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Short-term amino acid infusion improves protein balance in critically ill patients.

Liebau F, Sundström M, van Loon LJ, Wernerman J, Rooyackers O - Crit Care (2015)

Bottom Line: Parenteral amino acid supplementation significantly improved protein balance on both occasions, from a median of -4 to +7 μmol phenylalanine/kg/hr (P =0.001) on the first study day and from a median of 0 to +12 μmol phenylalanine/kg/hr (P =0.018) on the second study day.Amino acid oxidation rates, estimated by phenylalanine hydroxylation, did not increase during the 3-hour amino acid infusion.A positive correlation (r =0.80; P <0.0001) was observed between total amino acids and/or protein given to the patient and whole-body protein balance.

View Article: PubMed Central - PubMed

Affiliation: Division of Anesthesia and Intensive Care, Department of Clinical Sciences, Intervention and Technology (CLINTEC), Karolinska Institutet and Karolinska University Hospital, Hälsovägen 13, Huddinge, 14186, Sweden. Felix.liebau@karolinska.se.

ABSTRACT

Introduction: Evidence behind the recommendations for protein feeding during critical illness is weak. Mechanistic studies are needed to elucidate the effects of amino acid and/or protein supplementation on protein metabolism before larger clinical trials with higher levels of protein feeding are initiated.

Methods: We studied the effects of parenteral amino acid supplementation (equivalent to 1 g/kg/day) over the course of 3 hours on whole-body protein turnover in critically ill patients in the intensive care unit (ICU) during the first week after admission. Patients were studied at baseline during ongoing nutrition and during extra amino acid supplementation. If the patient was still in the ICU 2 to 4 days later, these measurements were repeated. Protein kinetics were measured using continuous stable isotope-labeled phenylalanine and tyrosine infusions.

Results: Thirteen patients were studied on the first study occasion only, and seven were studied twice. Parenteral amino acid supplementation significantly improved protein balance on both occasions, from a median of -4 to +7 μmol phenylalanine/kg/hr (P =0.001) on the first study day and from a median of 0 to +12 μmol phenylalanine/kg/hr (P =0.018) on the second study day. The more positive protein balance was attributed to an increased protein synthesis rate, which reached statistical significance during the first measurement (from 58 to 65 μmol phenylalanine/kg/hr; n =13; P =0.007), but not during the second measurement (from 58 to 69 μmol phenylalanine/kg/hr; n =7; P =0.09). Amino acid oxidation rates, estimated by phenylalanine hydroxylation, did not increase during the 3-hour amino acid infusion. A positive correlation (r =0.80; P <0.0001) was observed between total amino acids and/or protein given to the patient and whole-body protein balance.

Conclusion: Extra parenteral amino acids infused over a 3-hour period improved whole-body protein balance and did not increase amino acid oxidation rates in critically ill patients during the early phase (first week) of critical illness.

No MeSH data available.


Related in: MedlinePlus

Statistical correlations between total amino acid and/or protein feeding and whole protein balance (A) and protein oxidation rate (B) in 13 critically ill patients during baseline and parenteral amino acid supplementation (AA) on 2 study days. On the first study day, 13 patients were studied, and on the second study day, 7 of these patients were still being treated in the intensive care unit and were studied again. All measurements performed for all patients are included. The protein balance is presented in grams of protein per kilogram of body weight per day. This was calculated assuming that the phenylalanine content of the human whole-body protein pool is 4% [12]. A positive correlation with r =0.80 (P <0.0001) was observed between the amino acid and/or protein feeding and whole-body protein balance. No correlation with phenylalanine oxidation was observed (r =0.02; P =0.88).
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Fig6: Statistical correlations between total amino acid and/or protein feeding and whole protein balance (A) and protein oxidation rate (B) in 13 critically ill patients during baseline and parenteral amino acid supplementation (AA) on 2 study days. On the first study day, 13 patients were studied, and on the second study day, 7 of these patients were still being treated in the intensive care unit and were studied again. All measurements performed for all patients are included. The protein balance is presented in grams of protein per kilogram of body weight per day. This was calculated assuming that the phenylalanine content of the human whole-body protein pool is 4% [12]. A positive correlation with r =0.80 (P <0.0001) was observed between the amino acid and/or protein feeding and whole-body protein balance. No correlation with phenylalanine oxidation was observed (r =0.02; P =0.88).

Mentions: When the actual amino acid and/or protein intake for all the patients at all time points was compared with the protein balance, a positive correlation was observed (r =0.80; P <0.0001) (Figure 6). No correlation with protein oxidation rates was observed (r =0.02; P =0.88) (Figure 6). For these comparisons, the protein balance and protein oxidation rates are presented in grams of protein per kilogram of body weight per day. The calculations were performed assuming that the phenylalanine content of the human whole-body protein pool was 4% [12].Figure 6


Short-term amino acid infusion improves protein balance in critically ill patients.

Liebau F, Sundström M, van Loon LJ, Wernerman J, Rooyackers O - Crit Care (2015)

Statistical correlations between total amino acid and/or protein feeding and whole protein balance (A) and protein oxidation rate (B) in 13 critically ill patients during baseline and parenteral amino acid supplementation (AA) on 2 study days. On the first study day, 13 patients were studied, and on the second study day, 7 of these patients were still being treated in the intensive care unit and were studied again. All measurements performed for all patients are included. The protein balance is presented in grams of protein per kilogram of body weight per day. This was calculated assuming that the phenylalanine content of the human whole-body protein pool is 4% [12]. A positive correlation with r =0.80 (P <0.0001) was observed between the amino acid and/or protein feeding and whole-body protein balance. No correlation with phenylalanine oxidation was observed (r =0.02; P =0.88).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4403712&req=5

Fig6: Statistical correlations between total amino acid and/or protein feeding and whole protein balance (A) and protein oxidation rate (B) in 13 critically ill patients during baseline and parenteral amino acid supplementation (AA) on 2 study days. On the first study day, 13 patients were studied, and on the second study day, 7 of these patients were still being treated in the intensive care unit and were studied again. All measurements performed for all patients are included. The protein balance is presented in grams of protein per kilogram of body weight per day. This was calculated assuming that the phenylalanine content of the human whole-body protein pool is 4% [12]. A positive correlation with r =0.80 (P <0.0001) was observed between the amino acid and/or protein feeding and whole-body protein balance. No correlation with phenylalanine oxidation was observed (r =0.02; P =0.88).
Mentions: When the actual amino acid and/or protein intake for all the patients at all time points was compared with the protein balance, a positive correlation was observed (r =0.80; P <0.0001) (Figure 6). No correlation with protein oxidation rates was observed (r =0.02; P =0.88) (Figure 6). For these comparisons, the protein balance and protein oxidation rates are presented in grams of protein per kilogram of body weight per day. The calculations were performed assuming that the phenylalanine content of the human whole-body protein pool was 4% [12].Figure 6

Bottom Line: Parenteral amino acid supplementation significantly improved protein balance on both occasions, from a median of -4 to +7 μmol phenylalanine/kg/hr (P =0.001) on the first study day and from a median of 0 to +12 μmol phenylalanine/kg/hr (P =0.018) on the second study day.Amino acid oxidation rates, estimated by phenylalanine hydroxylation, did not increase during the 3-hour amino acid infusion.A positive correlation (r =0.80; P <0.0001) was observed between total amino acids and/or protein given to the patient and whole-body protein balance.

View Article: PubMed Central - PubMed

Affiliation: Division of Anesthesia and Intensive Care, Department of Clinical Sciences, Intervention and Technology (CLINTEC), Karolinska Institutet and Karolinska University Hospital, Hälsovägen 13, Huddinge, 14186, Sweden. Felix.liebau@karolinska.se.

ABSTRACT

Introduction: Evidence behind the recommendations for protein feeding during critical illness is weak. Mechanistic studies are needed to elucidate the effects of amino acid and/or protein supplementation on protein metabolism before larger clinical trials with higher levels of protein feeding are initiated.

Methods: We studied the effects of parenteral amino acid supplementation (equivalent to 1 g/kg/day) over the course of 3 hours on whole-body protein turnover in critically ill patients in the intensive care unit (ICU) during the first week after admission. Patients were studied at baseline during ongoing nutrition and during extra amino acid supplementation. If the patient was still in the ICU 2 to 4 days later, these measurements were repeated. Protein kinetics were measured using continuous stable isotope-labeled phenylalanine and tyrosine infusions.

Results: Thirteen patients were studied on the first study occasion only, and seven were studied twice. Parenteral amino acid supplementation significantly improved protein balance on both occasions, from a median of -4 to +7 μmol phenylalanine/kg/hr (P =0.001) on the first study day and from a median of 0 to +12 μmol phenylalanine/kg/hr (P =0.018) on the second study day. The more positive protein balance was attributed to an increased protein synthesis rate, which reached statistical significance during the first measurement (from 58 to 65 μmol phenylalanine/kg/hr; n =13; P =0.007), but not during the second measurement (from 58 to 69 μmol phenylalanine/kg/hr; n =7; P =0.09). Amino acid oxidation rates, estimated by phenylalanine hydroxylation, did not increase during the 3-hour amino acid infusion. A positive correlation (r =0.80; P <0.0001) was observed between total amino acids and/or protein given to the patient and whole-body protein balance.

Conclusion: Extra parenteral amino acids infused over a 3-hour period improved whole-body protein balance and did not increase amino acid oxidation rates in critically ill patients during the early phase (first week) of critical illness.

No MeSH data available.


Related in: MedlinePlus