Maria José Santiago

The use of continuous renal replacement therapy in series with extracorporeal membrane oxygenation

A large percentage of patients on extracorporeal membrane oxygenation (ECMO) require continuous renal replacement therapy (CRRT) usually performed through a different venous access or by introducing a filter into the ECMO circuit. Here, we evaluated the efficacy and safety of including a CRRT machine in the circuit by connecting its inlet line after the centrifugal pump and its outlet line before the oxygenator. We tested the function of the combined system initially in a closed circuit, followed by an experimental animal study, and, finally, in a clinical trial with six children. Both machines functioned adequately and there were no significant changes in the pressures of the ECMO circuit after the introduction of the CRRT device, thus achieving the preset negative balances and normalization of the serum urea and creatinine concentrations. The mean life of the filters was about 138 h, and only one filter needed changing due to clotting. Our study shows that the introduction of a CRRT device into the ECMO circuit is a safe and effective technique that improves fluid balance, increases filter life, and does not cause complications. For these reasons, this may be a good method for performing CRRT in patients on ECMO.

Hypophosphatemia and phosphate supplementation during continuous renal replacement therapy in children

Severe hypophosphatemia can cause generalized muscle weakness, paralysis of the respiratory muscles, myocardial dysfunction, reduced peripheral vascular resistance, and encephalopathy. Here we conducted a prospective study to determine the incidence of hypophosphatemia in 47 children on continuous renal replacement therapy and to evaluate the efficacy and safety of adding phosphate to the replacement and dialysate solutions of 38 pediatric patients. During continuous renal replacement therapy, 68% of patients were found to have hypophosphatemia, significantly more than the 12% of patients at the beginning of therapy. There was no higher incidence of hypophosphatemia among patients requiring insulin, diuretics, parenteral nutrition, or high doses of vasoactive drugs. In the children to whom phosphate was not added to replacement and dialysate solutions, 85% presented with an incidence of hypophosphatemia and 36% required intravenous phosphate replacement, rates significantly higher than in those patients where phosphate was added to the solutions. Phosphate supplementation did not cause any instability of the mixtures or other complications. We show here that the incidence of hypophosphatemia in children on continuous renal replacement therapy is very high. Further, we show that the addition of phosphate to replacement and dialysate solutions is safe and that it reduces the incidence of hypophosphatemia and the need for intravenous phosphate treatment.

Complications of continuous renal replacement therapy in critically ill children: a prospective observational evaluation study

IntroductionContinuous renal replacement therapy (CRRT) frequently gives rise to complications in critically ill children. However, no studies have analyzed these complications prospectively. The purpose of this study was to analyze the complications of CRRT in children and to study the associated risk factors.MethodsA prospective, single-centre, observational study was performed in all critically ill children treated using CRRT in order to determine the incidence of complications related to the technique (problems of catheterization, hypotension at the time of connection to the CRRT, hemorrhage, electrolyte disturbances) and their relationship with patient characteristics, clinical severity, need for vasoactive drugs and mechanical ventilation, and the characteristics of the filtration techniques.ResultsOf 174 children treated with CRRT, 13 (7.4%) presented problems of venous catheterization; this complication was significantly more common in children under 12 months of age and in those weighing less than 10 kg. Hypotension on connection to CRRT was detected in 53 patients (30.4%). Hypotension was not associated with any patient or CRRT characteristics. Clinically significant hemorrhage occurred in 18 patients (10.3%); this complication was not related to any of the variables studied. The sodium, chloride, and phosphate levels fell during the first 72 hours of CRRT; the changes in electrolyte levels during the course of treatment were not found to be related to any of the variables analyzed, nor were they associated with mortality.ConclusionsCRRT-related complications are common in children and some are potentially serious. The most common are hypotension at the time of connection and electrolyte disturbances. Strict control and continuous monitoring of the technique are therefore necessary in children on CRRT.

Circuit life span in critically ill children on continuous renal replacement treatment: a prospective observational evaluation study.

IntroductionOne of the greatest problems with continuous renal replacement therapy (CRRT) is early coagulation of the filters. Few studies have monitored circuit function prospectively. The purpose of this study was to determine the variables associated with circuit life in critically ill children with CRRT.MethodsA prospective observational study was performed in 122 children treated with CRRT in a pediatric intensive care unit from 1996 to 2006. Patient and filter characteristics were analyzed to determine their influence on circuit life. Data were collected on 540 filters in 122 patients and an analysis was performed of the 365 filters (67.6%) that were changed due to circuit coagulation.ResultsThe median circuit life was 31 hours (range 1 to 293 hours). A univariate and multivariate logistic regression study was performed to assess the influence of each one of the factors on circuit life span. No significant differences in filter life were found according to age, weight, diagnoses, pump, site of venous access, blood flow rate, ultrafiltration rate, inotropic drug support, or patient outcome. The mean circuit life span was longer when the heparin dose was greater than 20 U/kg per hour (39 versus 29.1 hours; P = 0.008), with hemodiafiltration compared with hemofiltration (34 versus 22.7 hours; P = 0.001), with filters with surface areas of 0.4 to 0.9 m2 (38.2 versus 26.1 hours; P = 0.01), and with a catheter size of 6.5 French or greater (33.0 versus 25.0 hours; P = 0.04). In the multivariate analysis, hemodiafiltration, heparin dose of greater than 20 U/kg per hour, filter surface area of 0.4 m2 or greater, and initial creatinine of less than 2 mg/dL were associated with a filter life of more than 24 and 48 hours. Total effluent rate of greater than 35 mL/kg per hour was associated only with a filter life of more than 24 hours.ConclusionCircuit life span in CRRT in children is short but may be increased by the use of hemodiafiltration, higher heparin doses, and filters with a high surface area.

Postpyloric enteral nutrition in the critically ill child with shock: a prospective observational study

BackgroundTolerance to enteral nutrition in the critically ill child with shock has not been studied. The purpose of the study was to analyze the characteristics of enteral nutrition and its tolerance in the critically ill child with shock and to compare this with non-shocked patients.MethodsA prospective, observational study was performed including critically ill children with shock who received postpyloric enteral nutrition (PEN). The type of nutrition used, its duration, tolerance, and gastrointestinal complications were assessed. The 65 children with shock who received PEN were compared with 461 non-shocked critically ill children who received PEN.ResultsSixty-five critically ill children with shock, aged between 21 days and 22 years, received PEN. 75.4% of patients with shock received PEN exclusively. The mean duration of the PEN was 25.2 days and the maximum calorie intake was 79.4 kcal/kg/day. Twenty patients with shock (30.7%) presented gastrointestinal complications, 10 (15.4%) abdominal distension and/or excessive gastric residue, 13 (20%) diarrhoea, 1 necrotising enterocolitis, and 1 duodenal perforation due to the postpyloric tube. The frequency of gastrointestinal complications was significantly higher than in the other 461 critically ill children (9.1%). PEN was suspended due to gastrointestinal complications in 6 patients with shock (9.2%). There were 18 deaths among the patients with shock and PEN (27.7%). In only one patient was the death related to complications of the nutrition.ConclusionAlthough most critically ill children with shock can tolerate postpyloric enteral nutrition, the incidence of gastrointestinal complications is higher in this group of patients than in other critically ill children.

Transpyloric enteral nutrition in the critically ill child with renal failure

ObjectiveTo study the efficacy and tolerance of transpyloric enteral nutrition (TEN) in the critically ill child with acute renal failure (ARF).DesignProspective observational study.SettingPaediatric intensive care unit.PatientsCritically ill children with ARF who received TEN were included in the study. They were compared with the remaining 473 critically ill children receiving TEN in this period. Tolerance of nutrition and gastrointestinal complications were assessed.InterventionTranspyloric enteral nutrition.Measurements and resultsFifty-three critically ill children with ARF aged between 3 days and 17 years received TEN. Children with ARF more frequently received parenteral nutrition before TEN (56.6%) than the other patients (17.5%). The incidence of shock, hepatic alterations and mortality was significantly higher in patients with ARF than in the remaining children. In children with ARF the mean duration of the TEN was 16.5 ± 27.3 days and the maximum caloric intake was 77 ± 26.7 kcal/kg/day. Thirteen patients (24.5%) presented gastrointestinal complications, 9 (17%) abdominal distension and/or excessive gastric residue, 5 (9.4%) diarrhoea, 1 necrotising enterocolitis and 1 duodenal perforation. The frequency of gastrointestinal complications was significantly higher in children with ARF. TEN was definitive suspended in five patients due to gastrointestinal complications. Four of these patients were treated with continuous renal replacement therapy. Thirty percent of patients died during TEN. In only one patient was the death related to complications of the nutrition.ConclusionsCritically ill children with ARF tolerate TEN, although the incidence of gastrointestinal complications is higher than in other critically ill children.

Nutritional status and clinical outcome of children on continuous renal replacement therapy: a prospective observational study

BackgroundNo studies on continuous renal replacement therapy (CRRT) have analyzed nutritional status in children. The objective of this study was to assess the association between mortality and nutritional status of children receiving CRRT.MethodsProspective observational study to analyze the nutritional status of children receiving CRRT and its association with mortality. The variables recorded were age, weight, sex, diagnosis, albumin, creatinine, urea, uric acid, severity of illness scores, CRRT-related complications, duration of admission to the pediatric intensive care unit, and mortality.ResultsThe sample comprised 174 critically ill children on CRRT. The median weight of the patients was 10 kg, 35% were under percentile (P) 3, and 56% had a weight/P50 ratio of less than 0.85. Only two patients were above P95. The mean age for patients under P3 was significantly lower than that of the other patients (p = 0.03). The incidence of weight under P3 was greater in younger children (p = 0.007) and in cardiac patients and in those who had previous chronic renal insufficiency (p = 0.047). The mortality analysis did not include patients with pre-existing renal disease. Mortality was 38.9%. Mortality for patients with weight < P3 was greater than that of children with weight > P3 (51% vs 33%; p = 0.037). In the univariate and multivariate logistic regression analyses, the only factor associated with mortality was protein-energy wasting (malnutrition) (OR, 2.11; 95% CI, 1.067-4.173; p = 0.032).ConclusionsThe frequency of protein-energy wasting in children who require CRRT is high, and the frequency of obesity is low. Protein-energy wasting is more frequent in children with previous end-stage renal disease and heart disease. Underweight children present a higher mortality rate than patients with normal body weight.

Bispectral index and middle latency auditory evoked potentials in children younger than two-years-old.

BACKGROUND:We analyzed the values of the bispectral index (BIS) and midlatency auditory evoked potentials (MLAEP) and their correlation with the modified Ramsay score (RS) during wakefulness and natural sleep in healthy children without pharmacological sedation. METHODS:Fifty-three healthy children younger than 2-yr-old were studied. Children were evaluated simultaneously using the modified RS, the BIS, and MLAEPs. Each patient was studied only once. The correlation and agreement were studied. The correlation among the three methods was determined using the Spearman Rank Correlation test and the agreement among the methods was assessed using by Cohen’s Kappa test. RESULTS:There was a moderate-to-good correlation (r) among the three methods (P = 0.01): BIS and MLAEP (r = 0.574), BIS and RS (r = −0.504), and MLAEP and RS (r = −0.624). However, the level of agreement (&kgr;) was only poor to fair: BIS and MLAEP (&kgr; = 0.392), BIS and RS (&kgr; = 0.270), and MLAEP and RS (&kgr; = 0.409). All the correlations were lower in children between 1 and 6 mo-of-age. When the children were asleep (RS: 3–5), the BIS values were higher in children younger than 1 mo-of-age than in children older than 6 mo-of-age (P after Bonferroni correction = 0.028). CONCLUSIONS:The BIS, MLAEP, and RS have a good correlation in children younger than 2 yr not receiving pharmacological sedation, though the level of agreement was poor.

Citrate anticoagulation for CRRT in children: comparison with heparin.

Regional anticoagulation with citrate is an alternative to heparin in continuous renal replacement therapies, which may prolong circuit lifetime and decrease hemorrhagic complications. A retrospective comparative cohort study based on a prospective observational registry was conducted including critically ill children undergoing CRRT. Efficacy, measured as circuit survival, and secondary effects of heparin and citrate were compared. 12 patients on CRRT with citrate anticoagulation and 24 patients with heparin anticoagulation were analyzed. Median citrate dose was 2.6 mmol/L. Median calcium dose was 0.16 mEq/kg/h. Median heparin dose was 15 UI/kg/h. Median circuit survival was 48 hours with citrate and 31 hours with heparin (P = 0.028). 66.6% of patients treated with citrate developed mild metabolic alkalosis, which was directly related to citrate dose. There were no cases of citrate intoxication: median total calcium/ionic calcium index (CaT/I) of 2.16 and a maximum CaT/I of 2.33, without metabolic acidosis. In the citrate group, 45.5% of patients developed hypochloremia and 27.3% hypomagnesemia. In the heparin group, 27.8% developed hypophosphatemia. Three patients were moved from heparin to citrate to control postoperatory bleeding. In conclusion citrate is a safe and effective anticoagulation method for CRRT in children and it achieves longer circuit survival than heparin.

Stability of continuous renal replacement therapy solutions after phosphate addition: an experimental study.

The incidence of hypophosphatemia is high in critically ill children on continuous renal replacement therapy (CRRT) and the addition of phosphate supplements to the replacement and dialysis fluids reduces the frequency of hypophosphatemia. The objective of this study was to determine the in vitro stability of the CRRT solutions after phosphate addition. Three different concentrations of phosphate, 2.5, 4.6 and 7.7 mg/dL, in the replacement and dialysis fluids were analyzed. The pH, glucose, total calcium, phosphate, and magnesium were determined before adding the phosphate and at 2, 24, and 48 h after its addition. The bags were macroscopically observed for possible precipitation. After addition of the phosphate, its concentration remained stable and there were no significant changes in the concentrations of the other components. There were no visible signs of precipitation up to 48 h. The addition of phosphate to the CRRT fluids at concentrations of up to 7.7 mg/dL does not cause problems with precipitation or instability of the mixture.