Objective To explore the monitoring and management of vascular crisis after free flap transplantation. Methods 8 cases of vascular crisis in 5/kloc-0 cases of free flap transplantation were analyzed retrospectively, as well as the postoperative monitoring methods and rescue measures of crisis flap. Results Among 8 cases of vascular crisis flap, 6 cases survived after rescue and 2 cases failed. Conclusion Close monitoring, timely detection of vascular crisis of skin flap and taking targeted measures according to the causes of blood circulation disorder can effectively prevent skin flap necrosis.

Vascular crisis; Free flap; tissue transplantation

With the continuous improvement of microscopic technology, free flap transplantation with vascular anastomosis has been widely used in the field of repair and trauma reconstruction. However, vascular crisis caused by various reasons is a common complication after operation. It is very important to find the vascular crisis of the flap in time and prevent the flap from necrosis. In this paper, 8 cases of vascular crisis of free skin flap encountered in clinic were combined to summarize the experience and lessons of monitoring and handling vascular crisis.

Clinical data of 1

1. 1 general information: from June 2003 to February 2007, there were 5 cases of free flap transplantation in our hospital, of which 8 cases had vascular crisis. The repair sites included forearm in 3 cases, calf in 2 cases, foot in 3 cases and latissimus dorsi muscle flap in 3 cases.

1.2 clinical manifestations of vascular crisis: arterial crisis: it is common in 1 ~ 3 hours after operation, mainly manifested as pale skin flap, deepening wrinkles, decreased skin temperature, prolonged or disappeared capillary filling time, and reduced or no bleeding at the distal end of acupuncture skin flap. Venous crisis: it is more common in 10 ~ 24h after operation, mainly manifested as purplish red skin flap, swelling, more marginal bleeding, shortened capillary filling time, then the skin flap is bluish-black, gradually aggravated, and blisters appear on the surface.

1.3 management of vascular crisis: among the 8 cases of vascular crisis, 3 cases had poor arterial blood supply, of which 2 cases survived after timely surgical exploration and repair, and 1 case had distal necrosis after skin flap transplantation. The necrotic flap was removed and the wound was covered with free skin graft. Postoperative venous reflux disorder occurred in 5 cases. After heat preservation, intravenous drip of 30mg toxin and analgesia, the blood supply of 1 case was improved. 1 case of hematoma under the transplanted flap formed a compression flap, which blocked the venous return of the flap. Then the suture was removed at the bedside, the hematoma was removed, the movable bleeding point was clamped, and the flap quickly returned to normal after the bleeding was completely stopped and the affected limb was raised. Two cases survived after reoperation to explore blood vessels. 1 case progressed slowly, and the color and texture changed after 2 days. Due to lack of experience, it was impossible to explore in time, and finally it could not be saved, and the flap was necrotic.

2 discussion

2. 1 Mechanism of vascular crisis of free flap

Long-term ischemia of skin flap after transplantation will trigger a series of pathophysiological reactions, lead to the release of oxygen free radicals and cause damage to microvascular endothelial cells. Injured endothelial cells release a variety of cytokines, leading to acute inflammatory reaction and inducing platelet aggregation. Cytokine-activated neutrophils gather in microcirculation, which aggravates inflammatory reaction and blocks capillary bed. Due to continuous hypoxia and depletion of energy compounds, Na-K pump fails, causing endothelial cells to expand and occlude vascular lumen. Finally, due to the loss of fibrinolytic activity of endothelial cells, blood stasis and activation of coagulation chain reaction, the microcirculation of the flap was completely embolized and eventually necrotic. 2.2 Causes of vascular crisis of free flap

Vascular crisis is mostly venous crisis. The poor elasticity of vein wall is easy to be damaged, anastomosis is relatively difficult, and thrombosis is easy to form after compression, which is the fundamental reason that venous crisis is far more than arterial crisis. The common causes of crisis are: poor vascular bed, tortuous vascular pedicle, poor quality of blood vessels in the recipient area, vascular intima injury caused by poor anastomosis quality, unreasonable skin flap design, arterial compression of veins or nerves, intractable vasospasm caused by emotional tension, atherosclerosis and so on.

2.3 principles of management of vascular crisis of free flap

Timely observation and treatment after operation is the key to prevent the serious consequences of vascular crisis. Whether the crisis flap can be successfully rescued depends largely on the early detection of microcirculation disturbance and the timely exploration of damaged blood vessels. Some scholars believe that vascular crisis is most likely to occur within 72 hours after operation, and the hope of re-operation within 4 ~ 6 hours after vascular crisis is the greatest. Regular observation (half an hour 1 time) of skin flap color, temperature, tension, capillary filling reaction and acupuncture bleeding within 24 hours after operation is an effective means to judge whether there is blood supply disorder in the skin flap. Once it is determined that the flap has vascular crisis, it should be explored and rescued immediately. Blindly waiting and watching will increase the difficulty of the operation and may even lose the chance of successful rescue.

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