The Clinical Research Of Single Shot Hypobaric Unilateral Spinal Anaesthesia In Geriatric Patients With Chronic Obstructive Pulmonary Disease Undergoing Hip Replacement Surgery

Objective:Part 1: Unilateral spinal anaesthesia(USp A)has been reported to potentiate spinal anaesthesia and is used in geriatric patients.It is very important of local anaesthetic dose for spinal anaesthesia in geriatric patients.The purpose of this study was to determine of the median effective dose(ED50)of 0.5% hypobaric bupivacaine and0.5% hypobaric ropivacaine USp A for geriatric patients undergoing elective hip replacement surgery.Part 2: Many geriatric patients undergoing hip replacement surgery usually combine with chronic obstructive pulmonary disease,it is very important for geriatric patients to find a safety and effectivity anesthesia method.The risk of pulmonary complications and mortality are increase post-operation when perform general anesthesia.The present study was designed to evaluate the safety and effectivity of single shot hypobaric unilateral spinal anaesthesia and general anesthesia in geriatric patients with chronic obstructive pulmonary disease undergoing hip replacement surgery,and evaluate the advantage and disadvantage respective.Methods:Part 1: A total of 60 geriatric patients with American Society of Anesthesiologists(ASA)physical status I and ?,and scheduled for elective hip replacement surgery were enrolled in this study.The patients were randomized into 2 groups to receive either intrathecal 0.5% hypobaric bupivacaine unilateral spinal anaesthesia(USp A)(Group B),or 0.5% hypobaric ropivacaine unilateral spinal anaesthesia (USp A)(Group R).Effective anaesthesia was defined as a T10 sensory blockade level maintained for more than 60 min,and a Bromage score of 3 on the operation side within 10 min after injection with no additional epidural anaesthetic required during surgery.If the response of the previous patient was effective,the dose of intrathecal hypobaric local anaesthetic for the next patient was decreased to next level in that group.Conversely,if the response of the patient was ineffective,the dose of intrathecal hypobaric local anaesthetic for the next patient was increased to upper level in that group.The ED50 of 0.5% hypobaric bupivacaine and 0.5% hypobaric ropivacaine was calculated using the Dixon and Massey formula.Part 2: A total of 90 geriatric patients with American Society of Anesthesiologists(ASA)physical status I and ?,and scheduled for elective hip replacement surgery were enrolled in this study,all patients combine with chronic obstructive pulmonary disease.All patients divide into three groups randomize,General anesthesia group(Group G),Hypobaric bupivacaine(Group B),and Hypobaric ropivacaine(Group R).According to the results of the first part,all patients in Group B received single shot hypobaric unilateral spinal anaesthesia with 0.5% bupivacaine 5mg and in Group R received single shot hypobaric unilateral spinal anaesthesia with 0.5%ropivacaine 7mg.All patients remained the lateral position until the end of surgery.Observed and recorded the variations of mean arterial blood pressure(MAP)and heart rate(HR)at baseline and after anesthesia 5,10,15 and 30 min in three groups,the sensory blockade level was determined and the motor block was evaluated with a modified Bromage scale in Group B and Group R.The side effects and complications of anaesthesia were recorded in three groups.Recorded and evaluated the pulmonary complications,and the patients need to transfer to ICU undergoing respiratory support therapy.Results:Part 1: No significant differences were found between the two groups in terms of demographic data(age,weight,gender and height,ASA classification,surgery duration,and sensory block duration)(P>0.05),and no significant differences of the incidences of USp A side effects,such as hypotension,nausea and vomiting,shivering,PDPH,urinary retention,respiratory depression and number of ephedrine bolus during the perioperative period in two groups(P>0.05).The ED50 of 0.5%hypobaric bupivacaine USp A was 4.66(95% CI: 4.69--4.63)mg and that of 0.5%hypobaric ropivacaine USp A was 6.43(95% CI: 6.47--6.39)mg for geriatric patients undergoing hip replacement surgery.Part 2: The significant differences were found when the MAP at the time of 5min and 10 min after anesthesia compared with the baseline values in Group G(P?0.05).There were significant increase including pulmonary complications,number of patients transfer to ICU and the time of residence ICU in group G compared with group B and group R(P?0.05).The side effects including hypotension,nausea and vomiting,shivering,respiratory depression,and number of ephedrine bolus were significant increase in group G compared with group B and group R(P?0.05).Conclusion:Part 1: The ED50 of 0.5% hypobaric bupivacaine and ropivacaine was 4.66(95% CI:4.69--4.63)mg and 6.43(95% CI: 6.47--6.39)mg,respectively,for USp A in geriatric patients(age?70 yr)undergoing elective hip replacement surgery.Part 2: There were lower incidences of side effects and very good hemodymamic stability when perform hypobaric unilateral spinal anesthesia for geriatric patients with chronic obstructive pulmonary disease undergoing hip replacement surgery compared with general anesthesia,and advantage of lower pulmonary complications.On the contrary,there were significant increase including pulmonary complications,number of patients transfer to ICU and the time of residence ICU when perform general anesthesia in the patients with anticoagulants,and disadvantage of higher respiratory support therapy.