A Study Of Hypobaric Bupivacaine Used In Combined Spinal Epidural Anesthesia For Elderly Unilateral Hip Replacement

Background: As China has stepped into an aging society gradually,the number of elderly patients who need hip replacement is growing.Moreover, these patients are associated with many internal diseases,such as high blood pressure, coronary heart diseases, chronic lungdiseases, diabetes and so on. Consequently, those patients’ tolerance ofanesthesia and surgery is at low level, and the risk of perioperativeperiod is high[86]. Therefore, it is particularly important to select thecorrect narcotic drugs and anesthesia for these patients. Generalanesthesia has a great impact on the normal physiology of the elderlypeople, which can cause significant hemodynamic changes, and increasethe risk of complications, so more and more anesthetists prefer lumbarepidural anesthesia and peripheral nerve block to reduce these risks.However, peripheral nerve block need a high level of requirement forthe equipment, and the operating techniques are difficult to master,because of which it is difficult for most hospitals to carry out. At homeand abroad, the optional programs for defining the drugs proportion inspinal anesthesia still exist a certain amount of controversies in certainsurgeries. Traditionally, it is inclined to choose hyperbaric bupivacaine,because of its rapid onset, effective anesthesia, and easy to control,while the hypobaric bupivacaine acts oppositely. In recent years, agrowing number of clinical studies, however, show that, for somespecial surgeries, such as unilateral hip replacement surgery for elderly people, hypobaric bupivacaine is better and maybe has its uniqueadvantages. Because it is easier to form unilateral subarachnoid block,and has less influence on the circulation. What’s more, this method canavoid causing any pain because of posture changes, and lead to a fasterrecovery postoperatively. Based on the views above, the present studycompared hypobaric and hyperbaric bupivacaine used in unilateral hipreplacement surgery for elderly people in order to provide a referencefor clinical anesthesia.Purpose: Explore the safety and efficacy of hypobaric bupivacaineused in combined spinal and epidural anesthesia (CSEA) for the elderlypeople with unilateral hip replacement.Methods:60elderly patients with unilateral hip arthroplasty werecompletely randomly divided into two groups, and30for each group.Group A with0.375%bupivacaine3ml (2ml0.5%bupivacaine and2mlsterile distilled water diluted to4ml, then3ml out); group B with0.375%bupivacaine3ml (2ml0.5%bupivacaine and2ml sterile10%glucose diluted to4ml, then3ml out). Combined spinal epiduralanesthesia were used in both groups. Measurements: changes of vitalsigns; time to reach the T10dermatome level; the maximum blockagedermatome level，and unilateral block incidence at the15th minute;motor block score at the150th minute; adverse reactions includinghypotension、bradycardia、shivering、nausea、vomiting which happenedintraoperatively, and postoperative headaches, nervous systemcomplications and their incidence; the times of using ephedrine andatropine intraoperatively.Results: The time to reach T10in group A was longer than that in group B after giving anesthetic（sP﹤0.05）; the average of the maximumblockage dermatome level in group A was higher than that in group B（P﹤0.05）; the unilateral block incidence was higher in group A than thatin group B at the15th minute （P﹤0.05）; the motor blockade score washigher in group B than that in group A at the150th minutes（P﹤0.05）);blood pressure fluctuations in group B was higher than that in group A(P﹤0.05or0.01); the times of using ephedrine intraoperatively wasmore in group B than in group A （P﹤0.05）; compared with group B,the intraoperative incidence of hypotension、shivering, nausea, vomitingwas lower in group A（P﹤0.05or0.01); there was no significance forthe incidence of intraoperative bradycardia, postoperative headache, andneurological complications between group A and group B（P﹥0.05）.Conclusions:Hypobaric bupivacaine, used in unilateral hipreplacement surgery for elderly patients, is easier to form unilateralsubarachnoid block, favors the intraoperative hemodynamic stability,promotes recovery in motor function postoperatively, and reduces theincidence of complications. Moreover, this method can reduce or avoidthe pain caused by posture changes when using hyperbaric anesthesia,and improve patients’ satisfaction. Therefore, hypobaric bupivacaine forelderly unilateral hip replacement surgery is safe and effective, and insome special surgeries, it may be superior to hyperbaric bupivacaine.