A Preliminary Report On Different Dose Of Oxytocin In High Intensity Focused Ultrasound In The Treatment Of Uterine Fibroids

Objective: To study the effects of different doses of oxytocin in the treatment of uterine fibroids with high intensity focused ultrasound(HIFU), providing evidence for choosing suitable dose of oxytocin for clinical treatment of uterine fibroids cooperated with HIFU.Methods: 60 patients with single uterine fibroids, were divided randomly into three groups A, B, and C, with 20 patients in each group. Contrast-enhanced ultrasonography was conducted for each group before and 20 min after intravenous infusion of oxytocin and was analyzed quantitatively using Qontra Xt ultrasound software. Fibroids perfusion time intensity curve and four parameters, including Peak intensity(Peak), Peak time(TP), the Sharpness of a bolus injection(Sharpness) and the area under the curve(AUC) for each group were obtained and analyzed. Among them, the Peak was found to be proportional to average blood volume in fibroids; Sharpness was related to the degree of the tissue perfusion and washout; TP was related to the speed of the tissue perfusion; AUC was proportional to average blood flow in the fibroids. Systolic blood pressure, diastolic blood pressure, heart rate, blood oxygen saturation and adverse reactions before as well as l min, 5 min, 10 min, and 20 min after intravenous infrusion of oxytocin was recorded for each patient. Patients in each group underwent HIFU at the same irradiation power of 400 w, and the treated time, irradiation time, intensity, energy and the changes in gray scale was noted for each groups. Three days after HIFU treatment enhanced nuclear magnetic resonance(MRI) was done to evaluate volume of necrosed tissue and ablation rate.Results: In this study, a total of 60 patients had successful HIFU treatment outcome where no statistically significant differences was noted between the three groups for the patients age, height, weight, and fibroids length and volume(P > 0.05). Although all the three doses of oxytocin was found to effect the average blood volume, tissue perfusion rate and average blood flow to the uterine fibroids individually(P<0.05), on Kruskal-Wallis H singned-rank test, there was no significant differences in the changes of blood perfusion of uterine fibroids among these three doeses. All the three doses of oxytocin, 0.12 U/min, 0.24 U/ min and 0.36 U/min, was found to be safe in treating patient with uterine fibroids. In patients of each groups, neither any obvious differences in the blood pressure and heart rate before and after intravenous infrusion of oxytocin, nor any serious complications was noted. In addition, the results also showed that there is no difference in the treatment efficacy of HIFU, with any of the different doses, 0.12 U/min, 0.24 U/ min or 0.36 U/min of oxytocin. All the doses demonstrated the ablation rate of 80% approximately.Conclusion: A suitable dosage of oxytocin reduces the blood perfusion to the uterine fibroids significantly. Moreover, maximum change in blood perfusion to uterine fibroid has been seen with oxytocin infusion rate of 0.12 U/min. Usage of oxytocin in the HIFU treatment of uterine fibroids is safe, and oxytocin dosage of 0.12 U/min might be the suitable dose in the treatment of uterine fibroids with HIFU.