***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Severe postoperative pain , which may persist for up to 3 days and may lead to postoperative complications , due to the patient 's inability to breathe deeply and cough , is frequently experienced in the area of the incision and chest tubes by thoracotomy patients . Eighteen patients undergoing routine thoracotomies were tested preoperatively for arterial blood gases and pulmonary function and given chest x – rays . Anesthesia consisted of thiopental , succinylcholine , N2O , enflurane , and pancuronium . Before incision closure , 6 intercostal spaces were injected by the surgeon with 3 ml of a r and omly determined drug mixture . Patients received either bupivacaine and saline solution , bupivacaine and LMW dextran 40 , or saline and LMW dextran 40 .  Arterial blood gases , pulmonary function , chest x-rays , narcotic dosage , sensory level , and subjective responses were evaluated for 3 days postoperatively . Results demonstrate that intercostal nerve blocks can markedly reduce postoperative pain and improve pulmonary function in such patients . Significant differences from controls were seen in Paoz , Paces , vital capacity , forced expiratory flow rates , analgesic requirements , and patient comfort . The duration of the block with bupivacaine and saline was less than 12 hours , while the mean duration of the block with bupivacaine and dextran 40 was 36 hours Twenty patients scheduled for lateral thoracotomy were r and omly allocated to receive either epidural morphine at regular intervals or subcutaneous nicomorphine on dem and for postoperative pain relief . The daily dose of opiate administered was greater in the group receiving subcutaneous nicomorphine than in the epidural group although four patients in the latter needed additional subcutaneous injections of opiate . During the first three days of the postoperative course , a profound decrease of the forced vital capacity ( FVC ) , the forced expiratory volume in one second ( FEV1 ) , peak expiratory flow rate ( PEF ) and the arterial oxygen tension ( PaO2 ) was found in both groups , whereas the visual analogue pain score showed a marked increase , and the arterial pH and carbon dioxide tension ( PaCO2 ) remained unchanged . No significant difference could be demonstrated between the group;s . The conclusion is that epidural morphine may produce sufficient pain relief after thoracotomy , but compared with conventional pain treatment the benefits are limited Administration of large doses of fentanyl is a popular method to provide postoperative analgesia after thoracotomy . It is however unclear whether epidural lumbar ( L ) or epidural thoracic ( T ) administration of fentanyl confers any major advantage over intravenous ( iv ) infusion . Using a r and omized prospect i ve study design , we compared the potential benefits of L , T , and iv fentanyl administration after  thoracotomy  in 50 patients .  Epidural catheters were not injected during surgery . Postoperatively a fentanyl infusion ( 5 micrograms/ml ) was started at 1 microgram.kg-1.h-1 after a bolus of 1 microgram/kg and adjusted to maintain a score < or = 30/100 at rest using a visual analog scale ( VAS ) for pain . Data were prospect ively collected before surgery , at fixed intervals during the 48 h of fentanyl infusions , and the day of discharge . There was no difference between the groups in overall quality of analgesia at rest and after coughing , quantity of fentanyl delivered ( L = 1.15 + /- 0.38 , T = 1.22 + /- 0.23 , iv = 1.27 + /- 0.3 micrograms.kg-1.h-1 ) , incidence of pruritus needing treatment ( L = 2 , T = 1 , iv = 0 patients ) , need to decrease fentanyl infusion rate because of side effects ( L = 2 , T = 2 , iv = 4 patients ) , importance of pulmonary infiltrates , or arterial blood gas values . One patient ( L group ) needed  naloxone  ( 0.04 mg iv ) . Intravenous patients were more frequently nauseated ( P = .009 ) and needed boluses of fentanyl more often ( L = 3 + /- 9 , iv = 6 + /- 12 , T = 4 + /- 8 ; P = .04 ) . ( ABSTRACT TRUNCATED AT 250 WORDS In this clinical , r and omized , prospect i ve study , we compared the effects of three different analgesia techniques ( thoracic epidural analgesia [ TEA ] with and without preoperative initiation and IV patient-controlled analgesia [ IV-PCA ] ) on postthoracotomy pain in 69 patients . In two groups , a thoracic epidural catheter was inserted preoperatively . Group Pre-TEA had bupivacaine and morphine solution preoperatively and intraoperatively . Postoperative analgesia was maintained with epidural PCA with a similar solution . Group Post-TEA , with no intraoperative medication , had the same postoperative analgesia as Group Pre-TEA plus the bolus dose . Group IV-PCA received only IV-PCA with morphine for postoperative analgesia . Pain was evaluated every 4 h during the first 48 h at rest , cough , and movement . Pre-TEA was associated with decreased pain compared with the other groups . Six months later , the patients were asked about their pain . The incidence and the intensity of pain were most frequent in Group IV-PCA ( 78 % ) and were the least in Group Pre-TEA ( 45 % ) ( Group Pre-TEA versus Group IV-PCA , P = 0.0233 ; Group Pre-TEA versus Group IV-PCA , P = 0.014 ) . Patients having pain on the second postoperative day had 83 % chronic pain . TEA with preoperative initiation is a preferable method in preventing acute and long-term thoracotomy pain Four different pain treatments ( single intercostal block with bupivacaine , repeated intercostal block , epidural morphine and epidural bupivacaine infusions ) were compared in 39 patients subjected to lung surgery under general anaesthesia . The patients ' own estimate of the postoperative pain was not significantly different between the groups , but the epidurally treated patients required fewer doses of supplementary analgesic than those given just a single dose of intercostal bupivacaine . Bupivacaine levels in blood were below the toxic range in all groups . The concentration of antidiuretic hormone in blood was increased early during the operation , and had only partly returned to normal on the first postoperative morning . Growth hormone in plasma was increased only at the end of the operation . Catecholamine levels in blood increased gradually , reaching their peak postoperatively . There were only slight differences between the groups in these posterior and anterior pituitary and sympatho‐adrenal responses to surgical stress . Thus , neither repeated intercostal blockade nor epidural administration of morphine or bupivacaine could prevent the endocrine responses to thoracic surgery , in spite of significant , albeit incomplete , pain relief . This was probably caused in part by residual pain , and also by poor access of the extradural medications to the autonomic afferent pathways mediating nociceptive signals from thoracic organs and tissues This study was undertaken to evaluate the effectiveness of 0.5 % bupivacaine ( 360 mg/day ) as a continuous infusion through an indwelling intercostal catheter inserted intraoperatively in the management of pain after thoracotomy . Eighty-six patients were r and omized into three groups : group 1 = intercostal bupivacaine , group 2 = intercostal saline solution , and group 3 = fixed-schedule intramuscular buprenorphine . Supplementary buprenorphine was given as required . Pain and pulmonary function were assessed throughout the first 5 days after operation . Pain score was lower in group 1 than in group 2 for the first 8 hours after operation ( p < 0.02 ) . During the first 3 postoperative days , mean postoperative pain scores of 5 or more were recorded in 9 % of group 1 patients versus 40 % of group 2 patients ( p < 0.05 ) and 13 % of group 3 patients ( not significant ) . Total doses of buprenorphine  were lower in groups 1 and 2 than in group 3 ( p < 0.001 ) . No between-group differences in pulmonary function were observed . Respiratory complications occurred in no patients in groups 1 and 3 versus 5 in group 2 ( p < 0.05 ) . Continuous intercostal bupivacaine provided similar early pain control as compared with fixed-schedule narcotics but induced better analgesia with fewer complications than on-dem and narcotics alone ( group 2 ) The purpose of this study was to compare meperidine to meperidine with bupivacaine when used for patient-controlled epidural analgesia ( PCEA ) after thoracotomy . For 3 days after thoracotomy patients received thoracic PCEA with meperidine 0.1 % plain or with added bupivacaine 0.1 % or 0.01 % . No background infusion was used . All patients received indomethacin postoperatively for the duration of the study . Patients were assessed with respect to meperidine consumption , analgesia , and side effects . Sixty-six patients participated . Patients in all three groups obtained effective analgesia with median meperidine consumption of 5 - 6 mg/h . There were no significant differences between groups in meperidine consumption or pain scores at rest or with coughing . The addition of bupivacaine 0.1 % reduced the incidence of pruritus ( P = 0.036 ) , but 5 of 23 patients in this group were withdrawn from the study because of significant hypotension , oliguria , and /or motor or sensory block ( P = 0.006 ) . We conclude that the addition of bupivacaine 0.1 % or 0.01 % to thoracic PCEA meperidine 0.1 % does not affect meperidine requirements or analgesia after thoracotomy . The addition of bupivacaine 0.1 % may reduce pruritus , but is associated with signs of excessive sensory , motor , or autonomic blockade in a significant number of patients . ( Anesth Analg 1996;83:81 - 6 OBJECTIVE Long-term pain is a common sequela of thoracotomy , occurring in approximately 50 % of patients 2 years after thoracic surgery . Despite this alarming statistic , little is known about the factors responsible for the transition of acute to chronic pain . The aim of the present study is to identify predictors of long-term post-thoracotomy pain . DESIGN Follow-up was for 1.5 years for patients who had participated in a prospect i ve , r and omized , controlled trial of preemptive , multimodal analgesia .  SETTING Subjects were recruited from a tertiary care center . PATIENTS Thirty patients who had undergone lateral thoracotomy  were followed up by telephone , administered a structured interview , and classified according to long-term pain status . MAIN OUTCOME MEASURES Present pain status was measured by a verbal rating scale ( VAS ) . Measures obtained within the first 48 h after surgery were compared between patients with and without pain 1.5 years later . These include VAS pain scores at rest and after movement , McGill Pain Question naire data , patient-controlled morphine consumption ( mg ) , and pain thresholds to pressure applied to a rib contralateral to the thoracotomy incision . RESULTS Fifty-two percent of patients reported long-term pain . Early postoperative pain was the only factor that significantly predicted long-term pain . Pain intensity 24 h after surgery , at rest , and after movement was significantly greater among patients who developed long-term pain compared with pain-free patients . A significant predictive relationship was also found at 24 and 48 h using the McGill Pain Question naire . Cumulative morphine was comparable for the two groups . Pain thresholds to pressure applied to a rib contralateral to the incision did not differ significantly between the groups . CONCLUSION Aggressive management of early postoperative pain may reduce the likelihood of long-term post-thoracotomy pain Twenty‐five ASA 1 or 2 patients undergoing thoracotomy were entered into a prospect i ve , r and omised , double‐blind study comparing thoracic epidural fentanyl alone and thoracic epidural fentanyl combined with 0.2 % bupivacaine .  Pain relief , pulmonary function and cardiovascular stability were assessed . Pain relief was superior in the bupivacaine series ( p < 0.05 ) during the first day after operation and this was accompanied by better oxygenation ( p < 0.05 ) ; the difference did not persist into the second day . Forced expiratory variables were reduced in both series to 50–60 % of the values before operation throughout the study ( p < 0.05 ) and differences did not occur between the groups . The incidence of side effects attributable to epidural fentanyl was high , but hypotension did not occur . Small doses of bupivacaine administered together with fentanyl into the thoracic epidural space improve analgesia without causing hypotension The effects of diamorphine hydrochloride 0.1 mg/kg , given either extradurally or intramuscularly for postoperative analgesia were compared in two r and omised double‐blind studies involving 39 patients undergoing thoracotomy and major gynaecological surgery . Assessment s were made at fixed intervals after the administration of diamorphine and consisted of the measurement of pain or analgesic effect . Segmental , sympathetic and any adverse effects were sought . There was no significant difference in the quality of analgesia between the two groups in either trial . Ext 
    Output:
    
RESULTS : Continuous paravertebral block was as effective as thoracic epidural analgesia with local anesthetic ( LA ) but was associated with a reduced incidence of hypotension .
Paravertebral block reduced the incidence of pulmonary complications compared with systemic analgesia , whereas thoracic epidural analgesia did not .
Thoracic epidural analgesia was superior to intrathecal and intercostal techniques , although these were superior to systemic analgesia ; interpleural analgesia was inadequate .
: Either thoracic epidural analgesia with LA plus opioid or continuous paravertebral block with LA can be recommended .