Study On Occurrence Regularity About Deep Venous Thrombosis Within 24 Hours Of Closed Lower Extremity Fractures And After Delayed Admission

Objective: To investigate the occurrence of Deep Vein Thrombosis(DVT)after closed fractures of lower extremities,and to analyze the relationship between different pre-hospital waiting times and the incidence of lower limb DVT.After excluding the influence of pre-hospital waiting factors,analyzed admitted to hospital 24 hours and old lower extremity fractures of incidence regularity of DVT.Methods: A retrospective analysis of 3052 lower limb closed fractures(including pelvic fractures and acetabular fractures)admitted to the Honghui Hospital of Xi'an Jiaotong University from July 2014 to August 2019.The contents collected include the patient's age,gender,fracture site,time of injury,time of admission,causes of obsolescence of old fractures,combined multiple injuries,whether chronic hepatitis,whether combined with medical diseases [including primary hypertension,type 2 Diabetes,Coronary Heart Disease(CHD)and stroke],laboratory test results at admission(including hemoglobin,hematocrit,fibrinogen,plasma D-dimer),both lower extremities Venous ultrasound examination time and examination results.All patients underwent double-limb venous ultrasonography within 24 hours of admission.According to the results of venous ultrasound of the lower extremities,the patients were divided into thrombosis group and non-thrombosis group.The risk factors of all fractures,hospitalization within 24 hours after injury,and old fracture patients were analyzed.Grouped according to the waiting time before the hospital(injury time to the time of ultrasound examination),the curve of the waiting time before the hospital and the incidence of lower limb DVT were drawn.First,single-factor analysis was used to screen for risk factors,and then multi-factor logistic regression analysis was used to determine independent risk factors.According to different influencing factors,the groups were grouped according to the number of waiting days before hospitalization,and the curve of the incidence of DVT in lower limbs with different waiting days in hospital was drawn to further explain the influence of this factoron the occurrence of DVT in lower limbs.Results: Among 3052 cases of closed lower limb fractures,the incidence of lower limb DVT was 29.16%(890/3052),and the incidence of proximal thrombosis and mixed thrombosis was 3.64%(111/3052).There were significant differences in sex,age,fracture site,coronary atherosclerotic heart disease,chronic hepatitis,essential hypertension,type2 diabetes,waiting days before hospital,hemoglobin and hematocrit between thrombus group and non thrombus group(P < 0.05).The results of multivariate logistic regression analysis showed that age,fracture site,waiting time before hospitalization and hematocrit were independent risk factors for lower limb DVT.From the waiting days before hospitalization and the change curve of the incidence of lower limb DVT,it can be seen that after closed fracture of lower limb,the incidence of lower limb DVT in patients admitted within 24 hours was the lowest,21.61%.With the extension of prehospital waiting time,the incidence of lower extremity DVT gradually increased,reaching the highest at 8-14 days,at 47.47%.When> 14 days,the incidence of DVT gradually decreased.The same regularity applies to the incidence of proximal thrombosis and mixed thrombosis.With the prolongation of the waiting time before hospitalization,the amount of plasma D-dimer gradually decreased and reached a minimum at> 21 d.The hemoglobin and hematocrit gradually decreased,and reached a minimum in 8-14 days,and then gradually increased.After excluding the influence of pre-hospital waiting factors,statistical analysis was performed using the same method to find that the independent risk factors for lower limb DVT in 1046 patients with closed lower limb injuries who were admitted within 24 hours were age,fracture site,and hematocrit.The independent risk factors of 170 patients with old closed fracture of lower extremity were male with multiple injuries.Among the causes of obsolescence of old fractures,the incidence of DVT was the highest in patients with other diseases.Conclusion:1.Lower extremity DVT will occur within 24 hours after lower limb closed fracture,and proximal thrombosis and mixed thrombosis will also occur.Older age,subtrochanteric fractures,femoral shaft fractures,intertrochanteric fractures,and lower hematocrit in patients are more likely to cause lower limb DVT among patients admitted within 24 hours after closed fracture of lower extremity.2.The incidence of lower extremity DVT in different prehospital waiting times is different.With the extension of prehospital waiting time,the incidence of lower extremity DVT gradually increased,reaching the highest in 8-14 days,and then gradually decreased.The lower the hematocrit,the higher the incidence of lower limb DVT.3.DVT can still occur in old fracture of lower extremity.Male patients with multiple injuries are more likely to have DVT in old fractures.Patients with closed fractures of the lower limbs should be screened and diagnosed as soon as possible after admission to prevent further progress of thrombosis,increase the burden of medical treatment and fatal pulmonary embolism.