Prophylactic Peritoneal Dialysis Following Cardiopulmonary Bypass in Children Is Associated with Decreased Inflammation and Improved Clinical Outcomes

Deriving and validating a protocol to determine the need for prophylactic peritoneal dialysis in neonates after cardiopulmonary bypass surgery

BACKGROUND

Prophylactic peritoneal dialysis (PD) in neonates undergoing cardiopulmonary bypass (CPB) is safe and improves outcomes. We sought to (1) derive the pre-operative characteristics of neonates who are most likely to benefit from PD after CPB and (2) validate a new prophylactic PD protocol based on our retrospective analysis.

METHODS

First, we retrospectively evaluated neonates requiring cardiac surgery with CPB from October 2012 to June 2016. We categorized neonates as those who "needed PD" and those who "did not need PD" based on prior experience with neonates requiring kidney support therapy. Pre-operative serum creatinine ≥ 0.8 mg/dL, pre-operative weight ≤ 2.5 kg, or having an open chest post-operatively were independently associated with "needed PD." Next, beginning in March 2019, we implemented a new prophylactic PD protocol in which only those who met at least one of the three criteria derived in the retrospective analysis had a PD catheter placed in the OR.

RESULTS

In Era 2, after the implementation of a new prophylactic PD protocol, 100% of neonates in the "needed PD" group had a PD catheter placed in the OR, which was more than in the prior era (Era 1 = 86.6%) (p = 0.05). Only 26.1% in the "did not need PD" group had a PD catheter placed in the OR which was less than in the prior era (Era 1 = 50.6%) (p < 0.01).

CONCLUSIONS

We successfully developed and implemented an evidence-based prophylactic PD protocol that has improved our ability to provide prophylactic PD in neonates after CPB.

An evaluation of the outcomes associated with peritoneal catheter use in neonates undergoing cardiac surgery: A multicenter study

Objective

The study objective was to determine if intraoperative peritoneal catheter placement is associated with improved outcomes in neonates undergoing high-risk cardiac surgery with cardiopulmonary bypass.

Methods

This propensity score-matched retrospective study used data from 22 academic pediatric cardiac intensive care units. Consecutive neonates undergoing Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 3 to 5 cardiac surgery with cardiopulmonary bypass at centers participating in the NEonatal and Pediatric Heart Renal Outcomes Network collaborative were studied to determine the association of the use of an intraoperative placed peritoneal catheter for dialysis or passive drainage with clinical outcomes, including the duration of mechanical ventilation.

Results

Among 1490 eligible neonates in the NEonatal and Pediatric Heart Renal Outcomes Network dataset, a propensity-matched analysis was used to compare 395 patients with peritoneal catheter placement with 628 patients without peritoneal catheter placement. Time to extubation and most clinical outcomes were similar. Postoperative length of stay was 5 days longer in the peritoneal catheter placement cohort (17 vs 22 days, P = .001). There was a 50% higher incidence of moderate to severe acute kidney injury in the no-peritoneal catheter cohort (12% vs 18%, P = .02). Subgroup analyses between specific treatments and in highest risk patients yielded similar associations.

Conclusions

This study does not demonstrate improved outcomes among neonates with placement of a peritoneal catheter during cardiac surgery. Outcomes were similar apart from longer hospital stay in the peritoneal catheter cohort. The no-peritoneal catheter cohort had a 50% higher incidence of moderate to severe acute kidney injury (12% vs 18%). This analysis does not support indiscriminate peritoneal catheter use, although it may support the utility for postoperative fluid removal among neonates at risk for acute kidney injury. A multicenter controlled trial may better elucidate peritoneal catheter effects.

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.

Peritoneal catheters in neonates undergoing complex cardiac surgery: a multi-centre descriptive study

BACKGROUND

The use of peritoneal catheters for prophylactic dialysis or drainage to prevent fluid overload after neonatal cardiac surgery is common in some centres; however, the multi-centre variability and details of peritoneal catheter use are not well described.

METHODS

Twenty-two-centre NEonatal and Pediatric Heart Renal Outcomes Network (NEPHRON) study to describe multi-centre peritoneal catheter use after STAT category 3-5 neonatal cardiac surgery using cardiopulmonary bypass. Patient characteristics and acute kidney injury/fluid outcomes for six post-operative days are described among three cohorts: peritoneal catheter with dialysis, peritoneal catheter with passive drainage, and no peritoneal catheter.

RESULTS

Of 1490 neonates, 471 (32%) had an intraoperative peritoneal catheter placed; 177 (12%) received prophylactic dialysis and 294 (20%) received passive drainage. Sixteen (73%) centres used peritoneal catheter at some frequency, including six centres in >50% of neonates. Four centres utilised prophylactic peritoneal dialysis. Time to post-operative dialysis initiation was 3 hours [1, 5] with the duration of 56 hours [37, 90]; passive drainage cohort drained for 92 hours [64, 163]. Peritoneal catheter were more common among patients receiving pre-operative mechanical ventilation, single ventricle physiology, and higher complexity surgery. There was no association with adverse events. Serum creatinine and daily fluid balance were not clinically different on any post-operative day. Mortality was similar.

CONCLUSIONS

In neonates undergoing complex cardiac surgery, peritoneal catheter use is not rare, with substantial variability among centres. Peritoneal catheters are used more commonly with higher surgical complexity. Adverse event rates, including mortality, are not different with peritoneal catheter use. Fluid overload and creatinine-based acute kidney injury rates are not different in peritoneal catheter cohorts.

Early postoperative weight-based fluid overload is associated with worse outcomes after neonatal cardiac surgery

OBJECTIVES

Evaluate the association of postoperative day (POD) 2 weight-based fluid balance (FB-W) > 10% with outcomes after neonatal cardiac surgery.

METHODS

Retrospective cohort study of 22 hospitals in the NEonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) registry from September 2015 to January 2018. Of 2240 eligible patients, 997 neonates (cardiopulmonary bypass (CPB) n = 658, non-CPB n = 339) were weighed on POD2 and included.

RESULTS

Forty-five percent (n = 444) of patients had FB-W > 10%. Patients with POD2 FB-W > 10% had higher acuity of illness and worse outcomes. Hospital mortality was 2.8% (n = 28) and not independently associated with POD2 FB-W > 10% (OR 1.04; 95% CI 0.29-3.68). POD2 FB-W > 10% was associated with all utilization outcomes, including duration of mechanical ventilation (multiplicative rate of 1.19; 95% CI 1.04-1.36), respiratory support (1.28; 95% CI 1.07-1.54), inotropic support (1.38; 95% CI 1.10-1.73), and postoperative hospital length of stay (LOS 1.15; 95% CI 1.03-1.27). In secondary analyses, POD2 FB-W as a continuous variable demonstrated association with prolonged durations of mechanical ventilation (OR 1.04; 95% CI 1.02-1.06], respiratory support (1.03; 95% CI 1.01-1.05), inotropic support (1.03; 95% CI 1.00-1.05), and postoperative hospital LOS (1.02; 95% CI 1.00-1.04). POD2 intake-output based fluid balance (FB-IO) was not associated with any outcome.

CONCLUSIONS

POD2 weight-based fluid balance > 10% occurs frequently after neonatal cardiac surgery and is associated with longer cardiorespiratory support and postoperative hospital LOS. However, POD2 FB-IO was not associated with clinical outcomes. Mitigating early postoperative fluid accumulation may improve outcomes but requires safely weighing neonates in the early postoperative period. A higher resolution version of the Graphical abstract is available as Supplementary information.

Biomarker-based risk model to predict persistent multiple organ dysfunctions after congenital heart surgery: a prospective observational cohort study

BACKGROUND

Multiple organ dysfunction syndrome (MODS) is an important cause of post-operative morbidity and mortality for children undergoing cardiac surgery requiring cardiopulmonary bypass (CPB). Dysregulated inflammation is widely regarded as a key contributor to bypass-related MODS pathobiology, with considerable overlap of pathways associated with septic shock. The pediatric sepsis biomarker risk model (PERSEVERE) is comprised of seven protein biomarkers of inflammation and reliably predicts baseline risk of mortality and organ dysfunction among critically ill children with septic shock. We aimed to determine if PERSEVERE biomarkers and clinical data could be combined to derive a new model to assess the risk of persistent CPB-related MODS in the early post-operative period.

METHODS

This study included 306 patients < 18 years old admitted to a pediatric cardiac ICU after surgery requiring cardiopulmonary bypass (CPB) for congenital heart disease. Persistent MODS, defined as dysfunction of two or more organ systems on postoperative day 5, was the primary outcome. PERSEVERE biomarkers were collected 4 and 12 h after CPB. Classification and regression tree methodology were used to derive a model to assess the risk of persistent MODS.

RESULTS

The optimal model containing interleukin-8 (IL-8), chemokine ligand 3 (CCL3), and age as predictor variables had an area under the receiver operating characteristic curve (AUROC) of 0.86 (0.81-0.91) for differentiating those with or without persistent MODS and a negative predictive value of 99% (95-100). Ten-fold cross-validation of the model yielded a corrected AUROC of 0.75 (0.68-0.84).

CONCLUSIONS

We present a novel risk prediction model to assess the risk for development of multiple organ dysfunction after pediatric cardiac surgery requiring CPB. Pending prospective validation, our model may facilitate identification of a high-risk cohort to direct interventions and studies aimed at improving outcomes via mitigation of post-operative organ dysfunction.

Early Peritoneal Dialysis and Postoperative Outcomes in Infants After Pediatric Cardiac Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

Peritoneal dialysis (PD) is used in several cardiac surgical units after cardiac surgery, and early initiation of PD after surgery may have the potential to influence postoperative outcomes. This systematic review and meta-analysis aims to summarize the evidence for the association between early PD after cardiac surgery and postoperative outcomes.

DATA SOURCES

MEDLINE, Embase, and PubMed from 1981 to November 1, 2021.

STUDY SELECTION

Observational studies and randomized trials reporting on early PD after pediatric cardiac surgery.

DATA EXTRACTION

Random-effects meta-analysis was used to estimate the pooled odds ratios (ORs) and their 95% CIs for postoperative mortality and pooled mean difference (MD) (95% CI) for duration of mechanical ventilation and ICU length of stay.

DATA SYNTHESIS

We identified nine studies from the systematic review, and five were considered suitable for meta-analysis. Early initiation of PD after cardiac surgery was associated with a reduction in postoperative mortality (OR, 0.43 (95% CI, 0.23-0.80); number of estimates = 4). Early commencement of PD shortened duration of mechanical ventilation (MD [95% CI], -1.09 d [-1.86 to -0.33 d]; I2 = 56.1%; p = 0.06) and intensive care length of stay (MD [95% CI], -2.46 d [-3.57 to -1.35 d]; I2 = 18.7%; p = 0.30], respectively. All three estimates had broad 95% prediction intervals (crossing null) denoting major heterogeneity between studies and wide range of possible study estimates in similar future studies. Overall, studies reporting on the effects of early PD included only a subset of infants undergoing cardiac surgery (typically high-risk infants), so selection bias may be a major issue in published studies.

CONCLUSIONS

This review suggests that early initiation of PD may be associated with beneficial postoperative outcomes in infants after cardiac surgery. However, these results were based on studies of varying qualities and risk of bias. Early identification of high-risk infants after cardiac surgery is important so that prevention or early mitigation strategies can be applied to this cohort. Future prospective studies in high-risk populations are needed to study the role of early PD in influencing postoperative outcomes.

Study protocol and statistical analysis plan for the Early Peritoneal Dialysis in Infants after Cardiac Surgery (EPICS) trial

Background: Peritoneal dialysis (PD) is a commonly used therapy after infant cardiac surgery. It is unclear whether early PD commenced soon after admission to an intensive care unit (ICU) after cardiac surgery results in better outcomes. Objective: To describe the study protocol and statistical analysis plan for the Early Peritoneal Dialysis in Infants after Cardiac Surgery (EPICS) trial. Design, setting, participants and intervention: The EPICS trial is an open, randomised, two-group, single-centre clinical study of infants ≤ 180 days of age who had cardiac surgery (in Risk-Adjusted Classification for Congenital Heart Surgery version 1 categories 3-6) with cardiopulmonary bypass. Participants will be randomly assigned 1:1 to early PD (treatment group) or no early PD (control group). Those assigned to the treatment group will begin receiving PD soon after ICU admission and continue receiving it for 24 hours. Those in the control group will not receive PD during the first 24 hours. Main outcome measures: The primary outcome is a composite measure consisting of one or more of death, cardiac arrest, emergency chest reopening, and requirement for extracorporeal membrane oxygenation (ECMO) within 90 days. The main secondary outcomes are duration of mechanical ventilation, ICU length of stay, hospital length of stay, vasoactive-inotropic score at 24 hours, and cumulative per cent fluid balance by end of Day 2. At Day 90, events such as mortality, requirement for ECMO, cardiac arrest, chest reopening, volume of packed red blood cell transfusion, postoperative infection, readmission to ICU, renal injury and brain injury will be assessed. Conclusions: The EPICS trial aims to evaluate the role of early PD after infant cardiac surgery in lowering the rate of a composite major outcome. In addition, it will test the effect of early PD on duration of mechanical ventilation, and on ICU and hospital length of stay. Trial registration: ACTRN12617001614381.

Strategies to mitigate inflammation in management of complex congenital heart disease complicated by "multisystem inflammatory syndrome in children"

A 6-month-old boy, a case of Shone's complex, presented in decompensated state was found to have severe mitral stenosis along with multisystem inflammatory syndrome in children (MISC) warranting urgent surgical intervention. Various modalities including cytokine-adsorbing hemofilter were used to target inflammation. Postoperatively, the child recovered from low cardiac output accompanied by decrease in the levels of inflammatory markers, inopressors, and ventilatory requirements. Open heart surgery in itself is a proinflammatory process and is best avoided during the active inflammatory phase of MISC. In the rare and unavoidable circumstance exemplified by this index case, multipronged strategy targeting inflammation as described can be successfully implemented.

Filtering Down to Risks and Solutions: Risk Factors and Stratification After Pediatric Cardiac Surgery

Acute kidney injury after cardiac surgery (CS-AKI) is common in neonatal and pediatric populations and is a risk factor for poor outcomes, such as mortality and increased hospital resource utilization. This review presents a summary of CS-AKI risk factors, integration of biomarkers, and the need to improve risk stratification for targeting future clinical trials. To date, studies examining CS-AKI risk factors cannot be generalized easily owing to variability in patient age, surgical complexity or population, AKI definition, and center-specific practices. However, certain risk associations, such as younger age at surgery, history of prematurity, cardiopulmonary bypass time, and surgical complexity, have been identified across multiple, but not all, studies. CS-AKI appears to have different severity and duration phenotypes, and serum creatinine is limited in its ability to identify CS-AKI early and predict CS-AKI course. Treatment strategies are largely supportive, and efforts are ongoing to use biomarkers and clinical features to risk-stratify patients, which in turn may facilitate differential CS-AKI phenotyping and management with supportive care bundles, clinical decision support techniques, and modulation of modifiable risk factors.

Transient and persistent acute kidney injury phenotypes following the Norwood operation: a retrospective study

BACKGROUND

Acute kidney injury is a common complication following the Norwood operation. Most neonatal studies report acute kidney injury peaking within the first 48 hours after cardiac surgery. The aim of this study was to evaluate if persistent acute kidney injury (>48 postoperative hours) after the Norwood operation was associated with clinically relevant outcomes.

METHODS

Two-centre retrospective study among neonates undergoing the Norwood operation. Acute kidney injury was initially identified as developing within the first 48 hours after cardiac surgery and stratified into transient (≤48 hours) and persistent (>48 hours) using the neonatal modification of the Kidney Disease: Improving Global Outcomes serum creatinine criteria. Severe was defined as stage ≥2. Primary and secondary outcomes were mortality and duration of ventilation and hospital length of stay.

RESULTS

One hundred sixty-eight patients were included. Transient and persistent acute kidney injuries occurred in 24 and 17%, respectively. Cardiopulmonary bypass and aortic cross clamp duration, and incidence of cardiac arrest were greater among those with persistent kidney injury. Mortality was four times higher (41 versus 12%, p < 0.001) and mechanical ventilation duration 50 hours longer in persistent acute kidney injury patients (158 versus 107 hours; p < 0.001). In multivariable analysis, persistent acute kidney injury was not associated with mortality, duration of ventilation or length of stay. Severe persistent acute kidney injury was associated with a 59% increase in expected ventilation duration (aIRR:1.59, 95% CI:1.16, 2.18; p = 0.004).

CONCLUSIONS

Future large studies are needed to determine if risk factors and outcomes change by delineating acute kidney injury into discrete timing phenotypes.

Acute pediatric kidney replacement therapies in Europe: demographic results from the EurAKId Registry

BACKGROUND

Acute kidney injury (AKI), particularly that requiring dialysis, is a severe complication in hospitalized children associated with high morbidity and mortality. A prospective European AKI registry (EurAKId registry, NCT02960867) was created to describe the epidemiology and outcomes of pediatric patients treated with acute dialysis.

METHODS

Children were recruited who were between 0 and 18 years of age and were treated both in and outside the Pediatric Intensive Care Unit (PICU) with peritoneal dialysis (PD), hemodialysis (HD) or continuous kidney replacement therapy (CKRT) for AKI or metabolic derangement, fluid overload (FO), sepsis, or respiratory distress. Five age groups and 12 categories of primary diseases were defined.

RESULTS

Data on 340 patients were analyzed, of whom 86% received dialysis for AKI and 14% for reasons other than AKI. Boys accounted for 60% of the patients. Illness severity was greater in children with cardiac and hematologic diseases than those with kidney diseases. Most patients received dialysis in the PICU (84%). The most frequently used dialysis modality was CKRT (64%), followed by PD (14%) and HD (14%). The overall survival rate was 65%. Survival was significantly lower in children with three comorbidities than in children with no comorbidities (41% and 83%, p < 0.001).

CONCLUSIONS

The EurAKId registry is the first prospective registry considering pediatric acute kidney replacement therapies (KRT) in both critical and non-critical care settings, focusing on the three dialysis modalities in Europe. The clinical indications for KRT have expanded; our population was characterized by critically ill patients, primarily boys, who frequently received dialysis in the PICU with CKRT.

Peritoneal dialysis in children with sepsis-associated AKI (SA-AKI): an experience in a low- to middle-income country

Background: In critically ill children, sepsis-associated acute kidney injury (SA-AKI) has significant morbidity and mortality.Aim: To estimate whether early initiation of peritoneal dialysis (PD) has a better short-term outcome than standard PD.Methods: Early PD (n = 25) was defined as a need for PD in Kidney Disease: Improving Global Outcomes (KDIGO) stage 2 AKI, while those fulfilling the criteria for stage 3 KDIGO were categorised as a standard PD group (n = 25). The primary outcome measure was the estimated glomerular filtration rate (eGFR) at discharge or at 4 weeks after initiation of PD, whichever occurred earlier.Results: A prospective cohort of 50 children (32 boys) aged 2 months to 16 years with SA-AKI who underwent PD were recruited. The most frequent indication for PD was fluid overload (40%), followed by persistent metabolic acidosis (36%). Children in the early PD group had lower creatinine and higher eGFR at discharge/4-week follow-up (p < 0.001). The duration of PD was less if it was commenced early (p < 0.04); 24 of 25 (96%) children in the early PD group were off PD within 6 days of initiation compared with 13 of 25 (52%) in the standard PD group (p < 0.001).Conclusions: Compared with standard PD, early PD in SA-AKI resulted in a favourable renal outcome, decreased duration of PD and early discontinuation of dialysis.Abbreviations : AKI: acute kidney injury; CRRT: continuous renal replacement therapy; CS-AKI: cardiac surgery-associated acute kidney injury; eGFR: estimated glomerular filtration rate; ELAIN: early versus late initiation of renal replacement therapy in critically ill patients with acute kidney injury; ESCAPE: effect of strict blood pressure control and ACE inhibition on the progression of chronic kidney disease in paediatric patients; HIC: high-income countries; ISN: international society of nephrology; KDIGO: Kidney Disease: Improving Global Outcomes; LMIC: low- to middle-income countries; PD: peritoneal dialysis; PICU: paediatric intensive care unit; RRT: renal replacement therapy; SA-AKI: sepsis-associated acute kidney injury; SYL: Saving Young Lives; SOFA: sequential (sepsis-related) organ failure assessment score; STARRT-AKI: standard versus accelerated initiation of renal replacement therapy in acute kidney injury.

Cardiac critical care of the post-operative congenital heart disease patient

Cardiac critical care has become an increasingly complex subspecialty, involving multiple subspecialists to support patients with congenital heart disease. This requires understanding of their physiology and the impact of medical interventions. The purpose of this article is to provide a concise review of the current strategies utilized by cardiac intensivists to optimize outcomes for this vulnerable patient population, with the goal of broadening the knowledge of other members of the multi-disciplinary team.

Evaluation of Hypervolemia in Children

Hypervolemia is a condition with an excess of total body water and when sodium (Na) intake exceeds output. It can have different causes, such as hypervolemic hyponatremia (often associated with decreased, effective circulating blood volume), hypervolemia associated with metabolic alkalosis, and end-stage renal disease. The degree of hypervolemia in critically ill children is a risk factor for mortality, regardless of disease severity. A child (under 18 years of age) with hypervolemia requires fluid removal and fluid restriction. Diuretics are able to increase or maintain urine output and thus improve fluid and nutrition management, but their benefit in preventing or treating acute kidney injury is questionable.

Association of postoperative fluid overload with adverse outcomes after congenital heart surgery: a systematic review and dose-response meta-analysis

BACKGROUND

Pediatric cardiac surgery is commonly associated with acute kidney injury (AKI) and significant fluid retention, which complicate postoperative management and lead to increased rates of morbidity. This meta-analysis aimed to accumulate current literature evidence and evaluate the correlation of fluid overload degree with adverse outcome in patients undergoing congenital heart surgery.

METHODS

Medline, Scopus, CENTRAL, Clinicaltrials.gov, and Google Scholar were systematically searched from inception. All studies reporting the effects of fluid overload on postoperative clinical outcomes were selected. A dose-response meta-analytic method using restricted cubic splines was implemented in R-3.6.1.

RESULTS

Twelve studies were included, with a total of 3111 pediatric patients. Qualitative synthesis indicated that fluid overload was linked to significantly higher risk of mortality, AKI, prolonged hospital, and intensive care unit (ICU) stay, as well as with increased duration of mechanical ventilation, inotrope need, and infection rate. Meta-analysis demonstrated a linear correlation between fluid overload and the risk of mortality (χ² = 6.22, p value = 0.01) and AKI (χ² = 35.84, p value < 0.001), while a positive curvilinear relationship was estimated for the outcomes of hospital (χ² = 18.84, p value = 0.0001) and ICU stay (χ² = 63.69, p value = 0.0001).

CONCLUSIONS

The present meta-analysis supports that postoperative fluid overload is significantly linked to elevated risk of prolonged hospital stay, AKI development, and mortality in pediatric patients undergoing cardiac surgery. These findings warrant replication by future prospective studies, which should define the optimal cutoff values and assess the effectiveness of therapeutic strategies to limit fluid overload in the postoperative setting.

Passive Peritoneal Drainage Impact on Fluid Balance and Inflammatory Mediators: A Randomized Pilot Study

BACKGROUND

Infants after cardiopulmonary bypass are exposed to increasing inflammatory mediator release and are at risk of developing fluid overload. The aim of this pilot study was to evaluate the impact of passive peritoneal drainage on achieving negative fluid balance and its ability to dispose of inflammatory cytokines.

METHODS

From September 2014 to November 2016, infants undergoing STAT category 3, 4, and 5 operations were randomized to receive or not receive intraoperative prophylactic peritoneal drain. We analyzed time to negative fluid balance and perioperative variables for each group. Pro- and anti-inflammatory cytokines were measured from serum and peritoneal fluid in the passive peritoneal drainage group and serum in the control group postoperatively.

RESULTS

Infants were randomized to prophylactic passive peritoneal drain group (n = 13) and control (n = 12). The groups were not significantly different in pre- and postoperative peak lactate levels, postoperative length of stay, and mortality. Peritoneal drain patients reached time to negative fluid balance at a median of 1.42 days (interquartile range [IQR]: 1.00-2.91), whereas the control at 3.08 (IQR: 1.67-3.88; P = .043). Peritoneal drain patients had lower diuretic index at 72 hours, median of 2.86 (IQR: 1.21-4.94) versus 6.27 (IQR: 4.75-11.11; P = .006). Consistently, tumor necrosis factor-α, interleukin (IL)-4, IL-6, IL-8, IL-10, and interferon-γ were present at higher levels in peritoneal fluid than serum at 24 and 72 hours. However, serum cytokine levels in peritoneal drain and control group, at 24 and 72 hours postoperatively, did not differ significantly.

CONCLUSIONS

The prophylactic passive peritoneal drain patients reached negative fluid balance earlier and used less diuretic in early postoperative period. The serum cytokine levels did not differ significantly between groups at 24 and 72 hours postoperatively. However, there was no significant difference in mortality and postoperative length of stay.

Prophylactic Peritoneal Drainage is Associated with Improved Fluid Output after Congenital Heart Surgery

Infants undergoing congenital heart surgery (CHS) with cardiopulmonary bypass (CPB) are at risk of acute kidney injury (AKI) and fluid overload. We hypothesized that placement of a passive peritoneal drain (PPD) can improve postoperative fluid output in such infants. We analyzed 115 consecutive patients, age birth to 60 days, admitted to the PICU after CHS with CPB between 2012 and 2018. Patients who needed postoperative ECMO were excluded. Linear and logistic regression models compared postoperative fluid balances, diuretics administration, AKI, vasoactive-inotropic scores (VIS), time intubated, and length of stay after adjusting for pre/operative predictors including STAT category, bypass time, age, weight, and open chest status. PPD patients had higher STAT category (p = 0.001), longer CPB times (p = 0.001), and higher VIS on POD 1-3 (p ≤ 0.005 daily). PPD patients also had higher AKI rates (p = 0.01) that did not reach significance in multivariable modeling. There were no postoperative deaths. Postoperative hours of intubation, hospital length of stay, and POD 1-5 fluid intake did not differ between groups. Over POD 1-5, PPD use accounted for 48.8 mL/kg increased fluid output (95% CI [2.2, 95.4], p = 0.043) and 3.41 mg/kg less furosemide administered (95% CI [1.69, 5.14], p < 0.001). No PPD complications were observed. Although PPD placement did not affect end-outcomes, it was used in higher acuity patients. PPD placement is associated with improved fluid output despite lower diuretic administration and may be a useful postoperative fluid management adjunct in some complex CHS patients.

Acute Kidney Injury and Fluid Overload in Pediatric Cardiac Surgery

PURPOSE OF REVIEW

Acute kidney injury (AKI) and fluid overload affect a large number of children undergoing cardiac surgery, and confers an increased risk for adverse complications and outcomes including death. Survivors of AKI suffer long-term sequelae. The purpose of this narrative review is to discuss the short and long-term impact of cardiac surgery associated AKI and fluid overload, currently available tools for diagnosis and risk stratification, existing management strategies, and future management considerations.

RECENT FINDINGS

Improved risk stratification, diagnostic prediction tools and clinically available early markers of tubular injury have the ability to improve AKI-associated outcomes. One of the major challenges in diagnosing AKI is the diagnostic imprecision in serum creatinine, which is impacted by a variety of factors unrelated to renal disease. In addition, many of the pharmacologic interventions for either AKI prevention or treatment have failed to show any benefit, while peritoneal dialysis catheters, either for passive drainage or prophylactic dialysis may be able to mitigate the detrimental effects of fluid overload.

SUMMARY

Until novel risk stratification and diagnostics tools are integrated into routine practice, supportive care will continue to be the mainstay of therapy for those affected by AKI and fluid overload after pediatric cardiac surgery. A viable series of preventative measures can be taken to mitigate the risk and severity of AKI and fluid overload following cardiac surgery, and improve care.

Renal replacement therapy in the pediatric cardiac intensive care unit

OBJECTIVE

There is an increased risk of mortality in patients in whom acute kidney injury and fluid accumulation develop after cardiothoracic surgery, and the risk is especially high when renal replacement therapy is needed. However, renal replacement therapy remains an essential intervention in managing these patients. The objective of this study was to identify risk factors for mortality in surgical patients requiring renal replacement therapy in a pediatric cardiac intensive care unit.

METHODS

We performed a retrospective review of patients requiring renal replacement therapy for acute kidney injury or fluid accumulation after cardiothoracic surgery between January 2009 and December 2017. Survivors and nonsurvivors were compared with respect to multiple variables, and a multivariable logistic regression analysis was performed to identify independent risk factors associated with mortality.

RESULTS

The mortality rate for the cohort was 75%. Nonsurvivors were younger (nonsurvivors: 0.8 years; interquartile range, 0.1-8.2; survivors: 14.6 years; interquartile range, 4.2-19.7; P = .002) and had a lower weight-for-age z-score (nonsurvivors: -1.5; interquartile range, -3.1 to -0.4; survivors: -0.5; interquartile range, -0.9 to 0.3; P = .02) compared with survivors. There was no difference with respect to fluid accumulation. In multivariable analysis, a longer duration of stage 3 acute kidney injury before initiation of renal replacement therapy was independently associated with mortality (adjusted odds ratio, 1.39; 95% confidence interval, 1.05-1.83; P = .021).

CONCLUSIONS

Mortality in patients requiring renal replacement therapy after congenital heart disease surgery is high. A longer duration of acute kidney injury before renal replacement therapy initiation is associated with increased mortality.

Peritoneal Dialysis Vs Diuretics in Children After Congenital Heart Surgery

BACKGROUND

This study sought to evaluate outcomes of patients undergoing congenital heart surgery who underwent peritoneal dialysis (PD) vs a diuretic regimen.

METHODS

This study conducted a comprehensive search in Medline, EMBASE, Scopus, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews from the databases' inception through April 24, 2018. Independent reviewers selected studies and extracted data. A random effects meta-analysis was performed to pool the outcomes of interest across studies.

RESULTS

A total of 8 studies (2 prospective studies, 2 randomized clinical trials, and 4 retrospective studies) with 507 patients were included in this review. A total of 204 (40%) patients underwent PD, whereas the remaining patients underwent fluid removal with diuretics. The analyses demonstrated a significantly shorter time of mechanical ventilation in those patients who underwent PD (mean difference, -1.25 days; 95% confidence interval, -2.18 to -0.33; P = .008) and increased odds of mortality (odds ratio, 2.27; 95% confidence interval, 1.13 to 4.56; P = .02) compared with the diuretic group. No differences were identified in terms of incidence of negative fluid balance by postoperative day 1, presence of peritonitis, and intensive care unit length of stay.

CONCLUSIONS

The meta-analysis did not identify differences between the 2 groups with regard to negative fluid balance after postoperative day 1, incidence of peritonitis, or length of intensive care unit stay. There is a need for large, prospective, multicenter studies to evaluate the benefits and complications associated with PD use further in selected children after congenital heart surgery. Because some of the outcomes were present in only 2 studies, results from the pooled analysis may be underpowered.

Acute dialysis in children: results of a European survey

The number of children with acute kidney injury (AKI) requiring dialysis is increasing. To date, systematic analysis has been largely limited to critically ill children treated with continuous renal replacement therapy (CRRT). We conducted a survey among 35 European Pediatric Nephrology Centers to investigate dialysis practices in European children with AKI. Altogether, the centers perform dialysis in more than 900 pediatric patients with AKI per year. PD and CRRT are the most frequently used dialysis modalities, accounting for 39.4% and 38.2% of treatments, followed by intermittent HD (22.4%). In units treating more than 25 cases per year and in those with cardiothoracic surgery programs, PD is the most commonly chosen dialysis modality. Also, nearly one quarter of centers, in countries with a gross domestic product below $35,000/year, do not utilize CRRT at all. Dialysis nurses are exclusively in charge of CRRT management in 45% of the cases and pediatric intensive care nurses in 25%, while shared management is practiced in 30%. In conclusion, this survey indicates that the choice of treatment modalities for dialysis in children with AKI in Europe is affected by the underlying ethiology of the disease, organization/set-up of centers and socioeconomic conditions. PD is utilized as often as CRRT, and also intermittent HD is a commonly applied treatment option. A prospective European AKI registry is planned to provide further insights on the epidemiology, management and outcomes of dialysis in pediatric AKI.

Early Peritoneal Dialysis and Major Adverse Events After Pediatric Cardiac Surgery: A Propensity Score Analysis

OBJECTIVES

Early peritoneal dialysis may have a role in modulating the inflammatory response after cardiopulmonary bypass. This study sought to test the effect of early peritoneal dialysis on major adverse events after pediatric cardiac surgery involving cardiopulmonary bypass.

DESIGN

In this observational study, the outcomes in infants post cardiac surgery who received early peritoneal dialysis (within 6 hr of completing cardiopulmonary bypass) were compared with those who received late peritoneal dialysis. The primary outcome was a composite of one or more of cardiac arrest, emergency chest reopening, requirement for extracorporeal membrane oxygenation, or death. Secondary outcomes included duration of mechanical ventilation, length of intensive care, and hospital stay. A propensity score methodology utilizing inverse probability of treatment weighting was used to minimize selection bias due to timing of peritoneal dialysis.

SETTING

Cardiac ICU, The Royal Children's Hospital, Melbourne, VIC, Australia.

PATIENTS

From 2012 to 2015, infants who were commenced on peritoneal dialysis after cardiac surgery were included.

MEASUREMENTS AND MAIN RESULTS

Among 239 eligible infants, 56 (23%) were commenced on early peritoneal dialysis and 183 (77%) on late peritoneal dialysis. At 90 days, early peritoneal dialysis as compared with late peritoneal dialysis was associated with a decreased risk of primary outcome (relative risk, 0.16; 95% CI, 0.05-0.47; p < 0.001 and absolute risk difference, -18.1%; 95% CI, -25.1 to -11.1; p < 0.001). Early peritoneal dialysis was also associated with a decrease in duration of mechanical ventilation and intensive care stay. Among infants with a cardiopulmonary bypass greater than 150 minutes, early peritoneal dialysis was also associated with a survival advantage (relative risk, 0.14; 95% CI, 0.03-0.84; p = 0.03 and absolute risk difference, -7.8; 95% CI, -13.6 to -2; p = 0.008).

CONCLUSIONS

Early peritoneal dialysis in infants post cardiac surgery is associated with a decrease in the rate of major adverse events. The role of early peritoneal dialysis warrants the conduct of randomized trials both in high and low-to-middle income countries; any beneficial effects if confirmed have the potential to strongly influence outcomes for children born with congenital heart disease.

Fluid Management With Peritoneal Dialysis After Pediatric Cardiac Surgery

Children who undergo cardiac surgery with cardiopulmonary bypass are a unique population at high risk for postoperative acute kidney injury (AKI) and fluid overload. Fluid management is important in the postoperative care of these children as fluid overload is associated with increased morbidity and mortality. Peritoneal dialysis catheters are an important tool in the armamentarium of a cardiac intensivist and are used for passive drainage for fluid removal or dialysis for electrolyte and uremia control in AKI. Prophylactic placement of a peritoneal catheter is a safe method of fluid removal that is associated with few major complications. Early initiation of peritoneal dialysis has been associated with improved clinical markers and outcomes such as early achievement of a negative fluid balance, lower vasoactive medication needs, shorter duration of mechanical ventilation, and decreased mortality. In this review, we discuss the safety and potential benefits of peritoneal catheters for dialysis or passive drainage in children following cardiopulmonary bypass.

Comprehensive Management Considerations of Select Noncardiac Organ Systems in the Cardiac Intensive Care Unit

As the acuity and complexity of pediatric patients with congenital cardiac disease have increased, there are many noncardiac issues that may be present in these patients. These noncardiac problems may affect clinical outcomes in the cardiac intensive care unit and must be recognized and managed. The Pediatric Cardiac Intensive Care Society sought to provide an expert review of some of the most common challenges of the respiratory, gastrointestinal, hematological, renal, and endocrine systems in pediatric cardiac patients. This review provides a brief overview of literature available and common practices.

Fluid Overload in Critically Ill Children

Background: A common practice in the management of critically ill patients is fluid resuscitation. An excessive administration of fluids can lead to an imbalance in fluid homeostasis and cause fluid overload (FO). In pediatric critical care patients, FO can lead to a multitude of adverse effects and increased risk of morbidity. Objectives: To review the literature highlighting impact of FO on a multitude of outcomes in critically-ill children, causative vs. associative relationship of FO with critical illness and current pediatric fluid management guidelines. Data Sources: A literature search was conducted using PubMed/Medline and Embase databases from the earliest available date until June 2017. Data Extraction: Two authors independently reviewed the titles and abstracts of all articles which were assessed for inclusion. The manuscripts of studies deemed relevant to the objectives of this review were then retrieved and associated reference lists hand-searched. Data Synthesis: Articles were segregated into various categories namely pathophysiology and sequelae of fluid overload, assessment techniques, epidemiology and fluid management. Each author reviewed the selected articles in categories assigned to them. All authors participated in the final review process. Conclusions: Recent evidence has purported a relationship between mortality and FO, which can be validated by prospective RCTs (randomized controlled trials). The current literature demonstrates that "clinically significant" degree of FO could be below 10%. The lack of a standardized method to assess FB (fluid balance) and a universal definition of FO are issues that need to be addressed. To date, the impact of early goal directed therapy and utility of hemodynamic parameters in predicting fluid responsiveness remains underexplored in pediatric resuscitation.

Prevention of Acute Kidney Injury in Children Undergoing Cardiac Surgery: A Narrative Review

Children undergoing cardiac surgery are at risk of developing acute kidney injury (AKI). Preventing cardiac surgery-associated AKI (CS-AKI) is important as it is associated with increased early- and long-term mortality and morbidity. Targeting modifiable risk factors (eg, avoiding poor renal perfusion, nephrotoxic drugs, and fluid overload) reduces the risk of CS-AKI. There is currently no strong evidence for the routine use of pharmacological approaches (eg, aminophylline, dexmedetomidine, fenoldopam, and steroids) to prevent CS-AKI. There is robust evidence to support the role of early peritoneal dialysis as a nonpharmacologic approach to prevent CS-AKI.

Furosemide Response Predicts Acute Kidney Injury After Cardiac Surgery in Infants and Neonates

OBJECTIVE

Cardiac surgery-induced acute kidney injury occurs frequently in neonates and infants and is associated with postoperative morbidity/mortality; early identification of cardiac surgery-induced acute kidney injury may be crucial to mitigate postoperative morbidity. We sought to determine if hourly or 6-hour cumulative urine output after furosemide in the first 24 hours after cardiopulmonary bypass could predict development of cardiac surgery-induced acute kidney injury and other deleterious outcomes.

DESIGN

Retrospective chart review.

SETTING

Pediatric cardiac ICU.

PATIENTS

All infants younger than 90 days old admitted to the cardiac ICU from October 2012 to December 2015 who received at least one dose of furosemide in the first 24 hours after cardiopulmonary bypass surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Ninety-nine patients met inclusion and exclusion criteria. In total, 45.5% developed cardiac surgery-induced acute kidney injury. Median time between cardiopulmonary bypass and furosemide was 7.7 hours (interquartile range, 4.4-9.5). Six-hour cumulative urine output was 33% lower (p = 0.031) in patients with cardiac surgery-induced acute kidney injury. Area under the curve for prediction of cardiac surgery-induced acute kidney injury was 0.69 (p = 0.002). Other models demonstrated urine output response to furosemide had significant area under the curves for prediction of peak fluid over load greater than 15% (0.68; p = 0.047), prolonged peritoneal dialysis (area under the curve, 0.79; p = 0.007), prolonged mechanical ventilation (area under the curve, 0.79; p < 0.001), prolonged hospitalization (area under the curve, 0.62; p = 0.069) and mortality (area under the curve, 0.72; p = 0.05).

CONCLUSIONS

Urine output response to furosemide within 24 hours of cardiopulmonary bypass predicts cardiac surgery-induced acute kidney injury development and other important morbidity in children younger than 90 days old; prospective validation is warranted.

Maternal obesity and excessive maternal weight gain during pregnancy: effects on outcomes after neonatal cardiac surgical procedures

Introduction Maternal obesity is associated with an increased risk for adverse perinatal outcomes. Obesity is also associated with a chronic inflammatory state and metabolic derangements that affect the newborn. The additional use of cardiopulmonary bypass during the neonatal period could impact the systemic inflammatory response in the immediate postoperative period that manifests as cardiac depression and multi-organ dysfunction. This study aimed to determine the association of maternal obesity and excessive weight gain during pregnancy with the immediate postoperative morbidity of neonatal patients undergoing cardiopulmonary bypass.

METHODS

A retrospective review of neonates who underwent cardiopulmonary bypass within the first 30 days of life at our institution between 2011 and 2013 was conducted. Postoperative variables investigated included the duration of length of mechanical ventilation, length of stay in the ICU, peak vasoactive inotrope scores, and peak lactate level. Maternal obesity was defined as 1st trimester body mass index ⩾30 kg/m2. Excessive weight gain was defined as ⩾12 kg gained during pregnancy. In order to determine the association between maternal obesity or excessive weight gain and postoperative variables, we used multiple linear regression, adjusting for birth weight and risk adjustment for congenital heart surgery score.

RESULTS

Records from 58 mother-baby dyads were examined. After controlling for birth weight and risk adjustment for congenital heart surgery score, there were no significant associations between maternal obesity and excessive weight gain during pregnancy versus all postoperative outcomes measured.

CONCLUSION

Despite the known negative impact of maternal obesity on perinatal outcomes, we were unable to find associations between maternal obesity and excessive weight gain during pregnancy versus postoperative outcomes.

The role of fluid overload in the prediction of outcome in acute kidney injury

Our understanding of the epidemiology and the impact of acute kidney injury (AKI) and fluid overload on outcomes has improved significantly over the past several decades. Fluid overload occurs commonly in critically ill children with and without associated AKI. Researchers in pediatric AKI have been at the forefront of describing the impact of fluid overload on outcomes in a variety of populations. A full understanding of this topic is important as fluid overload represents a potentially modifiable risk factor and a target for intervention. In this state-of-the-art review, we comprehensively describe the definition of fluid overload, the impact of fluid overload on kidney function, the impact of fluid overload on the diagnosis of AKI, the association of fluid overload with outcomes, the targeted therapy of fluid overload, and the impact of the timing of renal replacement therapy on outcomes.

Peritoneal Drainage Versus Pleural Drainage After Pediatric Cardiac Surgery

BACKGROUND

We aimed to determine whether infants undergoing cardiac surgery would more efficiently attain negative fluid balance postoperatively with passive peritoneal drainage as compared to traditional pleural drainage.

METHODS

A prospective, randomized study including children undergoing repair of tetralogy of Fallot (TOF) or atrioventricular septal defect (AVSD) was completed between September 2011 and June 2013. Patients were randomized to intraoperative placement of peritoneal catheter or right pleural tube in addition to the requisite mediastinal tube. The primary outcome measure was fluid balance at 48 hours postoperatively. Variables were compared using t tests or Fisher exact tests as appropriate.

RESULTS

A total of 24 patients were enrolled (14 TOF and 10 AVSD), with 12 patients in each study group. Mean fluid balance at 48 hours was not significantly different between study groups, -41 ± 53 mL/kg in patients with periteonal drainage and -9 ± 40 mL/kg in patients with pleural drainage (P = .10). At 72 hours however, postoperative fluid balance was significantly more negative with peritoneal drainage, -52.4 ± 71.6 versus +2.0 ± 50.6 (P = .04). On subset analysis, fluid balance at 48 hours in patients with AVSD was more negative with peritoneal drainage as compared to pleural, -82 ± 51 versus -1 ± 38 mL/kg, respectively (P = .02). Fluid balance at 48 hours in patients with TOF was not significantly different between study groups.

CONCLUSION

Passive peritoneal drainage may more effectively facilitate negative fluid balance when compared to pleural drainage after pediatric cardiac surgery, although this benefit is not likely universal but rather dependent on the patient's underlying physiology.

Acute kidney injury and fluid overload in infants and children after cardiac surgery

Acute kidney injury is a common and serious complication after congenital heart surgery, particularly among infants. This comorbidity has been independently associated with adverse outcomes including an increase in mortality. Postoperative acute kidney injury has a complex pathophysiology with many risk factors, and therefore no single medication or therapy has been demonstrated to be effective for treatment or prevention. However, it has been established that the associated fluid overload is one of the major determinants of morbidity, particularly in infants after cardiac surgery. Therefore, in the absence of an intervention to prevent acute kidney injury, much of the effort to improve outcomes has focused on treating and preventing fluid overload. Early renal replacement therapy, often in the form of peritoneal dialysis, has been shown to be safe and beneficial in infants with oliguria after heart surgery. As understanding of the pathophysiology of acute kidney injury and the ability to confidently diagnose it earlier continues to evolve, it is likely that novel preventative and therapeutic interventions will be available in the future.

AKI after pediatric cardiac surgery for congenital heart diseases-recent developments in diagnostic criteria and early diagnosis by biomarkers

Background

Acute kidney injury (AKI) after cardiac surgery in children with congenital heart disease is a common complication. AKI is also associated with high morbidity and mortality. The Kidney Diseases Improving Global Outcomes (KDIGO) criteria for AKI classification are now widely used for the definition of AKI. It is noteworthy that a statement about children was added to the criteria. Many studies aimed at finding useful biomarkers are now being performed by using these criteria. Clinicians should be aware of the recent progress in understanding AKI in children.

Main contents

Unlike adult patients, young age is one of the major risk factors for AKI in pediatric cardiac surgery. The mechanism of the development of AKI in children might be different from that in adults because the surgical procedure and CPB technique in pediatric patients are greatly different from those in adult patients.

There are many biomarkers for early detection of AKI, and some of them are widely used in hospitals. One of the major benefits of such biomarkers is the rapidness of expression for detecting increases in their expression levels. Neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, cystatin C, and albumin have been investigated in some studies, and the usefulness of these biomarkers for detection of AKI and diagnosis of disease severity has been shown.

Although there are many interventions for preventing and treating AKI after cardiac surgery in children, there is still no specific effective treatment. Peritoneal dialysis is effective for only maintaining a negative fluid balance early after cardiac surgery. The long-term prognosis of AKI is an issue of interest. Although mortality and morbidity of AKI in the acute phase of disease remain high, the long-term condition in pediatric patients is relatively acceptable unlike in adults.

Conclusions

KDIGO criteria are advocated as a diagnostic tool for common perception. Early recognition and intervention for AKI can be achieved by using several biomarkers. Further studies are needed to establish effective treatment for AKI.

Impact of contrast exposure from computed tomography angiography on acute kidney injury after neonatal cardiopulmonary bypass surgery

OBJECTIVE

Acute kidney injury (AKI) is a frequent complication after cardiopulmonary bypass (CBP) for cardiac surgery in neonates. It is unclear if exposure to computed tomography angiography (CTA) in the preoperative period increases the risk of AKI. We hypothesized a short interval between CTA and CPB surgery would be associated with higher rates of AKI in infants.

DESIGN

In this single center retrospective review of patients between 2012 and 2015, neonates less than one month old were analyzed if they had CTA prior to cardiac surgery with CPB. Baseline, demographic, fluid balance, and laboratory data was analyzed. AKI was staged according to KDIGO criteria.

RESULTS

Fifty-six neonates were analyzed. AKI developed in 42 (75%) of patients; severe AKI (KDIGO stages 2 and 3) occurred in 18 (32%). Patient characteristics were similar at baseline and at time of CTA between those with and without severe AKI. Patients with severe AKI had longer CPB time, lower postoperative urine output, higher peak serum creatinine, and longer hospital length of stay. When considering intervals between CTA and CPB surgery ≤1 day (n = 19), ≤3 days (n = 28), and >3 days (n = 28); there was no difference in AKI incidence nor postoperative outcomes among these three interval cohorts.

CONCLUSION

Routine exposure to CTA and CPB surgery in close succession does not appear to increase the risk of AKI after neonatal cardiac surgery. Though other risks need to be weighed (eg, sedation, intubation, radiation exposure), this result may enable more liberal utilization of CTA for preoperative surgical planning of congenital heart operations in patients with unclear or complex anatomy.

Early peritoneal dialysis reduces lung inflammation in mice with ischemic acute kidney injury

Although dialysis has been used in the care of patients with acute kidney injury (AKI) for over 50 years, very little is known about the potential benefits of uremic control on systemic complications of AKI. Since the mortality of AKI requiring renal replacement therapy (RRT) is greater than half in the intensive care unit, a better understanding of the potential of RRT to improve outcomes is urgently needed. Therefore, we sought to develop a technically feasible and reproducible model of RRT in a mouse model of AKI. Models of low- and high-dose peritoneal dialysis (PD) were developed and their effect on AKI, systemic inflammation, and lung injury after ischemic AKI was examined. High-dose PD had no effect on AKI, but effectively cleared serum IL-6, and dramatically reduced lung inflammation, while low-dose PD had no effect on any of these three outcomes. Both models of RRT using PD in AKI in mice reliably lowered urea in a dose-dependent fashion. Thus, use of these models of PD in mice with AKI has great potential to unravel the mechanisms by which RRT may improve the systemic complications that have led to increased mortality in AKI. In light of recent data demonstrating reduced serum IL-6 and improved outcomes with prophylactic PD in children, we believe that our results are highly clinically relevant.

Decreasing IV Potassium in Pediatric Cardiac Intensive Care: Quality Improvement Project

OBJECTIVES

IV potassium supplementation is commonly used in the pediatric cardiovascular ICU. However, concentrated IV potassium chloride doses can lead to life-threatening complications. We report results of a quality improvement project aimed at decreasing concentrated IV potassium chloride exposure.

DESIGN

Retrospective evaluation of a quality improvement project aimed at reducing IV potassium chloride exposure.

SETTING

Pediatric cardiac ICU.

PATIENTS

All patients admitted to pediatric cardiac ICUs in April 2013 to September 2013 (preprotocol) and October 2013 to April 2014 (postprotocol).

INTERVENTIONS

A quality improvement team developed a potassium protocol aimed at maintaining serum potassium levels 3.0-5.5 mEq/L, via algorithm focused on early enteral supplementation. All patients receiving IV diuretics who had a serum potassium level less than 4.5 mEq/L and urine output more than 0.5 mL/kg/hr had protocol initiated with potassium chloride-containing IV fluids or enteral potassium chloride. Concentrated IV potassium chloride infusions were limited to asymptomatic patients with serum potassium less than 2.0 mEq/L and high-risk patients at less than 3.0 mEq/L. Serum potassium levels were measured once daily, and protocolized adjustments were made based on this level and concurrent diuretic therapy.

MEASUREMENTS AND MAIN RESULTS

Serum potassium, potassium chloride supplementation, patient cost, fluid administration, and arrhythmia incidence were compared pre and post protocol. Four hundred forty-three admissions were included (234 pre protocol and 209 post protocol). No significant differences were found in demographics. There was no difference in mean morning serum potassium after protocol implementation (3.85 [0.77] mEq/L before protocol and 3.89 [0.75] mEq/L after protocol; p = 0.90). Concentrated IV potassium chloride administration was decreased by 86% (331 vs 47 doses). With protocol, there was decreased incidence in days with one measured episode of hyperkalemia (11 vs 4/1,000 patient-days; p = 0.02) and a trend toward decreased hypokalemia (433 vs 400/1,000 patient-days; p = 0.05). Arrhythmia incidence was similar (p = 0.59).

CONCLUSIONS

Protocolized potassium management in pediatric cardiac intensive care patients decreased concentrated IV potassium chloride exposure and incidence of hyperkalemia. Lower potassium treatment threshold for IV potassium chloride was not associated with increased arrhythmias.

Fluid Management: Pharmacologic and Renal Replacement Therapies

OBJECTIVES

Focusing on critically ill children with cardiac disease, we will review common causes of fluid perturbations, clinical recognition, and strategies to minimize and treat fluid-related complications.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSIONS

Meticulous fluid management is vital in critically ill children with cardiac disease. Fluid therapy is important to maintain adequate blood volume and perfusion pressure in order to support cardiac output, tissue perfusion, and oxygen delivery. However, fluid overload and acute kidney injury are common and are associated with increased morbidity and mortality. Understanding the etiologies for disturbances in volume status and the pathophysiology surrounding those conditions is crucial for providing optimal care.

Immediate Consequences of Acute Kidney Injury: The Impact of Traditional and Nontraditional Complications on Mortality in Acute Kidney Injury

Acute kidney injury (AKI) that requires renal replacement therapy is associated with a mortality rate that exceeds 50% in the intensive care unit, which is greater than other serious illnesses such as acute lung injury and myocardial infarction. Much information is now available regarding the complications of AKI that contribute to mortality and may be usefully categorized as "traditional" and "nontraditional". Traditional complications are the long-recognized complications of AKI such as hyperkalemia, acidosis, and volume overload, which may be typically corrected with renal replacement therapy. "Nontraditional" complications include complications such as sepsis, lung injury, and heart failure that may arise due to the effects of AKI on inflammatory cytokines, immune function, and cell death pathways such as apoptosis. In this review, we discuss both traditional and nontraditional complications of AKI with a focus on factors that contribute to mortality, considering both pathophysiology and potential remedies. Because AKI is the most common inpatient consult to nephrologists, it is essential to be aware of the complications of AKI that contribute to mortality to devise appropriate treatment strategies to prevent and manage AKI complications with the ultimate goal of reducing the unacceptably high mortality rate of AKI.

Postoperative Hydrocortisone Infusion Reduces the Prevalence of Low Cardiac Output Syndrome After Neonatal Cardiopulmonary Bypass

OBJECTIVE

Neonatal cardiac surgery with cardiopulmonary bypass is often complicated by morbidity associated with inflammation and low cardiac output syndrome. Hydrocortisone "stress dosing" is reported to provide hemodynamic benefits in some patients with refractory shock. Development of cardiopulmonary bypass-induced adrenal insufficiency may provide further rationale for postoperative hydrocortisone administration. We sought to determine whether prophylactic, postoperative hydrocortisone infusion could decrease prevalence of low cardiac output syndrome after neonatal cardiac surgery with cardiopulmonary bypass.

DESIGN

Double-blind, randomized control trial.

SETTING

Pediatric cardiac ICU and operating room in tertiary care center.

PATIENTS

Forty neonates undergoing cardiac surgery with cardiopulmonary bypass were randomized (19 hydrocortisone and 21 placebo). Demographics and known risk factors were similar between groups.

INTERVENTIONS

After cardiopulmonary bypass separation, bolus hydrocortisone (50 mg/m²) or placebo was administered, followed by continuous hydrocortisone infusion (50 mg/m²/d) or placebo tapered over 5 days. Adrenocorticotropic hormone stimulation testing (1 μg) was performed before and after cardiopulmonary bypass, prior to steroid administration. Blood was collected for cytokine analysis before and after cardiopulmonary bypass.

MEASUREMENTS AND MAIN RESULTS

Subjects receiving hydrocortisone were less likely to develop low cardiac output syndrome (5/19, 26% vs 12/21, 57%; p = 0.049). Hydrocortisone group had more negative net fluid balance at 48 hours (-114 vs -64 mL/kg; p = 0.01) and greater urine output at 0-24 hours (2.7 vs 1.2 mL/kg/hr; p = 0.03). Hydrocortisone group weaned off catecholamines and vasopressin sooner than placebo, with a difference in inotrope-free subjects apparent after 48 hours (p = 0.033). Five placebo subjects (24%) compared with no hydrocortisone subjects required rescue steroids (p = 0.02). Thirteen (32.5%) had adrenal insufficiency after cardiopulmonary bypass. Patients with adrenal insufficiency randomized to receive hydrocortisone had lower prevalence of low cardiac output syndrome compared with patients with adrenal insufficiency randomized to placebo (1/6 vs 6/7, respectively; p = 0.02). Hydrocortisone significantly reduced proinflammatory cytokines. Ventilator-free days, hospital length of stay, and kidney injury were similar.

CONCLUSIONS

Prophylactic, postoperative hydrocortisone reduces low cardiac output syndrome, improves fluid balance and urine output, and attenuates inflammation after neonatal cardiopulmonary bypass surgery. Further studies are necessary to show if these benefits lead to improvements in more important clinical outcomes.

Cardiac intensive care for the neonate and child after cardiac surgery

PURPOSE OF REVIEW

The focus of postoperative care in the pediatric patient with congenital heart disease has become a reduction in length of stay and morbidity. This review will discuss strategies to achieve this goal and recent studies to support current practices.

RECENT FINDINGS

Most agree that prolongation of the length of stay following a cardiac surgery contributes to morbidity. Postoperative feeding difficulty, hyperglycemia, acute kidney injury, fluid overload, and prolonged intubation contribute significantly to length of stay.

SUMMARY

Postoperative care of the neonate and child following a cardiac surgery remains challenging with limited data to drive our practices. Patients remain at risk for significant morbidity, and future studies should focus on recognizing predictors of morbidity, prevention, and treatment.

Renal replacement therapy in neonates

The incidence of acute kidney injury (AKI) has steadily increased in the last decade in neonates and infants. Despite the extensive proposed pharmacologic approaches to treat or prevent AKI, renal replacement therapy is the only available therapeutic approach to manage the consequences of significant AKI and maintain electrolyte homeostasis and fluid balance in infants with AKI. The objective of this article is to summarize the different approaches and modalities of renal replacement therapy in neonatal intensive care units.