Assessment of whole body protein metabolism in critically ill children: can we use the ((15)N)glycine single oral dose method?

摘要

Background & aims: Most stable-isotope methods to evaluate whole body protein metabolism in patients are invasive and difficult to use in children. In this study protein metabolism was evaluated with the non-invasive [(15)N]glycine single oral dose method in critically ill children and the value of the method is discussed. Methods: [(15)N]glycine (100mg) was given orally to children (mean age 5.5years; range 0.6-15.5years) with meningococcal septic shock (MSS, [Formula: see text] ), pneumonia [Formula: see text], and to healthy, fed and post-absorptive children [Formula: see text]. Urine was collected during 9h, total amount of NH(3), labelled NH(3) and nitrogen were measured, and protein turnover, synthesis and breakdown were calculated using urinary NH(3) as end-product. Results: Mean protein turnover in children with MSS, pneumonia and fed and post-absorptive healthy children was 0.63+/-0.13, 0.38+/-0.10, 0.28+/-0.03 and 0.28+/-0.02g N/kg/9h, respectively. Mean protein synthesis was 0.55+/-0.12, 0.29+/-0.09, 0.18+/-0.02, 0.20+/-0.02g N/kg/9h, respectively. Mean protein breakdown was 0.56+/-0.14, 0.28+/-0.12, 0.08+/-0.03, 0.28+/-0.02g N/kg/9h, respectively. Protein turnover, synthesis and breakdown were significantly increased in MSS patients compared to fed healthy children [Formula: see text] and post-absorptive children [Formula: see text]. Protein turnover, protein synthesis, protein breakdown were significantly correlated with disease severity and body temperature [Formula: see text]. Conclusion: Results of whole body protein metabolism measured with the [(15)N]glycine single oral dose method in children with MSS and in healthy children were in line with expectations based on results obtained in earlier reports and with different methods.