The acute effects of intralipid on lung function

To determine whether the oleic acid contained in intralipid injures the lung, we measured fractional lobar perfusion, lobar shunt, and edema (wet to dry weight ratios, W/D) in 20 open-chested mechanically ventilated dogs. Five dogs received oleic acid 0.03 g/kg injected into a lower lobe pulmonary artery. Ten received 0.5 cc/kg of 20% intralipid which contains the equivalent amount of oleic acid, five of these animals being heparinized. The same dose of oleic acid was also suspended in intralipid and administered to five heparinized dogs. Shunt and edema were measured in another five heparinized closed-chested dogs receiving 2 g/kg of intralipid IV over 1 hr. Half hour after intralipid or oleic acid, shunts did not change. At 2 1/2 hr, oleic acid alone increased lobar shunt from 4.6 +/- 1.4 to 40.8 +/- 24.9% while intralipid shunt remained unchanged with and without heparin. Lobar perfusion fell significantly with oleic acid from 29.3 +/- 2.3 to 17.8 +/- 5.6% while showing no change in the lobes not receiving oleic acid. When oleic acid was suspended in intralipid, shunt and perfusion changed less than with oleic acid alone. Mean W/D of the oleic acid lower lobe exceeded (P less than 0.05) W/D of the other lobes, including the lobe receiving oleic acid suspended in intralipid which had a W/D greater than the lobes receiving intralipid only. We conclude that intralipid has no acute deleterious effects on pulmonary gas exchange, blood flow distribution, or edema. Our data suggest that intralipid may protect the lung from the deleterious effects of fatty acids.