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Experimental fat embolism induces urine 2,3-dinor-6-ketoprostaglandin F sub 1 alpha and 11-dehydrothromboxane B sub 2 excretion in pigs

1997; Lippincott Williams & Wilkins; Volume: 25; Issue: 7 Linguagem: Inglês

10.1097/00003246-199707000-00025

1530-0293

Markku Rautanen, Eero Gullichsen, Asko Riutta, Kari Kuttila, Istvan Mucha, O Nelimarkka, J Niinikoski,

Sepsis Diagnosis and Treatment

Objective To evaluate the in vivo production of prostacyclin and thromboxane A2 during the initial phase of experimental fat embolism as assessed, respectively, by determinations of urine 2,3-dinor-6-ketoprostaglandin F1 alpha and 11-dehydrothromboxane B2 excretion. Design Randomized, controlled trial. Setting Animal laboratory. Subjects Twenty seven domestic pigs, weighing 24 to 31 kg. Interventions All pigs were anesthetized and mechanically ventilated during the experiment. Eighteen pigs were subjected to an intracaval infusion of 10% allogeneic bone marrow suspension at a dose of 100 mg/kg over 5 mins. Nine pigs received only bone marrow suspension (fat embolism group). Nine pigs were given an intravenous bolus of aspirin (300 mg) 1 hr before the bone marrow suspension infusion. After the induction of fat embolism, intravenous aspirin was administered at a dose of 150 mg/hr for 2 hrs (aspirin-treated group). Nine pigs were infused with saline (control group). Measurements and Main Results In the fat embolism group, cardiac index decreased within 30 mins, while mean arterial pressure remained unchanged. Central venous pressure and pulmonary artery occlusion pressure remained relatively stable over time in the animals with fat embolism. Mean pulmonary arterial pressure and pulmonary vascular resistance increased immediately after the bone marrow suspension infusion from 23 +/- 0.8 (SEM) to 34 +/- 1.3 mm Hg and from 305 +/- 28 to 585 +/- 45 dyne[center dot]sec/cm sup 5, respectively; these variables remained increased throughout the study period. Simultaneously, pulmonary shunt in the fat embolism group increased persistently from the baseline of 12.3 +/- 2.8%, and reached its maximum of 26.1 +/- 4.8% at the end of the experiment. Instant and gradual decreases in Pao2 (from 95 +/- 4 to 67 +/- 5 torr [12.6 +/- 0.5 to 8.9 +/- 0.7 kPa]), hemoglobin oxygen saturation (from 97.2 +/- 0.4 to 91.8 +/- 1.8%), and oxygen delivery (from 16.3 +/- 1.0 to 12.6 +/- 0.4 mL/min/kg) were observed in the fat embolism group. In the bone marrow suspension-infused animals, urine 2,3-dinor-6-ketoprostaglandin F1 alpha excretion increased transiently from 451 +/- 63 up to 1466 +/- 499 pg/micro mol creatinine, while urine 11-dehydrothromboxane B2 excretion increased transiently from 385 +/- 36 up to 2307 +/- 685 pg/micro mol creatinine. In the aspirin-treated animals, urinary excretion of these prostanoid metabolites was reduced by 81% and 88%, respectively. The changes in mean pulmonary arterial pressure and Pao2 were ameliorated, and the alterations in pulmonary shunt and Sao2 were abolished in the animals with aspirin treatment. Conclusions Pulmonary hypertension, increased pulmonary vascular tone, and increased pulmonary shunt are hallmarks of the present fat embolism model. These hemodynamic responses may, at least partly, be related to the changed balance between prostacyclin and thromboxane A2 production. (Crit Care Med 1997; 25:1215-1221)