Effect of elevated triglycerides on the diffusing capacity of man.

In view of the decreased diffusing capacity recently reported in man during lipid infusion, studies have now been made on the effects of hyperlipidemia on the diffusing capacity for carbon monoxide (DLco). In normal volunteers and patients with hyperlipidemias, DLco and plasma triglyceride concentrations were determined during fat tolerance tests and while the patients were on diets that increased or decreased triglyceride concentrations. During the fat tolerance tests, the largest triglyceride and DLco changes were from 346 mg per 100 ml with a DLco of 18.8 ml per min per mm Hg to 1,545 mg per 100 ml with a DLco of 23.4 ml per min per mm Hg. While patients were on speical diets, the largest triglyceride and DLco changes were from 5,102 mg per 100 ml and 29.0 ml per min per mm Hg to 492 mg per 100 ml and 26.4 ml per min per mm Hg, respectively. Sta tistical tests showed no significant change of DLco with change in triglyceride concentration. The data suggest that there is normally no association between change in triglyceride concentration and change in DLco, and that triglycerides normally transported in plasma, even when present in extreme amounts as chylomicrons or very-low-density lipoprotein, do not affect the DLco.