Effect of nutrition on inspiratory muscles and FEV1 in patients with emphysema

ABSTRACT

Malnutrition is an effective factor in respiratory muscles dysfunction in patients with chronic obstructive pulmonary disease [COPD]. The present study was performed to evaluate the effect of improved nutrition on inspiratory muscles in patients with advanced COPD. Total of 33 patients suffering from emphysema were studied during a 3-year period using a quasi experimental [before- after study] method. All of them had forced expiratory volume in one second [FEV1] < 30% and had received Atrovent, Salmeterol, Becotide [in maximum doses] and oxygen therapy for at least one year. Initially, FEV1 and airways resistance of patients were measured using body plethysmography .After a 35 Kcal/kg diet including 20-40% fat, 40% protein and 20% carbohydrates, these patients were followed by monthly scheduled visits. Spirometric parameters were measured again 3 and 6 months later and the results were analyzed using Freedman method. Pulmonary function tests of the under study patients at the beginning, 3 and 6 months later were as follows respectively; FEV1; 18.3%, 19.57%, 20.95%, airways resistance; 65.3%, 63.7%, 64.9% and maximal inspiratory pressure [MIP]; 2.59, 3.062 and 3.29 cmH2O. There was a significant difference in FEV1 and MIP of patients in 3 and 6 months period [P < 0.05]. Meanwhile, there was no significant difference in airways resistance of patients [P=0.08]. Improved nutrition results in increased MIP and FEV1 without changing in other indices [i.e. constant airways resistance indicates constant treatment status of the patient]. Thus, an appropriate nutritional diet including sufficient calorie with small frequent meals at least for six months can increase FEV1 by reinforcing inspiratory muscles resulting in improved pulmonary function