Does undernutrition contribute to diaphragm weakness in patients with severe COPD?
OBJECTIVE
The assumption that undernourishment contributes to diaphragm weakness in chronic obstructive pulmonary disease (COPD) remains unproven.


METHODS
We, therefore, studied diaphragm strength, measured as transdiaphragmatic pressure during a maximal voluntary sniff (Sn P(di)) and cervical magnetic stimulation (Tw P(di)), in two groups of 10 patients with severe COPD. The groups had equally severe COPD as judged by FEV(1) and thoracic gas volume (V(tg)). The malnourished group had a mean body mass index (BMI) of 17.3 kg/m(2) compared with 27 kg/m(2) for the normally nourished group (mean difference -9.7 kg/m(2); 95% confidence intervals -6.8 to -12.6 kg/m(2),P <0.0001).


RESULTS
There was no significant difference between Tw P(di) (mean difference 2.1 cm H(2)O; 95% CI-3 to + 7.4 cm H(2)O, P=0.39) or Sn P(di) (mean difference -2.4 cm H(2)O; 95% CI-21 cm H(2)O to +16 cm H(2)O,P =0.8).


CONCLUSIONS
We conclude that undernourishment of the severity studied does not contribute to diaphragm weakness in severe COPD.
Department of Respiratory Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Carl-Hugo
CH
Hamnegard
Björn
B
Bake
John
J
Moxham
Michael I
MI
Polkey
D000328:Adult; D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D003964:Diaphragm / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009748:Nutrition Disorders / Q000503:physiopathology*; D011312:Pressure; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012129:Respiratory Function Tests; D013147:Spirometry