ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12616001652460

Ethics application status

Approved

Date submitted

25/11/2016

Date registered

30/11/2016

Date last updated

24/11/2020

Date data sharing statement initially provided

19/07/2019

Date results provided

24/11/2020

Type of registration

Prospectively registered

Titles & IDs

Public title

Protein absorption in critical illness

Scientific title

To determine if critical illness impairs protein absorption compared to health

Secondary ID [1]

NIL

Universal Trial Number (UTN)

Trial acronym

PACE

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Critically ill

Protein absorption

Condition category

Condition code

Diet and Nutrition

Other diet and nutrition disorders

Oral and Gastrointestinal

Normal oral and gastrointestinal development and function

Intervention/exposure

Study type

Observational

Patient registry

False

Target follow-up duration

Target follow-up type

Description of intervention(s) / exposure

Each subject/patient will be studied on one occasion only. Following consent a small intestinal feeding catheter will be inserted using the Cortrak device by a trained research dietitian or intensive care physician. Patients and healthy subjects will undergo an overnight fast (no food or fluid, including water) from midnight until study commencement. The plasma phenylalanine and leucine pool will primed for 2.5 hours with a single intravenous dose of d5-phenylalanine (2.2 ug/kg), L-[3,5-D2]-tyrosine (0.674 ug/kg) and L-[1-13C]-leucine (0.110 ug/kg), after which a intraduodenal infusion for 1 hour of L-[1-13C]phenylalanine-labelled and L-[1-13C]-leucine casein milk protein will be commenced (25 g, 100 kcal, 1.7 kcal/min). Following this a continuous IV infusion of 5 hours of the tracers d5-phenylalanine (0.055 umol/kg/min), L-[3,5-D2]-tyrosine (0.017 umol/kg/min) and L-[1-13C]-leucine (0.110 umol/kg/min) will be administered. At study completion, healthy subjects will be provided with a buffet meal, and enteral feeds will be recommenced in ICU patients.

Protein infusions will be prepared by the hospital pharmacy department to ensure dosing accuracy and safety precautions. Administration of infusions will be by trained intensive care research practitioners.

Intervention code [1]

Not applicable

Comparator / control treatment

The study will recruit 15 ICU patients and 10 healthy control volunteers. The volunteers will receive identical treatment to those with critical illness

Control group

Active

Outcomes

Primary outcome [1]

Rate and extent of labelled phenylalanine absorption. This is a composite primary outcome assessed by the rate of appearance and disappearance of phenylalanine from the ingested protein compared with the body stores (i.e. exogenous and endogenous phenylalanine rate of appearance). This is assessed through analysis of tracer levels in the blood samples.

Timepoint [1]

Blood samples taken prior to IV priming dose (-180 min, -60 min and -30 min). Then at time point 0, 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360.

Primary outcome [2]

Rate and extent of labelled leucine absorption. This is a composite primary outcome assessed by the rate of appearance and disappearance of leucine from the ingested protein compared with the body stores (i.e. exogenous and endogenous leucine rate of appearance). This is assessed through analysis of tracer levels in the blood samples.

Timepoint [2]

Blood samples taken prior to IV priming dose (-180 min, -60 min and -30 min). Then at time point 0, 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360.

Secondary outcome [1]

Amino acid concentrations

Timepoint [1]

Prior to IV priming dose (-180 min, -60 min and -30 min). Then at time point 0, 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360. Plasma amino acids will be determined by stable isotope dilution tandem mass spectrometry.

Secondary outcome [2]

Fractional synthetic rate (FSR) of mixed muscle protein

Timepoint [2]

Prior to IV priming dose and at the commencement of the 6 hour continuous IV infusion. Measured via muscle biopsy. Muscle biopsies taken at 0 min and 360 min. Local anaesthetic will be injected and using a Bergstrom needle a small muscle biopsy (~55mg) will be collected from the middle region of the vastus lateralis muscle at 0 and 360min.

Secondary outcome [3]

Glucose concentrations. Blood glucose will be determined immediately by the glucose oxidase method, with accuracy confirmed by the hexokinase technique at predefined time points.

Timepoint [3]