Skinfold anthropometry--the accurate method for fat free mass measurement in COPD.

PURPOSE: Fat free mass index (FFMI) is an independent predictor of metabolic and functional consequences in COPD. For its measurement dual energy X-ray absorptiometry (DEXA), skin-fold anthropometry (SFA), bioelectrical impedance analysis (BIA) and bioimpedance spectroscopy (BIS) are used in clinical practice. The aim of our pilot study was to analyse precisely and critically which method is most accurate and available for common use in clinical practice for measurement of FFM by assessment against relevant DEXA in patients with COPD. METHODS: This was an observational cross-sectional study of consecutive COPD subjects. FFM by methods of SFA, two versions of BIA, and BIS was compared with that from clinically relevant DEXA in 41 outpatients (mean age 66.5 ± 7.7 yrs) with stable COPD, 34 men and 7 women, with mean BMI 28.2 ± 6.1 kg.m(-2). RESULTS: All methods underestimate FFM in comparison with DEXA. In the general evaluation non-significant differences with the smallest mean bias were demonstrated for SFA (1.2 kg) and BIA (3.8 kg), but there was a difference of more than 9 kg using BIS and BIA COPD methods (p < 0.0001). The best agreement between DEXA and SFA was demonstrated via Lin's concordance coefficient and Bland-Altman test. CONCLUSIONS: SFA has been demonstrated as an accurate, available and cheap method for determination of FFM and FM with application of the Durnin Womersley equation for body density and with the Siri equation for FM in patients with COPD. SFA can be easily applied in routine clinical practice.

The importance and dosage of amino acids in nutritional support of various pathological conditions in ICU patients.

BACKGROUND: Normal adults require twenty L-amino acids (AA) for protein synthesis. Functional AA regulate key metabolic pathways that are necessary for maintenance, growth, reproduction and immunity. Dietary supplementation with one or a mixture of these AA may be beneficial for ameliorating health problems at various stages of the life cycle and for optimizing of the efficiency of metabolic transformations. During disease, other amino acids also become essential. The principal goal of protein/amino acid administration in various pathological conditions in intensive care unit (ICU) patients is to provide the precursors of protein synthesis in tissues with high turnover and to protect skeletal muscle mass and function. Amino acid requirements in parenteral nutrition (PN) are higher when the patient is stressed/traumatized/infected than in the unstressed state. In severely ill ICU patients a higher provision of protein and amino acids has been associated with a lower mortality. METHODS AND RESULTS: An overview of the effects and dosage of amino acids in nutritional support of various pathological conditions in ICU patients is presented. CONCLUSION: It was demonstrated that 2.0-2.5 g protein substrate/kg normal body weight/day is safe and could be optimal for the most critically ill adults to decrease the risk of morbidity and mortality in some pathological conditions.