human
***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background —In patients with ischemic heart disease , high thoracic epidural analgesia ( TEA ) has been proposed to improve abnormalities of coronary function by inhibiting cardiac sympathetic tone . We evaluated the effect of TEA on myocardial blood flow in patients with ischemic heart disease . Methods and Results —Twenty male patients with multivessel ischemic heart disease were studied . An epidural catheter was inserted between the second and third thoracic vertebral interspace ( Th2 to Th3 ) . Analgesia was induced by epidural injection of bupivacaine 0.5 % , and a sensory block from the sixth cervical ( C6 to C7 ) to Th10 ( Th8 to Th11 ) vertebral interspace was achieved . Myocardial blood flow was measured with dynamic 13N-ammonia PET with and without TEA at rest , during pharmacological vasodilation with dipyridamole , and during sympathetic stimulation with the cold pressor test . Myocardial blood flow during dipyridamole increased similarly , regardless of TEA , in all regions except in myocardium subtended by collateral arteries in which blood flow increased more with than without TEA ( P<0.05 ) . Without TEA , myocardial blood flow during the cold pressor test remained unchanged compared with myocardial blood flow at rest . In contrast , with TEA , myocardial blood flow increased in all vascular territories . Coronary vascular resistance increased during the cold pressor test without TEA , whereas with TEA , coronary resistance decreased in myocardium subtended by nonstenotic and stenotic coronary vessels and remained unchanged in myocardium subtended by occluded vessels . Conclusions —In patients with multivessel ischemic heart disease , TEA partly normalizes the myocardial blood flow response to sympathetic stimulation We investigated whether perioperative extensive epidural block ( C3-L ) affects postoperative immune response in patients undergoing radical esophagectomy . Patients undergoing radical esophagectomy were r and omly assigned to either general anesthesia with continuous epidural infusion via 2 epidural catheters that was continued for postoperative analgesia ( group E , n = 15 ) or intraoperative general anesthesia and postoperative IV morphine analgesia ( group G , n = 15 ) . Plasma levels of stress hormones , cytokines , C-reactive protein ( CRP ) , leukocyte counts , and distribution of lymphocyte subsets were assessed before and after surgery and on postoperative days ( PODs ) 1 and 3 . In comparison with group E , significant increases in plasma epinephrine level at the end of surgery ( P < 0.05 ) and norepinephrine level at the end of surgery ( P < 0.01 ) and on POD1 ( P < 0.01 ) and POD3 ( P < 0.01 ) and significant decrease in cluster of differentiation ( CD4/CD8 ratio ) at the end of surgery ( P < 0.05 ) were observed in group G. However , there were no significant differences in other variables between groups . In both groups , plasma cortisol , adrenocorticotropic hormone , interleukin (IL)-1β , IL-6 , IL-10 , and CRP levels were increased after surgery ( each group P < 0.01 ) and IL-1β , IL-6 , IL-10 , and CRP were still increased on POD1 and POD3 ( each change , each group P < 0.01 ) . Leukocyte counts were increased on POD1 ( each group P < 0.05 ) and POD3 ( each group P < 0.01 ) . The proportion of lymphocytes decreased from the end of surgery to POD3 ( each group P < 0.01 ) . The proportion of B cells was increased on POD1 ( each group P < 0.01 ) ; that of natural killer cells was decreased at POD1 and POD3 ( each group P < 0.01 ) . We conclude that tissue damage and inflammation apparently overcome the effects of extensive epidural block on stress response and immune function in radical esophagectomy The aim of this trial was to compare  multimodal optimization  with  conventional perioperative management  in a consecutive series of patients undergoing a wide range of colorectal procedures Background Perioperative myocardial ischemia occurs in 35 % of unselected elderly patients undergoing hip fracture surgery .  Perioperative epidural analgesia may reduce the incidence of adverse cardiac events . Methods The effect of early administration of epidural analgesia during the stressful presurgical period , on preoperative cardiac events was evaluated in a prospect i ve r and omized study in 68 patients with hip fractures who either had known coronary artery disease or were at high risk for coronary artery disease . On admission to the emergency room , patients were assigned to receive a usual care analgesic regimen ( intramuscular meperidine , control group , n = 34 ) or continuous epidural infusion of local anesthetic and opioid ( epidural group , n = 34 ) . Monitoring in the preoperative period included a preoperative history and physical examination , daily assessment of cardiac adverse events , serial electrocardiograms , cardiac enzymes , and pain scores . Results Preoperative adverse cardiac events were significantly more prevalent in the control group compared with the epidural group ( 7 of 34 vs. 0 of 34;P = 0.01 ) . Adverse cardiac events included fatal myocardial infa rct ion in three , fatal congestive heart failure in one , nonfatal congestive heart failure in one , and new onset atrial fibrillation in two . The incidence of intraoperative and postoperative adverse cardiac events was similar for the two groups . The significant difference between groups in the incidence of preoperative cardiac events prompted interruption of the study after the planned interim analysis . Conclusions The authors ’ data indicate that compared with conventional analgesia , early administration of continuous epidural analgesia is associated with a lower incidence of preoperative adverse cardiac events in elderly patients with hip fracture who have or are at risk for coronary artery disease . Preoperative epidural analgesia may be advantageous for this surgical population Background Because general anesthesia with tracheal intubation can elicit life-threatening bronchospasm in patients with bronchial hyperreactivity , epidural anesthesia is often preferred . However , segmental high thoracic epidural anesthesia ( sTEA ) causes pulmonary sympathetic and respiratory motor blockade . Whether it can be safely used for chest wall surgery as a primary anesthetic technique in patients with chronic obstructive pulmonary disease or asthma is unclear . Furthermore , ropivacaine supposedly evokes less motor blockade than bupivacaine and might minimize side effects . To test the feasibility of the technique and the hypotheses that ( 1 ) sTEA with ropivacaine or bupivacaine does not change lung function and ( 2 ) there is no difference between sTEA with ropivacaine or bupivacaine , the authors studied 20 patients with severe chronic obstructive pulmonary disease ( forced expiratory volume in 1 s [ FEV1 ] = 52.1 ± 17.3 % of predicted [ mean ± SD ] ) or asthma who were undergoing breast surgery . Methods In a double-blind , r and omized fashion , sTEA was performed with 6.6 ± 0.5 ml of either ropivacaine , 0.75 % ( n = 10 ) , or bupivacaine , 0.75 % ( n = 10 ) . FEV1 , vital capacity , FEV1 over vital capacity , spread of analgesia ( pin prick ) , h and and foot skin temperatures , mean arterial pressure , heart rate , and local anesthetic plasma concentrations were measured with patients in the sitting and supine positions before and during sTEA . Results Segmental high thoracic epidural anesthesia ( segmental spread C4–T8 [ bupivacaine ] and C5–T9 [ ropivacaine ] ) significantly decreased FEV1 from 1.22 ± 0.54 l ( supine ) to 1.09 ± 0.56 l ( ropivacaine ) and from 1.23 ± 0.49 l to 1.12 ± 0.46 l ( bupivacaine ) . In contrast , FEV1 over vital capacity increased from 64.6 ± 13.5 to 68.2 ± 14.5 % ( ropivacaine ) and from 62.8 ± 12.4 to 66.5 ± 13.6 % ( bupivacaine ) . There was no difference between ropivacaine and bupivacaine . Skin temperatures increased significantly , whereas arterial pressure and heart rate significantly decreased indicating widespread sympathetic blockade . All 20 patients tolerated surgery well . Conclusions Despite sympathetic blockade , sTEA does not increase airway obstruction and evokes only a small decrease in FEV1 as a sign of mild respiratory motor blockade with no difference between ropivacaine and bupivacaine . Therefore , sTEA can be used in patients with severe chronic obstructive pulmonary disease and asthma undergoing chest wall surgery  as an alternative technique to general anesthesia Optimal analgesia is important after thoracotomy in pulmonary-limited patients to avoid pain-related pulmonary complications . Thoracic epidural anesthesia ( TEA ) can provide excellent pain relief . However , potential paralysis of respiratory muscles and changes in bronchial tone might be unfavorable in patients with end-stage chronic obstructive pulmonary disease ( COPD ) . Therefore , we evaluated the effect of TEA on maximal inspiratory pressure , pattern of breathing , ventilatory mechanics , and gas exchange in 12 end-stage COPD patients .  Pulmonary resistance , work of breathing , dynamic intrinsic positive end-expiratory pressure , and peak inspiratory and expiratory flow rates were evaluated by assessing esophageal pressure and airflow . An increase in minute ventilation ( 7.50 ± 2.60 vs 8.70 ± 2.10 L/min;P = 0.04 ) by means of increased tidal volume ( 0.46 ± 0.16 vs 0.53 ± 0.14 L/breath;P = 0.003 ) was detected after TEA . These changes were accompanied by an increase in peak inspiratory flow rate ( 0.48 ± 0.17 vs 0.55 ± 0.14 L/s;P = 0.02 ) and a decrease in pulmonary resistance ( 20.7 ± 9.9 vs 16.6 ± 8.1 cm H2O · L−1 · s−1;P = 0.02 ) . Peak expiratory flow rate , dynamic intrinsic positive end-expiratory pressure , work of breathing , Pao2 , and maximal inspiratory pressure were unchanged ( all P > 0.50 ) . We conclude that TEA with bupivacaine 0.25 % can be used safely in end-stage COPD patients BACKGROUND Epidural block is widely used to manage major abdominal surgery and postoperative analgesia , but its risks and benefits are uncertain . We compared adverse outcomes in high-risk patients managed for major surgery with epidural block or alternative analgesic regimens with general anaesthesia  in a multicentre r and omised trial . METHODS 915 patients undergoing major abdominal surgery with one of nine defined comorbid states to identify high-risk status were r and omly assigned intraoperative epidural anaesthesia and postoperative epidural analgesia for 72 h with general anaesthesia ( site of epidural selected to provide optimum block ) or control . The primary endpoint was death at 30 days or major postsurgical morbidity . Analysis by intention to treat involved 447 patients assigned epidural and 441 control . FINDINGS 255 patients ( 57.1 % ) in the epidural group and 268 ( 60.7 % ) in the control group had at least one morbidity endpoint or died ( p=0.29 ) . Mortality at 30 days was low in both groups ( epidural 23 [ 5.1 % ] , control 19 [ 4.3 % ] , p=0.67 ) . Only one of eight categories of morbid endpoints in individual systems ( respiratory failure ) occurred less frequently in patients managed with epidural techniques ( 23 % vs 30 % , p=0.02 ) . Postoperative epidural analgesia was associated with lower pain scores during the first 3 postoperative days . There were no major adverse consequences of epidural-catheter insertion . INTERPRETATION Most adverse morbid outcomes in high-risk patients undergoing major abdominal surgery are not reduced by use of combined epidural and general anaesthesia and postoperative epidural analgesia . However , the improvement in analgesia , reduction in respiratory failure , and the low risk of serious adverse consequences suggest that many high-risk patients undergoing major intra-abdominal surgery will receive substantial benefit from combined general and epidural anaesthesia intraoperatively with continuing postoperative epidural analgesia It has been suggested that the incidence of early graft occlusion after arterial reconstructive surgery to the leg may be decreased by epidural analgesia . This effect may be mediated by the suppression of the usual cortisol response to surgery , which results in increased circulating plasminogen activator inhibitor-1 with consequent adverse effects on fibrinolysis . To investigate this and other potential mechanisms , 30 patients undergoing arterial reconstructive surgery to the leg were r and omized to receive either general anaesthesia or general anaesthesia plus epidural analgesia . Post-operative analgesia was 
    Output:
    
agent
The majority of evidence favors an ability of epidural analgesia to reduce postoperative cardiovascular and pulmonary complications only after major vascular surgery or in high-risk patients .
This finding may become irrelevant because of rapid conversion of major surgery to minimally invasive techniques ( e.g. , endoluminal abdominal aortic repair ) that carry less risk of complications .
There is also consistent evidence that epidural analgesia with local anesthetics is associated with faster resolution of postoperative ileus after major abdominal surgery .
Again , this finding may also become irrelevant with the adoption of laparoscopic techniques and multimodal fast-track programs for abdominal surgery .
There is no current evidence that perineural analgesia , continuous wound catheters using local anesthetics , IV patient-controlled analgesia with opioids , or addition of multimodal systemic analgesics have any clinical ly significant beneficial effect on postoperative complications .
CONCLUSIONS : Overall , there is insufficient evidence to confirm or deny the ability of postoperative analgesic techniques to affect major postoperative mortality or morbidity .
This is primarily due to typically insufficient subject numbers to detect differences in currently low incidences of postoperative complications
***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background —In patients with ischemic heart disease , high thoracic epidural analgesia ( TEA ) has been proposed to improve abnormalities of coronary function by inhibiting cardiac sympathetic tone . We evaluated the effect of TEA on myocardial blood flow in patients with ischemic heart disease . Methods and Results —Twenty male patients with multivessel ischemic heart disease were studied . An epidural catheter was inserted between the second and third thoracic vertebral interspace ( Th2 to Th3 ) . Analgesia was induced by epidural injection of bupivacaine 0.5 % , and a sensory block from the sixth cervical ( C6 to C7 ) to Th10 ( Th8 to Th11 ) vertebral interspace was achieved . Myocardial blood flow was measured with dynamic 13N-ammonia PET with and without TEA at rest , during pharmacological vasodilation with dipyridamole , and during sympathetic stimulation with the cold pressor test . Myocardial blood flow during dipyridamole increased similarly , regardless of TEA , in all regions except in myocardium subtended by collateral arteries in which blood flow increased more with than without TEA ( P<0.05 ) . Without TEA , myocardial blood flow during the cold pressor test remained unchanged compared with myocardial blood flow at rest . In contrast , with TEA , myocardial blood flow increased in all vascular territories . Coronary vascular resistance increased during the cold pressor test without TEA , whereas with TEA , coronary resistance decreased in myocardium subtended by nonstenotic and stenotic coronary vessels and remained unchanged in myocardium subtended by occluded vessels . Conclusions —In patients with multivessel ischemic heart disease , TEA partly normalizes the myocardial blood flow response to sympathetic stimulation We investigated whether perioperative extensive epidural block ( C3-L ) affects postoperative immune response in patients undergoing radical esophagectomy . Patients undergoing radical esophagectomy were r and omly assigned to either general anesthesia with continuous epidural infusion via 2 epidural catheters that was continued for postoperative analgesia ( group E , n = 15 ) or intraoperative general anesthesia and postoperative IV morphine analgesia ( group G , n = 15 ) . Plasma levels of stress hormones , cytokines , C-reactive protein ( CRP ) , leukocyte counts , and distribution of lymphocyte subsets were assessed before and after surgery and on postoperative days ( PODs ) 1 and 3 . In comparison with group E , significant increases in plasma epinephrine level at the end of surgery ( P < 0.05 ) and norepinephrine level at the end of surgery ( P < 0.01 ) and on POD1 ( P < 0.01 ) and POD3 ( P < 0.01 ) and significant decrease in cluster of differentiation ( CD4/CD8 ratio ) at the end of surgery ( P < 0.05 ) were observed in group G. However , there were no significant differences in other variables between groups . In both groups , plasma cortisol , adrenocorticotropic hormone , interleukin (IL)-1β , IL-6 , IL-10 , and CRP levels were increased after surgery ( each group P < 0.01 ) and IL-1β , IL-6 , IL-10 , and CRP were still increased on POD1 and POD3 ( each change , each group P < 0.01 ) . Leukocyte counts were increased on POD1 ( each group P < 0.05 ) and POD3 ( each group P < 0.01 ) . The proportion of lymphocytes decreased from the end of surgery to POD3 ( each group P < 0.01 ) . The proportion of B cells was increased on POD1 ( each group P < 0.01 ) ; that of natural killer cells was decreased at POD1 and POD3 ( each group P < 0.01 ) . We conclude that tissue damage and inflammation apparently overcome the effects of extensive epidural block on stress response and immune function in radical esophagectomy The aim of this trial was to compare  multimodal optimization  with  conventional perioperative management  in a consecutive series of patients undergoing a wide range of colorectal procedures Background Perioperative myocardial ischemia occurs in 35 % of unselected elderly patients undergoing hip fracture surgery .  Perioperative epidural analgesia may reduce the incidence of adverse cardiac events . Methods The effect of early administration of epidural analgesia during the stressful presurgical period , on preoperative cardiac events was evaluated in a prospect i ve r and omized study in 68 patients with hip fractures who either had known coronary artery disease or were at high risk for coronary artery disease . On admission to the emergency room , patients were assigned to receive a usual care analgesic regimen ( intramuscular meperidine , control group , n = 34 ) or continuous epidural infusion of local anesthetic and opioid ( epidural group , n = 34 ) . Monitoring in the preoperative period included a preoperative history and physical examination , daily assessment of cardiac adverse events , serial electrocardiograms , cardiac enzymes , and pain scores . Results Preoperative adverse cardiac events were significantly more prevalent in the control group compared with the epidural group ( 7 of 34 vs. 0 of 34;P = 0.01 ) . Adverse cardiac events included fatal myocardial infa rct ion in three , fatal congestive heart failure in one , nonfatal congestive heart failure in one , and new onset atrial fibrillation in two . The incidence of intraoperative and postoperative adverse cardiac events was similar for the two groups . The significant difference between groups in the incidence of preoperative cardiac events prompted interruption of the study after the planned interim analysis . Conclusions The authors ’ data indicate that compared with conventional analgesia , early administration of continuous epidural analgesia is associated with a lower incidence of preoperative adverse cardiac events in elderly patients with hip fracture who have or are at risk for coronary artery disease . Preoperative epidural analgesia may be advantageous for this surgical population Background Because general anesthesia with tracheal intubation can elicit life-threatening bronchospasm in patients with bronchial hyperreactivity , epidural anesthesia is often preferred . However , segmental high thoracic epidural anesthesia ( sTEA ) causes pulmonary sympathetic and respiratory motor blockade . Whether it can be safely used for chest wall surgery as a primary anesthetic technique in patients with chronic obstructive pulmonary disease or asthma is unclear . Furthermore , ropivacaine supposedly evokes less motor blockade than bupivacaine and might minimize side effects . To test the feasibility of the technique and the hypotheses that ( 1 ) sTEA with ropivacaine or bupivacaine does not change lung function and ( 2 ) there is no difference between sTEA with ropivacaine or bupivacaine , the authors studied 20 patients with severe chronic obstructive pulmonary disease ( forced expiratory volume in 1 s [ FEV1 ] = 52.1 ± 17.3 % of predicted [ mean ± SD ] ) or asthma who were undergoing breast surgery . Methods In a double-blind , r and omized fashion , sTEA was performed with 6.6 ± 0.5 ml of either ropivacaine , 0.75 % ( n = 10 ) , or bupivacaine , 0.75 % ( n = 10 ) . FEV1 , vital capacity , FEV1 over vital capacity , spread of analgesia ( pin prick ) , h and and foot skin temperatures , mean arterial pressure , heart rate , and local anesthetic plasma concentrations were measured with patients in the sitting and supine positions before and during sTEA . Results Segmental high thoracic epidural anesthesia ( segmental spread C4–T8 [ bupivacaine ] and C5–T9 [ ropivacaine ] ) significantly decreased FEV1 from 1.22 ± 0.54 l ( supine ) to 1.09 ± 0.56 l ( ropivacaine ) and from 1.23 ± 0.49 l to 1.12 ± 0.46 l ( bupivacaine ) . In contrast , FEV1 over vital capacity increased from 64.6 ± 13.5 to 68.2 ± 14.5 % ( ropivacaine ) and from 62.8 ± 12.4 to 66.5 ± 13.6 % ( bupivacaine ) . There was no difference between ropivacaine and bupivacaine . Skin temperatures increased significantly , whereas arterial pressure and heart rate significantly decreased indicating widespread sympathetic blockade . All 20 patients tolerated surgery well . Conclusions Despite sympathetic blockade , sTEA does not increase airway obstruction and evokes only a small decrease in FEV1 as a sign of mild respiratory motor blockade with no difference between ropivacaine and bupivacaine . Therefore , sTEA can be used in patients with severe chronic obstructive pulmonary disease and asthma undergoing chest wall surgery  as an alternative technique to general anesthesia Optimal analgesia is important after thoracotomy in pulmonary-limited patients to avoid pain-related pulmonary complications . Thoracic epidural anesthesia ( TEA ) can provide excellent pain relief . However , potential paralysis of respiratory muscles and changes in bronchial tone might be unfavorable in patients with end-stage chronic obstructive pulmonary disease ( COPD ) . Therefore , we evaluated the effect of TEA on maximal inspiratory pressure , pattern of breathing , ventilatory mechanics , and gas exchange in 12 end-stage COPD patients .  Pulmonary resistance , work of breathing , dynamic intrinsic positive end-expiratory pressure , and peak inspiratory and expiratory flow rates were evaluated by assessing esophageal pressure and airflow . An increase in minute ventilation ( 7.50 ± 2.60 vs 8.70 ± 2.10 L/min;P = 0.04 ) by means of increased tidal volume ( 0.46 ± 0.16 vs 0.53 ± 0.14 L/breath;P = 0.003 ) was detected after TEA . These changes were accompanied by an increase in peak inspiratory flow rate ( 0.48 ± 0.17 vs 0.55 ± 0.14 L/s;P = 0.02 ) and a decrease in pulmonary resistance ( 20.7 ± 9.9 vs 16.6 ± 8.1 cm H2O · L−1 · s−1;P = 0.02 ) . Peak expiratory flow rate , dynamic intrinsic positive end-expiratory pressure , work of breathing , Pao2 , and maximal inspiratory pressure were unchanged ( all P > 0.50 ) . We conclude that TEA with bupivacaine 0.25 % can be used safely in end-stage COPD patients BACKGROUND Epidural block is widely used to manage major abdominal surgery and postoperative analgesia , but its risks and benefits are uncertain . We compared adverse outcomes in high-risk patients managed for major surgery with epidural block or alternative analgesic regimens with general anaesthesia  in a multicentre r and omised trial . METHODS 915 patients undergoing major abdominal surgery with one of nine defined comorbid states to identify high-risk status were r and omly assigned intraoperative epidural anaesthesia and postoperative epidural analgesia for 72 h with general anaesthesia ( site of epidural selected to provide optimum block ) or control . The primary endpoint was death at 30 days or major postsurgical morbidity . Analysis by intention to treat involved 447 patients assigned epidural and 441 control . FINDINGS 255 patients ( 57.1 % ) in the epidural group and 268 ( 60.7 % ) in the control group had at least one morbidity endpoint or died ( p=0.29 ) . Mortality at 30 days was low in both groups ( epidural 23 [ 5.1 % ] , control 19 [ 4.3 % ] , p=0.67 ) . Only one of eight categories of morbid endpoints in individual systems ( respiratory failure ) occurred less frequently in patients managed with epidural techniques ( 23 % vs 30 % , p=0.02 ) . Postoperative epidural analgesia was associated with lower pain scores during the first 3 postoperative days . There were no major adverse consequences of epidural-catheter insertion . INTERPRETATION Most adverse morbid outcomes in high-risk patients undergoing major abdominal surgery are not reduced by use of combined epidural and general anaesthesia and postoperative epidural analgesia . However , the improvement in analgesia , reduction in respiratory failure , and the low risk of serious adverse consequences suggest that many high-risk patients undergoing major intra-abdominal surgery will receive substantial benefit from combined general and epidural anaesthesia intraoperatively with continuing postoperative epidural analgesia It has been suggested that the incidence of early graft occlusion after arterial reconstructive surgery to the leg may be decreased by epidural analgesia . This effect may be mediated by the suppression of the usual cortisol response to surgery , which results in increased circulating plasminogen activator inhibitor-1 with consequent adverse effects on fibrinolysis . To investigate this and other potential mechanisms , 30 patients undergoing arterial reconstructive surgery to the leg were r and omized to receive either general anaesthesia or general anaesthesia plus epidural analgesia . Post-operative analgesia was 
    Output:
    