Changes in Hemodynamics in Jejunal Flaps of Rabbits due to Ischemia, Venous Congestion, and Reperfusion as Measured by Means of Colored Microspheres

Abstract

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.

Adequate Venous Drainage

“…Restoring arterial inflow within 3 hours could usually achieve a successful salvage and a patent esophagus; however, relieving venous congestion that occurs for more than 30 minutes resulted in persistent and prolonged congestion of the flap and, often, late complications. These observations are parallel to those of Tsuchida and colleagues, 15 which revealed that a longer period of time is required to recover normal blood inflow after releasing the venous occlusion. Venous congestion for only 5 minutes induces hemorrhage in the lamina propria of the jejunum, and venous congestion lasting more than 30 minutes leads to an irreversible change in the entire jejunal wall.…”

Head and neck reconstruction using cephalic vein transposition in the vessel‐depleted neck

“…Jejunal lamina propria haemorrhage commences 5 minutes following venous congestion, moreover irreversible tissue injury is evident at 30 minutes. 13,14 The challenge becomes greater in the situations where the EJV and IJV are unavailable. Insufficient venous drainage through the smaller neck veins would cause venous engorgement hence enhancing vessel size discrepancy and the risk of failure.…”

The Comparative Effects of Total Hepatic Vascular Isolation Techniques Performed at Different Durations in Rat

“…Venous outflow blockage (congestion) leads to interstitial edema, venous wall injury, extravascular bleeding, and hemorrhagic necrosis [3,4]. In addition, venous thrombi caused by congestion may induce vasospasm, which prolongs anoxia after reperfusion and exaggerates the injury.…”

“…However, tissue integrity and cellular function after venous congestion were shown to be poorer than arterial ischemia in segmental rat small bowel [3]. Also, venous congestion has been a greater concern than arterial ischemia in the viability of vascularized tissue flaps [4]. We tested the hypothesis that during hepatic vascular isolation, abdominal visceral ischemia rather than venous congestion may have beneficial effect on reperfusion injury and survival outcomes.…”