Amanda Hassinger

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

Objective: Fluid overload has been independently associated with increased morbidity and mortality in pediatric patients with renal failure, acute lung injury, and sepsis. Pediatric patients who undergo cardiopulmonary bypass are at risk for poor cardiac, pulmonary, and renal outcomes. They are also at risk of fluid overload from cardiopulmonary bypass, which stimulates inflammation, release of antidiuretic hormone, and capillary leak. This study tested the hypothesis that patients with fluid overload in the early postcardiopulmonary bypass period have worse outcomes than those without fluid overload. We also examined the timing of the association between postcardiopulmonary bypass acute kidney injury and fluid overload. Design, Setting, and Patients: Secondary analysis of a prospective observational study of 98 pediatric patients after cardiopulmonary bypass at a tertiary care, academic, PICU. Interventions: None. Measurements and Main Results: Early postoperative fluid overload, defined as a fluid balance 5% above body weight by the end of postoperative day 1, occurred in 30 patients (31%). Patients with early fluid overload spent 3.5 days longer in the hospital, spent 2 more days on inotropes, and were more likely to require prolonged mechanical ventilation than those without early fluid overload (all p < 0.001). Fluid overload was associated with the development of acute kidney injury and more often preceded it than followed it. Conversely, acute kidney injury was not associated with more fluid accumulation. Patients with fluid overload were administered higher fluid volume over the study period, 395.4 ± 150 mL/kg vs. 193.2 ± 109.1 mL/kg (p < 0.001), and had poor urinary response to diuretics. Cumulative fluid administered was an excellent predictor of pediatric-modified Risk, Injury, Failure, Loss, and End-stage “Failure” (area under the receiver-operating characteristic curve, 0.963; 95% CI, 0.916–1.000; p = 0.002). Conclusions: Early postoperative fluid overload is independently associated with worse outcomes in pediatric cardiac surgery patients who are 2 weeks to 18 years old. Patients with fluid overload have higher rates of postcardiopulmonary bypass acute kidney injury, and the occurrence of fluid overload precedes acute kidney injury. However, acute kidney injury is not consistently associated with fluid overload.

Predictive power of serum cystatin C to detect acute kidney injury and pediatric-modified RIFLE class in children undergoing cardiac surgery

Objective: Acute kidney injury is a frequent and serious complication of cardiopulmonary bypass. In current clinical practice, serum creatinine is used to detect acute kidney injury. Cystatin C is a novel biomarker for kidney function that has been shown to be superior to serum creatinine in predicting acute kidney injury in adults after cardiopulmonary bypass. The aim of this study was to determine whether early cystatin C levels predict acute kidney injury associated with cardiopulmonary bypass in pediatric patients undergoing cardiac surgery and if cystatin C could predict pediatric-modified RIFLE (Risk, Injury, Failure, Loss, End-stage kidney disease) class and renal injury as determined by estimated glomerular filtration rate. We also investigated whether ultrafiltration during cardiopulmonary bypass affects cystatin C levels. Design: Prospective, observational cohort study. Setting: Cardiac intensive care unit in a tertiary, academic pediatric hospital. Patients: One hundred pediatric patients who underwent cardiac surgery involving cardiopulmonary bypass. Interventions: None. Measurements and Main Results: Acute kidney injury was defined as a 50% increase in serum creatinine from a preoperative baseline anytime through postoperative day 4. Severity of acute kidney injury was determined by pediatric RIFLE class using estimated glomerular filtration rate criteria only. Renal injury was also determined by an absolute estimated glomerular filtration rate <80 mL/min/1.73 m2. Cystatin C levels were measured before and after ultrafiltration. Twenty-eight patients (28%) developed acute kidney injury. Cystatin C predicted acute kidney injury as early as 8 hrs after surgery. When applying pediatric RIFLE criteria to the entire study, 30 patients reached “risk” and five developed “injury.” Cystatin C was a good predictor of the development of “injury” (under the receiver operating characteristic curve, 0.834–0.875) and of renal injury by estimated glomerular filtration rate (under the receiver operating characteristic curve, 0.717–0.835) (all p < .05). Cystatin C levels decreased perioperatively and correlated with volume of fluid removed by ultrafiltration. Conclusions: Cystatin C is an early predictor of acute kidney injury in children after cardiopulmonary bypass. Cystatin C is a good predictor of pediatric RIFLE classification and of decreased estimated glomerular filtration rate after cardiopulmonary bypass. Serum cystatin C may be cleared by ultrafiltration.

Acute Kidney Injury in Pediatric Severe Sepsis: An Independent Risk Factor for Death and New Disability.

Objectives:The prevalence of septic acute kidney injury and impact on functional status of PICU survivors are unknown. We used data from an international prospective severe sepsis study to elucidate functional outcomes of children suffering septic acute kidney injury. Design:Secondary analysis of patients in the Sepsis PRevalence, OUtcomes, and Therapies point prevalence study: acute kidney injury was defined on the study day using Kidney Disease Improving Global Outcomes definitions. Patients with no acute kidney injury or stage 1 acute kidney injury (“no/mild acute kidney injury”) were compared with those with stage 2 or 3 acute kidney injury (“severe acute kidney injury”). The primary outcome was a composite of death or new moderate disability at discharge defined as a Pediatric Overall Performance Category score of 3 or higher and increased by 1 from baseline. Setting:One hundred twenty-eight PICUs in 26 countries. Patients:Children with severe sepsis in the Sepsis PRevalence, OUtcomes, and Therapies study. Interventions:None. Measurements and Main Results:One hundred two (21%) of 493 patients had severe acute kidney injury. More than twice as many patients with severe acute kidney injury died or developed new moderate disability compared with those with no/mild acute kidney injury (64% vs 30%; p < 0.001). Severe acute kidney injury was independently associated with death or new moderate disability (adjusted odds ratio, 2.5; 95% CI, 1.5–4.2; p = 0.001) after adjustment for age, region, baseline disability, malignancy, invasive mechanical ventilation, albumin administration, and the pediatric logistic organ dysfunction score. Conclusions:In a multinational cohort of critically ill children with severe sepsis and high mortality rates, septic acute kidney injury is independently associated with further increased death or new disability.

Risk Factors for Delayed Enteral Nutrition in Critically Ill Children.

Objective: Delayed enteral nutrition, defined as enteral nutrition started 48 hours or more after admission to the PICU, is associated with an inability to achieve full enteral nutrition and worse outcomes in critically ill children. We reviewed nutritional practices in six medical-surgical PICUs and determined risk factors associated with delayed enteral nutrition in critically ill children. Design: Retrospective cross-sectional study using medical records as source of data. Setting: Six medical-surgical PICUs in northeastern United States. Patients: Children less than 21 years old admitted to the PICU for 72 hours or more excluding those awaiting or recovering from abdominal surgery. Measurements and Main Results: A total of 444 children with a median age of 4.0 years were included in the study. Enteral nutrition was started at a median time of 20 hours after admission to the PICU. There was no significant difference in time to start enteral nutrition among the PICUs. Of those included, 88 children (19.8%) had delayed enteral nutrition. Risk factors associated with delayed enteral nutrition were noninvasive (odds ratio, 3.37; 95% CI, 1.69–6.72) and invasive positive-pressure ventilation (odds ratio, 2.06; 95% CI, 1.15–3.69), severity of illness (odds ratio for every 0.1 increase in pediatric index of mortality 2 score, 1.39; 95% CI, 1.14–1.71), procedures (odds ratio, 3.33; 95% CI, 1.67–6.64), and gastrointestinal disturbances (odds ratio, 2.05; 95% CI, 1.14–3.68) within 48 hours after admission to the PICU. Delayed enteral nutrition was associated with failure to reach full enteral nutrition while in the PICU (odds ratio, 4.09; 95% CI, 1.97–8.53). Nutrition consults were obtained in less than half of the cases, and none of the PICUs used tools to assure the adequacy of energy and protein nutrition. Conclusions: Institutions in this study initiated enteral nutrition for a high percentage of patients by 48 hours of admission. Noninvasive positive-pressure ventilation was most strongly associated with delay enteral nutrition. A better understanding of these risk factors and assessments of nutritional requirements should be explored in future prospective studies.

The Current State of the Diagnosis and Management of Acute Kidney Injury by Pediatric Critical Care Physicians.

Objectives: Increasingly prevalent in pediatric intensive care, acute kidney injury imparts significant short- and long-term consequences. Despite advances in acute kidney injury research, clinical outcomes are worsening. We surveyed pediatric critical care physicians to describe the current state of acute kidney injury diagnosis and management in critically ill children. Design: Anonymous electronic questionnaire. Participants: Pediatric critical care physicians from academic centers, the Pediatric Acute Lung Injury and Sepsis Investigators network, and/or the pediatric branch of Society of Critical Care Medicine. Interventions: None. Measurements and Main Results: Of 201 surveys initiated, 170 surveys were more than 50% completed and included in our results. The majority of physicians (74%) diagnosed acute kidney injury using serum creatinine and urine output. Acute kidney injury guidelines or criteria were used routinely by 54% of physicians; Risk, Injury, Failure, Loss, and End stage criteria were the most commonly used. Awareness of any acute kidney injury guideline or definition was associated with five-fold higher odds of using any guideline (odds ratio, 5.22; 95% CI, 1.84–14.83) and four-fold higher odds of being dissatisfied with available acute kidney injury biomarkers (odds ratio, 4.88; 95% CI, 1.58–15.05). Less than half of respondents recognized the limitations of serum creatinine. Physicians unaware of the limitations of serum creatinine had two-fold higher odds of being unaware of newer biomarker availability (odds ratio, 2.34; 95% CI, 1.14–4.79). Novel biomarkers were available to 37.6% of physicians for routine use. Physicians with access to novel biomarkers more often practiced in larger (odds ratio, 3.09; 95% CI, 1.18–8.12) and Midwestern (odds ratio, 3.38; 95% CI, 1.47–7.78) institutions. More physicians with access to a novel biomarker reported satisfaction with current acute kidney injury diagnostics (66%) than physicians without access (48%); this finding approached significance (p = 0.07). Conclusions: Half of PICU attending physicians surveyed are not using recent acute kidney injury guidelines or diagnostic criteria in their practice. There is a positive association between awareness and clinical use of acute kidney injury guidelines. Serum creatinine and urine output are still the primary diagnostics; novel biomarkers are frequently unavailable.

Identifying Hesitation and Discomfort with Diagnosing Sepsis: Survey of a Pediatric Tertiary Care Center

Objective: Pediatric sepsis remains a significant cause of morbidity and mortality despite the development of strategies proven to improve diagnosis and treatment. Specifically, early recognition and urgent therapy initiation are consistently associated with improved outcomes. However, providers bring these principles inconsistently to the bedside. The objective of this study was to describe practitioner knowledge of, and attitudes toward, sepsis as a means of identifying potentially modifiable factors delaying life-saving treatment. We hypothesized there would be difficulties with sepsis recognition and self-reported discomfort with making the diagnosis among all provider groups in a pediatric tertiary care center. Methods: Emergency department and inpatient pediatric physicians, nurses, and respiratory therapists in a single, freestanding children’s hospital received an electronic survey. Likert scales permitted anonymous self-reporting of comfort and diagnostic delays. Seven clinical vignettes assessed diagnostic knowledge. Independent sample t tests and Chi-square compared responses. Results: Three hundred two staff participated (73% response rate), 41% of whom had at least 10 years of clinical experience. One in 5 was uncomfortable alerting coworkers to a patient with suspected sepsis or septic shock, and almost half were uncomfortable doing so in cases of compensated shock. Every role self-reported diagnostic delays, including faculty physicians. On average, physicians answered a greater percentage of vignette questions correctly (66%), compared with nurses (58%; P = 0.013) and respiratory therapists (52%; P = 0.005). Conclusions: Sepsis knowledge deficits, provider discomfort, and diagnostic delays are prevalent within a tertiary care children’s hospital. Their presence and scale suggest areas for future research and targeted intervention.

Negative-Pressure Ventilation in Pediatric Acute Respiratory Failure

BACKGROUND: The objective of this work was to describe the use of negative-pressure ventilation (NPV) in a heterogeneous critically ill, pediatric population. METHODS: A retrospective chart review was conducted of all patients admitted to a pediatric ICU with acute respiratory failure supported with NPV from January 1, 2012 to May 15, 2015. RESULTS: Two hundred thirty-three subjects at a median age of 15.5 months were supported with NPV for various etiologies, most commonly bronchiolitis (70%). Median (interquartile range) duration of support was 18.7 (8.7–34.3) h. The majority were NPV responders (70%), defined as not needing escalation to any form of positive-pressure ventilation. In non-responders, escalation occurred at a median (interquartile range) of 6.9 (3.3–16.6) h. More NPV non-responders had upper-airway obstruction (P = .02), and fewer had bronchiolitis (P = .008) compared with responders. A bedside scoring system developed on these data was 98% specific in predicting NPV failure by 4 h after NPV start (area under the curve 0.759, 95% CI 0.675–0.843, P < .001). Complications from NPV were rare (3%); however, delayed enteral nutrition (33%) and continuous intravenous sedation use (51%) in children while receiving NPV were more frequent. The annual percentage of pediatric ICU admissions requiring intubation declined by 28% in the 3 y after NPV introduction, compared with the 3 y prior. CONCLUSIONS: NPV is a noninvasive respiratory support for pediatric acute respiratory failure from all causes with few complications and a 70% response rate. Children receiving NPV often required intravenous sedation for comfort, and one third received delayed enteral nutrition. Those who required escalation from NPV worsened within 6 h; this may be predictable with a bedside scoring system.

Procalcitonin to Detect Bacterial Infections in Critically Ill Pediatric Patients

The diagnostic power of procalcitonin (PCT) in the pediatric intensive care unit (PICU) is uncertain. This study aimed to determine the diagnostic ability of PCT to detect serious bacterial infections (SBI) in a heterogeneous PICU population. This was a retrospective cohort study of patients on whom a PCT level was obtained within 48 hours of admission to a PICU from 2013 to 2015. Discriminatory ability of PCT to predict SBI was examined by test and receiver operating characteristics (AUC [area under the curve]-ROC). Seventy-five patients were included and 28 (37%) had an SBI (median PCT = 6.48 ng/mL) compared with 47 (63%) in the noninfection group (median PCT = 0.23 ng/mL, P < .0001). PCT was able to adequately predict SBI (AUC-ROC = 0.83, 95% CI 0.74-0.93; P < .0001), and a PCT ≥1.28 ng/mL was the optimal threshold to detect SBI with a positive predictive value of 76.7% and negative predictive value of 88.9%. PCT adequately predicted SBI in a heterogeneous PICU population and may be useful for minimizing antibiotic consumption.

677: DESCRIPTION OF CRITICALLY ILL CHILDREN WITH VERY ELEVATED PROCALCITONIN LEVELS

Crit Care Med 2016 • Volume 44 • Number 12 (Suppl.) discharge. There were no differences between survivors and non-survivors in age, sex, race, comorbidities, recent hospitalization, history of penicillin allergy, source of infection, or MDR gram-negative organism. History of solid organ transplant was more common in the survivor group, while vasopressor and ventilator use prior to index culture were more common in the non-survivors. ICU and hospital LOS prior to index culture was longer in the non-survivor group vs. survivor group (7 vs. 4 days, p<0.001; and 14 vs. 7 days, p=0.006). Patients who were documented as being treated for active infection were included in a multiple logistic regression. In this analysis, achievement of source control was the only variable independently associated with an increase in survival to hospital discharge. Conclusions: A higher than expected percentage of critically ill surgical patients with MDR gram-negative infections survived to hospital discharge. Achievement of source control was predictive of increased survival.

985: USE OF NONINVASIVE METHODS TO DETECT SEPSIS-INDUCED ACUTE KIDNEY INJURY IN CRITICALLY ILL CHILDREN

Learning Objectives: Sepsis is the most common cause of acute kidney injury (AKI) in critically ill pediatric patients in the United States. Current clinical practice relies on serum creatinine (SCr), creatinine clearance, and urine output to detect AKI; despite these being late and insensitive markers of AKI. The resistive index (RI) in the renal artery, as determined by Doppler methods, has proven to be a useful technique to quantify alterations in renal blood flow. Renal near infrared regional spectroscopy (RNIRS) is a novel technology that has shown to correlate with elevated SCr values 48hr later when placed on infants after cardiac surgery. Our study was performed to test the hypothesis that RNIRS and or RI could detect clinical changes consistent with sepsis-associated AKI before the changes in SCr occur. Methods: Prospective observational study of critically ill pediatric patients aged 2 weeks to 20 yr old with suspected or confirmed sepsis. RNIRS probes were in place until 48 hr after sepsis resolution. Using bedside Sonosite ultrasound machine, renal arterial RI was evaluated every 12–24 hr. The primary outcome of AKI was determined by an increase in adjusted SCr by 25% from baseline using the definition of “Risk” “Injury” “Failure” “Loss” and “End-stage” (pRIFLE) AKI staging criteria. SCr values were adjusted for net fluid balance. Results: Of the 18 patients enrolled in the study, four patients (22.2%) developed “Risk” according to pRIFLE criteria. Lower RNIRS values were associated with SCr increases 1 and 2 days later in septic AKI (rs=-0.775; p=0.041 and rs=-0.900; p=0.039 respectively). There were no meaningful associations between RI and changes in SCr. 8 patients had technical problems with the application of RNIRS including displacement of probes with movement, sweating. Conclusions: Lower RNIRS on sepsis day 2 and 3 were associated with changes in renal function on sepsis day 3 to 4 and days 5 to 6 in critically ill children. RNIRS can be technically challenging in children with obesity, scoliosis, excessive sweating. Bedside Doppler RI was not reliable in predicting AKI in this study.