***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Tissue damage during surgery induces coagulation factors and activates platelets . Surgical pain may provoke release of catecholamines , leading to hypercoagulability . We have investigated the effect of surgical pain on blood coagulability and fibrinolysis in orthopaedic operations using tourniquets in 22 patients undergoing total knee replacement . Patients were allocated to one of two groups to receive extradural anaesthesia ( EA ; n = 11 ) or general anaesthesia ( GA ; n = 11 ) . The EA group received lumbar extradural block with lidocaine . The GA group received only general anaesthesia , maintained with 1.5 - 2.5 % sevoflurane and 66 % nitrous oxide in oxygen . Using a thrombelastogram technique , blood coagulability and fibrinolysis were measured . Mean maximum amplitude ( MA ) , which reflects coagulability , increased after tourniquet inflation ( 11 % ) in group GA whereas MA in group EA did not change . After tourniquet deflation , MA values in both GA and EA groups increased significantly ( 10 % and 20 % , respectively ) ( P < 0.05 ) , and there was also a significant difference in MA between groups ( P < 0.05 ) . The fibrinolytic rate did not change in either group during tourniquet inflation , but increased significantly ( 160 % ) after tourniquet deflation . There was no significant difference in fibrinolytic rate between the groups . We conclude that the hypercoagulability seen in group GA could have been caused by surgical or tourniquet pain , or both , and that extradural anaesthesia is a useful technique to prevent hypercoagulability This study compared the effects of general and regional anesthesia on cognitive and psychosocial functioning in elderly persons . Sixty-four patients between 60 and 86 yr of age undergoing knee arthroplasty were r and omly assigned to receive either general or regional anesthesia . A battery of psychometric tests , including the Satz-Mogel form of the Wechsler Adult Intelligence Scale-Revised , the Wechsler Memory Scale-Revised and the Sickness Impact Profile , and various neuropsychological measures were administered by a blinded observer just before surgery and again 3 months later . Analyses of covariance revealed improvements in most measures that were equivalent between groups . The results indicated that there were no cognitive or psychosocial effects of general or regional anesthesia after 3 months in elderly persons undergoing knee arthroplasty . In this patient population , general anesthesia poses no more risk to long-term mental function than regional anesthesia We have studied the effect of extradural analgesia on postoperative venous thrombosis in patients undergoing knee arthroplasty . Forty-eight patients were allocated r and omly to receive either general anaesthesia or extradural analgesia with local anaesthetics for 3 days . All patients wore compressive elastic stockings and no anticoagulant drugs were administered . Bilateral venography was performed 10 days after surgery . Continuous extradural analgesia did not impede mobilization of the patients . One case of nonfatal pulmonary embolism occurred in a patient who received general anaesthesia . The use of continuous extradural analgesia result ed in a significant difference in the total incidence of deep vein thrombosis ( 18 % compared with 59 % after general anaesthesia ( P = 0.02 ] . The incidence of calf vein thrombosis was 12 % compared with 45 % after general anaesthesia ( P = 0.05 ) Seventy-two patients were r and omized into a prospect i ve clinical trial to evaluate the effects of epidural ( EA ) versus general anesthesia ( GA ) on the incidence of thromboembolic disease ( TED )  following total knee arthroplasty ( TKA ) . Males received aspirin 650 mg po bid and females low-dose warfarin daily to maintain the prothrombin time at 15 to 16 seconds for pharmacologic prophylaxis against TED . Thirty-four patients had EA and 38 GA for their primary TKA .  Contrast venography and ventilation-perfusion scanning were performed on the sixth , seventh , and eighth postoperative days , and these were interpreted in a blinded fashion . The mean age of the 45 males and 27 females was 64 years ( range , 42 - 84 years ) . There were no significant differences between the two groups with respect to hematocrit , operative time , blood loss , number of units transfused , or hospital stay . Twelve of the 34 patients ( 35 % ) receiving an EA and 10 of the 38 patients ( 26 % ) receiving GA developed TED , an overall incidence of 31 % ( p greater than 0.05 ) Fifty-three percent of the clots were located in the popliteal vein above the trifurcation or more proximal . However , the incidence of proximal vein thrombosis was significantly less in patients receiving an EA ( 46 % ) rather than a GA ( 64 % ) . The incidence and distribution of clots was not affected by the type of pharmacologic prophylaxis , gender , or use of methylmethacrylate . Ten percent of the patients had a positive scan by strict criteria and were thought to have a pulmonary embolism ( PE ) . In patients with a femoral vein clot , the incidence of PE was 67 % . One bleeding complication occurred in a patient who took double the appropriate warfarin dose . ( ABSTRACT TRUNCATED AT 250 WORDS Background Mood states during epidural opioids are not known . The authors studied the change in mood during the 48‐h period of epidural morphine and epidural fentanyl in 47 patients after elective hip or knee joint arthroplasty . Methods An epidural catheter was inserted at the L2‐L3 or L3‐L4 interspace . Anesthesia was induced with thiopenthal and maintained with isoflurane and nitrous oxide . One hour before the conclusion of the operation , patients received an epidural bolus injection of 2 mg morphine ( n = 23 ) or 100 micro gram fentanyl ( n = 24 ) , followed by the same opiate ( 125 micro gram/ml morphine or 25 micro gram/ml fentanyl ) epidurally delivered by a patient‐controlled analgesia ( PCA ) pump in the postoperative period for 48 h. Mood was assessed using the bipolar form of the Profile of Mood States before operation and 24 h , 48 h , and 72 h after operation . Results There was no significant difference in pain intensity between the groups during epidural PCA .  Mood states became more positive over time in the patients who received morphine ( P < 0.01 at 48 h ) and negative in those who were given fentanyl ( P < 0.01 at 24 and 48 h , respectively ) compared with those before the operation , and they were more positive in the morphine than in the fentanyl group at 24 h , 48 h ( P < 0.05 ) , and 72 h ( P < 0.01 ) . Patients in the morphine group were more composed , agreeable , elated , confident , energetic , and clearheaded than were those in the fentanyl group ( P < 0.05 ) . There was no correlation between mood scores and pain scores in either group . There was an inverse correlation at 48 h between mood scores and plasma fentanyl concentrations ( r = ‐0.58 , P < 0.05 ) . Conclusion Mood states are significantly more positive during epidural morphine PCA than they are during epidural fentanyl PCA Background : Both epidural analgesia and intravenous patient‐controlled analgesia ( PCA ) have been found efficacious after various types of surgery . We compared the efficacy , safety , side effects and patient satisfaction of these methods in a r and omized double‐blind fashion after elective anterior cruciate ligament reconstruction of the knee The purpose of this study was to determine if intra-articular injection of morphine or bupivacaine significantly decreased postoperative pain as well as the use of intravenous narcotics for pain relief in patients undergoing total knee arthroplasty ( TKA ) . In a prospect i ve , double-blind , r and omized fashion , 105 patients undergoing TKA were divided into the following 4 groups defined by the intra-articular injection they received : group 1 ( n = 27 ) received saline solution , group 2 ( n = 26 ) received morphine sulfate ( 5 mg ) , group 3 ( n = 24 ) received bupivacaine ( 50 mg ) , and group 4 ( n = 28 ) received a combination of morphine sulfate and bupivacaine . The injections were administered immediately after wound closure by the Hemovac drainage tubing that remained clamped for 45 minutes after surgery to allow for absorption . Before surgery and at 2 , 4 , 6 , 24 , and 48 hours after surgery , pain intensity was recorded using a visual analog scale . Postoperative supplemental intravenous morphine and /or  meperidine  was administered via a patient-controlled analgesia device , and 24-hour drug usage was tabulated . Results were suggestive of a modest short-term reduction in pain scores in the morphine and bupivacaine treatment groups compared with placebo ( saline ) ; however , results were statistically significant only at 4 hours because of the great variability in the pain score data . The total amount of postoperative pain medication used in the first 24 hours after surgery was not statistically significant between the 4 treatment groups . Thus , the results put into question the benefit of postoperative intra-articular administration of morphine or bupivacaine in patients undergoing TKA Postoperative analgesia after two extradural tramadol regimens was compared with that obtained using a st and ard extradural morphine regimen in patients undergoing total knee replacement .  Extradural anaesthesia with light general anaesthesia was used . Patients received extradurally either : tramadol 50 mg by bolus injection followed by infusion ( 5mg.h‐1 for 12 h and 2.5mg.h‐1 for a further 12 h ) ( group T50 ) , tramadol 100 mg by bolus injection followed by infusion ( 10 mg.h‐1 for 12 h and 5mg.h‐1 for a further 12 h ) ( group T100 ) or morphine sulphate 2 mg by bolus injection followed by infusion ( 0.2 mg.h‐1 for 12 h and at 0.1 mg.h‐1 for a further 12 h ) ( group M ) . Analgesia was allocated according to a controlled double‐blind design . Visual analogue pain scores were markedly poorer ( p < 0.05 ) and patient‐controlled analgesic consumption was significantly greater ( p < 0.01 ) in the two tramadol groups when compared with the morphine group . The study was discontinued after recruitment of 12 patients , as analgesia was deemed inadequate in those receiving tramadol extradurally . However , further study of this drug may be warranted to examine its effectiveness where postoperative pain is expected to be less severe , and to assess the effect of larger extradural doses and of co‐administration of tramadol and morphine by this route OBJECTIVE --To evaluate the efficacy and safety of two subcutaneous prophylactic regimens for postoperative deep vein thrombosis after total hip replacement . DESIGN -- Prospect i ve open r and omised multicentre trial . SETTING --28 European departments of orthopaedic surgery . INTERVENTION -- All patients had bilateral phlebography 10 days after surgery . 31 patients receiving low molecular weight heparin  and 29 receiving unfractionated heparin  were excluded from the efficacy analysis for various reasons . PATIENTS --349 patients undergoing total hip replacement between September 1988 and May 1989 . 174 patients received subcutaneously a low molecular weight heparin ( Fraxiparine ) with anti-factor Xa activity of 41 IU/kg/day for three days , then 62 IU/kg/day from day 4 to day 10 . 175 patients received subcutaneous unfractionated heparin at intervals of eight hours ; doses were adjusted to maintain the activated thromboplastin time at two to five seconds above control values . MAIN OUTCOME MEASURE -- Total incidence of deep vein thrombosis and incidence of proximal deep vein thrombosis on bilateral phlebography . RESULTS --The total incidence of deep vein thrombosis was 16 % in patients receiving unfractionated heparin and 12.6 % in patients receiving low molecular weight heparin ( p = 0.45 ) , and the incidence of thrombosis of the proximal veins was 13.1 % and 2.9 % respectively ( p less than 0.001 ) . Four patients receiving unfractionated heparin and one receiving low molecular weight heparin developed pulmonary embolism . The incidence of bleeding complications was low and comparable in the two groups . CONCLUSION --Low molecular weight heparin is at least as effective as unfractionated heparin in preventing deep vein thrombosis and is more effective at preventing thrombosis of the proximal veins in patients undergoing hip replacement . Low molecular weight heparin is not more likely to cause bleeding complications and is simpler to give than unfractionated heparin This prospect i ve , r and omized , double-blind trial evaluated the efficacy of rectal indomethac 
    Output:
    
The choice of epidural agents may also influence the extent to which epidural analgesia differs from systemic analgesia .
REVIEW ER 'S CONCLUSIONS Epidural analgesia may be useful for postoperative pain relief following major lower limb joint replacements .
However , the benefits may be limited to the early ( four to six hours ) postoperative period .
An epidural infusion of local anesthetic or local anesthetic-narcotic mixture may be better than epidural narcotic alone .
The current evidence is insufficient to draw conclusions on the frequency of rare complications from epidural analgesia , postoperative morbidity or mortality , functional outcomes , or length of hospital stay