Splanchnic and peripheral tissue perfusion in experimental fat embolism

Objective : To investigate the acute effects of experimental fat embolism on splanchnic and peripheral perfusion and oxygenation in pigs. Design : Randomized, controlled trial. Setting : Animal laboratory. Subjects : Eighteen domestic pigs, weighing 25 to 31 kg. Interventions : The 18 pigs were randomized to either the fat embolism or control groups. Nine anesthetized and mechanically ventilated pigs were intracavally Infused with a 10% allogenelc bone marrow suspension at a dose of 100 mglkg over 5 mins (the fat embolism group) ; nine control pigs received normal saline in the same volume and speed (control group). Measurements and Main Results : Mean pulmonary arterial pressure, pulmonary vascular resistance, and pulmonary shunt increased, and Pao 2 decreased immediately after the bone marrow suspension infusion. In the fat embolism animals, oxygen delivery decreased, oxygen content difference widened, and total oxygen consumption remained high, Indicating enhanced oxygen extraction. Further, superior mesenteric artery blood flow and mesenteric oxygen delivery decreased, while intramucosal pH In the small bowel was stable. Subcutaneous Po 2 decreased in both groups, whereas transcutaneous Po 2 decreased only in the animals receiving bone marrow suspension. Skin red cell flux showed no significant changes. Conclusions : The present model of fat embolism results in significant Impairment In systemic oxygenation. Despite this fact, the Intestinal oxygenation remains unaffected probably due to sufficient compensatory mechanisms. Transcutaneous Po 2 measurements may provide a useful index for early detection of fat embolism.