Comparison Of The Clinical Effect Between High- And Low- Vacuum Drainage After Total Hip Arthroplasty

?Objective?Total hip arthroplasty(THA)has been developed as one of the most mature surgery in orthopaedic field.However,in consideration of the severe surgical trauma and abundant soft tissues surrounding the hip such as blood vessels and nerves,the THA procedure usually leads to massive intraoperative and postoperative blood loss.In order to drain out the postoperative blood loss,which is considered can decrease the risk of postoperative hematoma formation,the use of drainage has historically been a routine method in THA.Recently,some researchers also claimed that the benefit of using drainage after THA is not so obvious,and it may lead to more postoperative blood loss.Therefore,controversy concerning the management of drainage always exists among many clinicians.However,many researchers neglected the fact that postoperative drainage blood is a relatively dilute blood product with low hematocrit value.By simply considering the drainage volume as postoperative visible blood loss,we actually overestimated the visible blood loss but underestimated the hidden blood loss.The true blood loss in drainage fluid should be properly calculated according to the hematocrit value of it.Essentially,the benefit of postoperative drainage is based on the precondition that the drainage device can effectively discharge those early bleeding after the surgery.Drainage efficiency is mainly depends on the suction pressure of the drainage device.However,few researchers concentrated on the clinical effect of different drainage suction pressure after THA.Thus,we aimed to prospectively compare the clinical effect between high-and lowvacuum suction drainage after THA with a more accurate calculating method.We mainly focused on the differences in the aspects of perioperative blood loss,early postoperative recovery and postoperative complications between the two kinds of drainage devices.?Methods?Patients who underwent THA in our hospital between March 2017 and December 2017 were randomly divided into high-vacuum group(maximal negative pressure of 98 kPa,53 patients)and low-vacuum group(maximal negative pressure of 20 kPa,51 patients).We examined the hematocrit value of all the postoperative drainage blood.And accordingly,we calculated the true blood loss of postoperative drainage and the hidden blood loss after THA.We statistically compared the hematocrit value of drainage blood,postoperative drainage volume,true postoperative drainage blood loss,visible blood loss,total blood loss,allogenic blood transfusion,hidden blood loss,rate of hidden blood loss,perioperative hemoglobin changes,early postoperative recovery and postoperative complications between the two groups.Measurement data was analyzed by independent-samples t-test,enumeration data was analyzed by chi-square test,P<0.05 was considered significant.?Results?There were no statistical differences between the two groups regarding gender,age,height,weight,body mass index,preoperative Harris score,anesthesia method and operation time(P>0.05).Hematocrit value of drainage blood in the two groups are both relatively low,but the comparison between them was not statistically significant(19.25±4.89% VS 20.29±4.23%,P>0.05).There was also no statistical difference on the comparison of intraoperative blood loss between the two groups(P > 0.05).The high-vacuum group had significantly more drainage volume at 12 hours,24 hours and 48 hours after operation(P<0.001).After calculated by the hematocrit value of drainage blood,patients in the high-vacuum group had more true postoperative drainage blood loss and perioperative visible blood loss(P<0.001).There were no statistical differences between the two groups regarding perioperative total blood loss and allogenic blood transfusion(P>0.05).However,compared with the low-vacuum group,patients in the high-vacuum group had less hidden blood loss(647.64±299.85 ml VS 783.53±292.56 ml,P<0.05)and significantly lower percentage of hidden blood loss(53.84±9.55% VS 67.58±6.80%,P<0.001).The perioperative hemoglobin changes in the two groups are basically similar except at the postoperative 1st day,when the patients in high-vacuum group had lower hemoglobin values(111.42±15.28g/L VS 117.88±16.43g/L).In terms of the early postoperative recovery,patients in the high-vacuum group had lower VAS pain scores(3.30±0.59 VS 3.86±0.49,P < 0.001)and more mild swelling degree(103.42±2.17% VS 104.62±1.76%,P<0.05)on the 3rd day postoperatively.There were no statistical differences between the two groups regarding VAS pain scores of the 7th postoperative day,time of leaving bed and Harris scores after 6 weeks.In the aspect of postoperative complications,no wound hematoma and deep infection occurred in the both groups.There were no significant differences between the two groups regarding the aspects of early postoperative fever,delayed wound healing,superficial wound infection,and the formation of deep venous thrombosis(P > 0.05).Two patients in the high-vacuum group experienced the formation of ecchymosis around the wound,but the figure in the low-vacuum group was nine,the difference was statistically significant(P<0.05).?Conclusion?The clinical effect of high vacuum suction drainage is positive for reducing the hidden blood loss,early postoperative pain,swelling and the risk of ecchymosis formation after THA but not increasing the perioperative total blood loss.