Postoperative Transcutaneous Blood-oxygen Saturation Assay For The Continuously Monitoring Of Vascular Crisis Of The Free Flap

Objective To evaluate the effect of transcutaneous pulse oximeter on the continuousl monitoring of postoperative vascular crisis of axial pattern flaps.Method Animal models of axial pattern flap were made with bilateral hypogastrium superficial epigastric artery skin flaps in thirty adult made new Zealand rabbits and were randomly divided into three groups: aterial interruption group ,venous interruption group, and total vascular interruption group. SPO2 of the flap was detected continuously in the three groups, and the readings was compared with the shift of temperature and color of the free flap.Result The differential saturation of percutaneous oxygen (SPO2) decreased violently at lowest threshold after temporary arterial interruption, and regained to normal level after the vessel was reopened for178±17s. The SPO2 decreased slowly at lowest threshold after venous interruption, and regained to normal level after the vessel was reopened for 635±37s. There was significant differences in decreasing time and reopening time between the arterial interruption and the venous interruption group(P<0.001).The shifting time and reopening time of SPO2 of the total vascular interruption group was similar to that of the arterial interruption group ,but obviously shorter than that of the venous interruption group. The shifting time of temperature and color of the flap were significantly longer than those of SPO2.Conclusion Transcutaneous blood-oxygen saturation monitor can reflect tissue perfusion rapidly, accurately and continuously it. it is an ideal method for continuously monitoring the vessel thrombosis of the free flap . The Pulse oximeter can be easily and continually monitored with simple, inexpensive equipment and be able to detect and distinguish between microcirculatory changes occurring as a result of arterial, venous or total vascular occlusion. An online alarm system was developed to inform medical staff at the exact moment when the Pulse oximeter detected a definite fall in the blood-oxygen saturation in free flap. This modification allowed the possibility of immediate surgical intervention and proved successful.