Sunday, October 10, 2004

Venous Pressure Monitoring: A Powerful Tool For Flap Salvage

Eri Fukaya, MD, Hiroyuki Sakurai, MD, PhD, Motohiro Nozaki, MD, PhD, and Nobuo Isono, MD.

Flap failure, a critical problem in free tissue transfer is a result of flap circulation insufficiency. The cause may be a lack of arterial inflow or drainage problems due to venous congestion. In either case, early detection and re-operation is crucial for flap salvation. Venous congestion is considered more harmful to the flap than ischemia and venous thrombosis is more common as a cause of flap failure than arterial thrombosis. Despite the various devices and monitoring techniques introduced, most surgeons still depend on clinical observations such as flap color, capillary refill, bleeding from the flap and tissue turgor to determine flap viability. In cases of venous congestion due to thrombosis, even after its reexploration, there is a deep concern for a recurring thrombosis and the flap itself becomes discolored from the previous insult making it difficult to make clinical judgments.

We experienced four cases requiring reexploration for salvage from a venous thrombosis after free tissue transfer. There were no problems of arterial inflow in all four cases and reanastomosis of the veins were conducted after a thrombectomy. During the reoperations, we inserted a catheter into a side branch of the vein in the transferred tissue for venous pressure monitoring and the delivery of thrombolytics. In one case where a flap had just been rescued from a previous insult of venous thrombosis, we were able to recognize a redeveloping thrombosis rapidly . This would have been difficult to detect otherwise due to the fact that the flap was in a clinically poor condition from the congestion and reperfusion injury. The postoperative course of the other three cases were uneventful with stable venous pressure. All four flaps were salvaged.

Venous pressure measurement is reflective of flap circulation, is reproducible and can be monitored continuously. In case of a thrombosis, the flap circulation will be compromised and the venous pressure will rise. These physiological changes can be observed instantaneously thus monitoring venous pressure is effective in the early detection of flap circulation insufficiency. Aside from monitoring, the catheter is able to deliver antithrombotic drugs such as heparin and urokinase at a high dose locally to prevent an additional thrombosis from developing. Our experience suggests that an in situ venous catheter for monitoring venous pressure and to deliver thrombolytics serve as a powerful device for free flap salvage following prolonged venous thrombosis.

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