Timing of Fluid Overload and Association With Patient Outcome

Fluid accumulation in critically ill children: a systematic review and meta-analysis

Background

Fluids are often administered for various purposes, such as resuscitation, replacement, maintenance, nutrition, or drug infusion. However, its use is not without risks. Critically ill patients are highly susceptible to fluid accumulation (FA), which is associated with poor outcomes, including organ dysfunction, prolonged mechanical ventilation, extended hospital stays, and increased mortality. This study aimed to assess the association between FA and poor outcomes in critically ill children.

Methods

In this systematic review and meta-analysis, we searched PubMed, Embase, ClinicalTrials.gov, and Cochrane Library databases from inception to May 2024. Relevant publications were searched using the following terms: child, children, infant, infants, pediatric, pediatrics, critically ill children, critical illness, critical care, intensive care, pediatric intensive care, pediatric intensive care unit, fluid balance, fluid overload, fluid accumulation, fluid therapy, edema, respiratory failure, respiratory insufficiency, pulmonary edema, mechanical ventilation, hemodynamic instability, shock, sepsis, acute renal failure, acute kidney failure, acute kidney injury, renal replacement therapy, dialysis, mortality. Paediatric studies were considered eligible if they assessed the effect of FA on the outcomes of interest. The main outcome was all-cause mortality. Pooled analyses were performed by using random-effects models. This review was registered on PROSPERO (CRD42023432879).

Findings

A total of 120 studies (44,682 children) were included. Thirty-five FA definitions were identified. In general, FA was significantly associated with increased mortality (odds ratio [OR] 4.36; 95% confidence interval [CI] 3.53-5.38), acute kidney injury (OR 1.98; 95% CI 1.60-2.44), prolonged mechanical ventilation (weighted mean difference [WMD] 38.1 h, 95% CI 19.35-56.84), and longer stay in the intensive care unit (WMD 2.29 days; 95% CI 1.19-3.38). The percentage of FA was lower in survivors when compared to non-survivors (WMD -4.95 [95% CI, -6.03 to -3.87]). When considering only studies that controlled for potential confounding variables, the pooled analysis revealed 6% increased odds of mortality associated with each 1% increase in the percentage of FA (adjusted OR = 1.06 [95% CI, 1.04-1.09).

Interpretation

FA is significantly associated with poorer outcomes in critically ill children. Thus, clinicians should closely monitor fluid balance, especially when new-onset or worsening organ dysfunction occurs in oedematous patients, indicating potential FA syndrome. Future research should explore interventions like restrictive fluid therapy or de-resuscitation methods. Meanwhile, preventive measures should be prioritized to mitigate FA until further evidence is available.

Funding

None.

An update on the role of fluid overload in the prediction of outcome in acute kidney injury

Over the past two decades, our understanding of the impact of acute kidney injury, disorders of fluid balance, and their interplay have increased significantly. In recent years, the epidemiology and impact of fluid balance, including the pathologic state of fluid overload on outcomes has been studied extensively across multiple pediatric and neonatal populations. A detailed understating of fluid balance has become increasingly important as it is recognized as a target for intervention to continue to work to improve outcomes in these populations. In this review, we provide an update on the epidemiology and outcomes associated with fluid balance disorders and the development of fluid overload in children with acute kidney injury (AKI). This will include a detailed review of consensus definitions of fluid balance, fluid overload, and the methodologies to define them, impact of fluid balance on the diagnosis of AKI and the concept of fluid corrected serum creatinine. This review will also provide detailed descriptions of future directions and the changing paradigms around fluid balance and AKI in critical care nephrology, including the incorporation of the sequential utilization of risk stratification, novel biomarkers, and functional kidney tests (furosemide stress test) into research and ultimately clinical care. Finally, the review will conclude with novel methods currently under study to assess fluid balance and distribution (point of care ultrasound and bioimpedance).

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.

Pattern of Fluid Overload and its Impact on Mortality Among Mechanically Ventilated Children: Secondary Analysis of the ReLiSCh Trial

OBJECTIVES

To assess the pattern of fluid overload (FO) and its impact on mortality among mechanically ventilated children.

METHODS

In this secondary analysis of an open-label randomized controlled trial (ReLiSCh trial, October 2020-September 2021), hemodynamically stable mechanically ventilated children (n = 100) admitted to a tertiary level pediatric intensive care unit (PICU) in North India were enrolled. The primary outcome was pattern of FO (FO% >10% and cumulative FO% from day 1-7); and secondary outcomes were pattern of FO among survivors and non-survivors, and prescription practices of maintenance fluid.

RESULTS

The median (IQR) age was 3.5 (0.85-7.5) y and 57% were males. Common diagnoses were pneumonia (27%), scrub typhus (14%), Landry-Guillain-Barré syndrome (9%), dengue (8%), central nervous system infections (7%) and staphylococcal sepsis (6%). Common organ dysfunction included acute respiratory distress syndrome (ARDS) (41%), shock (38%), and acute kidney injury (AKI) (9%). The duration PICU stay was 11 (7-17) d and mortality was 12%. The FO% >10% was noted in 19% children; and there was significant increase in cumulative FO% from day 1-7 [1.2 (0.2-2.6)% to 8.5 (1.7-14.3)%, (p = 0.000)]. Among non-survivors, higher proportion had FO% >10% (66.7% vs. 12.5%, p 0.0001); and trend towards higher cumulative FO% on first seven days. From day 1-7, the percentage of maintenance fluid received increased from 60 (50-71)% to 70 (60-77)% (p = 0.691).

CONCLUSIONS

One-fifth of mechanically ventilated children had FO% >10% and there was significant increase in cumulative FO% from day 1-7. Non-survivors had significantly higher degree of FO.

Fluid Balance and Its Association With Mortality and Health-Related Quality of Life: A Nonprespecified Secondary Analysis of the Life After Pediatric Sepsis Evaluation

OBJECTIVES

To evaluate the association between fluid balance (FB) and health-related quality of life (HRQL) among children at 1 month following community-acquired septic shock.

DESIGN

Nonprespecified secondary analysis of the Life After Pediatric Sepsis Evaluation. FB was defined as 100 × [(cumulative PICU fluid input - cumulative PICU fluid output)/PICU admission weight]. Three subgroups were identified: low FB (< 5%), medium FB (5%-15%), and high FB (> 15%) based on cumulative FB on days 0-3 of ICU stay. HRQL was measured at ICU admission and 1 month after using Pediatric Quality of Life Inventory 4.0 Generic Core or Infant Scales or the Stein-Jessop Functional Status Scale. The primary outcome was a composite of mortality or greater than 25% decline in HRQL 1 month after admission compared with baseline.

SETTING

Twelve academic PICUs in the United States.

PATIENTS

Critically ill children between 1 month and 18 years, with community-acquired septic shock who survived to at least day 4.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred ninety-three patients were included of whom 66 (23%) had low FB, 127 (43%) had medium FB, and 100 (34%) had high FB. There was no difference in Pediatric Risk of Mortality Score 3 (median 11 [6, 17]), age (median 5 [1, 12]), or gender (47% female) between FB groups. After adjusting for potential confounders and comparing with medium FB, higher odds of mortality or greater than 25% HRQL decline were seen in both the low FB (odds ratio [OR] 2.79 [1.20, 6.57]) and the high FB (OR 2.16 [1.06, 4.47]), p = 0.027. Compared with medium FB, low FB (OR 4.3 [1.62, 11.84]) and high FB (OR 3.29 [1.42, 8.00]) had higher odds of greater than 25% HRQL decline.

CONCLUSIONS

Over half of the children who survived septic shock had low or high FB, which was associated with a significant decline in HRQL scores. Prospective studies are needed to determine if optimization of FB can improve HRQL outcomes.

Fluid Overload Precedes and Masks Cryptic Kidney Injury in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

Given the complex interrelatedness of fluid overload (FO), creatinine, acute kidney injury (AKI), and clinical outcomes, the association of AKI with poor outcomes in critically ill children may be underestimated due to definitions used. We aimed to disentangle these temporal relationships in a large cohort of children with acute respiratory distress syndrome (ARDS).

DESIGN

Retrospective cohort study.

SETTING

Quaternary care PICU.

PATIENTS

Seven hundred twenty intubated children with ARDS between 2011 and 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Daily fluid balance, urine output (UOP), and creatinine for days 1-7 of ARDS were retrospectively abstracted. A subset of patients had angiopoietin 2 (ANGPT2) quantified on days 1, 3, and 7. Patients were classified as AKI by Kidney Disease Improving Global Outcomes (KDIGO) stage 2/3 then grouped by timing of AKI onset (early if days 1-3 of ARDS, late if days 4-7 of ARDS, persistent if both) for comparison of PICU mortality and ventilator-free days (VFDs). A final category of "Cryptic AKI" was used to identify subjects who met KDIGO stage 2/3 criteria only when creatinine was adjusted for FO. Outcomes were compared between those who had Cryptic AKI identified by FO-adjusted creatinine versus those who had no AKI. Conventionally defined AKI occurred in 26% of patients (early 10%, late 3%, persistent 13%). AKI was associated with higher mortality and fewer VFDs, with no differences according to timing of onset. The Cryptic AKI group (6% of those labeled no AKI) had higher mortality and fewer VFDs than patients who did not meet AKI with FO-adjusted creatinine. FO, FO-adjusted creatinine, and ANGPT2 increased 1 day prior to meeting AKI criteria in the late AKI group.

CONCLUSIONS

AKI was associated with higher mortality and fewer VFDs in pediatric ARDS, irrespective of timing. FO-adjusted creatinine captures a group of patients with Cryptic AKI with outcomes approaching those who meet AKI by traditional criteria. Increases in FO, FO-adjusted creatinine, and ANGPT2 occur prior to meeting conventional AKI criteria.

Impact of the Magnitude and Timing of Fluid Overload on Outcomes in Critically Ill Children: A Report From the Multicenter International Assessment of Worldwide Acute Kidney Injury, Renal Angina, and Epidemiology (AWARE) Study

OBJECTIVES

With the recognition that fluid overload (FO) has a detrimental impact on critically ill children, the critical care nephrology community has focused on identifying clinically meaningful targets for intervention. The current study aims to evaluate the epidemiology and outcomes associated with FO in an international multicenter cohort of critically ill children. The current study also aims to evaluate the association of FO at predetermined clinically relevant thresholds and time points (FO ≥ 5% and FO ≥ 10% at the end of ICU days 1 and 2) with outcomes.

DESIGN

Prospective cohort study.

SETTING

Multicenter, international collaborative of 32 pediatric ICUs.

PATIENTS

A total of 5,079 children and young adults admitted consecutively to pediatric ICUs as part of the Assessment of the Worldwide Acute Kidney Injury, Renal Angina and Epidemiology Study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The FO thresholds at the time points of interest occurred commonly in the cohort (FO ≥ 5%Day1 in 38.1% [ n = 1753], FO ≥ 10%Day1 in 11.7% [ n = 537], FO ≥ 5%Day2 in 53.3% [ n = 1,539], FO ≥ 10%Day2 in 25.1% [ n = 724]). On Day1, multivariable modeling demonstrated that FO ≥ 5% was associated with fewer ICU-free days, and FO ≥ 10% was associated with higher mortality and fewer ICU and ventilator-free days. On multivariable modeling, FO-peak, Day2 FO ≥ 5%, and Day2 FO ≥ 10% were associated with higher mortality and fewer ICU and ventilator-free days.

CONCLUSIONS

This study found that mild-to-moderate FO as early as at the end of ICU Day1 is associated with adverse outcomes. The current study fills an important void in the literature by identifying critical combinations of FO timing and quantity associated with adverse outcomes (FO ≥ 5%Day1, FO ≥10%Day1, FO ≥ 5%Day2, and FO ≥ 10%Day2). Those novel findings will help guide the development of interventional strategies and trials targeting the treatment and prevention of clinically relevant FO.

Neonatal fluid overload-ignorance is no longer bliss

Excessive accumulation of fluid may result in interstitial edema and multiorgan dysfunction. Over the past few decades, the detrimental impact of fluid overload has been further defined in adult and pediatric populations. Growing evidence highlights the importance of monitoring, preventing, managing, and treating fluid overload appropriately. Translating this knowledge to neonates is difficult as they have different disease pathophysiologies, and because neonatal physiology changes rapidly postnatally in many of the organ systems (i.e., skin, kidneys, and cardiovascular, pulmonary, and gastrointestinal). Thus, evaluations of the optimal targets for fluid balance need to consider the disease state as well as the gestational and postmenstrual age of the infant. Integration of what is known about neonatal fluid overload with individual alterations in physiology is imperative in clinical management. This comprehensive review will address what is known about the epidemiology and pathophysiology of neonatal fluid overload and highlight the known knowledge gaps. Finally, we provide clinical recommendations for monitoring, prevention, and treatment of fluid overload.

Variability in Clinician Awareness of Intravenous Fluid Administration in Critical Illness: A Prospective Cohort Study

Intravenous (IV) fluids are commonly administered to critically ill children, but clinicians lack effective guidance for the correct dose and duration of therapy resulting in variation of prescribing habits which harm children. It is unknown if clinicians recognize the amount of IV fluid that patients receive. We aimed to determine clinician's accuracy in the identification of the volume of IV fluids patients will receive over the next 24 hours. Prospective cohort study enrolled all patients admitted to the pediatric intensive care unit (PICU) from May to August 2021 at the University of Michigan's C.S. Mott Children's Hospital PICU. For each patient, clinicians estimated the volume of IV fluid that patients will receive in the next 24 hours. The primary outcome was accuracy of the estimation defined as predicted volume of IV fluids versus actual volume administered within 10 mL/kg or 500 mL depending on patient's weight. We tested for differences in accuracy by clinician type using chi-square tests. There were 259 patients for whom 2,295 surveys were completed by 177 clinicians. Clinicians' estimates were accurate 48.8% of the time with a median difference of 10 (1–26) mL/kg. We found that accuracy varied between clinician type: bedside nurses were most accurate at 64.3%, and attendings were least accurate at 30.5%. PICU clinicians have poor recognition of the amount of IV fluids their patients will receive in the subsequent 24-hour period. Estimate accuracy varied by clinician's role and improved over time, which may suggest opportunities for improvement.

Consensus-Based Recommendations on Priority Activities to Address Acute Kidney Injury in Children: A Modified Delphi Consensus Statement

IMPORTANCE

Increasing evidence indicates that acute kidney injury (AKI) occurs frequently in children and young adults and is associated with poor short-term and long-term outcomes. Guidance is required to focus efforts related to expansion of pediatric AKI knowledge.

OBJECTIVE

To develop expert-driven pediatric specific recommendations on needed AKI research, education, practice, and advocacy.

EVIDENCE REVIEW

At the 26th Acute Disease Quality Initiative meeting conducted in November 2021 by 47 multiprofessional international experts in general pediatrics, nephrology, and critical care, the panel focused on 6 areas: (1) epidemiology; (2) diagnostics; (3) fluid overload; (4) kidney support therapies; (5) biology, pharmacology, and nutrition; and (6) education and advocacy. An objective scientific review and distillation of literature through September 2021 was performed of (1) epidemiology, (2) risk assessment and diagnosis, (3) fluid assessment, (4) kidney support and extracorporeal therapies, (5) pathobiology, nutrition, and pharmacology, and (6) education and advocacy. Using an established modified Delphi process based on existing data, workgroups derived consensus statements with recommendations.

FINDINGS

The meeting developed 12 consensus statements and 29 research recommendations. Principal suggestions were to address gaps of knowledge by including data from varying socioeconomic groups, broadening definition of AKI phenotypes, adjudicating fluid balance by disease severity, integrating biopathology of child growth and development, and partnering with families and communities in AKI advocacy.

CONCLUSIONS AND RELEVANCE

Existing evidence across observational study supports further efforts to increase knowledge related to AKI in childhood. Significant gaps of knowledge may be addressed by focused efforts.

Renal angina index predicts fluid overload in critically ill children: an observational cohort study

Background

Fluid overload and acute kidney injury are common and associated with poor outcomes among critically ill children. The prodrome of renal angina stratifies patients by risk for severe acute kidney injury, but the predictive discrimination for fluid overload is unknown.

Methods

Post-hoc analysis of patients admitted to a tertiary care pediatric intensive care unit (PICU). The primary outcome was the performance of renal angina fulfillment on day of ICU admission to predict fluid overload ≥15% on Day 3.

Results

77/139 children (55%) fulfilled renal angina (RA+). After adjusting for covariates, RA+ was associated with increased odds of fluid overload on Day 3 (adjusted odds ratio (aOR) 5.1, 95% CI 1.23–21.2, p = 0.025, versus RA-). RA- resulted in a 90% negative predictive value for fluid overload on Day 3. Median fluid overload was significantly higher in RA+ patients with severe acute kidney injury compared to RA+ patients without severe acute kidney injury (% fluid overload on Day 3: 8.8% vs. 0.73%, p = 0.002).

Conclusion

Among critically ill children, fulfillment of renal angina was associated with increased odds of fluid overload versus the absence of renal angina and a higher fluid overload among patients who developed acute kidney injury. Renal angina directed risk classification may identify patients at highest risk for fluid accumulation. Expanded study in larger populations is warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02540-6.

Timing and Clinical Significance of Fluid Overload in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

Fluid overload is associated with worse outcomes in adult and pediatric acute respiratory distress syndrome. However, the time-course of fluid overload and its relationship to outcome has not been described. We aimed to determine the relationship between the timing of fluid overload and outcomes over the first 7 days after acute respiratory distress syndrome onset in children.

DESIGN

Retrospective cohort study.

SETTING

Single tertiary care PICU.

PATIENTS

Intubated children with acute respiratory distress syndrome between 2011 and 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Daily and cumulative total fluid intake, total output, urine output, and fluid balance were collected for each 24-hour period from days 1 to 7 after acute respiratory distress syndrome onset. We tested the association between daily cumulative fluid metrics with PICU mortality and probability of extubation by 28 days using multivariable logistic and competing risk regression, respectively. In a subset of children, plasma was collected on day 1 and day 3 of acute respiratory distress syndrome and angiopoietin-2 quantified. Of 723 children with acute respiratory distress syndrome, 132 died (18%). In unadjusted analysis, nonsurvivors had higher cumulative fluid balance starting on day 3. In multivariable analysis, a positive cumulative fluid balance on days 5 through 7 was associated with increased mortality. Higher cumulative fluid balance on days 4 to 7 was associated with lower probability of extubation. Elevated angiopoietin-2 on day 1 predicted early (within 3 d) fluid overload greater than or equal to 10%, and elevated angiopoietin-2 on day 3 predicted late (between days 4 and 7) fluid overload.

CONCLUSIONS

Fluid overload after day 4 of acute respiratory distress syndrome, but not before, was associated with worse outcomes. Higher angiopoietin-2 predicted subsequent fluid overload. Our results suggest that future interventions aimed at managing fluid overload may have differential efficacy depending on when in the time-course of acute respiratory distress syndrome they are initiated.

Early Cumulative Fluid Balance and Outcomes in Pediatric Allogeneic Hematopoietic Cell Transplant Recipients With Acute Respiratory Failure: A Multicenter Study

OBJECTIVES

To evaluate the associations between early cumulative fluid balance (CFB) and outcomes among critically ill pediatric allogeneic hematopoietic cell transplant (HCT) recipients with acute respiratory failure, and determine if these associations vary by treatment with renal replacement therapy (RRT).

METHODS

We performed a secondary analysis of a multicenter retrospective cohort of patients (1mo - 21yrs) post-allogeneic HCT with acute respiratory failure treated with invasive mechanical ventilation (IMV) from 2009 to 2014. Fluid intake and output were measured daily for the first week of IMV (day 0 = day of intubation). The exposure, day 3 CFB (CFB from day 0 through day 3 of IMV), was calculated using the equation [Fluid in - Fluid out] (liters)/[PICU admission weight](kg)*100. We measured the association between day 3 CFB and PICU mortality with logistic regression, and the rate of extubation at 28 and 60 days with competing risk regression (PICU mortality = competing risk).

RESULTS

198 patients were included in the study. Mean % CFB for the cohort was positive on day 0 of IMV, and increased further on days 1-7 of IMV. For each 1% increase in day 3 CFB, the odds of PICU mortality were 3% higher (adjusted odds ratio (aOR) 1.03, 95% CI 1.00-1.07), and the rate of extubation was 3% lower at 28 days (adjusted subdistribution hazard ratio (aSHR) 0.97, 95% CI 0.95-0.98) and 3% lower at 60 days (aSHR 0.97, 95% CI 0.95-0.98). When day 3 CFB was dichotomized, 161 (81%) had positive and 37 (19%) had negative day 3 CFB. Positive day 3 CFB was associated with higher PICU mortality (aOR 3.42, 95% CI 1.48-7.87) and a lower rate of extubation at 28 days (aSHR 0.30, 95% CI 0.18-0.48) and 60 days (aSHR 0.30, 95% 0.19-0.48). On stratified analysis, the association between positive day 3 CFB and PICU mortality was significantly stronger in those not treated with RRT (no RRT: aOR 9.11, 95% CI 2.29-36.22; RRT: aOR 1.40, 95% CI 0.42-4.74).

CONCLUSIONS

Among critically ill pediatric allogeneic HCT recipients with acute respiratory failure, positive and increasing early CFB were independently associated with adverse outcomes.

Acute Kidney Injury in Pediatric Cardiac Intensive Care Children: Not All Admissions Are Equal: A Retrospective Study

OBJECTIVES

To describe the incidence, associated characteristics, and outcomes of the maximum severity of acute kidney injury (AKI) in a heterogeneous population of critically ill children with cardiac disease.

DESIGN

Retrospective cohort study.

SETTING

Pediatric cardiac intensive care unit (PCICU).

PARTICIPANTS

Patients admitted to the PCICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From January 2018 to July 2020 all patients admitted to a tertiary PCICU were included. Only the first admission was considered. Neonates ≤seven days old were excluded. Of 742 patients, 53 were medical cases, 69 catheterization laboratory cases, and 620 surgical cases (with five subgroups). The median age was 2.47 years (interquartile range [IQR], 0.38-9.85 years), with a median Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery score of 2 (IQR, 1-3). Median PCICU length of stay was three days (IQR, 2-7 days), and 21 (2.8%) patients died. Any incidence of AKI occurred in 70% of patients, 26% of which were classified as mild (stage 1) and 43% as severe (stages 2 and 3). AKI was diagnosed by urine output criteria in 56%, serum creatinine in 28%, and both in 16% of patients. Severe AKI occurred in subgroups as follows: medical (38%), catheterization laboratory (45%), correction (35%), palliation (55%), transplantation (85%), mechanical assistance (70%), and redo surgery (58%). Severe AKI patients were significantly older (p = 0.004), had a higher Pediatric Index of Mortality 3 score (p = 0.0004), had a higher cumulative fluid balance (p < 0.0001), and had a longer cardiopulmonary bypass time (p < 0.0001). Early AKI (≤24 hours from admission) was the most frequent presentation, with a greater proportion of severe cases in the early group compared with the intermediate (>24 and ≤48 hours) and late (>48 hours) (p < 0.0001) groups. Presentation of late severe AKI had a higher mortality (odds ratio, 4.9; 95% confidence interval, 1.8-15; p = 0.001).

CONCLUSIONS

Severe AKI occurs in 43% of cardiac children and is diagnosed early, most often by urine output criteria. Severe AKI incidence varies significantly within subgroups of cardiac patients. Late AKI is associated with worse outcomes.

Early restrictive fluid resuscitation has no clinical advantage in experimental severe pediatric acute respiratory distress syndrome

Intravenous fluids are widely used to treat circulatory deterioration in pediatric acute respiratory distress syndrome (PARDS). However, the accumulation of fluids in the first days of PARDS is associated with adverse outcome. As such, early fluid restriction may prove beneficial, yet the effects of such a fluid strategy on the cardiopulmonary physiology in PARDS are unclear. In this study, we compared the effect of a restrictive with a liberal fluid strategy on a hemodynamic response and the formation of pulmonary edema in an animal model of PARDS. Sixteen mechanically ventilated lambs (2-6 wk) received oleic acid infusion to induce PARDS and were randomized to a restrictive or liberal fluid strategy during a 6-h period of mechanical ventilation. Transpulmonary thermodilution determined extravascular lung water (EVLW) and cardiac output (CO). Postmortem lung wet-to-dry weight ratios were obtained by gravimetry. Restricting fluids significantly reduced fluid intake but increased the use of vasopressors among animals with PARDS. Arterial blood pressure was similar between groups, yet CO declined significantly in animals receiving restrictive fluids (P = 0.005). There was no difference in EVLW over time (P = 0.111) and lung wet-to-dry weight ratio [6.1, interquartile range (IQR) = 6.0-7.3 vs. 7.1, IQR = 6.6-9.4, restrictive vs. liberal, P = 0.725] between fluid strategies. Both fluid strategies stabilized blood pressure in this model, yet early fluid restriction abated CO. Early fluid restriction did not limit the formation of pulmonary edema; therefore, this study suggests that in the early phase of PARDS, a restrictive fluid strategy is not beneficial in terms of immediate cardiopulmonary effects.