance.

Fluid management in hospitalized pediatric patients

The proper use of intravenous fluids has likely been responsible for saving more lives than any other group of substances. Proper use includes prescribing an appropriate electrolyte and carbohydrate solution, at a calculated rate or volume, for the right child, at the right time. Forming intravenous fluid plans for hospitalized children requires an understanding of water and electrolyte physiology in healthy children and how different pathology deviates from the norm. This review highlights fluid management in several disease types, including liver disease, diabetic ketoacidosis, syndrome of inappropriate antidiuretic hormone, diabetes insipidus, kidney disease, and intestinal failure as well as in those with nonphysiologic fluid losses. For each disease, the review discusses specific considerations, evaluations, and management strategies to consider when customizing intravenous fluid plans. Ultimately, all hospitalized children should receive an individualized fluid plan with recurrent evaluations and fluid modifications to provide optimal care.

Current Practice of Fluid Maintenance and Replacement Therapy in Mechanically Ventilated Critically Ill Children: A European Survey

Appropriate fluid management in mechanically ventilated critically ill children remains an important challenge and topic of active discussion in pediatric intensive care medicine. An increasing number of studies show an association between a positive fluid balance or fluid overload and adverse outcomes. However, to date, no international consensus regarding fluid management or removal strategies exists. The aim of this study was to obtain more insight into the current clinical practice of fluid therapy in mechanically ventilated critically ill children. On behalf of the section of cardiovascular dynamics of the European Society of Pediatric and Neonatal Intensive Care (ESPNIC) we conducted an anonymous survey among pediatric intensive care unit (PICU) specialists in Europe regarding fluid overload and management. A total of 107 study participants responded to the survey. The vast majority of respondents considers fluid overload to be a common phenomenon in mechanically ventilated children and believes this complication is associated with adverse outcomes, such as mortality and duration of respiratory support. Yet, only 75% of the respondents administers a lower volume of fluids (reduction of 20% of normal intake) to mechanically ventilated critically ill children on admission. During PICU stay, a cumulative fluid balance of more than 5% is considered to be an indication to reduce fluid intake and start diuretic treatment in most respondents. Next to fluid balance calculation, the occurrence of peripheral and/or pulmonary edema (as assessed including by chest radiograph and lung ultrasound) was considered an important clinical sign of fluid overload entailing further therapeutic action. In conclusion, fluid overload in mechanically ventilated critically ill children is considered an important problem among PICU specialists, but there is great heterogeneity in the current clinical practice to avoid this complication. We identify a great need for further prospective and randomized investigation of the effects of (restrictive) fluid strategies in the PICU.