Méthodes d'exploration du métabolisme protéique

Biochemical assessment of nutritional status in patients with chronic obstructive pulmonary disease and acute respiratory failure on admission to an intensive care unit

Although chronic obstructive pulmonary disease (COPD) is associated with weight loss and malnutrition, there is a paucity of relevant data on COPD patients with acute respiratory failure (ARF). We studied 30 consecutive patients on the day of admission to our intensive care unit for ARF. In addition to a clinical work-up, the following biochemical parameters were determined: markers of nutritional status (albumin - ALB, transferrin - TRF, transthyretin - TTR, retinol binding protein - RBP, fibronectin), inflammation (C-reactive protein - CRP, alpha(1) glycoprotein acid - alpha(1)GPA) and catabolism (plasma phenylalanine - PHE, urinary 3-methylhistidine - 3-MH). Values were expressed as mean +/- SD and compared to those of 10 healthy subjects matched for age. COPD-ARF patients had a poor protein status (ALB = 30 +/- 5 vs 42 +/- 3 g.l(-1); TTR = 118 +/- 75 vs 251 +/- 43 mg.l(-1); RBP = 23 +/- 12 vs 46 +/- 8 mg.l(-1); p < 0.001), were hypercatabolic (3-MH Cr = 31 +/- 12 vs 22 +/- 7 mumol.mmol Cr (-1); PHE = 62 +/- 27 vs 46 +/- 10 mumol.l(-1); p < 0.001) and inflamed (CRP = 68 +/- 50 vs 12 +/- 5 mg.l(-1); alpha(1)GPA = 1.2 +/- 0.4 vs 0.5 +/- 0.1 g.l(-1); p < 0.001). Severity of the disease correlated with short half-life proteins and protein catabolism markers but not with inflammation markers. Considering ALB, TTR, RBP, the 3- MH Cr ratio and PHE values, the 30 COPD patients fell into 3 groups: chronic malnutrition (n = 7), acute malnutrition (n = 2), and acute + chronic malnutrition (n = 18). 3 patients had normal nutritional status. We conclude that an assessment of nutritional status at admission to intensive care units could contribute towards a rapid formulation of specific nutritional therapy.