None listed
Conditions
Brief summary
Nutrition aimed at optimizing the provision of energy and protein during critical illness has been proposed as a potential therapy to improve both long- and short-term outcomes. So far, existing evidence is inconclusive. As ICU patients represent a very heterogenous population, in varying temporal phases of disease and recovery, it can be expected that a “one size fits all” approach will fail to improve outcomes. It has been hypothesized that in certain patients nutrition will not be able to suppress the endogenous energy and amino acid supply and basically the patent is overfed when eucaloric nutrition is supplied. Given the lack of improvements in patient-centered outcomes that have resulted from trials of ICU nutrition, a better physiological understanding of macronutrient turnover is an essential step towards designing novel therapeutic approaches. We plan to investigate whole-body protein, glucose and lipid turnover in ICU patients in relation to metabolic rate. This initial study is designed as a feasibility and pilot trial of a multi-substrate stable isotope tracer method for critically ill patients fed by the enteral route.
Interventions
At time 0 an enteral infusion of [U-13C6]-glucose (at a rate calculated to obtain a 30% enrichment of enteral glucose content), [1-13C]-phenylalanine (at a rate calculated to obtain a 30% enrichment of enteral phenylalanine content) and 3-O-methylglucose (infusion 20 mg/kg/h) is added to the ongoing enteral nutrition to measure absorption and enteral utilization of substrates. Simultaneously, a measurement of energy expenditure by indirect calorimetry is started to be continued during the entire
At time 0 an enteral infusion of [U-13C6]-glucose (at a rate calculated to obtain a 30% enrichment of enteral glucose content), [1-13C]-phenylalanine (at a rate calculated to obtain a 30% enrichment of enteral phenylalanine content) and 3-O-methylglucose (infusion 20 mg/kg/h) is added to the ongoing enteral nutrition to measure absorption and enteral utilization of substrates. Simultaneously, a measurement of energy expenditure by indirect calorimetry is started to be continued during the entire protocol. At t 120 minutes, primed intravenous infusions of [ring-2H5]-phenylalanine (bolus 0.5 mg/kg, infusion 0.5 mg/kg/h), [ring-2H4]-Tyrosine (bolus 0.15 mg/kg), [2H2]-Tyrosine (bolus 0.3 mg/kg, infusion 0.3 mg/kg/h), 2H2-glucose (bolus 3 mg/kg, infusion 2.4 mg/kg/h) and 2H2-glycerol (bolus 0.15 mg/kg, infusion 0.33 mg/kg/h) are initiated to measure endogenous substrate turnover. After 150 minutes, plasma samples will be draw from the arterial line four times at 10 minute intervals to determine steady-state concentration of all the tracers. Whole-body protein turnover from phenylalanine kinetics, glucose turnover, intestinal glucose absorption, and lipolysis from glycerol rate of appearance are calculated from these values. The final sample is also analyzed for glucose, triglyceride, free fatty acids, glycerol, amino acid and urea concentrations. All aspects of patient care are governed by the attending intensivist, but the rates of enteral and parenteral nutrition are to remain constant 3 hours prior to and during the study period.
Sponsors
Prof Olav Rooyackers
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Diagnosis
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
All patients in the ICU of Karolinska University Hospital Huddinge >/=18 years of age and receiving invasive mechanical ventilation will be screened for participation.
Exclusion criteria
Exclusion criteria are i. factors present that limit the precision of indirect calorimetry (FiO2 >0.6, significant gas leaks) ii. no arterial line available for blood samples and iii. lack of informed consent by the patient or family member.
Outcome results
None listed