Alteration of pulmonary function by filtration of intravenous nutrient mixture

In view of contradicting results concerning alteration in lung function during hyperalimentation and the administration of intravenous lipid emulsion, a study was planned to determine possible changes in pulmonary blood perfusion during administration of total nutrient admixture (TNA) and the effect of filtration. Sixteen patients (8 men, 8 women; mean age 65.6 yr) with no previous lung disease received TNA at the rate of 4-5 g lipid/h as preoperative treatment for 5-9 days (mean 6.7 days). The 5-microns filter was randomly used in eight patients. The lung blood perfusion parameters measured repeatedly during this period included blood gases, percentage of the predicted value of vital capacity (VC), and pulmonary diffusing capacity for carbon monoxide (DLCO), as well as the value of the dead space volume and the tidal volume ratio (VD/VT) and the calculated shunt (QS/QT). TNA infusion appears to cause only a slight decrease in PaO2 and DLCO and a similar increase in VC and QS/QT, whereas VD/VT decreased significantly. The latter effect was abolished by filtration of TNA. There were no significant differences between the two groups. We therefore conclude that short-term preoperative administration of TNA at the rate of 4-5 g lipid/h in patients without preexisting lung disease does not jeopardize lung functions. Filtration of the TNA is, however, recommended to avoid the potential hazardous effects of long-term treatment of TNA on lung function.