Pulmonary fat embolism after intralipid therapy--a post-mortem artefact? Light and electron microscopic investigations in low-birth-weight infants.

The lungs of 22 low-birth-weight infants were investigated, mean gestational age 29 weeks (range 25 to 35). Thirteen of the 22 newborns had been treated with Intralipid--10% for an average of 20 days (range 3 hours to 75 days). The mean maximum rate of fat infusion was 2.0 g/kg/day (range 0.5 to 3.6). Nine of the 22 newborns had been fed formula and given supplemental amounts of amino acids and glucose intravenously, but no Intralipid. The lungs were fixated in situ immediately after death with glutaraldehyde. Neither in the Intralipid group nor in the non-Intralipid controls was intravascular fat accumulation identified, either by light microscopy or by electron microscopy. It is speculated that an agglomeration of lipoprotein globules to larger stainable lipid droplets cannot take place in the short interval between the actual time of death and the time of fixation of the lung tissue. Thus, fat globules found in lungs of premature infants and described as fat embolism might have been post mortem artefacts.