Evaluating abdominal oedema during experimental sepsis using an isotope technique

Summary Purpose: Abdominal oedema is common in sepsis. A technique for the study of such oedema may guide in the fluid regime of these patients. Procedures: We modified a double-isotope technique to evaluate abdominal organ oedema and fluid extravasation in 24 healthy or endotoxin-exposed (� septic� ) piglets. Two different markers were used: red blood cells (RBC) labelled with Technetium99m ( 99m Tc) and Transferrin labelled with Indium111 ( 111 In). Images were acquired on a dual-head gamma camera. Microscopic evaluation of tissue biopsies was performed to compare data with the isotope technique. Results: No 99m Tc activity was measured in the plasma fraction in blood sampled after labelling. Similarly, after molecular size gel chromatography, 111 In activity was exclusively found in the high molecular fraction of the plasma. Extravasation of transferrin, indicating the degree of abdominal oedema, was 4AE06 times higher in the LPS group compared to the healthy controls (P<0AE0001). Abdominal free fluid, studied in 3 animals, had as high 111 In activity as in plasma, but no 99m Tc activity. Intestinal lymphatic vessel size was higher in LPS (3AE 7±1 AE1 lm) compared to control animals (0AE 6+0 AE2 lm; P<0AE001) and oedema correlated to villus diameter (R 2 =0 AE918) and lymphatic diameter (R 2 =0 AE758). A correlation between a normalized index of oedema formation (NI) and intra-abdominal pressure (IAP) was also found: NI = 0AE46*IAP)3AE 3( R 2 =0 AE56). Conclusions: The technique enables almost continuous recording of abdominal oedema formation and may be a valuable tool in experimental research, with the potential to be applied in the clinic.