Practical issues of nutrition during continuous renal replacement therapy

Abstract

Continuous renal replacement therapy (CRRT) in critically ill patients has significant impact on one's ability to provide efficient nutritional therapy. CRRT may help in the prevention of intestinal oedema and the maintenance of the proper function of the gastrointestinal tract by enabling strict control of the fluid balance. It facilitates early introduction of nutrition via the enteral route, as well as allowing for the composition of high-volume feeding mixtures. It is necessary to take into consideration that during CRRT, together with blood purification of toxic substances, nutritive elements are also eliminated to some extent (micro-and macronutrients). In this article, the authors discuss the impact of CRRT on nutritive elements loss, energetic balance and present the principles of adjusting feeding prescriptions to changes implied by CRRT.Anaesthesiology Intensive Therapy 2017, vol. 49, no 4, 309-316 Key words: critical care, nutrition; kidney injury; continuous renal replacement therapy, energy requirements, protein needs Nutritional therapy is one of the basic elements of the multifaceted treatment of patients in intensive care units (ICUs). The Nutrition Day ICU survey, based on a seven-year observation period of nutritional practices in 880 units from 46 countries, has demonstrated that the majority of ICU patients do not receive the recommended amounts of calories and proteins [1]. According to the findings of this survey, as well as of some other studies, an increasing energy-protein deficit is positively correlated with prolonged ICU stay, which in turn increases the risk of infections and death. On the other hand, it should be clearly emphasised that an excessive energy supply may also be associated with complications and increased mortality [1,2]. Adequate tailoring of nutritional therapy is a great challenge; firstly, because the nutritional status of patients on admission to an ICU can differ markedly, ranging from cachexia to morbid obesity while secondly, the critical conditions presented by patients have extremely relevant metabolic implications. Unfortunately, the majority of studies that are the basis for guidelines of nutritional therapy are observational or involve small groups of patients and are therefore characterised by low precision and relatively high changeability over time.Several randomised controlled studies have recently been published which have re-started the discussion on optimal nutritional practices in the ICU setting. One of the issues inadequately described and connected with nutritional therapy in ICU patients, concerns the effects of other elements of the multifaceted treatment of critically ill patients on the efficacy of nutritional interventions. It should be clearly stressed that continuous renal replacement therapy (CRRT) belongs to those interventions which most highly affect the outcomes of nutritional therapy in critically ill pa-310 Anaesthesiol Intensive Ther 2017, vol. 49, no 4, 309-316 tients. Firstly, the use of CRRT facilitates optimal nut...

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“…EN is the preferred mode of administration . Other caloric sources of calories, also called nonintentional calories, should be taken into account . Mostly these come from medication, and propofol is the most common example.…”

“…Effluent samples in CRRT are fat free and contain only trace amounts of cholesterol and triglycerides. There is no arteriovenous gradient for fats across the CRRT filter, which implies the absence of membrane adsorption . Fats may accelerate the blockage of capillaries and filter clotting.…”

How Does Continuous Renal Replacement Therapy Affect Septic Acute Kidney Injury?

“…A prospective study of 10 critically ill adult patients undergoing continuous vein-venous hemofiltration, through detecting the glucose and citrate concentration of pre-filter and post-filter, calculated the extra glucose and citrate intake during CRRT. In this study, substantial uptake of both glucose and citrate delivered exogenous energy and provided 0–512 kcal/day [45], if the replacement fluid contains a high level of lactates, the values exceeding 1,300 kcal during 24 h of treatment [46]. Glucose, citrate, or lactates added to the replacement fluid are absorbed into the body during CRRT, which can provide extra energy by tricarboxylic acid cycle.…”

“…The effects of CRRT on fluid balance described above can help in the early initiation (up to 48 h) of enteral nutrition [46], which is recommended in the guidelines of many scientific societies (i.e., European Society for Nutrition and Metabolism, American Society for Parenteral and Enteral Nutrition, International Symposium on Intensive Care and Emergency Medicine). The initiation of CRRT can reduce the existing edema, thus favoring affective gastrointestinal motility and the ability of absorbing nutrients administered eternally, which is the preferable route in ICU patients.…”

“…The impact of CRRT on the possibility to administer adequate nutritional intervention to critically ill patients is significant due to increased loss of amino acids, L-carnitine, and some vitamins as well as microelements during the procedure [46]. …”