Preemptive Analgesia Of Morphine For The Patients Undergoing Cardiac Surgery

Background For the patients undergoing cardiac sugery,the pain evoked by surgery may result in abnormal haemodynamics andarrythmia. Therefore, methods for effective pain control are required.Experimental and clinical data suggest that morphine possesses uniquecardioprotective and antiinflammatory properties, however, the preemptiveanalgesic effect of morphine in cardiac sugery remains unknown. ObjectiveTo evaluate the preemptive analgesic effect of morphine in patients undergoingcardiac surgery. Methods Ninety patients undergoing cardiac surgerywere randomed to three groups and received different analgesic method:(1)Group S: the PCA was implemented using the mixture of sufentanil (100ug),tropisetron (5mg), and saline with basal infusion of2ml/h, bolus dose of2mland lockout time of20min. PCA was administered as soon as cardiac surgerycompleted.(2) Group M: Morphine with a bolus of2mg was administeredintravenously each20min after cardiopulmonary bupass stopped, and the totaldosage was8mg. Additionally, PCA treatment was given according to themethod of group S.(3) Group MS: Low-dose Morphine was pumped with0.3mg/h as a backgroud analgesia, combined with PCA treatment according tothe method of group S. VAS scores, Ramsay scores, haemodynamics data(SBP,HR) and SpO2at6,9,12,24,36,48h were compared in three groups. Sufentanilconsumption, and adverse effects were recorded and analyzed. Results (1) Compared with Group S and Group MS, the VAS score in Group M wassignificantly lower at6,9,12,24,36h（p<0.05）, and there was no differenceamong three groups in VAS scores at48h. No differece was found in VASscores between Group S and Group MS in above time point(p>0.05).(2)Compared with Group S, there was higher Ramsay score in Group M at6,9,12,24,36h（p<0.05）. The patients in Group MS had higher Ramsay scores at9,12,24,36h, compared with Group S（p<0.05）.(3) Sufentanil consumption inGroup M (80±5.4ml） was significantly lower than that in Group S（92±7.7ml）and Group MS（89±6.8ml)（p<0.05）.(4) HR and SBP in Group S annd GroupMS were significantly higher than that in Group M, and there was no differencein SpO2among three groups.(5) There was no difference in the adverse effectssuch as dizziness, lethargy, vomitting, prurtus among three groups(p>0.05), andthe incidence of urinary retention in Group MS was higher than Group S andGroup M. The total incidence of adverse effects in Group MS(43.3%) wassignificantly higher than that in Group S(20%) and Group M(23.3%（)p<0.05）.Conclusions Morphine provided effect of preemptive analgesia in patientsundergoing cardiac surgery. It reduced the VAS scores, Ramsay scores, andsufentanil consumption. Additionally, it didn’t increase the incidence of adverseeffects and may present a better analgesia stragety in the patients undergoingcardiac surgery.