Acute renal failure and outcome of children with solitary kidney undergoing cardiac surgery

The Epidemiology and Management of Pediatric AKI in Asia

Because of the lack of early recognition and referral, the incidence of pediatric acute kidney injury (AKI) in Asia still is underestimated. Although each diagnostic criteria has its own merits, the Kidney Disease Improving Global Outcomes classification now is widely accepted. In Asia, the spectrum of pediatric AKI is wide-ranging, from pediatric AKI in highly sophisticated tertiary-care pediatric intensive care units in resource-rich regions due to advanced procedures such as transplantation, cardiac surgery, and other hospital-acquired causes, to primary care preventable causes, such as infectious diseases, snakebite, and so forth in rural parts of the developing world. The development and application of novel biomarkers, concepts such as the Renal Angina Index and advanced renal replacement therapy have revolutionized the era of treating AKI, but the cost and feasibility are the key determinants, especially in rural areas. In view of availability and expenses, peritoneal dialysis should be the first choice in less-developed areas, however, because of various barriers, it still needs more effort. Effective educational steps to both medical carers and families are needed urgently.

Bedside ultrasonography screening for congenital renal anomalies in children with congenital heart diseases undergoing cardiac repair

Introduction

Ultrasound (US) assessment of renal anomalies in children requiring pediatric cardiac surgery is not a standard practice. This study is highlighting the role of bedside US performed by intensivist to detect occult renal anomalies associated with congenital heart disease (CHD).

Methods

A cross sectional study for 100 consecutive children with CHD admitted to Pediatric Cardiac Intensive Care Unit (PCICU) in 2015. US of kidneys screening was performed by trained pediatric cardiac intensivists to ascertain the presence of both kidneys in renal fossae without gross anomalies and to investigate if early detection of occult kidney anomaly would have any impact on outcome.

Results

After screening of 100 consecutive children with CHD with renal US, we identified in 94 cases (94%) normal right and left kidney in the standard sonographer shape within the renal fossae. In 6 cases further investigation revealed ectopic kidney in 3 patients (50%), solitary functional kidney in 2 patients (33%) and bilateral grade IV hydronephrosis in one patient (17%). Urinary tract infection developed peri-operatively in 66% of the cases with kidney anomalies with statistical significance compared to patients with normal renal US (P: 0.0011). No significant renal impairment was noted in these patients post-surgery. We observed no specific association between the type of renal anomaly and specific CHD.

Conclusion

Routine renal US in children with CHD demonstrated prevalence of associated congenital renal anomalies in 6% of children undergoing cardiac surgery. The presence of occult renal anomalies was associated with higher UTI risk. Performing routine renal US as a standard practice in children with CHD is justifiable.

Perioperative renal failure in pediatric heart transplant recipients: outcome and risk factors

PRF is encountered in 10-13% of adult heart transplants. Only one study of a single center's experience with PRF has been reported in pediatric patients. This study examines the effect of PRF on pediatric heart transplant outcome using the UNOS database. A total of 3598 patients met inclusion criteria, of whom 254 (7%) had PRF. The PRF group comprised 31 recipients requiring PRE and 223 recipients requiring POST. Compared with No-PRF patients, PRE patients had similar survival rate and POST patients had decreased survival rate at 30 days, one, five, and 10-yr post-transplant (p < 0.001). PRF patients also had significantly lower graft survival at one, five, and 10 yr (p < 0.001). Risk factors for developing PRF included ECMO, ventilator, and inotropic support at listing and CHD as the listing diagnosis. PRF increased the duration of hospital stay and the incidence of chronic severe renal dysfunction. PRF that requires POST (whether or not it began pretransplant) has a significant negative impact on pediatric heart transplant outcome. Specific characteristics identify patients at particular high risk of developing PRF.

Short-term outcome of solitary kidney patients undergoing on-pump cardiac surgery

OBJECTIVE

The outcome of patients with solitary kidney undergoing on-pump cardiac surgery is unknown. We sought to assess the in-hospital mortality and complications in these patients compared with patients with normal renal function.

METHODS

This is a retrospective review of prospectively collected data over an 8-year period of all patients who underwent cardiac surgery. Our cohort consisted of 3363 consecutive patients divided into: solitary kidney (n=31, 0.9%) and normal kidneys (n=3332, 99.1%). Postoperative complications and in-hospital mortality were analysed.

RESULTS

Solitary kidney patients had higher incidence of renal failure (26% vs 5%, p-value<0.001), higher incidence of gastrointestinal complications (10% vs 1%, p-value 0.009) and higher blood transfusions (74% vs 43%, p-value<0.001) compared with patients with normal kidneys. There was an increased length of both intensive care unit stay (3.8 vs 2.2 days, p-value 0.031) and hospital stay (15.6 vs 8.5 days, p-value 0.026) among patients with solitary kidney compared with normal kidney patients. Multivariate analysis showed that solitary kidney is an independent predictor of postoperative renal failure (odds ratio (OR) 7.1 (95%CI 3.1-16.6)), gastrointestinal complications (OR 8.5 (95%CI 2.5-29.4)) and blood transfusion (OR 3.8 (95%CI 1.6-9.0)) after adjusting for age and gender. In-hospital mortality, however, was similar in both groups.

CONCLUSION

Although solitary kidney patients have similar short-term mortality as normal kidney patients, the rates of postoperative renal failure, gastrointestinal complications and blood transfusion are significantly higher among solitary kidney patients. Our findings have important clinical implications and prior knowledge of such entity with appropriate risk stratification at admission could help in reducing the risk of these potential complications.

Low renal oximetry correlates with acute kidney injury after infant cardiac surgery

Acute kidney injury (AKI) is a frequent complication after cardiopulmonary bypass surgery during infancy. Standard methods for evaluating renal function are not particularly sensitive nor are proximate indicators of renal dysfunction that allow intervention in real time. Near-infrared spectroscopy (NIRS) is a newer noninvasive technology that continuously evaluates regional oximetry and may correlate with renal injury and adverse outcomes after cardiac surgery in infants. This prospective observational study enrolled 40 infants (age, <12 months) undergoing biventricular repair. Continuous renal oximetry data were collected for the first 48 postoperative hours and correlated with postoperative course, standard laboratory data, and the occurrence of acute renal injury. Subjects with low renal oximetry (below 50% for >2 h) had significantly higher postoperative peak creatinine levels by 48 h (0.8 ± 0.4 vs. 0.52 ± 0.2; p = 0.003) and a higher incidence of AKI (50 vs. 3.1%; p = 0.003) than those with normal renal oximetry. These subjects also required more ventilator days and greater vasoactive support, and they had elevated lactate levels. Prolonged low renal near-infrared oximetry appears to correlate with renal dysfunction, decreased systemic oxygen delivery, and the overall postoperative course in infants with congenital heart disease undergoing biventricular repair.

Anesthetic concerns and perioperative complications in repair of myelomeningocele: a retrospective review of 135 cases

Myelomeningocele (MMC) a complex congenital spinal anomaly, results from neural tube defect during first 4 weeks of gestation. Medical records of 135 children who underwent excision and repair of MMC from January 2003 to December 2006 were analyzed, retrospectively. Data on associated illnesses, anesthetic management, perioperative complications, and outcome were recorded. The patient population consisted of older infants with unrepaired MMC. The average age of presentation was 1 year and 8 months. The commonest site of presentation was lumbar (39.3%). Leaking MMC was present in 19.3% of cases, most had associated electrolyte imbalance. Hydrocephalus was the commonest association (67.4%) followed by Chiari-II malformation (58.4%). Renal abnormality was present in 9% of cases and 24.4% of children had scoliosis. Two infants (1.5%) presented with inspiratory stridor. Intraoperative cardiac and respiratory problems were observed in 15.6% and 11.1%, of cases, respectively. Two children (1.5%) suffered cardiac arrest; both had associated Chiari-II malformation and hydrocephalus. Postoperative ventilation was required in 8.9% of children, primarily due to inadequate reversal from neuromuscular blockade. Infection, cerebrospinal fluid leak, and pseudomeningocele were common surgical complications. Improvement of motor, sensory, and sphincteric function was observed in 30.5%, 22.9%, and 14.1%, respectively. To conclude, surgical repair of MMC may at times pose life-threatening complications mostly because of associated anomalies. Children with associated Chiari malformation and/or hydrocephalus need special attention during perioperative period.

Assays of urine levels of HNL/NGAL in patients undergoing cardiac surgery and the impact of antibody configuration on their clinical performances

BACKGROUND

Acute kidney injury (AKI) is one of the most serious postoperative complications of cardiac surgery. The lack of early and powerful markers for AKI makes the morbidity and mortality still very high. HNL (Human neutrophil lipocalin)/NGAL (Neutrophil gelatinase-associated lipocalin) was recently shown as a novel biomarker for AKI after cardiac surgery.

METHODS

Serial urine samples from 59 patients undergoing cardiac surgery were analyzed by polyclonal antibody based radioimmunoassay (RIA), monoclonal-polyclonal antibody based enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found 10 to 100-fold increases in urine HNL/NGAL levels in about half of the patients 2 h after termination of the operation and elevated levels in all patients 72 h post operation. The urine levels of HNL/NGAL showed a weak, but significant relation with kidney function as measured by plasma levels of cystatin C or creatinine. The 2 h-HNL/NGAL levels were positively correlated to extracorporeal circulation time (p<0001). The assays were well correlated, but had different clinical performances.

CONCLUSIONS

We confirmed that urine HNL/NGAL may be a useful early biomarker of postoperative kidney injury. The results indicate that the antibody configuration of the assay has an impact on the clinical performance of the assay.