The Study Of Safety And Efficacy Of Patient Controlled Analgesia-target Controlled Infusion Of Sufentanil In The Elderly Patients

BackgroundPatient-controlled analgesia(PCA) is an analgesia mode which is controlled by the patients themselves according to their own needs within the limits of computer setting. It came into use in 1950'. It embodies the medication rules of ideal analgesia, and relieves patients'pain immediately and effectively. PCA is widely used in clinical anasethesia now. There are different modes of PCA now, including intravenous PCA, epidural PCA, intrathecal PCA, nerve block PCA, subcutaneouly PCA, and so on.Target-controlled infusion(TCI) is an intravenous infusion system, based on pharmacokinetic and pharmacodynamic model. The target-concentration is controlled by a computer, and it can be adjusted by patients themselves. It is a great milestone in the history of intravenous anaesthesia, and is widely used in clinical anaesthesia now because of its accuracy and controllability.It is called patient controlled analgesia-target controlled infusion (PCA-TCI) when TCI is used for postoperative patient-controlled analgesia. Firstly, PCA-TCI is a target-controlled infusion obtaining a target concentration quickly previous set by the computer, secondly, it is a patient-controlled analgesia system. The target concentration increases or decreases according to the requirement of the patients, it thus highly consistents with the basic rules of individualization for analgesia. Sufentanil is a newμ-receptor agonist, with the strongest analgesic effect in the fentanyl family. It is also a good analgesic anaesthetic for PCA-TCI because of its short on-set time and long duration, without cumulative character when used for hours.Nowadays, with the development of the quality of life and medical conditions, the average life span in our country is becoming longer, the ratio of the old people is becoming larger, the elderly inpatients are becoming more and more. So the method for postoperative analgesia of the elderly patients arises the concern of the society.In this study we observed the impact of PCA-TCI of sufentanil on the respiratory function of the elderly patients, calculated the EC50 of plasma concentration of sufentanil for respiratory depression in the elderly patients with Dixon's up-and-down method, and evaluated the safety and efficacy of PCA-TCI of sufentanil in the elderly patients for postoperative analgesia.Part one EC50 of plasma concentration of sufentanil for respiratory depression in the elderly patients after spinal anaesthesiaObjectiveTo determine the EC50 of plasma concentration of sufentanil administered by target-controlled infusion for respiratory depression in the elderly patients after spinal anaesthesia with Dixon's up-and-down method.MethodsUnder the permission of Ethics Committee of the hospital, thirty patients, ASAâ… ^â…¡, aged 65⁸5yrs, weight 45⁷8kg, BMI<30kg/m2, scheduled for selectived operation of lower limbs or perineal region were included in this study. Exclusive criterion were: long-term drug or alcohol abuse history, chronic obstructive disease of lung, hypersensitive to opioids and intrathecal contraindication. Spinal anaesthesia was performed L2-3 by left recumbent with 25G needle, 0.5% Ropivacaine 2.0ml 10mg(finished in 10¹5s) was gave. When sensor block plane was fixed at T10, PCA-TCI of sufentanil was performed, the plasma concentration increased or decreased according to the response of previous patient. The plasma target concentration for the first patient was 0.15μg/L according to the result of preliminary test, the concentration for the next patient would decrease to a lower level if there happened respiratory depression in this patient, increased if not. The equation value of the logarithm of two next target concentration was 0.025. BP, ECG and SpO2 were monitored; VT,MV,RR,PETCO2,FEV1%,O2I-E and PV circle were recorded with Datex-Ultima breathing mechanics monitoring device by side stream method. Respiratory depression was judged when the patient felt dyspneaed or RR≤8 bpm or the apnea time≥15s and/or SpO2≤90%or PETCO2≥55mmHg, and/or PaCO2≥55mmHg.ResultThe study was over at the 19th patient. The EC50 of plasma concentration of sufentanil for respiratory depression in the elderly patients after spinal anaesthesia was 0.16μg/L(95% confidence interval was 0.155～0.165μg/L). After TCI of sufentanil started, RR decreased to 20.1～23.4% (p<0.05) at 30～40min, FEV1% decreased to 12.9% (p>0.05) at 35～40min, PETCO2 increased to 16.5～23.9% (p<0.05) at 35～40min. There weren't significantly differece of other resperation parameter at the other time compared to T0.ConclusionThe EC₅₀ of plasma concentration of sufentanil for respiratory depression in the elderly under spinal anaesthesia was 0.16μg/L when the sense blockage plane was T10, 95% confidence interval was 0.155～0.165μg/L. We recommended sufentanil plasma target concentration <0.16μg/L for analgesia in the elderly patients. Part two Patient controlled analgesia-target controlled infusion of sufentanil for postoperative analgesia in the elderly patients after transurethral resection of benign prostatic hyperplasia(TURP)ObjectiveTo evaluate the safety and efficacy of patient controlled analgesia-target controlled infusion of sufentanil for postoperative analgesia in the elderly patients after TURP.MethodUnder the permission of Ethics Committee of the hospital, sixty elderly patients, ASAâ… ^â…¡, aged 65～90, scheduled for operation of TURP were randomized divided into four groups(n=15). Groupâ… : controlled group, PCEA with morphine 0.06mg/L+ 0.2%Ropivacaine+0.9%Normal saline all together 50ml, loading dose 5ml, continuous 1ml/h, bolus 1ml, lock time 10 min; groupâ…¡: PCA-TCI, sufentanil plasma target concentration(CP) was set initial 0.06μg/L, minimum CP 0.04μg/L; groupâ…¢: PCA-TCI, sufentanil plasma target concentration(CP) was set initial 0.08μg/L, minimum CP 0.05μg/L; groupâ…£: sufentanil plasma target concentration(CP) was set initial 0.10μg/L, minimum CP 0.05μg/L. The anesthetic was the same for groupâ…¡,â…¢andâ…£, it was mixture of sufentanil lμg/L and 0.9%Normal saline all together 50 ml. After the operation, when the sense block scale decreased to T10, the analgesia device was started. The visual simulation score(VAS), Ramsay sedation score, Bromage score, sufentanil plasma target concentration(CP), contractive blood pressure(SBP), diastolic blood pressure(DBP), heart rate(HR), saturation of blood oxygen(SpO2), respiratory rate(RR) and patients'satisfaction with the analgesia device, the frequency of pressing bolus by the patient(D1) and the frequency of bolus dose delivered(D2) were monitored and recorded at 0h before the equipment started and 1,2,4,8,16,24h after the analgesia device was started; the time when the patient broke wind and possible adverse reaction were recorded.ResultAll patients in the four groups were satisfied with the PCA device. There was no significant difference in Ramsay score and adverse reaction (p>0.05); there was no significant difference in VAS and D1/D2 among groupâ… ,â…¢andâ…£(p>0.05), VAS score in groupâ…¡at 1,2,4h was higher (p<0.05) compared to groupâ…¢andâ…£; the motion blockage recovered time was shorter in groupâ…¡,â…¢,â…£compared to groupâ… (p<0.05); all patients broke wind in 24h, the time was longer in groupâ… compared to other three group(p<0.05). Sufentanil CP of groupâ…¢was lower than in groupâ…£and was higher than in groupâ…¡at 1 and 2h(p<0.01), and it was lower than in groupâ…¡at 8 and 16h (p<0.05).ConclusionPCA-TCI of sufentanil used in elderly patients for postoperative analgesia after TURP is effective and safe. In PCA-TCI when sufentanil CP was set initial 0.08μg/L and minimum 0.05μg/L, the VAS was lower and drug consumption was less.