Study On The Peripheral Resistance Of Hypogastrium Superficial Epigastric Artery Skin Flaps Of Rabbits Injected With Papaverine By Different Approaches

Background:With the development of microscopic surgery,transplantation of skin flaps has become the most effective method for repairing the traumatic tissue defection.There were visible muscle layer on the blood vessel,which has high sensitivity to all kinds of physical and chemical stimulation.So spasm occured to the anastomotic and the nearby section vessel very easily,which was the common complication during or after the microsurgical operation.The severe and lasting vasospasm resulted in transplanted tissue ischemia and hypoxia and even necrosis, thus induced the failure of operation.In clinical application,after operation of microscopic vascular of skin flaps,vasodilatator such as papaverine was frequently used to prevent and relieve vasospasm,increase cyclic blood flow of skin flaps and significantly reinforced skin flaps survivial capability.There were two major injection approaches:(1) using intramuscular injection in the buttocks many times per day for many days;(2) intravenous injection for 24 hours.Although clinical effects were good,the two methods still existed different degree of defect.If couldn't control the speed of drug in intravenous injection,or injected too much,which would easily lead to severe bad reaction such as arrhythmia and blood pressure decrease,and aggravate ischemia and hypoxia in transplanted tissue;to intramuscular injection in muscle of buttocks,if dosage is too great,patients could not tolerant,but dosage is too low,the effects of spasmolysis were poor.Experiment results also showed that papaverine has been absorbed and distributed by 30～60 mg after intramuscular injection or intravenous injection,the concentration of drug acted on the remote end was very tiny, by calculating only several microgram could reach fingers.However,vasodilator drugs has not been conventional used in locally applied of flaps,and how to effects? At present,there was not system study about injection approaches of vasodilators by close distance of flaps.Objective:To investigate the influence of quantified papaverine(1.5 mg/kg) by different injection approaches on peripheral resistance of hypogastrium superficial epigastric artery skin flaps of rabbits,we explore the best administration approach to increase the survival ratio of skin flaps and reduce the adverse drug reactions and complications,which has considerable practical value.Material and methods:①Twenty-four male New Zealand rabbits were selected and randomized into 4 groups(n=6):skin flaps pedicle subcutaneous injection group,skin flaps center subcutaneous injection group,intramuscular injection group and intravenous injection group.The experimental procedure was accorded with animal ethical standards.②Bilateral hypogastric flap models were set up,and quantified papaverine(1.5 mg/kg) was administrated in each group by different approaches 1-7 hours postoperatively,once per day.③The resistance index of skin flaps were observed and comparative analysis by color Doppler ultrasound before operation,before injection,10 minutes and 1 hour after injection with one week after operation at close-distance targeted position(skin flap pedicle, skin flap center) and long-distance systemic(intramuscular injection,intravenous injection).④The results were analyzed by SPSS11.5 statistical package including paired T test and duncan's test,A P value of＜0.05 was considered significant.Results:Twenty-four rabbits were included in final analysis.①The resistance index of flap blood flow in each group after operation was higher than before operation(P＜0.05).②The postoperative index of flap blood in skin flaps center group at 10 minutes after injection was no significant difference from intravenous injection group(P＞0.05).But they were lower than skin flaps pedicle subcutaneous injection group and intramuscular injection group,both of them have a statistical signification(P＜0.05).There was no statistical difference among these postoperative resistance index of flap blood flow of the skin flaps pedicle subcutaneous injection group and skin flaps center subcutaneous injection group and intravenous injection group at 10 minutes after injection on the first and second and fourth day(P＞0.05). But they were significantly lower than the intramuscular injection group(P＜0.05). There was no statistical difference among these postoperative resistance index of flap blood flow of the skin flap pedicle subcutaneous injection group and intramuscular injection group and intravenous injection group at 10 minutes after injection on the third and fifth day(P＞0.05),but the postoperative resistance index of flap blood flow of the skin flap center subcutaneous injection group was the lowest than others and it was a statistical signification(P＜0.05).There was no statistical difference among these postoperative resistance index of flap blood flow of the all group at 10 minutes after injection on the sixth and seventh day(P＞0.05).③There was no statistical difference among these postoperative resistance index of flap blood flow of the all groups at 1 hour after injection(P＞0.05),the postoperative resistance index of flap blood flow of the skin flap center subcutaneous injection group was the lowest at 1 hour after injection on the first and second and third day,there was a statistical signification compared with the intramuscular injection group(P＜0.05),but no statistical difference compared with other two groups(P＞0.05).The postoperative resistance index of flap blood flow of the skin flap center subcutaneous injection group was the lowest at 1 hour after injection on fourth day,there was statistical signification(P＜0.05).The postoperative resistance index of flap blood flow of the intramuscular injection group was slightly higher than preoperative at 1 hour after injection on fifth day(0.542±0.058),the others three resistance index were slightly lower preoperative,there was no statistical difference among three groups(P＞0.05). There was no statistical difference among these postoperative resistance index of flap blood flow of the all group at 1 hour after injection on sixth and seventh day(P＞0.05).Conclusion:①The papaverine could significantly decrease resistance index by skin flap pedicle subcutaneous injection and skin flap center intravenous injection and subcutaneous injection and intramuscular injection after operation.②After skin flap operating,papaverine injection in skin flap center achieves the best effect of decreasing resistance index,and intramuscular injection shows the worst effect of decreasing resistance.