Subcutaneous and gut tissue perfusion and oxygenation changes as related to oxygen transport in experimental peritonitis
Antonsson, J.B.; Kuttila, K.; Niinikoski, J.; Haglund, U.H.
Circulatory Shock 41(4): 261-267
1993
ISSN/ISBN: 0092-6213 PMID: 8143353 Document Number: 420497
Peritonitis and septic shock may lead to tissue hypoxia, but this risk is not identical in all organ systems. This study was undertaken to measure changes in tissue oxygenation and perfusion in the gut wall and subcutaneous tissue, respectively, and to examine their relation to oxygen delivery and consumption. Twelve pigs were anesthesized and mechanically ventilated. An ultrasonic flow probe was placed around the superior mesenteric artery for registration of blood flow. A mesenteric vein was cannulated for blood sampling. For calculation of gut intramural pH (pH-i), a Silastic balloon (Tonomitor) was placed in the lumen of the midileum. pH-i was calculated from tonometrically measured PCO-2 and arterial bicarbonate concentration. The subcutaneous PO-2 was measured by means of an oxygen-permeable Silastic tube implanted in the subcutis of the abdominal wall. Oxygen delivery (DO-2) and consumption (VO-2) were determined for the gut as well as for the whole body. In six randomly allocated animals, peritonitis was induced after a stabilization period of at least 1 hr, by instillation of autologous faeces into the abdominal cavity, while the other six animals served as controls. The animals were then followed for 5 hr. pH-i remained stable in the control group, whereas a drop from 7.37 to 7.02 took place in the peritonitis group. In the test group, subcutaneous oxygen tension (P-SCO-2) already began to fall 1 hr after the induction of peritonitis, and gained the minimum at the end of the study. In peritonitis, a moderate correlation was seen between pH-i and DO-2 (r = 0.51 +- 0.16); no statistical difference was noted if pH-i was correlated to gut DO-2 (r = 0.56 +- 0.18). There was a significantly better (P lt 0.05) correlation between P-SCO-2 and DO-2 (r = 0.67 +- 0.08).