None listed
Conditions
Brief summary
We are using a method to measure the contribution from enteral feeding to whole-body protein turnover in critically ill patients, using stable-isotope-labeled phenylalanine tracers. One underlying assumption is that, during continuous feeding, nutrients and tracers reach a steady state of uptake and distribution. Unpublished data from a pilot study in n=10 ICU patients show that this assumption may not always be tenable. We therefore plan to investigate in healthy subjects whether a continuous infusion of 13C-phenylalanine results in a steady state of 13C-phenylalanine enrichment in plasma. N=10 healthy subjects are given a continuous infusion of nutrition formula for a a total of 24 hrs. After an equilibration phase of 12 hrs a 13C-phenylalanine tracer is added to the infusion for the remaining 12 hrs. Blood samples are taken every 30 minutes during tracer infusion and plasma enrichment of 13C-phenylalanine is measured by gas chromatogrphy-mass spectrometry. The time course of 13C-Phe enrichment is analysed to detect deviation from steady-state conditions.
Interventions
During development of a methodology for studying enteral nutrition in ICU patients (see trial ID ACTRN12614000476639) we studied a pilot group of ICU patients to determine uptake kinetics of dietary stable-isotope-labeled phenylalanine during continuous enteral feeding. Relevant findings were a high inter-individual variability of 13C-phenylalanine plasma enrichment and uncertain steady state condition after 6 hrs of feeding (unpublished data).
The objective of the current trial is to determi
During development of a methodology for studying enteral nutrition in ICU patients (see trial ID ACTRN12614000476639) we studied a pilot group of ICU patients to determine uptake kinetics of dietary stable-isotope-labeled phenylalanine during continuous enteral feeding. Relevant findings were a high inter-individual variability of 13C-phenylalanine plasma enrichment and uncertain steady state condition after 6 hrs of feeding (unpublished data). The objective of the current trial is to determine whether a steady state of 13C-phenylalanine isotopic enrichment in plasma is reached after 6, 8, 10 or 12 hrs of 13-C-phenylalanine administration simultaneous with continuous enteral feeding. Subjects are admitted on the evening before the tracer study and stay under observation throughout the experiment. A nasogastric feeding tube is placed and a continuous infusion of a commercially available complete nutrition formula, Fresubin (registered trademark) Original, is started at a dose corresponding to 100% of estimated energy requirement. After a 12 hr equilibration period, a cannula for blood sampling is placed in an artery. Ongoing continuous nutrition is supplemented with a continuous infusion of 13C-labeled phenylalanine for another 12 hrs. The 13C-phenylalanine dose is calculated to yield an isotopic enrichment of 30.8% of the total dietary phenylalanine content, i.e. feeding formula + tracer Blood samples are taken every 30 minutes for the remaining 12 hrs. Isotopic enrichment of 13C-phenylalanine in plasma is measured by gas chromatography-mass spectrometry.
Sponsors
Prof Olav Rooyackers
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
Healthy adults
Exclusion criteria
Nutritional/metabolic disease, serious organ dysfunction
Outcome results
None listed