Cost analysis of two approaches to parenteral nutrition in critically ill children.

OBJECTIVE: In pediatric intensive care, two approaches to parenteral nutrition are available: individualized admixtures or commercial standard solutions. Even though individualized admixtures can be tailored to sometimes highly intricate requirements, standard solutions are able to meet the demands of the majority of pediatric patients. To address the growing importance of costs in intensive care, we investigated whether relevant differences between individualized admixtures and standard solutions in terms of costs can be found. DESIGN: Retrospective analysis. SETTING: University-affiliated intensive care unit. PATIENTS: Fifty consecutively admitted pediatric patients requiring parenteral nutrition. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Comparison of actual costs of individualized admixtures and theoretical costs of standard solutions. Mean actual costs of individualized admixtures of Euro 81.78 (+/- 16.33) per patient and day were significantly higher than the theoretical costs of standard solutions of Euro 61.21 (+/- 6.55). Cost differences increased with patients' body weights. CONCLUSIONS: Parenteral nutrition with standard solutions offers the potential of a relevant cost reduction compared with individualized admixtures in critically ill children.

Half-lives of albumin and cholinesterase in critically ill patients.

BACKGROUND: Albumin and plasma cholinesterase are markedly reduced in critical illness. However, the plasma half-lives of these two proteins have only been determined in very limited numbers of patients mostly outside intensive care. Therefore, we determined the kinetics of decrease of albumin and cholinesterase in a large population of critically ill patients. METHODS: Medical records of all patients of two university-affiliated surgical intensive care units during a time period of 8 years were retrospectively evaluated. To calculate the rate of fall, the first value in every episode of decreasing albumin or cholinesterase was arbitrarily set at 100% and the ensuing lower values were expressed as the respective fractions. RESULTS: Records of 3591 patients were evaluated. Regression analysis exhibited an exponential evolution of albumin and cholinesterase over time with corresponding mean apparent plasma half-lives of 11.8 days [95% confidence interval (CI): 10.8-12.9] for albumin and 7.8 days (95% CI: 7.4-8.3) for cholinesterase. CONCLUSIONS: These findings suggest that the apparent plasma half-lives of albumin and cholinesterase in critically ill surgical patients are considerably shorter than previously determined.

Binding of hydroxyethyl starch molecules to the platelet surface.

Hydroxyethyl starch (HES) solutions impair platelet function by reducing the availability of the fibrinogen receptor. This effect is not mediated by intracellular signal transduction pathways. Also, an unspecific coating of platelets by HES macromolecules may be responsible for its antiplatelet effects. To test this hypothesis, we investigated the binding of fluorochrome-coupled HES to the surface of human platelets using whole blood flow cytometry. Citrated whole blood from 8 volunteers was incubated (5 min, 22 degrees C, in the dark) with fluorescein isothiocyanate (FITC)-coupled HES (200-kDa molecular weight, 0.5 degree of substitution, 0.042 molar ratio of FITC-conjugation) resulting in 0%, 1%, 3%, 5%, 10%, 20%, and 40% hemodilution. The percentage of platelets binding FITC-HES was determined using a FACSCalibur flow cytometer and CellQuestPro software. The percentage of FITC-positive platelets increased in a concentration-dependent manner reaching statistical significance at 10% hemodilution. Binding was independent of fibrinogen receptor blockade. The present experiments clearly demonstrate that extracellular binding of HES to the platelet surface is, at least in part, responsible for the antiplatelet effects of HES by blocking the access of ligands to the platelet fibrinogen receptor.

The effects of hydroxyethyl starches on intracellular calcium in platelets.

UNLABELLED: Hydroxyethyl starch (HES) solutions impair platelet function. To determine whether this effect is achieved through interference of HES with intracellular activation processes, in which calcium is the key second messenger, we evaluated the agonist-induced increase of the cytoplasmic calcium concentration in the presence of HES of different molecular weights. Aliquots of citrated whole blood of 12 volunteers were incubated in vitr. with saline, HES 450 (molecular weight in kilodalton), HES 130, and HES 70, resulting in 20% hemodilution. An undiluted sample served as control. The samples were stained with Fluo-3 as the calcium-sensitive fluorescent probe with subsequent flow cytometric analysis. After determination of a baseline, platelets were activated with thrombin receptor activator peptide 6. Platelet activation with thrombin receptor activator peptide 6 resulted in a fast increase in fluorescence (approximately eightfold), representing intracellular calcium mobilization. None of the tested HES solutions exerted a statistically significant effect on the cytoplasmic calcium concentration compared with samples that were incubated with saline or that remained undiluted. These results indicate that the known inhibiting effect of HES on platelets is not achieved through interference with intracellular activation processes. IMPLICATIONS: Hydroxyethyl starch does not exert its known inhibitory effect on platelet function by interfering with intracellular activation processes.

Anticoagulation with prostaglandins and unfractionated heparin during continuous venovenous haemofiltration: a randomized controlled trial.

BACKGROUND: The objective of this prospective, randomized, controlled clinical study was to compare efficacy, safety, and costs of fixed-dose prostaglandins with adjusted-dose unfractionated heparin as anticoagulants for continuous venovenous haemofiltration. PATIENTS AND METHODS: Perioperative critically ill patients requiring continuous haemofiltration for acute renal failure received unfractionated heparin anticoagulation titrated to achieve an activated clotting time in the extracorporeal system of > 120 s. Patients were randomly assigned to receive a test infusion containing either prostaglandin I2 (5 ng/kg/min; group I; n = 15; 75 filters), prostaglandin E1 (5 ng/kg/min; group E; n = 18; 72 filters), or placebo (group H; n = 17; 63 filters). Heparin and test solutions were infused into the extracorporeal circuit before the haemofilter. All AN69-surface hollow fiber filters were primed with normal saline containing 5.000 IU heparin. RESULTS: The primary outcome measure--adequate haemofilter life span > 24 h--was compared by using Cochran's Q test. There was a significant difference in the frequencies of adequate haemofilter life span between the groups (36% group H, 65% group I, 59% group E; P < 0.05 versus group H). There were 6 bleeding episodes in group H, 2 in group E, and only 1 trivial bleeding episode in group I (P < 0.05 versus group H). Daily costs of haemofiltration were 61% higher in group I and 23% higher in group E than in group H (P < 0.05 versus group H). A heparin-sparing effect of prostaglandins was observed. CONCLUSIONS: Fixed-dose prostaglandins I2 and E1 reduced the incidence of haemofilter failure and bleeding when compared with adjusted-dose unfractionated heparin. There was no significant difference between the two prostaglandin groups. The increase in daily costs for haemofiltration treatment under prostaglandins is not clinically relevant.