Norma J. Maxvold

Pediatric acute renal failure: outcome by modality and disease

Abstract. Two hundred and twenty-six children who underwent renal replacement therapy (RRT) from 1992 to 1998 were retrospectively reviewed. The mean age, at the onset of RRT, was 74±11.7 months and weight was 25.3±9.7 kg. RRT therapies included hemofiltration (HF; n=106 children for an average of 8.7±2.3 days), hemodialysis (HD; n=61 children for an average of 9.5±1.7 days), and peritoneal dialysis (PD; n=59 children for an average of 9.6±2.1 days). Factors influencing patient survival included: (1) low blood pressure (BP) at onset of RRT (33% survival with low BP, vs 61% with normal BP, vs 100% with high BP; P<0.05), (2) use of pressors anytime during RRT (35% survival in those on pressors vs 89% survival in those not requiring pressors; P<0.01), (3) diagnosis (primary renal failure with a high likelihood of survival vs secondary renal failure; P<0.05), (4) RRT modality (40% survival with HF, vs 49% survival with PD, vs 81% survival with HD; P<0.01 HD vs PD or HF), and (5) pressor use was significantly higher in children on HF (74%) vs HD (33%) or PD (81%; P<0.05 HD vs HF or PD). In conclusion, pressor use has the greatest prediction of survival, rather than RRT modality. Patient survival in children with the need for RRT for ARF is similar to in adults and, as in adults, is best predicted by the underlying diagnosis and hemodynamic stability.

Amino acid loss and nitrogen balance in critically ill children with acute renal failure: a prospective comparison between classic hemofiltration and hemofiltration with dialysis.

Hypothesis: Amino acid (AA) loss is not equivalent on continuous venovenous hemofiltration (CVVH) compared with continuous venovenous hemodiafiltration (CVVHD). Amino acid supplementation may be necessary to adjust for a greater clearance on CVVH to maintain nitrogen balance similar to that of CVVHD. Objective: To compare AA losses and nitrogen balance between CVVH and CVVHD in children with acute renal failure. Setting: Pediatric patients in the pediatric intensive care unit of a tertiary referral center. Design: Prospective randomized crossover study in consecutive children who required hemofiltration. Patients: A total of 12 plasma clearance studies for AA and urea, consisting of 24‐hr collections of ultrafiltrate and urine for nitrogen balance, was performed on six patients during CVVH and CVVHD. Patients received total parenteral nutrition (TPN) with caloric intake 20% to 30% above their resting energy expenditure measured by indirect calorimetry and 1.5 g/kg/day protein of TPN. Study conditions were comprised of 2 L/hr/1.73 m2 of dialysate or prefiltered replacement fluid and hemofilter flow rates of 4 mL/kg/min were maintained for all patients. Methods and Main Results: Amino acid clearances were greater on CVVH than CVVHD, except for glutamic acid, where clearance was 6.73 ± 2.31 (SEM) mL/min/1.73 m2 on CVVH and 7.59 ± 2.79 mL/min/1.73 m2 for CVVHD (NS). The clearance difference between the two modalities was 30%. Urea clearance was equivalent (30.1 ± 1.74 mL/min/1.73 m2 and 29.0 ± .97 mL/min/1.73 m2) for CVVH and CVVHD, respectively. Amino acid loss on CVVH and CVVHD was similar (12.50 ± 1.29 g/day/1.73 m2 vs. 11.61 ± 1.86 g/day/1.73 m2, respectively), representing 12% and 11%, respectively, of the daily protein intake. The catabolic state, as measured by urea nitrogen appearance, was high for all patients during the 48‐hr study period with a mean of 291 mg/kg/day during CVVH, and 245 mg/kg/day for CVVHD. Nitrogen balance varied from a negative 12.95 g/day/1.73 m2 to a positive 4.93 g/day/1.73 m2 on CVVH and a negative 7.69 g/day/1.73 m2 to a positive 5.50 g/day/1.73 m2 on CVVHD. Conclusions: Clearance of AA is greater on CVVH than on CVVHD, but no significant difference in AA loss was present between the two therapies. Nitrogen balance often is not met on either therapy when a standard 1.5 g/kg/day protein and a resting energy expenditure of 120% to 130% of calories is delivered by TPN.

Pediatric hemofiltration: Normocarb dialysate solution with citrate anticoagulation

Abstract Fourteen children, newborn to 17 years of age, underwent continuous veno-venous hemofiltration with dialysis (CVVHD), using a new FDA-approved bicarbonate-based calcium-free dialysis solution (Normocarb) in combination with citrate anticoagulation. Dialysis prescription included use of the PRISMA system (Gambro, Lakewood, Colo., USA), with ACD-A (Baxter, Deerfield, Ill., USA) for anticoagulation and Normocarb (Dialysis Solution, Richmond Hills, Ontario, Canada) for dialysate. Diagnosis included 11 children with sepsis and 3 children with tumor lysis syndrome. Mean weight was 31.6±4.7 kg (range 3.7–62 kg) and average length of therapy was 11.4±3.7 days (range 6 h to 67 days). Length of circuit patency was 71.3±7.2 h (range 6 h to 127 h), which was influenced in part by a decision to change circuits at 72 h as per manufacturer’s recommendation. No bleeding occurred. This protocol utilizes industry-manufactured CVVHD machinery with both thermic and ultrafiltration control, with an effective anticoagulation protocol, and industry-produced bicarbonate dialysate. The use of industry machinery and solutions allows for consistent industrial quality assurance standards. This potentially may decrease the cost of therapy and minimize the risk of pharmacy errors that can occur with pharmacy-made dialysis solutions.

Venovenous versus venoarterial extracorporeal life support for pediatric respiratory failure : Are there differences in survival and acute complications?

Objectives: To examine the Extracorporeal Life Support Organization (ELSO) registry database of infants and children with acute respiratory failure to compare outcome and complications of venovenous (VV) vs. venoarterial (VA) Extracorporeal Life Support (ECLS). Design: Retrospective cohort study. Setting: ELSO registry for pediatric pulmonary support. Patients: All nonneonatal pediatric pulmonary support ECLS cases treated at U.S. centers and reported to the ELSO registry as of July 1997. Patients were excluded if they had one or more of the following diagnoses: hematologic‐oncologic, cardiac, abdominal surgical, burn, metabolic, airway, or immunodeficiency disorder. Interventions: Venoarterial or venovenous extracorporeal life support for severe pulmonary failure. Measurements and Main Results: From 1986 to June of 1997, 763 pediatric patients met the inclusion criteria. Overall, 595 were initially managed with VA bypass, and 168 with VV bypass. The VA group was younger (mean ± SD, 26.1 ± 42.2 months for VA vs. 63.5 ± 68.7 months for VV) and smaller (11.8 ± 15.1 kg vs. 22.9 ± 23.8 kg) (p < .001). There were no differences between groups in number of days on mechanical ventilation before ECLS, number of hours on ECLS, or number of hours on mechanical ventilation post‐ECLS in survivors. Mean pH and PaCO2 values, positive end‐expiratory pressure, and mean airway pressure just before placing the patient on ECLS were also similar. VA‐treated patients had higher FIO2 requirements (p = .034), lower PaO2 (p = .047), and lower PaO2/FIO2 ratio (p = .014) just before cannulation. There was a trend of higher peak inspiratory pressure in VA‐treated patients (p = .053). Overall, survival rate was not different for the two groups (55.8% for VA vs. 60.1% for VV; p = .33). Central nervous system complications were not different between the two groups. Examination of the same variables was then conducted after dividing the patients into four subgroups. There were no significant differences in survival or complications during bypass between VV and VA modes of ECLS in any subgroup. Stepwise logistic regression modeling was performed to control for variables associated with the outcome survival for VV and VA‐treated groups, and variables measured before bypass were identified as being associated with improved survival. There was a trend of improved survival in the VV‐treated patients (p = .12). Conclusions: Overall survival of pediatric patients with acute respiratory failure supported by VA or VV ECLS was comparable. A randomized clinical trial may be useful in clarifying these observations.

Continuous venovenous hemodiafiltration in infants and children

Continuous venovenous hemodiafiltration (CVVHD) is not commonly used in pediatric intensive care units due to the lack of suitable equipment needed for this technique of renal replacement therapy (RRT). We have used an adapted hemodialysis machine that includes a blood pump controller, an air leak detector, and a venous pressure monitor over the past year in the pediatric intensive care unit. Blood lines available for hemodialysis were used for CVVHD, limiting the extracorporeal circuit volume to 38 mL, which allows for CVVHD capability in an infant as small as 4.5 kg without a blood-primed circuit. We have compared this experience to previous continuous arteriovenous hemodiafiltration (CAVHD) at our institution. The two groups (CVVHD and CAVHD) were similar in age, weight, blood pressure, and indication for RRT. There was significantly less number of hemofilters used, an improved number of hours per hemofilter, and a significantly less change of RRT modality due to ineffective dialysis (CVVHD 0% v CAVHD 32%) when using CVVHD. Furthermore, an average of 48% less heparin was used in the CVVHD population. We conclude that CVVHD can be safely and effectively carried out in infants and small children with less heparinization, no need for arterial access, and less risk of ineffective RRT.

Management of acute renal failure in the pediatric patient: Hemofiltration versus hemodialysis

Although outcome data for acute renal failure (ARF) in the adult population (analyzed by etiology of ARF, severity of illness, and modality of treatment) are readily available, few similar data exist for the pediatric population. Pediatric survival rate data vary widely, based upon era of analysis, age and size of child, and cause of ARF. Few comparative data are available that address impact by modality chosen to treat ARF. Comparison of 122 children who were treated by hemodialysis (HD; n = 58) versus hemofiltration (HF; n = 64) reveals a combined survival rate of 65%. Survival by modality was higher for HD (83%) than for HF (48%). The major diagnosis treated with HF was sepsis (29/64; 45%), with a survival rate of 31%, whereas the major diagnosis treated with HD (27/58; 46%) was primary renal failure, with a survival rate of 96%. Seventy-one percent of children undergoing HF required pressor support for hypotension, whereas only 24% of those receiving HD needed pressor support (P < 0.01). We conclude that the choice of renal replacement therapy (RRT) modality needs to be determined by the best treatment available. To adequately evaluate therapy measures, further analyses of outcome need to consider those factors that determine choice of RRT and those that affect survival independent of ARF.

Extracorporeal life support for severe pediatric respiratory failure: An updated experience 1991–1993

Objective: The purpose of this study was to examine our recent experience with children who had acute respiratory failure managed with extracorporeal life support (ECLS) from 1991 to 1993, to determine whether a change in survival rate had occurred in comparison with our previous experience. Design: Historic and prospective cohort study. Setting: A tertiary pediatric referral center. Patients: All nonneonatal pediatric patients treated with ECLS for severe, life-threatening respiratory failure were examined. Overall, 25 patients have been managed with this life-support technique in the past 28 months. Eighty-four percent (21/25) were transferred to our medical center because of failure of conventional mechanical ventilation therapy. Descriptive data of the recent cohort were as follows (mean ± SD): age 60±75 months, weight 23.6±24.8 kg, and male gender 44%. Duration of intubation before ECLS was 5.8±2.7 days. Arterial blood gas values and ventilator settings immediately before ECLS were as follows: fraction of inspired oxygen, 0.98±0.08; mean airway pressure, 21.6±6.2 cm H2O; peak inspiratory pressure, 45.5±9.6 cm H2O; positive endexpiratory pressure, 11.0±4.3 cm H2O; partial pressure of oxygen (arterial), 56±20 mm Hg (7.4±2.7 kilopascals); partial pressure of carbon dioxide (arterial), 46±17 mm Hg (6.1±2.3 kPa); and estimated alveolar-arterial oxygen tension difference, 572±81 mm Hg (76.3±10.8 kPa). Mean duration of ECLS was 373±259 hours. Of 25 recently treated patients, 22 (88%) survived their lifethreatening respiratory illness to be discharged home; this represented a statistically improved survival rate in comparison with the 58% survival rate previously reported by us for similar patients (p Conclusions: Treatment with ECLS is an evolving pulmonary rescue therapy with an 88% survival rate in our recent experience. The survival rate has improved to levels that may not greatly improve in the near future, especially for patients less than 1 year of age. Better patient selection or improved management strategies or both may be responsible for the improved patient outcome.

Medication errors and patient complications with continuous renal replacement therapy

Continuous renal replacement therapy (CRRT) is commonly used for renal support in the intensive care unit. While the risk of medication errors in the intensive care unit has been described, errors related specifically to CRRT are unknown. The purpose of this study is to characterize medication errors related to CRRT and compare medication errors that occur with manually compounded solutions versus commercially available solutions. We surveyed three separate internet-based, pediatric list serves that are commonly used for communications for programs utilizing CRRT. Data regarding CRRT practices and medication errors were recorded. Medication errors were graded for degree of severity and compared between programs using manually compounded dialysis solutions versus commercially available dialysis solutions. In a survey with 31 program responses, 18 reported medication errors. Two of the 18 were related to heparin compounding, while 16/18 were due to solution compounding errors. Half of the medication errors were classified as causing harm, two of which were fatal. All medication errors were reported by programs that manually compounded their dialysis solutions. Medication errors related to CRRT are associated with a high degree of severity, including death. Industry-based, commercially available solutions can decrease the occurrence of medication errors due to CRRT.

Survival and renal function in pediatric patients following extracorporeal life support with hemofiltration.

Objective To determine variables associated with survival in pediatric patients treated with hemofiltration while receiving extracorporeal life support and to determine the probability for recovery of renal function among survivors. Design Retrospective database analysis. Setting University of Michigan pediatric nephrology database. Patients All pediatric patients treated with continuous hemofiltration while on extracorporeal life support at the University of Michigan between January 1990 and May 1999. A pediatric patient was defined as any child between birth and 18 yrs of age, including children treated in both the pediatric intensive care unit and neonatal intensive care unit. Indications for extracorporeal life support included both cardiac and pulmonary failure. Interventions Data analysis of patients who were treated with hemofiltration while on extracorporeal life support. Hemofiltration includes both ultrafiltration and hemofiltration with countercurrent dialysis. Measurements and Main Results Thirty-five patients with a mean age of 39 ± 65 months (median, 3 months) underwent hemofiltration while on extracorporeal life support. Forty-three percent survived to hospital discharge (95% CI, 26%–60%). All deaths occurred in the intensive care unit. Recovery of renal function occurred in 93% of survivors (95% CI, 79%–108%). Mean duration of hemofiltration in survivors, including time during and after extracorporeal life support, was 9 ± 6 days. All nonsurvivors were on renal replacement therapy at the time of death. In this analysis, decreased survival was significantly associated with the use of vasopressor infusions (p = .01) and the presence of complications (p = .006). Vasopressor infusions were required in 89% of patients, and 37% of patients experienced complications. Conclusions In patients receiving hemofiltration while on extracorporeal life support, survival is comparable to that reported in other extracorporeal life support or hemofiltration populations. Decreased survival in these patients may be associated with the use of vasopressor infusions and the occurrence of complications. Recovery of renal function occurs in most survivors.

High-efficiency dialysis for carbamazepine overdose.

Background: Carbamazepine intoxication is associated with seizures, coma, arrhythmias, and death. In acute intoxications, charcoal hemoperfusion enhances removal of the drug but is associated with thrombocytopenia, coagulopathy, hypothermia, and hypocalcemia. Alternatively, high-efficiency hemodialysis can be used without the side effects of charcoal hemoperfusion. Case Report: We report an 18-month-old comatose, convulsing child with plasma carbamazepine 27 μg/mL treated with high efficiency hemodialysis. Therapeutic carbamazepine levels were obtained after 4.5 hours of high-efficiency hemodialysis. The patient developed no untoward side effects, improved clinically, and was subsequently discharged home without sequelae. We conclude that high-efficiency hemodialysis is a safe, effective alternative to charcoal hemoperfusion in the pediatric population.