Changes in hemodynamics in jejunal flaps of rabbits due to ischemia, venous congestion, and reperfusion as measured by means of colored microspheres.

The effect on the jejunal hemodynamics of restoration of blood flow of the jejunal artery or vein in the free jejunal flap has not yet been elucidated. In the present study, a model of ischemia and reperfusion in the jejunal flap of rabbits, and that of venous congestion and reperfusion, were prepared. Jejunal blood flow was measured by means of colored microspheres, and changes in jejunal blood flow were analyzed. Three segmental jejunal flaps were designed on each rabbit (n = 16), with one artery and one vein kept intact. Arterial clamp and venous clamp groups were prepared with a control group in which there was no clamping. After clamping for 5 minutes (n = 7), the jejunal blood flow of the arterial clamp group decreased to 1.6 percent of that of the control group (p = 0.0002), and that of the venous clamp group decreased to 31.2 percent of that of the control group (p = 0.0041). At 5 minutes after release of clamping, the jejunal blood flow of the arterial clamp group recovered to only 74.1 percent of that of the control group, with no consistent tendency; that of the venous clamp group recovered to 45.9 percent of that of the control group (p = 0.0194), with an increase of only 14.7 percent over that of the clamped jejunal blood flow group. Thus, injury of the jejunal hemodynamics in the venous clamp group had already begun in response to clamping for 5 minutes. After clamping for 30 minutes (n = 9), the jejunal blood flow of the arterial clamp group decreased to 4.3 percent of that of the control group (p = 0.0060), and that of venous clamp group decreased to 12.5 percent of that of the control group (p = 0.0106). At 5 minutes after release of clamping, jejunal blood flow of the arterial clamp group recovered to 171.0 percent of that of the control group (p = 0.0295), and that of venous clamp group recovered to 41.7 percent of that of the control group (p = 0.0276). Jejunal blood flow of the arterial clamp group recovered to 409.7 percent of that of the venous clamp group (p < 0.0001). When measurement of jejunal blood flow was repeated twice after changing the color of microspheres, jejunal blood flow of the second measurement was approximately 24 percent greater in mean value than that of the first measurement. The histologic results of the jejunum of the arterial clamp group clamped for 30 minutes showed no injury, which was similar to the results of the control group. The jejunum of the venous clamp group clamped for 5 minutes showed injury with severe hemorrhage in the lamina propria, and irreversible injury 30 minutes thereafter, with massive hemorrhage in all layers of the jejunal wall. In conclusion, as microcirculatory hemodynamics and histologic results of the jejunum demonstrated evidence of injury even by venous congestion for 5 minutes, restoration of blood flow of the free jejunal flap must be started from the jejunal vein.