Early postoperative fluid overload precedes acute kidney injury and is associated with higher morbidity in pediatric cardiac surgery patients

Factors Associated With Pediatric Ventilator-Associated Conditions in Six U.S. Hospitals: A Nested Case-Control Study

OBJECTIVES

A newly proposed surveillance definition for ventilator-associated conditions among neonatal and pediatric patients has been associated with increased morbidity and mortality among ventilated patients in cardiac ICU, neonatal ICU, and PICU. This study aimed to identify potential risk factors associated with pediatric ventilator-associated conditions.

DESIGN

Retrospective cohort.

SETTING

Six U.S. hospitals PATIENTS:: Children less than or equal to 18 years old ventilated for greater than or equal to 1 day.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We identified children with pediatric ventilator-associated conditions and matched them to children without ventilator-associated conditions. Medical records were reviewed for comorbidities and acute care factors. We used bivariate and multivariate conditional logistic regression models to identify factors associated with ventilator-associated conditions. We studied 192 pairs of ventilator-associated conditions cases and matched controls (113 in the PICU and cardiac ICU combined; 79 in the neonatal ICU). In the PICU/cardiac ICU, potential risk factors for ventilator-associated conditions included neuromuscular blockade (odds ratio, 2.29; 95% CI, 1.08-4.87), positive fluid balance (highest quartile compared with the lowest, odds ratio, 7.76; 95% CI, 2.10-28.6), and blood product use (odds ratio, 1.52; 95% CI, 0.70-3.28). Weaning from sedation (i.e., decreasing sedation) or interruption of sedation may be protective (odds ratio, 0.44; 95% CI, 0.18-1.11). In the neonatal ICU, potential risk factors included blood product use (odds ratio, 2.99; 95% CI, 1.02-8.78), neuromuscular blockade use (odds ratio, 3.96; 95% CI, 0.93-16.9), and recent surgical procedures (odds ratio, 2.19; 95% CI, 0.77-6.28). Weaning or interrupting sedation was protective (odds ratio, 0.07; 95% CI, 0.01-0.79).

CONCLUSIONS

In mechanically ventilated neonates and children, we identified several possible risk factors associated with ventilator-associated conditions. Next steps include studying propensity-matched cohorts and prospectively testing whether changes in sedation management, transfusion thresholds, and fluid management can decrease pediatric ventilator-associated conditions rates and improve patient 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.

Duration of Postoperative Mechanical Ventilation as a Quality Metric for Pediatric Cardiac Surgical Programs

BACKGROUND

Few metrics exist to assess quality of care at pediatric cardiac surgical programs, limiting opportunities for benchmarking and quality improvement. Postoperative duration of mechanical ventilation (POMV) may be an important quality metric because of its association with complications and resource utilization. In this study we modelled case-mix-adjusted POMV duration and explored hospital performance across POMV metrics.

METHODS

This study used the Pediatric Cardiac Critical Care Consortium clinical registry to analyze 4,739 hospitalizations from 15 hospitals (October 2013 to August 2015). All patients admitted to pediatric cardiac intensive care units after an index cardiac operation were included. We fitted a model to predict duration of POMV accounting for patient characteristics. Robust estimates of SEs were obtained using bootstrap resampling. We created performance metrics based on observed-to-expected (O/E) POMV to compare hospitals.

RESULTS

Overall, 3,108 patients (65.6%) received POMV; the remainder were extubated intraoperatively. Our model was well calibrated across groups; neonatal age had the largest effect on predicted POMV. These comparisons suggested clinically and statistically important variation in POMV duration across centers with a threefold difference observed in O/E ratios (0.6 to 1.7). We identified 1 hospital with better-than-expected and 3 hospitals with worse-than-expected performance (p < 0.05) based on the O/E ratio.

CONCLUSIONS

We developed a novel case-mix-adjusted model to predict POMV duration after congenital heart operations. We report variation across hospitals on metrics of O/E duration of POMV that may be suitable for benchmarking quality of care. Identifying high-performing centers and practices that safely limit the duration of POMV could stimulate quality improvement efforts.

Different predictivity of fluid responsiveness by pulse pressure variation in children after surgical repair of ventricular septal defect or tetralogy of Fallot

BACKGROUND

Pulse pressure variation derived from the varied pulse contour method is based on heart-lung interaction during mechanical ventilation. It has been shown that pulse pressure variation is predictive of fluid responsiveness in children undergoing surgical repair of ventricular septal defect. Right ventricle compliance and pulmonary vascular capacitance in children with tetralogy of Fallot are underdeveloped as compared to those in ventricular septal defect. We hypothesized that the difference in the right ventricle-pulmonary circulation in the two groups of children would affect the heart-lung interaction and therefore pulse pressure variation predictivity of fluid responsiveness following cardiac surgery.

METHODS

Infants undergoing complete repair of ventricular septal defect (n=38, 1.05±0.75 years) and tetralogy of Fallot (n=36, 1.15±0.68 years) clinically presenting with low cardiac output were enrolled. Fluid infusion with 5% albumin or fresh frozen plasma was administered. Pulse pressure variation was recorded using pressure recording analytical method along with cardiac index before and after fluid infusion. Patients were considered as responders to fluid loading when cardiac index increased ≥15%. Receiver operating characteristic curves analysis was used to assess the accuracy and cutoffs of pulse pressure variation to predict fluid responsiveness.

RESULTS

The pulse pressure variation values before and after fluid infusion were lower in tetralogy of Fallot children than those in ventricular septal defect children (15.2±4.4% vs 19.3±4.4%, P<.001; 11.6±3.8 vs 15.4±4.3%, P<.001, respectively). In ventricular septal defect children, 27 were responders and 11 nonresponders. Receiver operating characteristic curve area was 0.89 (95% confidence interval, 0.77-1.01) and cutoff value 17.4% with a sensitivity of 0.89 and a specificity of 0.91. In tetralogy of Fallot children, 26 were responders and 10 were nonresponders. Receiver operating characteristic curve area was 0.79 (95% CI, 0.64-0.94) and cutoff value 13.4% with a sensitivity of 0.81 and a specificity of 0.80.

CONCLUSION

Pulse pressure variation is predictive of fluid responsiveness in ventricular septal defect and tetralogy of Fallot patients following cardiac surgery.

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.

Fluid Overload and Cumulative Thoracostomy Output Are Associated With Surgical Site Infection After Pediatric Cardiothoracic Surgery

OBJECTIVES

To determine the impact of cumulative, postoperative thoracostomy output, amount of bolus IV fluids and peak fluid overload on the incidence and odds of developing a deep surgical site infection following pediatric cardiothoracic surgery.

DESIGN

A single-center, nested, retrospective, matched case-control study.

SETTING

A 26-bed cardiac ICU in a 303-bed tertiary care pediatric hospital.

PATIENTS

Cases with deep surgical site infection following cardiothoracic surgery were identified retrospectively from January 2010 through December 2013 and individually matched to controls at a ratio of 1:2 by age, gender, Risk Adjustment for Congenital Heart Surgery score, Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery category, primary cardiac diagnosis, and procedure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twelve cases with deep surgical site infection were identified and matched to 24 controls without detectable differences in perioperative clinical characteristics. Deep surgical site infection cases had larger thoracostomy output and bolus IV fluid volumes at 6, 24, and 48 hours postoperatively compared with controls. For every 1 mL/kg of thoracostomy output, the odds of developing a deep surgical site infection increase by 13%. By receiver operative characteristic curve analysis, a cutoff of 49 mL/kg of thoracostomy output at 48 hours best discriminates the development of deep surgical site infection (sensitivity 83%, specificity 83%). Peak fluid overload was greater in cases than matched controls (12.5% vs 6%; p < 0.01). On receiver operative characteristic curve analysis, a threshold value of 10% peak fluid overload was observed to identify deep surgical site infection (sensitivity 67%, specificity 79%). Conditional logistic regression of peak fluid overload greater than 10% on the development of deep surgical site infection yielded an odds ratio of 9.4 (95% CI, 2-46.2).

CONCLUSIONS

Increased postoperative peak fluid overload and cumulative thoracostomy output were associated with deep surgical site infection after pediatric cardiothoracic surgery. We suspect the observed increased thoracostomy output, fluid overload, and IV fluid boluses may have altered antimicrobial prophylaxis. Although analysis of additional pharmacokinetic data is warranted, providers may consider modification of antimicrobial prophylaxis dosing or alterations in fluid management and diuresis in response to assessment of peak fluid overload and fluid volume shifts in the immediate postoperative period.

Novel Pump Control Technology Accelerates Drug Delivery Onset in a Model of Pediatric Drug Infusion

BACKGROUND

Laboratory data suggest that newly initiated drug infusions reach steady-state delivery after a significant time lag. Depending on drug and carrier flow rates and the infusion system's common volume, lag times may exceed 20 or more minutes, especially in the neonatal/pediatric critical care environment. This study tested the hypothesis that a computer-executed algorithm controlling infusion pumps in a coordinated fashion predictably hastens the achievement of the intended steady-state drug delivery in a model of neonatal/pediatric drug infusion.

METHODS

We constructed an in vitro model of neonatal/pediatric drug infusions through a pediatric 4-Fr central venous catheter at total system flows of 2 mL/h or 12 mL/h, representing a clinically relevant infusion range. Methylene blue served as the model infused drug for quantitative analysis. A novel algorithm, based on Taylor Dispersion Theory of fluid flow through tubes and executed by a computer, generated flow patterns that controlled and coordinated drug and carrier delivery by syringe pumps. We measured the time to achieve the intended steady-state drug delivery by conventional initiation of the drug infusion ("turning on the drug pump") and by algorithm-controlled infusion initiation.

RESULTS

At 2 mL/h total system flow, application of the algorithm reduced the time to achieve half of the intended drug delivery rate (T50) from 17 minutes [17, 18] to 3 minutes [3, 3] (median, interquartile range). At 12 mL/h total system flow, application of the algorithm reduced T50 from 6 minutes [6, 7] to 3 minutes [3, 3] The bootstrapped median difference is -14 (95% confidence interval [CI], -16 to -12, adjusted P=.00192) for 2 mL/h flow and -3 (95% CI, -4 to -3, adjusted P=.02061) for 12 mL/h flow. Compared with conventional initiation, the additional fluid required by the algorithm-directed infusion was 0.43 and 1.03 mL for the low- and high-infusion rates, respectively.

CONCLUSIONS

The output of infusion pumps can be predictably controlled and coordinated by a computer-executed algorithm in a model of neonatal/pediatric drug infusions. Application of an algorithm can reduce the time to achieve the intended rate of infused drug delivery with minimal incremental volume administration.

A Case-Control Analysis of Postoperative Fluid Balance and Mortality After Pediatric Cardiac Surgery

OBJECTIVES

A positive fluid balance after cardiac surgery may be associated with poor outcomes; however, previous studies looking at this association have been limited by the number of deaths in the study population. Our primary aim was to determine the relationship between postoperative cumulative fluid balance and mortality in cardiac surgical patients. Secondary aims were to study the association between fluid balance and duration of mechanical ventilation, intensive care and hospital length of stay.

DESIGN

Case-control study.

SETTING

A 30-bed multidisciplinary PICU.

PATIENTS

All patients admitted to the PICU following cardiac surgery from 2010 to 2014.

INTERVENTIONS

Deaths during PICU admission following cardiac surgery (cases) were matched 1:3 with children who survived to PICU discharge (controls) using the following criteria: age at surgery (within a 20% age range), Risk Adjusted Congenital Heart Surgery (RACHS-1) category, and year of admission.

MEASUREMENTS AND MAIN RESULTS

Of 1,996 eligible children, 46 died (2.3%) of whom 45 (98%) were successfully matched. Cumulative fluid balance on days 2 and 7 was not associated with PICU mortality. On multivariable analysis, factors associated with mortality were cardiopulmonary bypass time (per 10-min increase, odds ratio [95% CI], 1.06 [1.00-1.12]; p = 0.03), extracorporeal membrane oxygenation requirement within 3 days (46.6 [9.47-230.11]; p < 0.001), peak serum chloride (mmol/L) in the first 48 hours (1.12 [1.01-1.23]), and time to start peritoneal dialysis after surgery (in comparison to no peritoneal dialysis, odds ratio [95% CI] in those started on early peritoneal dialysis was 1.07 [0.33-3.41]; p = 0.90 and in late peritoneal dialysis 3.65 [1.21-10.99]; p = 0.02). Children with cumulative fluid balance greater than or equal to 5% by day 2 spent longer on mechanical ventilation (median [interquartile range], 211 hr [97-539] vs 93 hr [34-225]; p <0.001), in PICU (11 d [8-26] vs 6 [3-13]; p < 0.001) and in hospital (22 d [13-39] vs 14 d [8-30]; p = 0.001).

CONCLUSIONS

Early fluid overload is not associated with mortality. However, it is associated with increased duration of mechanical ventilation and PICU length of stay. Early peritoneal dialysis commencement (compared with late peritoneal dialysis) after surgery was associated with decreased mortality.

Management of severe perioperative bleeding: guidelines from the European Society of Anaesthesiology: First update 2016

: The management of perioperative bleeding involves multiple assessments and strategies to ensure appropriate patient care. Initially, it is important to identify those patients with an increased risk of perioperative bleeding. Next, strategies should be employed to correct preoperative anaemia and to stabilise macrocirculation and microcirculation to optimise the patient's tolerance to bleeding. Finally, targeted interventions should be used to reduce intraoperative and postoperative bleeding, and so prevent subsequent morbidity and mortality. The objective of these updated guidelines is to provide healthcare professionals with an overview of the most recent evidence to help ensure improved clinical management of patients. For this update, electronic databases were searched without language restrictions from 2011 or 2012 (depending on the search) until 2015. These searches produced 18 334 articles. All articles were assessed and the existing 2013 guidelines were revised to take account of new evidence. This update includes revisions to existing recommendations with respect to the wording, or changes in the grade of recommendation, and also the addition of new recommendations. The final draft guideline was posted on the European Society of Anaesthesiology website for four weeks for review. All comments were collated and the guidelines were amended as appropriate. This publication reflects the output of this work.

Fluid Overload and Kidney Injury Score: A Multidimensional Real-Time Assessment of Renal Disease Burden in the Critically Ill Patient

OBJECTIVE

Interruptive acute kidney injury alerts are reported to decrease acute kidney injury-related mortality in adults. Critically ill children have multiple acute kidney injury risk factors; although recognition has improved due to standardized definitions, subtle changes in serum creatinine make acute kidney injury recognition challenging. Age and body habitus variability prevent a uniform maximum threshold of creatinine. Exposure of nephrotoxic medications is common but not accounted for in kidney injury scores. Current severity of illness measures do not include fluid overload, a well-described mortality risk factor. We hypothesized that a multidimensional measure of renal status would better characterize renal severity of illness while maintaining or improving on correlation measures with adverse outcomes, when compared with traditional acute kidney injury staging.

DESIGN

A novel, real-time, multidimensional, renal status measure, combining acute kidney injury, fluid overload greater than or equal to 15%, and nephrotoxin exposure, was developed (Fluid Overload Kidney Injury Score) and prospectively applied to all patient encounters. Peak Fluid Overload Kidney Injury Score values prior to discharge or death were used to measure correlation with outcomes.

SETTING

Quarternary PICU of a freestanding children's hospital.

PATIENTS

All patients admitted over 18 months.

INTERVENTION

None.

RESULTS

Peak Fluid Overload Kidney Injury Score ranged between 0 and 14 in 2,830 PICU patients (median age, 5.5 yr; interquartile range, 1.3-12.9; 55% male), 66% of patients had Fluid Overload Kidney Injury Score greater than or equal to 1. Fluid Overload Kidney Injury Score was independently associated with PICU mortality and PICU and hospital length of stay when controlled for age, Pediatric Risk of Mortality-3, ventilator, pressor, and renal replacement therapy use (p = 0.047). Mortality increased from 1.5% in Fluid Overload Kidney Injury Score 0 to 40% in Fluid Overload Kidney Injury Score 8+. When urine output points were excluded, Fluid Overload Kidney Injury Score was more strongly correlated with mortality than fluid overload or acute kidney injury definitions alone.

CONCLUSION

A multidimensional score of renal disease burden was significantly associated with adverse PICU outcomes. Further studies will evaluate Fluid Overload Kidney Injury Score as a warning and decision support tool to impact patient-centered outcomes.

[Association between fluid overload and acute renal injury after congenital heart disease surgery in infants]

OBJECTIVE

To study the association between fluid overload and acute kidney injury (AKI) after congenital heart disease surgery in infants.

METHODS

A retrospective analysis was performed on 88 infants aged less than 6 months who underwent a radical surgery for congenital heart disease. The treatment outcomes were compared between the infants with AKI after surgery and those without. The effect of cumulative fluid overload on treatment outcomes 2 days after surgery was analyzed. The risk factors for the development of AKI after surgery were assessed by logistic regression analysis.

RESULTS

Compared with those without AKI after surgery, the patients with AKI had younger age, lower body weights, higher serum creatinine levels and higher vasoactive-inotropic score, as well as longer durations of intraoperative extracorporeal circulation and aortic occlusion (P<0.05). Compared with those without AKI after surgery, the patients with AKI had a higher transfusion volume, a higher incidence rate of low cardiac output syndrome, a longer duration of mechanical ventilation, a longer length of stay in the intensive care unit (ICU), a longer length of hospital stay, a higher application rate of extracorporeal membrane oxygenation, a higher 30-day mortality rate, and higher levels of cumulative fluid overload 2 and 3 days after surgery (P<0.05). The logistic regression analysis showed that fluid overload and low cardiac output syndrome were major risk factors for the development of AKI after surgery. The children with cumulative fluid overload >5% at 2 days after surgery had a higher incidence rate of low cardiac output syndrome, a longer duration of mechanical ventilation, a longer length of stay in the ICU, a longer length of hospital stay, and a higher mortality rate (P<0.05).

CONCLUSIONS

Infants with fluid overload after surgery for congenital heart disease tend to develop AKI, and fluid overload may be associated with poor outcomes after surgery.

Relationship among Mortality of Patients with Acute Kidney Injury after Cardiac Surgery, Fluid Balance and Ultrafiltration of Renal Replacement Therapy: An Observational Study

Background/Aims: The study aimed to investigate the relationship among mortality of patients with cardiac surgery-associated acute kidney injury (CSA-AKI), fluid balance, and ultrafiltration of renal replacement therapy (RRT). Methods: From January 2009 to October 2015, hospitalized patients with CSA-AKI receiving continuous or prolonged intermittent RRT were screened. The effects of fluid balance and ultrafiltration of RRT on clinical outcome were analyzed. Results: The 30-day mortality of all the 63 patients in the study was 58.6%. Compared with the death group, the survival group had a significantly lower fluid balance, larger ultrafiltration volume, and similar ultrafiltration rate during the first 3 days of RRT. Multivariate Cox regression analysis revealed that positive fluid balance during the first day of RRT, cardiac function of grade IV, and higher Sequential Organ Failure Assessment score were independent risk factors of 30-day mortality. Conclusion: Fluid balance was more relevant to short-term prognosis of CSA-AKI-RRT patients than ultrafiltration volume or ultrafiltration rate.

A simple technique to achieve vascular access for continuous venous-venous ultrafiltration in a toddler

Acute renal failure is associated with increased mortality in the Pediatric Intensive Care Unit. When anuric or oliguric renal failure occurs, the associated fluid overload may compromise respiratory function and has been shown to be associated with worse outcomes. Renal replacement therapy using continuous venous-venous hemofiltration (CVVH) allows for fluid, solute, and nitrogenous waste removal. However, large bore vascular access with placement of a double-lumen dialysis catheter is necessary to ensure effective flow rates to allow for CVVH. We present a technique to facilitate exchange of a 4 Fr double-lumen central venous catheter to an 8 Fr double-lumen dialysis catheter for CVVH in a 2-year-old toddler who developed acute renal failure following surgery for congenital heart disease. This technique may be particularly valuable in patients with associated conditions including fluid overload and coagulation disturbances which may increase the morbidity of vascular access techniques.

Fluid overload and outcomes in critically ill children: A single center prospective cohort study

OBJECTIVE

To prospectively evaluate the association between fluid overload (FO) and clinical outcomes, mortality, mechanical ventilation (MV), and duration and length of stay in a pediatric intensive care unit (PICU).

METHODS

Over a 12-month period, patients who were on MV for >24h or vasoactive support were prospectively included. Demographic and clinical data were recorded. Daily FO was calculated as [(fluid in-fluid out)/admission weight]×100%. Multivariate stepwise logistic regression analysis was used to determine predictors of survival.

RESULTS

224 patients were included; median age was 3.3 (IQR 0.7, 9.9) years, mortality was 15.6%. The median peak FO (PFO) was 12.5% (IQR 5, 25), PFO>10% was present in 55.8% of patients, and PFO>20% was present in 33%. The PFO in non-survivors was 17.8% (IQR 8, 30) and 11% (IQR 4, 23) in survivors (p=0.028). A survival analysis showed no association between PFO and mortality. A multivariate analysis identified vasoactive support, >3 organ failures and acute kidney injury (AKI) but not FO as independent risk factors for mortality. FO was associated with MV duration and PICU length of stay.

CONCLUSION

FO is frequent in a general PICU population, but PFO is not an independent risk factor for mortality. Future studies of FO should focus on patients with AKI and multiorgan failure for better classification of severity and potential interventions.

Fluid overload is an independent risk factor for acute kidney injury in critically Ill patients: results of a cohort study

BACKGROUND

Acute Kidney injury (AKI) is common and increases mortality in the intensive care unit (ICU). We carried out this study to explore whether fluid overload is an independent risk factor for AKI.

METHODS

Single-center prospective, observational study. Consecutively admitted, ICU patients were followed for development of AKI. Intravenous fluid volumes, daily fluid balances were measured, hourly urine volumes, daily creatinine levels were recorded.

RESULTS

Three hundred thirty nine patients were included; AKI developed in 141 (41.6%) patients; RISK in 27 (8%) patients; INJURY in 25 (7%); FAILURE in 89 (26%) by the RIFLE criteria. Fluid balance was significantly higher in patients with AKI; 1755 ± 2189 v/s 924 ± 1846 ml, p < 0.001 on ICU day 1. On multivariate regression analysis, a net fluid balance in first 24 h of ICU admission, OR 1.02 (95% CI 1.01,1.03 p = 0.003), percentage of fluid accumulation adjusted for body weight OR1.009 (95% CI 1.001,1.017, p = 0.02), fluid balance in first 24 h of ICU admission with serum creatinine adjusted for fluid balance, OR 1.024 (95% CI 1.012,1,035, p = 0.005), Age, OR 1.02 95% CI 1.01,1.03, p < 0.001, CHF, OR 3.1 (95% CI 1.16,8.32, p = 0.023), vasopressor requirement on ICU day one, OR 1.9 (95% CI 1.13,3.19, p = 0.014) and Colistin OR 2.3 (95% CI 1.3, 4.02, p < 0.001) were significant predictors of AKI. There was no significant association between fluid type; Chloride-liberal, Chloride-restrictive, and AKI.

CONCLUSIONS

Fluid overload is an independent risk factor for AKI.

Systemic angiopoietin-1/2 dysregulation following cardiopulmonary bypass in adults

AIM

Vascular leakage following cardiopulmonary bypass contributes to morbidity. Angiopoietin-1 and -2 are biomarkers of endothelial dysfunction. Our aim was to characterize Ang-1 and -2 association with clinical characteristics and outcomes.

METHODS

Observational cohort study measuring Ang-1/-2 with a panel of cytokines in adults undergoing cardiopulmonary bypass.

RESULTS

Ang-2 levels increased immediately postop whereas Ang-1 levels decreased over time. No significant correlation was found with other inflammatory mediators. High correlation was found between the hospital length of stay and Ang-2 increase at 24 h (rho = 0.590; p < 0.0001). The predictors of Ang-2 increase were female gender, cross clamp time, transfusion of blood and absence of angiotensin-converting enzyme inhibitor as a pre-op medication.

CONCLUSION

Angiopoietins can detect vascular leakage early and could impact patient's management to decrease length of stay after cardiac surgery.

Acute kidney injury after pediatric cardiac surgery

Acute kidney injury is a common complication after pediatric cardiac surgery. The definition, staging, risk factors, biomarkers and management of acute kidney injury in children is detailed in the following review article.

Perioperative intravenous fluid therapy in children: guidelines from the Association of the Scientific Medical Societies in Germany

This consensus- based S1 Guideline for perioperative infusion therapy in children is focused on safety and efficacy. The objective is to maintain or re-establish the child's normal physiological state (normovolemia, normal tissue perfusion, normal metabolic function, normal acid- base- electrolyte status). Therefore, the perioperative fasting times should be as short as possible to prevent patient discomfort, dehydration, and ketoacidosis. A physiologically composed balanced isotonic electrolyte solution (BS) with 1-2.5% glucose is recommended for the intraoperative background infusion to maintain normal glucose concentrations and to avoid hyponatremia, hyperchloremia, and lipolysis. Additional BS without glucose can be used in patients with circulatory instability until the desired effect is achieved. The additional use of colloids (albumin, gelatin, hydroxyethyl starch) is recommended to recover normovolemia and to avoid fluid overload when crystalloids alone are not sufficient and blood products are not indicated. Monitoring should be extended in cases with major surgery, and autotransfusion maneuvers should be performed to assess fluid responsiveness.

Preparing enhanced recovery after surgery for implementation in pediatric populations

Standardization in perioperative care has led to major improvements in surgical outcomes during the last two decades. Enhanced recovery after surgery (ERAS) programs are one example of a clinical pathway impacting both surgical outcomes and efficiency of care, but these programs have not yet been widely adapted for surgery in children. In adults, ERAS pathways have been shown to reduce length of stay, reduce complication rates, and improve patient satisfaction. These pathways improve outcomes through standardization of existing evidence-based best practices. Currently, the direct evidence for adapting ERAS pathways to pediatric surgery patients is limited. Challenges for implementation of ERAS programs for children include lack of direct translatability of adult evidence as well as varying levels acceptability of ERAS principles among pediatric providers and patients' families. We describe our newly implemented ERAS program for pediatric colorectal surgery patients in an era of limited direct evidence and discuss what further issues need to be addressed for broader implementation of pediatric ERAS pathways.

LEVEL OF EVIDENCE

Level 5.

The Kidney in Critical Cardiac Disease: Proceedings From the 10th International Conference of the Pediatric Cardiac Intensive Care Society

The field of cardiac intensive care continues to advance in tandem with congenital heart surgery. The focus of intensive care unit care has now shifted to that of morbidity reduction and eventual elimination. Acute kidney injury (AKI) after cardiac surgery is associated with adverse outcomes, including prolonged intensive care and hospital stays, diminished quality of life, and increased long-term mortality. Acute kidney injury occurs frequently, complicating the care of both postoperative patients and those with heart failure. Patients who become fluid overloaded and/or require dialysis are at high risk of mortality, but even minor degrees of AKI portend a significant increase in mortality and morbidity. Clinicians continue to seek methods of early diagnosis and risk stratification of AKI to prevent its adverse sequelae. Previous conventional wisdom that survivors of AKI fully recover renal function without subsequent consequences may be flawed.

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.

Association of Fluid Accumulation with Clinical Outcomes in Critically Ill Children with Severe Sepsis

OBJECTIVE

To evaluate whether early and acquired daily fluid overload (FO), as well as fluctuations in fluid accumulation, were associated with adverse outcomes in critically ill children with severe sepsis.

METHODS

This study enrolled 202 children in a pediatric intensive care unit (PICU) with severe sepsis. Early fluid overload was defined as ≥5% fluid accumulation occurring in the first 24 hours of PICU admission. The maximum daily fluid accumulation ≥5% occurring during the next 6 days in patients with at least 48 hours of PICU stay was defined as PICU-acquired daily fluid overload. The fluctuation in fluid accumulation was calculated as the difference between the maximum and the minimum daily fluid accumulation obtained during the first 7 days after admission.

RESULTS

Of the 202 patients, 61 (30.2%) died during PICU stay. Among all patients, 41 (20.3%) experienced early fluid overload, including 9 with a FO ≥10%. Among patients with at least 48 hours of PICU stay (n = 154), 36 (23.4%) developed PICU-acquired daily fluid overload, including 2 with a FO ≥10%. Both early fluid overload (AOR = 1.20; 95% CI 1.08-1.33; P = 0.001; n = 202) and PICU-acquired daily fluid overload (AOR = 5.47 per log increase; 95% CI 1.15-25.96; P = 0.032; n = 154) were independent risk factors associated with mortality after adjusting for age, illness severity, etc. However, fluctuations in fluid accumulation were not associated with mortality after adjustment. Length of PICU stay increased with greater fluctuations in fluid accumulation in all patients with at least 48 hours of PICU stay (FO <5%, 5%-10% vs. ≥10%: 4 [3-8], 7 [4-11] vs. 10 [6-16] days; P <0.001; n = 154) and in survivors (4 [3-8], 7 [5-11] vs. 10 [5-15] days; P <0.001; n = 121). Early fluid overload achieved an area under-the-receiver-operating-characteristic curve of 0.74 (95% CI 0.65-0.82; P <0.001; n = 202) for predicting mortality in patients with severe sepsis, with a sensitivity of 67.2% and a specificity of 80.1% at the optimal cut-off value of 2.65%.

CONCLUSIONS

Both early and acquired daily fluid overload were independently associated with PICU mortality in children with severe sepsis.

Fluid Overload Is Associated With Late Poor Outcomes in Neonates Following Cardiac Surgery

OBJECTIVES

Acute kidney injury is a severe complication of cardiac surgery associated with increased morbidity and mortality; yet, acute kidney injury classification for neonates remains challenging. We characterized patterns of postoperative fluid overload as a surrogate marker for acute kidney injury and as a risk factor of poor postoperative outcomes in neonates undergoing cardiac surgery.

DESIGN

Retrospective cohort study.

SETTING

Single, congenital heart center destination program.

PATIENTS

Four hundred thirty-five neonates undergoing cardiac surgery with cardiopulmonary bypass from January 2006 through December 2010.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographics, diagnosis, and perioperative clinical variables were collected, including daily weights and serum creatinine levels. A composite poor clinical outcome (death, need for renal replacement therapy or extracorporeal life support within 30 postoperative days) was considered the primary outcome measure. Twenty-one neonates (5%) had a composite poor outcome with 7 (2%) requiring renal replacement therapy, 8 (2%) requiring extracorporeal life support, and 14 (3%) dying between 3 and 30 days post surgery. Neonates with a composite poor outcome had significantly higher maximum fluid overload (> 20%) and were slower to diurese. A receiver-operating characteristic curve determined that fluid overload greater than or equal to 16% and serum creatinine greater than or equal to 0.9 on postoperative day 3 were the optimal cutoffs for significant discrimination on the primary outcome (area under the curve = 0.71 and 0.76, respectively). In multivariable analysis, fluid overload greater than or equal to 16% (adjusted odds ratio = 3.7) and serum creatinine adjusted odds ratio 0.9 (adjusted odds ratio = 6.6) on postoperative day 3 remained an independent risk factor for poor outcome. Fluid overload greater than or equal 16% was also significantly associated with cardiac arrest requiring cardiopulmonary resuscitation, prolonged ICU stay, and chest reexploration.

CONCLUSIONS

This study highlights the importance of monitoring fluid balance in the neonatal cardiac surgical population and suggests that daily fluid overload, a readily available, noninvasive marker of renal function, may be a sensitive and specific predictor of adverse outcomes.

Fluid Overload Is Associated With Higher Mortality and Morbidity in Pediatric Patients Undergoing Cardiac Surgery

OBJECTIVES

Fluid overload after pediatric cardiac surgery is common and has been shown to increase both mortality and morbidity. This study explores the risk factors of early postoperative fluid overload and its relationship with adverse outcomes.

DESIGN

Secondary analysis of the prospectively collected data of children undergoing open-heart surgery between 2004 and 2008.

SETTING

Tertiary national cardiac center.

PATIENTS

One thousand five hundred twenty consecutive pediatric patients (<18 years old) were included in the analyses.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In the first 72 hours of the postoperative period, the daily fluid balance was calculated as milliliter per kilogram and the daily fluid overload was calculated as fluid balance (L)/weight (kg) × 100. The primary endpoint was in-hospital mortality; the secondary outcomes were low cardiac output syndrome and prolonged mechanical ventilation. One thousand three hundred and sixty-seven patients (89.9%) had a cumulative fluid overload below 5%; 120 patients (7.8%), between 5% and 10%; and 33 patients (2.1%), above 10%. After multivariable analysis, higher fluid overload on the day of the surgery was independently associated with mortality (adjusted odds ratio, 1.14; 95% CI, 1.008-1.303; p = 0.041) and low cardiac output syndrome (adjusted odds ratio, 1.21; 95% CI, 1.12-1.30; p = 0.001). Higher maximum serum creatinine levels (adjusted odds ratio, 1.01; 95% CI, 1.003-1.021; p = 0.009), maximum vasoactive-inotropic scores (adjusted odds ratio, 1.01; 95% CI, 1.005-1.029; p = 0.042), and higher blood loss on the day of the surgery (adjusted odds ratio, 1.01; 95% CI, 1.004-1.025; p = 0.015) were associated with a higher risk of fluid overload that was greater than 5%.

CONCLUSIONS

Fluid overload in the early postoperative period was associated with higher mortality and morbidity. Risk factors for fluid overload include underlying kidney dysfunction, hemodynamic instability, and higher blood loss on the day of the surgery.

Early Initiation of Renal Replacement Therapy in Pediatric Heart Surgery Is Associated with Lower Mortality

Acute kidney injury (AKI) is frequent in the postoperative period of pediatric heart surgery and leads to significant morbidity and mortality. Renal replacement therapies (RRTs) are often used to treat AKI; however, these therapies have also been associated with higher mortality rates. Earlier initiation of RRT might improve outcomes. This study aims to investigate the relationship between the RRT and morbidity and mortality after pediatric heart surgery. We performed a single-center retrospective study of all children undergoing pediatric heart surgery between April 2010 and December 2012 at a tertiary children's hospital. A total of 480 patients were included. Of those, 109 (23 %) were neonates and 126 patients (26 %) developed AKI within the first 72 postoperative hours. Patients who developed AKI had longer PICU admissions [12 days (4-37.75) vs. 4 (2-11); p < 0.001] and hospital length of stay [27 (11-53) vs. 14 (8-24) p < 0.001] and higher mortality [22/126 (17.5 %) vs. 13/354 (3.7 %); p < 0.001]. RRT techniques were used in 32 (6.6 %) patients [18/109 (16 %) neonates and 14/371 (3.8 %) infants and children; p < 0.01], with 25 (78 %) receiving peritoneal dialysis (PD) and 7 (22 %) continuous RRT (CRRT). Patients who received PD within the first 24 postoperative hours had lower mortality compared with those in whom PD was initiated later [4/16 (25 %) vs. 4/9 (44.4 %)]. Mortality among patients who received CRRT was 28.6 % (2/7). No deaths were reported in patients treated with CRRT within the first 24 postoperative hours. Postoperative AKI is associated with higher mortality in children undergoing cardiac surgery. Early initiation of RRT, both PD in neonates and CRRT in pediatric patients, might improve morbidity and mortality associated with AKI.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Immune Therapy

OBJECTIVE

In this Consensus Statement, we review the etiology and pathophysiology of inflammatory processes seen in critically ill children with cardiac disease. Immunomodulatory therapies aimed at improving outcomes in patients with myocarditis, heart failure, and transplantation are extensively reviewed.

DATA SOURCES

The author team experience and along with an extensive review of the medical literature were used as data sources.

DATA SYNTHESIS

The authors synthesized the data in the literature to present current immumodulatory therapies. For each drug, the physiologic rationale, mechanism of action, and pharmacokinetics are synthesized, and the evidence in the literature to support the therapy is discussed.

CONCLUSIONS

Immunomodulation has a crucial role in the treatment of certain pediatric cardiac diseases. Immunomodulatory treatments that have been used to treat myocarditis include corticosteroids, IV immunoglobulin, cyclosporine, and azathioprine. Contemporary outcomes of pediatric transplant recipients have improved over the past few decades, partly related to improvements in immunomodulatory therapy to prevent rejection of the donor heart. Immunosuppression therapy is commonly divided into induction, maintenance, and acute rejection therapy. Common induction medications include antithymocyte globulin, muromonab-CD3, and basiliximab. Maintenance therapy includes chronic medications that are used daily to prevent rejection episodes. Examples of maintenance medications are corticosteroids, cyclosporine, tacrolimus, sirolimus, everolimus, azathioprine, and mycophenolate mofetil. Rejection of the donor heart is diagnosed either by clinically or by biopsy and is treated with intensification of immunosuppression.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Fluid Management

OBJECTIVE

In this Consensus Statement, we review the etiology and pathophysiology of fluid disturbances in critically ill children with cardiac disease. Clinical tools used to recognize pathologic fluid states are summarized, as are the mechanisms of action of many drugs aimed at optimal fluid management.

DATA SOURCES

The expertise of the authors and a review of the medical literature were used as data sources.

DATA SYNTHESIS

The authors synthesized the data in the literature in order to present clinical tools used to recognize pathologic fluid states. For each drug, the physiologic rationale, mechanism of action, and pharmacokinetics are synthesized, and the evidence in the literature to support the therapy is discussed.

CONCLUSIONS

Fluid management is challenging in critically ill pediatric cardiac patients. A myriad of causes may be contributory, including intrinsic myocardial dysfunction with its associated neuroendocrine response, renal dysfunction with oliguria, and systemic inflammation with resulting endothelial dysfunction. The development of fluid overload has been associated with adverse outcomes, including acute kidney injury, prolonged mechanical ventilation, increased vasoactive support, prolonged hospital length of stay, and mortality. An in-depth understanding of the many factors that influence volume status is necessary to guide optimal management.

Acute Kidney Injury and Fluid Overload in Neonates Following Surgery for Congenital Heart Disease

BACKGROUND

Acute kidney injury (AKI) and fluid overload have been shown to increase morbidity and mortality. The reported incidence of AKI in pediatric patients following surgery for congenital heart disease is between 15% and 59%. Limited data exist looking at risk factors and outcomes of AKI or fluid overload in neonates undergoing surgery for congenital heart disease.

METHODS

Neonates aged 6 to 29 days who underwent surgery for congenital heart disease and who were without preoperative kidney disease were included in the study. The AKI was determined utilizing the Acute Kidney Injury Network criteria.

RESULTS

Ninety-five neonates were included in the study. The incidence of neonatal AKI was 45% (n = 43), of which 86% had stage 1 AKI. Risk factors for AKI included cardiopulmonary bypass time, selective cerebral perfusion, preoperative aminoglycoside use, small kidneys by renal ultrasound, and risk adjustment for congenital heart surgery category. There were eight mortalities (five from stage 1 AKI group, three from stage 2, and zero from stage 3). Fluid overload and AKI both increased hospital length of stay and postoperative ventilator days.

CONCLUSION

To avoid increased risk of morbidity and possibly mortality, every attempt should be made to identify and intervene on those risk factors, which may be modifiable or identifiable preoperatively, such as small kidneys by renal ultrasound.

To use or not to use hydroxyethyl starch in intraoperative care: are we ready to answer the 'Gretchen question'?

PURPOSE OF REVIEW

The decision of the European Medicines Agency (EMA) against the use of hydroxyethyl starch (HES)-based volume replacement solutions in critically ill patients has led to a general uncertainty when dealing with HES-based solutions, even though HES-containing solutions can still be used for the treatment of hypovolaemia caused by acute (sudden) blood loss. This review discusses current evidence of the intraoperative use of HES-based solutions.

RECENT FINDINGS

HES solutions are often criticized for possible side-effects on the kidney, the coagulation system or tissue storage. Relevant differences exist between modern 6% HES 130/0.4 and older generation of starches. Because of pathophysiological differences between elective surgery and critical illness, the evidence on renal injury and coagulation impairment with HES administration cannot be generalized. Current data suggest that there is no clinically relevant impact of 6% HES 130/0.4 administration on perioperative renal function and coagulation. Over-resuscitation is a frequent problem associated with adverse outcomes. Due to the higher volume effect, fluid overload with HES is probably more harmful than with crystalloids, whereas goal-directed use of HES may be able to reduce intraoperative fluid accumulation and overload.

SUMMARY

The use of 6% HES 130/0.4 in elective surgery patients is associated with reduced fluid accumulation and no clinically relevant difference in bleeding or the rate of acute kidney injury as compared with crystalloid use alone. Current data do not allow a conclusion on mortality. As they provide no benefit, older starch preparations should not be used.

Pediatric Acute Respiratory Distress Syndrome: Fluid Management in the PICU

The administration of an appropriate volume of intravenous fluids, while avoiding fluid overload, is a major challenge in the pediatric intensive care unit. Despite our efforts, fluid overload is a very common clinical observation in critically ill children, in particular in those with pediatric acute respiratory distress syndrome (PARDS). Patients with ARDS have widespread damage of the alveolar-capillary barrier, potentially making them vulnerable to fluid overload with the development of pulmonary edema leading to prolonged course of disease. Indeed, studies in adults with ARDS have shown that an increased cumulative fluid balance is associated with adverse outcome. However, age-related differences in the development and consequences of fluid overload in ARDS may exist due to disparities in immunologic response and body water distribution. This systematic review summarizes the current literature on fluid imbalance and management in PARDS, with special emphasis on potential differences with adult patients. It discusses the adverse effects associated with fluid overload and the corresponding possible pathophysiological mechanisms of its development. Our intent is to provide an incentive to develop age-specific fluid management protocols to improve PARDS outcomes.

Early fluid overload is associated with acute kidney injury and PICU mortality in critically ill children

Fluid overload (FO) has been associated with an increased risk for adverse outcomes in critically ill patients. Information on the impact of FO on mortality in a general population of pediatric intensive care unit (PICU) is limited. We aimed to determine the association of early FO with the development of acute kidney injury (AKI) and mortality during PICU stay and evaluate whether early FO predicts mortality, even after adjustment for illness severity assessed by pediatric risk of mortality (PRISM) III. This prospective study enrolled 370 critically ill children. The early FO was calculated based on the first 24-h total of fluid intake and output after admission and defined as cumulative fluid accumulation ≥5% of admission body weight. Of the patients, 64 (17.3 %) developed early FO during the first 24 h after admission. The PICU mortality rate of the whole cohort was 18 of 370 (4.9%). The independent factors significantly associated with early FO were PRISM III, age, AKI, and blood bicarbonate level. The early FO was associated with AKI (odds ratio [OR] = 1.34, p < 0.001) and mortality (OR = 1.36, p < 0.001). The association of early FO with mortality remained significant after adjustment for potential confounders including AKI and illness severity. The area under the receiver operating characteristic curve (AUC) of early FO for predicting mortality was 0.78 (p < 0.001). This result, however, was not better than PRISM III (AUC = 0.85, p < 0.001).

CONCLUSION

Early FO was associated with increased risk for AKI and mortality in critically ill children.

WHAT IS KNOWN

Fluid overload is associated with an increased risk for adverse outcomes in specific clinical settings of pediatric population. What is New: Early fluid overload during the first 24 h after PICU admission is independently associated with increased risk for acute kidney injury and mortality in critically ill children.

The Influence of Fluid Overload on the Length of Mechanical Ventilation in Pediatric Congenital Heart Surgery

Fluid overload and prolonged mechanical ventilation lead to worse outcomes in critically ill children. However, the association between these variables in children following congenital heart surgery is unknown. The objectives of this study were to describe the association between fluid overload and duration of mechanical ventilation, oxygen requirement and radiologic findings of pulmonary and chest wall edema. This study is a retrospective chart review of patients who underwent congenital heart surgery between June 2010 and December 2013. Univariate and multivariate associations between maximum cumulative fluid balance and length of mechanical ventilation and OI were tested using the Spearman correlation test and multiple linear regression models, respectively. There were 85 eligible patients. Maximum cumulative fluid balance was associated with duration of mechanical ventilation (adjusted analysis beta coefficient = 0.53, CI 0.38-0.66, P < 0.001), length of stay in the pediatric intensive care unit (Spearman's correlation = 0.45, P < 0.001), and presence of chest wall edema and pleural effusions on chest radiograph (Mann-Whitney test, P = 0.003). Amount of red blood cells transfused and use of nitric oxide were independently associated with increased duration of mechanical ventilation (P = 0.012 and 0.014, respectively). Fluid overload is associated with prolonged duration of mechanical ventilation and PICU length of stay after congenital heart surgery. Fluid overload was also associated with physiological markers of respiratory restriction. A randomized controlled trial of a restrictive versus liberal fluid replacement strategy is necessary in this patient population, but in the meantime, accumulating observational evidence suggests that cautious use of fluid in the postoperative care may be warranted.

Kinetic estimated glomerular filtration rate and acute kidney injury in cardiac surgery patients

PURPOSE

To determine how a formula to estimate kinetically changing glomerular filtration rate (keGFR) relates to serum creatinine changes and to compare the discriminatory ability of keGFR to that of perioperative change in serum creatinine to predict acute kidney injury (AKI) and mortality.

MATERIALS AND METHODS

Retrospective cohort study at a single-tertiary-care Midwestern university hospital of 4022 patients admitted to the intensive care unit between January 2006 and January 2012 immediately after cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Of 4022 patients, 1031 (25.6%) developed at least AKI stage 1 and 1106 (27.5%) developed AKI-min. Patients who developed AKI stage 1 or AKI-min had a greater decrease in keGFR, both by absolute amounts and by percentage. After adjusting for other factors with logistic regression, keGFR had good discrimination (c statistic = 0.787 and 0.749, respectively) in predicting AKI and operative mortality.

CONCLUSION

Despite no change in immediate perioperative serum creatinine levels, keGFR fell and this predicted subsequent AKI. Using keGFR enables identification of patients who, despite unchanged postoperative creatinine, incur clinically significant kidney injury based on reduction in GFR and increased mortality.

Postoperative Fluid Overload is a Useful Predictor of the Short-Term Outcome of Renal Replacement Therapy for Acute Kidney Injury After Cardiac Surgery

To analyze the predictive value of postoperative percent fluid overload (PFO) of renal replacement therapy (RRT) for acute kidney injury (AKI) patients after cardiac surgery.Data from 280 cardiac surgery patients between 2005 January and 2012 April were collected for retrospective analyses. A receiver operating characteristic (ROC) curve was used to compare the predictive values of cumulative PFO at different times after surgery for 90-day mortality.The cumulative PFO before RRT initiation was 7.9% ± 7.1% and the median PFO 6.1%. The cumulative PFO before and after RRT initiation in intensive care unit (ICU) was higher in the death group than in the survival group (8.8% ± 7.6% vs 6.1% ± 5.6%, P = 0.001; -0.5[-5.6, 5.1]% vs 6.9[2.2, 14.6]%, P < 0.001). The cumulative PFO during the whole ICU stay was 14.3% ± 15.8% and the median PFO was 10.7%. The areas under the ROC curves to predict the 90-day mortality by PFO at 24 hours, cumulative PFO before and after RRT initiation, and PFO during the whole ICU stay postoperatively were 0.625, 0.627, 0.731, and 0.752. PFO during the whole ICU stay ≥7.2% was determined as the cut-off point for 90-day mortality prediction with a sensitivity of 77% and a specificity of 64%. Kaplan-Meier survival estimates showed a significant difference in survival among patients with cumulative PFO ≥ 7.2% and PFO < 7.2% after cardiac surgery (log-rank P < 0.001).Postoperative cumulative PFO during the whole ICU stay ≥7.2% would have an adverse effect on 90-day short-term outcome, which may provide a strategy for the volume control of AKI-RRT patients after cardiac surgery.

Severe acute kidney injury following cardiac surgery: short-term outcomes in patients undergoing continuous renal replacement therapy (CRRT)

BACKGROUND

Acute kidney injury (AKI) represents a major complication of cardiac surgery. Our aim was to evaluate, in patients undergoing continuous renal replacement therapy (CRRT) for cardiac surgery-associated AKI (CS-AKI), prognostic factors related to in-hospital survival and renal function recovery to independence from RRT.

METHODS

We conducted a retrospective analysis in patients with severe CS-AKI who underwent CRRT for at least 48 h. The sequential organ failure assessment (SOFA) score was calculated on a daily basis to evaluate illness severity throughout the intensive care unit (ICU) stay.

RESULTS

In 264 patients (age 66.4 ± 11.7 years, 192 males), 30-day survival was 57.6 % while survival to discharge from the hospital was 40.5 %. Renal function recovery occurred in 96.3 % of survivors and in 13.4 % of non-survivors (p < 0.001). Multivariate analysis selected advancing age, oliguria, sepsis and the highest level of SOFA score within the first week of CRRT (SOFA-max) as independent prognostic factors for failure to recover renal function. Female gender was associated with a higher probability of survival, while higher serum creatinine at the start of CRRT, oliguria, sepsis and SOFA-max were independently associated with mortality. The subgroup of patients with a day-1 SOFA score above the median (≥10) showed a lower probability of survival and a lower cumulative incidence of renal function recovery.

CONCLUSIONS

In a selected population of patients with severe CS-AKI requiring RRT, short-term outcomes appear strongly associated with the worst grade of illness severity during the first week of CRRT, thus reflecting the sequential occurrence of additional major complications during ICU stay. Renal function recovery and in-hospital survival appear mutually linked, sharing oliguria, sepsis and SOFA score as the main determinants of both outcomes.

Normalized lactate load is associated with development of acute kidney injury in patients who underwent cardiopulmonary bypass surgery

BACKGROUND AND OBJECTIVE

Cardiac surgery associated acute kidney injury is a major postoperative complication and has long been associated with adverse outcomes. However, the association of lactate and AKI has not been well established. The study aimed to explore the association of normalized lactate load with AKI in patients undergoing cardiac surgery.

METHODS

This was a prospective observational cohort study conducted in a 47-bed ICU of a tertiary academic teaching hospital from July 2012 to January 2014. All patients undergoing cardiopulmonary bypass surgery were included. Normalized lactate load (L) was calculated by the equation: [Formula: see text], where ti was time point for lactate measurement and vi was the value of lactate. L was transformed by natural log (Lln) to improve its normality. Logistic regression model was fitted by using stepwise method. Scale of Lln was examined by using fractional polynomial approach and potential interaction terms were explored.

RESULTS

A total of 117 patients were included during study period, including 17 AKI patients and 100 non-AKI patients. In univariate analysis Lln was significantly higher in AKI as compared with non-AKI group (1.43±0.38 vs 1.01±0.45, p = 0.0005). After stepwise selection of covariates, the main effect logistic model contained variables of Lln (odds ratio: 11.1, 95% CI: 1.22-101.6), gender, age, baseline serum creatinine and fluid balance on day 0. Although the two-term fractional polynomial model was the best-fitted model, it was not significantly different from the linear model (Deviance difference = 6.09, p = 0.107). There was no significant interaction term between Lln and other variables in the main effect model.

CONCLUSIONS

Our study demonstrates that Lln is independently associated with postoperative AKI in patients undergoing CPB. There is no significant interaction with early postoperative fluid balance.

Efficacy and safety of 6% hydroxyethyl starch 130/0.4 (Voluven) for perioperative volume replacement in children undergoing cardiac surgery: a propensity-matched analysis

INTRODUCTION

Six percent hydroxyethyl starch (HES) 130/0.4 is considered an alternative to human albumin (HA) and crystalloids for volume replacement in children undergoing cardiac surgery. In this large propensity-matched analysis, we aimed to assess the efficacy and safety of replacing HA with HES for intraoperative volume therapy in children undergoing cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

We retrospectively reviewed our database, including children who underwent cardiac surgery between January 2002 and December 2010. Four percent HA was used until 2005; it was replaced by HES thereafter. Demographic data, intra- and postoperative blood loss and blood component transfusions were recorded, together with the incidence of postoperative complications and mortality. We performed a propensity-matched analysis using 13 possible confounding factors to compare children who received either HES or HA intraoperatively. The primary objectives included the effects of both fluids on intraoperative fluid balance (difference between fluids in and fluids out (efficacy)) and blood loss and exposure to allogeneic blood products (safety). Secondary safety outcomes were mortality and the incidence of postoperative renal dysfunction.

RESULTS

Of 1,832 children reviewed, 1,495 were included in the analysis. Intraoperative use of HES was associated with a less positive fluid balance. Perioperative blood loss, volume of red blood cells and fresh frozen plasma administered, as well as the number of children who received transfusions, were also significantly lower in the HES group. No difference was observed regarding the incidence of postoperative renal failure requiring renal replacement therapy or of morbidity and mortality.

CONCLUSIONS

These results confirm that the use of HES for volume replacement in children during cardiac surgery with CPB is as safe as HA. In addition, its use might be associated with less fluid accumulation. Further large studies are needed to assess whether the reduction in fluid accumulation could have a significant impact on postoperative morbidity and mortality.