[Metabolic management and nutrition in critically ill patients with renal dysfunction : Recommendations from the renal section of the DGIIN, ÖGIAIN, and DIVI]

The kidney: the critical organ system for guiding nutrition therapy in the ICU-patient?

Most randomized controlled studies on nutrition in intensive care patients did not yield conclusive results or were neutral or negative concerning the primary endpoints but also in most secondary endpoints. However, there is a consistent observation that in several of these studies there was a negative effect of the nutrition intervention on the kidneys in one of the study arms. During the early phase and in unstable periods during further course of disease an inadequate clinical nutrition can damage the kidneys, can elicit or aggravate acute kidney injury and/ or increase requirements of renal replacement therapy (RRT). This relates to total energy intake, glucose intake/hyperglycemia and protein/ amino acid intake at various stages of renal dysfunction. The kidney could present a critical organ system for guiding nutrition therapy, a close monitoring of kidney function should be observed and nutrition therapy may need to be adapted accordingly. The long-held dogma of performing full nutrition and accept an otherwise not necessary RRT is definitely to be refuted.

The effects of higher versus lower protein delivery in critically ill patients: an updated systematic review and meta-analysis of randomized controlled trials with trial sequential analysis

BACKGROUND

A recent large multicentre trial found no difference in clinical outcomes but identified a possibility of increased mortality rates in patients with acute kidney injury (AKI) receiving higher protein. These alarming findings highlighted the urgent need to conduct an updated systematic review and meta-analysis to inform clinical practice.

METHODS

From personal files, citation searching, and three databases searched up to 29-5-2023, we included randomized controlled trials (RCTs) of adult critically ill patients that compared higher vs lower protein delivery with similar energy delivery between groups and reported clinical and/or patient-centred outcomes. We conducted random-effect meta-analyses and subsequently trial sequential analyses (TSA) to control for type-1 and type-2 errors. The main subgroup analysis investigated studies with and without combined early physical rehabilitation intervention. A subgroup analysis of AKI vs no/not known AKI was also conducted.

RESULTS

Twenty-three RCTs (n = 3303) with protein delivery of 1.49 ± 0.48 vs 0.92 ± 0.30 g/kg/d were included. Higher protein delivery was not associated with overall mortality (risk ratio [RR]: 0.99, 95% confidence interval [CI] 0.88-1.11; I2 = 0%; 21 studies; low certainty) and other clinical outcomes. In 2 small studies, higher protein combined with early physical rehabilitation showed a trend towards improved self-reported quality-of-life physical function measurements at day-90 (standardized mean difference 0.40, 95% CI - 0.04 to 0.84; I2 = 30%). In the AKI subgroup, higher protein delivery significantly increased mortality (RR 1.42, 95% CI 1.11-1.82; I2 = 0%; 3 studies; confirmed by TSA with high certainty, and the number needed to harm is 7). Higher protein delivery also significantly increased serum urea (mean difference 2.31 mmol/L, 95% CI 1.64-2.97; I2 = 0%; 7 studies).

CONCLUSION

Higher, compared with lower protein delivery, does not appear to affect clinical outcomes in general critically ill patients but may increase mortality rates in patients with AKI. Further investigation of the combined early physical rehabilitation intervention in non-AKI patients is warranted.

PROSPERO ID

CRD42023441059.

ISCCM Guidelines on Acute Kidney Injury and Renal Replacement Therapy

Acute kidney injury (AKI) is a complex syndrome with a high incidence and considerable morbidity in critically ill patients. Renal replacement therapy (RRT) remains the mainstay of treatment for AKI. There are at present multiple disparities in uniform definition, diagnosis, and prevention of AKI and timing of initiation, mode, optimal dose, and discontinuation of RRT that need to be addressed. The Indian Society of Critical Care Medicine (ISCCM) AKI and RRT guidelines aim to address the clinical issues pertaining to AKI and practices to be followed for RRT, which will aid the clinicians in their day-to-day management of ICU patients with AKI.

HOW TO CITE THIS ARTICLE

Mishra RC, Sodhi K, Prakash KC, Tyagi N, Chanchalani G, Annigeri RA, et al. ISCCM Guidelines on Acute Kidney Injury and Renal Replacement Therapy. Indian J Crit Care Med 2022;26(S2):S13-S42.

Serum Micronutrient Levels in Critically III Patients Receiving Continuous Renal Replacement Therapy: A Prospective, Observational Study

BACKGROUND

Acute kidney injury (AKI) treated with continuous renal replacement therapy (CRRT) may deplete micronutrient levels. Patients are also at risk for micronutrient depletion due to underlying illness(s), poor nutrient intake prior to intensive care unit (ICU) admission and/or increased requirements. We determined vitamin and trace element status before, during and after CRRT in critically ill patients.

METHODS

This prospective observational study performed in mixed medical and surgical ICU patients. Serial serum vitamin B6 and vitamin C concentrations were measured by HPLC and folic acid by ECLIA. Serum chromium, copper, selenium, and zinc were measured using ICP-MS. Serum ceruloplasmin was measured by the Erel method.

RESULTS

Fifty adult ICU patients with AKI were recruited. The median APACHE II score on ICU admission was high at 24.0 (6.0-33.0). The median days on CRRT was 2.0 (2.0-4.0) days. At baseline (within 10-15 minutes of CRRT initiation), serum vitamin C, selenium and zinc were below normal. Serum vitamin B6 levels at 72 hours on CRRT were significantly lower than at 24 hours (p=0.011). Serum vitamin C values fell significantly at 24 and 72 hours during CRRT (p=0.030 and p=0.001), respectively, and remained low 24 and 48 hours after CRRT was stopped (p=0.021). At baseline and during CRRT, 96% of participants had at least two or more micronutrient levels below the normal range.

CONCLUSION

Serum vitamin C, selenium and zinc concentrations were below the normal range at baseline. CRRT was associated with a significant further decrease in levels of vitamin C, selenium and zinc.

CLINICAL RELEVANCY STATEMENT

Critically ill patients who were experienced CRRT had serum vitamin C, selenium and zinc below the normal range during and after CRRT. Also, 96% of participants had at least two or more micronutrient levels below normal at baseline and during CRRT. This article is protected by copyright. All rights reserved.

Nutrients and micronutrients at risk during renal replacement therapy: a scoping review

PURPOSE OF REVIEW

Malnutrition is frequent in patients with acute kidney injury. Nutrient clearance during renal replacement therapy (RRT) potentially contributes to this complication. Although losses of amino acid, trace elements and vitamins have been described, there is no clear guidance regarding the role of micronutrient supplementation.

RECENT FINDINGS

A scoping review was conducted with the aim to review the existing literature on micronutrients status during RRT: 35 publications including data on effluent losses and blood concentrations were considered relevant and analysed. For completeness, we also included data on amino acids. Among trace elements, negative balances have been shown for copper and selenium: low blood levels seem to indicate potential deficiency. Smaller size water soluble vitamins were found in the effluent, but not larger size liposoluble vitamins. Low blood values were frequently reported for thiamine, folate and vitamin C, as well as for carnitine. All amino acids were detectable in effluent fluid. Duration of RRT was associated with decreasing blood values.

SUMMARY

Losses of several micronutrients and amino acids associated with low blood levels represent a real risk of deficiency for vitamins B1 and C, copper and selenium: they should be monitored in prolonged RRT. Further Research is urgently required as the data are insufficient to generate strong conclusions and prescription recommendations for clinical practice.

[Geriatric patients in the intensive care unit]

The percentage of geriatric patients treated in intensive care units continues to increase, comprising up to 30%. Age per se is not of great relevance for the outcome of intensive care treatment. Functional status and geriatric syndromes are crucial for prognosis. Frailty and delirium are very important and should be screened using the Clinical Frailty Scale (CFS) and Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), respectively. Furthermore, age-physiological organ changes as well as multimorbidity and associated polypharmacy play an important role. The latter should be assessed at the time of admission. Another goal of intensive care treatment of geriatric patients is to maintain and improve the nutritional status, which can be assessed with the help of an established tool (e.g. NRS 2002). In the treatment of critically ill geriatric patients with coronavirus disease 2019 (COVID-19), frailty is also crucial. It is particularly important in the intensive medical treatment of critically ill geriatric patients to clarify the question whether the patient benefits from each intensive care therapy, e.g., whether a desired therapeutic goal can be achieved, whether intensive care is in the (presumed) patient's will and whether the burdens during treatment are justified by the perspective of life. Furthermore, interdepartmental cooperation plays an important role in the intensive medical care of geriatric patients.

Nutritional assessment and support during continuous renal replacement therapy

Malnutrition is highly prevalent in patients with acute kidney injury, especially in those receiving renal replacement therapy (RRT). For the assessment of nutritional status, a combination of screening tools, anthropometry, and laboratory parameters is recommended rather than a single test. To avoid underfeeding and overfeeding during RRT, energy expenditure should be measured by indirect calorimetry or calculated using predictive equations. Nitrogen balance should be periodically measured to assess the degree of catabolism and to evaluate protein intake. However, there is limited data for nutritional targets specifically for patients on RRT, such as protein intake. The composition of commercial solutions for continuous renal replacement therapy (CRRT) varies. CRRT itself can be associated with both, nutrient losses into the effluent fluid and caloric gain from dextrose, lactate, and citrate. The role of micronutrient supplementation, and potential use of micronutrient enriched CRRT solutions in this setting is unknown, too. This review provides an overview of existing knowledge and uncertainties related to nutritional aspects in patients on CRRT and emphasizes the need for more research in this area.

[Medical nutrition therapy in intensive care medicine : Summary of the updated DGEM guideline]

The course of a critical illness is divided into several phases (early and late acute phase, post-acute phase) in which different metabolic processes take place. Accordingly, the medical nutrition therapy needs to be adapted to the patient's metabolic tolerance in each phase. When indicated, it should be started within 24 h. If oral administration is not possible, an enteral diet should be used. In individuals with contraindications, parenteral nutrition should be started. The target values for the diet of nonobese patients in the late acute phase are 24 kcal and 1.0 g protein (or 1.2 g amino acid) per kilogram bodyweight. The individual metabolic tolerance can be estimated based on the extent of insulin resistance and serum phosphate levels, and the nutrition therapy is adjusted accordingly.

Micronutrients in critically ill patients with severe acute kidney injury - a prospective study

Malnutrition is common in patients with acute kidney injury (AKI) and the risk of mortality is high, especially if renal replacement therapy is needed. Between April 2013 through April 2014, we recruited critically ill adult patients (≥18 years) with severe AKI in two University hospitals in London, UK, and measured serial plasma concentrations of vitamin B1, B6, B12, C and D, folate, selenium, zinc, copper, iron, carnitine and 22 amino acids for six consecutive days. In patients receiving continuous renal replacement therapy (CRRT), the concentrations of the same nutrients in the effluent were also determined. CRRT patients (n = 31) had lower plasma concentrations of citrulline, glutamic acid and carnitine at 24 hrs after enrolment and significantly lower plasma glutamic acid concentrations (74.4 versus 98.2 μmol/L) at day 6 compared to non-CRRT patients (n = 24). All amino acids, trace elements, vitamin C and folate were detectable in effluent fluid. In >30% of CRRT and non-CRRT patients, the plasma nutrient concentrations of zinc, iron, selenium, vitamin D3, vitamin C, trytophan, taurine, histidine and hydroxyproline were below the reference range throughout the 6-day period. In conclusion, altered micronutrient status is common in patients with severe AKI regardless of treatment with CRRT.