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The relationship between nutritional and inflammatory changes during critical illness

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Title: The relationship between nutritional and inflammatory changes during critical illness
Authors: Wandrag, Liesl
Item Type: Thesis or dissertation
Abstract: Muscle mass loss in the critically ill is substantial, between 1-2% per day. Muscle wasting and weakness delays patient recovery and rehabilitation. Understanding the relationship between nutritional and inflammatory markers will help to identify a notional “nutritional tipping point”, where anabolism exceeds catabolism, which will allow us to target nutritional therapy more successfully. Muscle depth on ultrasound, inflammatory markers, cytokines, urinary markers of protein breakdown and nitrogen balance data were collected in 78 critically ill patients. Patients lost a significant amount of muscle depth during their intensive care unit (ICU) stay. Results indicate that a nutritional tipping point is unlikely to exist during an ICU admission. Data suggests that nitrogen balance remains negative over 20 days, indicating that whilst patients should continue to receive standard nutrition support during their ICU stay, any additional nutritional strategy should be targeted outside of the ICU environment. Multilevel modelling indicated that each additional day spent on ICU was significantly associated with decreased C-reactive protein, muscle depth and interleukin-10 levels. With every year increase in a patient’s age muscle depth and 3-methylhistidine levels were significantly reduced and interleukin-10 levels were significantly increased. Sample size estimates from current data provide some guidance for future studies, however estimates should be viewed with caution. The feasibility of providing a leucine-enriched essential amino acid supplement to trauma ICU patients was furthermore assessed. Inflammatory and nutritional makers were assessed along with protein turnover. Although it was feasible to use the supplement in the trauma population, studying this patient group was more complicated than anticipated. Whole body protein turnover was enhanced in trauma patients with breakdown far exceeding synthesis. These studies suggest that although it may be feasible to provide amino acid supplementation to critically ill patients, this type of intervention should be targeted outside of the ICU environment.
Content Version: Open Access
Issue Date: Jul-2013
Date Awarded: Nov-2013
URI: http://hdl.handle.net/10044/1/17854
DOI: https://doi.org/10.25560/17854
Supervisor: Hickson, Mary
Frost, Gary
Brett, Stephen
Sponsor/Funder: National Institute for Health Research
Department: Department of Medicine
Publisher: Imperial College London
Qualification Level: Doctoral
Qualification Name: Doctor of Philosophy (PhD)
Appears in Collections:Medicine PhD theses

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