Clinical Application Of TcPO2and Laser Doppler Flowmetry For Postoperative Monitoring Of Free Flap

Background:Free flap transplantation plays an important role in plastic and reconstructive surgery for that free flap, such as wound covering, deformity reforming and other reparative surgeries that would lead to skin defect. As the great progress of microsurgery the success rate of free flap transplantation has reached to95%or higher in many reports, but every microsurgeon has to confront the possibility of vascular compromise, which will lead to unacceptable outcome. The way to avoid flap necrosis caused by vascular compromise is postoperative monitoring, which can help doctors to find the losing flap and try to save it. The ideal monitoring method should own such characteristics:sensitive, accurate, reliable, continuous, and harmless to patients and flaps. The ubiquitous monitoring method is the clinical assessment, which comprise color, temperature, swelling, capillary refill, and observing bleeding by punching. Clinical observation relies on subjective judgment, and observation cannot be done continuously, which make it hard to find out the vascular compromise. So many doctors and researchers have tried many instruments to achieve best postoperative monitoring.Methods:We applied LDPM and TcPO2to postoperative monitoring of25free flaps, which comprise5free groin flaps and20free anterolateral femoral flaps, from postoperative day1to7. And the traditional clinical observations were also performed routinely, and we compared the sensitivity and accuracy between clinical ways and the two objective monitoring ways.8superficial epigastric flaps of wistar rats were made to simulate artery and vein compromise individually, and LDPM and TcPO2were applied to monitor the whole process. And the traditional clinical observations were also performed routinely, and we compared the sensitivity and accuracy between clinical ways and the two objective monitoring ways.Results:19free anterolateral femoral flaps were uneventful and1case were found vein compromise3h after operation. All the five free groin flaps were uneventful. The outcome of monitoring is shown in chart1.TcPO2of the superficial epigastric flaps were27-35mmHg after elevated and resurured, after the superficial epigastric arteries were ligated, the TcPO2of the flap dropped within1sec and reached to less than5mmHg in1min. The LDPM dropped almost at the same time from6.2-9.8pU before artery ligated to0pU10sec after ligated. The TcPO2of the superficial epigastric flaps were29-35mmHg after elevated and resutured, after the superficial epigastric veins were ligated, the TcPO2of the flap dropped within1sec and reached to less than5mmHg in35sec. The LDPM dropped almost at the same time from6.3-10.3pU before artery ligated to0pU10sec after ligated. The color of flap changed inconspicuously during the arteries ligated. For the veins ligated, the color changed conspicuously but not so quickly, and almost10s delayed than TcPO2and45sec than LDPM.Conclusions:1. TcPO2and LDPM are more accurate and reliable than clinical assessment.2. TcPO2and LDPM can achieve continuously monitoring.3. LDPM is a better method than TcPO2.