Diaphragmatic function in severely malnourished patients with anorexia nervosa. Effects of renutrition.

Abstract

The effects of malnutrition and refeeding on nutritional indices, pulmonary function, and diaphragmatic contractile properties were studied in severely malnourished patients with anorexia nervosa. Fifteen patients were evaluated upon hospital admission (Day 0) and on Days 7, 30, and 45 after starting feeding. Spirometry, lung volumes, and arterial blood gases were measured at each time interval, as were contractile properties of the diaphragm as assessed by transdiaphragmatic pressure generated during electrical phrenic nerve stimulation (Pdistim) and a maximal sniff maneuver (Pdisniff). Anthropomorphic and biochemical measurements were performed at each time interval. Patients were severely malnourished upon admission; mean body weight was 37.1 +/- 4.7 kg (63% ideal body weight). During nutritional support, body weight increased significantly to 42.9 +/- 4.6 kg on Day 45 (p < 0.01), as did muscle mass: 11.2 +/- 4.1 kg on Day 0, to 16.6 +/- 4.9 kg on Day 45 (p < 0.01). Vital capacity and FEV1 increased significantly by Day 30 (p < 0.05). Lung volumes were unchanged. Mean arterial blood gas values were also within the normal range at Day 0; PaO2, 92.6 +/- 2.4 mm Hg and PacO2, 41.0 +/- 1.5 mm Hg. Four patients, however, had an increased PacO2 (> 42 mm Hg) at Day 0, which returned to normal by Day 30. Diaphragmatic contractility was severely depressed initially; Pdistim, 15.9 +/- 1.4 cm H2O; Pdisniff, 65.4 +/- 5 cm H2O; but it significantly increased with nutritional support by Day 30 to 22.5 +/- 1.9 and 84.6 +/- 4.7 cm H2O, respectively. We conclude that diaphragmatic function is severely impaired in malnuorished patients free of other coexisting

Abnormalities of the Respiratory Function and Control of Ventilation in Patients with Anorexia nervosa

“…In some previous studies performed in patients with this disease, a decrease in FVC, increases in RV and the RV/TLC ratio and a decrease in maximum respiratory pressure have been observed, all in relation with respiratory muscular weakness caused by extreme malnutrition [13, 14, 15]. In this sense, a marked decrease in muscular force of the diaphragm has been described in these patients, with improvement after nutritional replacement [16]. Among the mechanisms responsible for muscular dysfunction presented by patients with malnutrition, alterations in the size, distribution and myofibrillar content of muscular fibers, reduction in the incorporation of amino acids to the muscles and alterations in the protein composition and oxidative enzyme activity are found [9].…”

Nutritional depletion in patients on long-term oxygen therapy and/or home mechanical ventilation

“…The interest of FFM evaluation would have probably been strengthened if this parameter had been available in a higher number of patients. Malnutrition per se was previously reported to impair diaphragm function, as assessed by lung volumes, in severely malnourished patients with anorexia nervosa [23]. The apparently paradoxical inverse relationship between Pa,O 2 in room air and BMI and FFM may be explained by a higher oxygen consumption due to a bigger body cell mass.…”

Refeeding hypophosphatemia: a potentially fatal danger in the intensive care unit

“…Hypopotassemia may lead to muscle paralysis, rhabdomyolysis, muscle necrosis, respiratory failure, and myocardial contraction disorders and hypomagnesemia may cause changes in electrocardiography, tetanus, and convulsions (19). Altered diaphragmatic contractility, respiratory muscle fatigue, and respiratory failure were detected in the patients with malnutrition and hypophosphatemia, which resulted in longer durations of mechanical ventilation (20)(21)(22)(23). Reversible myocardial depression, reduction in oxygen binding capacity of the red blood cells, leukocyte dysfunction, and neuromuscular complications were reported (23)(24)(25)(26).…”