Chest
Volume 93, Issue 5, May 1988, Pages 977-983
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Clinical Investigations
Dietary Supplementation and Respiratory Muscle Performance in Patients with COPD

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We studied the effects of oral nutritional supplementation on respiratory muscle (RM) performance in 25 ambulatory patients with severe chronic obstructive pulmonary disease (COPD). There was a relationship between body weight and anthropometric parameters of nutritional status (triceps skinfold thickness [r=0.67; p<0.005], midarm muscle circumference (r=0.53; p<0.005), but body weight did not correlate with daily caloric intake, serum albumin, transferrin, or blood lymphocyte count. None of these measurements of nutritional status correlated with any measure of RM strength or endurance. In a randomized observer-blinded crossover trial, patients were allocated to one of two groups. In the first eight weeks of the study, group A received nutritional supplementation, and patients in group B were control subjects. In the second eight weeks, patients in group A were control subjects, and group B received supplement. Mean daily caloric intake and body weight increased in both groups while receiving supplement (both p<0.05). Calories provided by the supplement were frequently substituted for normal dietary calories. Any increases in RM performance in the group receiving supplement were matched by increases (due to learning) in controls. We conclude that oral dietary supplements have no important effects on RM performance in ambulatory patients with COPD.

Section snippets

Selection of Patients

Twenty-five ambulatory patients with severe COPD (forced expired volume in one second [FEV1] less than 50 percent of predicted) gave informed consent for study. All patients were in a stable phase of their disease. They did not have an acute exacerbation of their disease in the three months prior to this study or during the study. Patients with a known eating disorder, an infectious process, pulmonary disease other than COPD, lactose intolerance, other medical illness (diabetes mellitus,

Baseline Measurements in All 25 Patients

Mean (± SD) baseline data for the 25 patients are shown in Table 1. There was wide variability in weight as percentage of IBW (range, 61 to 108 percent), with 13 of 25 patients malnourished (<85 percent of IBW). Control daily caloric intake also varied widely between patients (range, 1,100 to 3,112 kcal/day). In all patients, serum albumin, serum transferrin, and blood lymphocyte counts were in the normal range. There was a correlation between body weight and both TSF (r=0.67; p<0.005) and MAMC

DISCUSSION

The major findings in this study of 25 ambulatory patients with severe COPD were that: (1) there was a small increase in body weight with eight weeks of dietary supplementation; (2) there was an inability of some patients to increase daily caloric intake; (3) there was a tendency to lose weight within one month of discontinuation of dietary supplements; (4) there was habituation to tests measuring PImax and PTP with stability of PEmax and SIP, and (5) there was no important change in RM

ACKNOWLEDGMENTS

We thank Ms. S. Gordon, nurse coordinator, and Mrs. P Bouchard, dietician, for their contributions.

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    Supported by a grant from Mead Johnson.

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