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: AIMS To compare 19 risk score algorithms with regard to their validity to predict 30-day and 1-year mortality after cardiac surgery . METHODS AND RESULTS Risk factors for patients undergoing heart surgery between 1996 and 2001 at a single centre were prospect ively collected . Receiver operating characteristics ( ROC ) curves were used to describe the performance and accuracy . Survival at 1 year and cause of death were obtained in all cases . The study included 6222 cardiac surgical procedures .  Actual mortality was 2.9 % at 30 days and 6.1 % at 1 year . Discriminatory power for 30-day and 1-year mortality in cardiac surgery was highest for logistic ( 0.84 and 0.77 ) and additive ( 0.84 and 0.77 ) European System for Cardiac Operative Risk Evaluation ( EuroSCORE ) algorithms , followed by Clevel and Clinic ( 0.82 and 0.76 ) and Magovern ( 0.82 and 0.76 ) scoring systems . None of the other 15 risk algorithms had a significantly better discriminatory power than these four . In coronary artery bypass grafting (CABG)-only surgery , EuroSCORE followed by New York State ( NYS ) and Clevel and Clinic risk score showed the highest discriminatory power for 30-day and 1-year mortality . CONCLUSION EuroSCORE , Clevel and Clinic , and Magovern risk algorithms showed superior performance and accuracy in open-heart surgery , and EuroSCORE , NYS , and Clevel and Clinic in CABG-only surgery . Although the models were originally design ed to predict early mortality , the 1-year mortality prediction was also reasonably accurate The role of pre-operative short-term pulmonary rehabilitation in patients with chronic obstructive pulmonary disease who undergo coronary artery bypass graft surgery has been assessed for the first time prospect ively . Forty-five patients posted for coronary artery bypass graft surgery  were r and omised to receive either short-term pulmonary rehabilitation ( group I ) or no such programme ( group II ) . Patients of both the groups were evenly matched with respect to age , sex , body surface area , duration and severity of chronic obstructive pulmonary disease and coronary artery disease . Normal individuals who evenly matched with the study group were assessed for normal respiratory function parameters . Pre-operative and post-operative peak expiratory flow rate , inspiratory capacity , post-operative ventilation time , post-operative pulmonary complication and hospital stay were determined in both the groups . Peak expiratory flow rate ( 220.0 + /- 12.9 and 324.3 + /- 84.3 in group I , 218.0 + /- 16.4 and 260.5 + /- 35.2 in group II ) and inspiratory capacity ( 844.0 + /- 147.4 and 1100.0 + /- 158.1 in group I , 830.0 + /- 117.4 and 1090 + /- 137 in group II ) were significantly lower before and after surgery respectively in both groups compared to normal values . Even though both groups showed a significant rise in post-operative peak expiratory flow rate and inspiratory capacity after surgery , the post-operative peak expiratory flow rate and inspiratory capacity in group I was significantly higher than in group II . In group I , the post-operative ventilation time ( 24.5 + /- 6.00 hours ) , post-operative complications ( n = 4 ) and hospital stay ( 12.4 + /- 3.6 days ) were significantly lower than in group II ( 35.2 + /- 22.3 hours , n = 11 , 18.8 + /- 6.6 days respectively ) . These data suggest that short-term pulmonary rehabilitation is feasible and effective in improving pulmonary functions before and after surgery and in reducing surgical morbidity and cost of medical care significantly CONTEXT Postoperative pulmonary complications ( PPCs ) after coronary artery bypass graft ( CABG ) surgery are a major source of morbidity and mortality , and increase length of hospital stay and re source utilization . The prehospitalization period before CABG surgery may be used to improve a patient 's pulmonary condition . The efficacy of preoperative inspiratory muscle training ( IMT ) in reducing the incidence of PPCs in high-risk patients undergoing CABG surgery has not yet been determined . OBJECTIVE To evaluate the prophylactic efficacy of preoperative IMT on the incidence of PPCs in high-risk patients scheduled for elective CABG surgery . DESIGN , SETTING , AND PATIENTS A single-blind , r and omized clinical trial conducted at the University Medical Center Utrecht , Utrecht , the Netherl and s , with enrollment between July 2002 and August 2005 . Of 655 patients referred for elective CABG surgery , 299 ( 45.6 % ) met criteria for high risk of developing PPCs , of whom 279 were enrolled and followed up until discharge from hospital . INTERVENTION Patients were r and omly assigned to receive either preoperative IMT ( n = 140 ) or usual care ( n = 139 ) . Both groups received the same postoperative physical therapy . MAIN OUTCOME MEASURES Incidence of PPCs , especially pneumonia , and duration of postoperative hospitalization . RESULTS Both groups were comparable at baseline . After CABG surgery , PPCs were present in 25 ( 18.0 % ) of 139 patients in the IMT group and 48 ( 35.0 % ) of 137 patients in the usual care group ( odds ratio [ OR ] , 0.52 ; 95 % confidence interval [ CI ] , 0.30 - 0.92 ) . Pneumonia occurred in 9 ( 6.5 % ) of 139 patients in the IMT group and in 22 ( 16.1 % ) of 137 patients in the usual care group ( OR , 0.40 ; 95 % CI , 0.19 - 0.84 ) . Median duration of postoperative hospitalization was 7 days ( range , 5 - 41 days ) in the IMT group vs 8 days ( range , 6 - 70 days ) in the usual care group by Mann-Whitney U statistic ( z = -2.42 ; P = .02 ) . CONCLUSION Preoperative IMT reduced the incidence of PPCs and duration of postoperative hospitalization in patients at high risk of developing a pulmonary complication undergoing CABG surgery . TRIAL REGISTRATION is rct n.org Identifier : IS RCT N17691887 This study evaluated the efficacy of the relaxation response on the post-operative recovery of 27 cardiac surgery patients r and omly assigned to one of two groups . Thirteen experimental group patients received educational information and practice d eliciting the relaxation response before and after surgery . The 14 patients in the control group received only information . Experimental and control groups were compared before and after surgery on both physiological and psychological recovery variables . There were no initial differences between experimental and control groups on demographic , physiological , and most psychological variables . The experimental group had lower incidence of postoperative supraventricular tachycardia ( SVT ) than the control group ( p = .04 ) despite having had the same occurrence previously . Experimental and control groups did not significantly differ over the course of study on any other physiological variables . Patients practicing the relaxation response had greater decreases in psychological tension ( p = .04 ) and anger ( p = .04 ) than those who received only educational information . The decreases in psychological tension may have been a result of regression to the mean because the experimental group started with elevated tension relative to the control group ( p = .04 ) . We conclude that practicing the relaxation response before and after surgery may reduce SVT , tension , and anger BACKGROUND Postoperative pneumonia ( PP ) is a major complication that has been linked to microaspiration of pathogens originating in the gastrointestinal tract . This prospect i ve study was performed to define the role of gastric bacterial aspiration in the development of PP . METHODS Informed consent was obtained before operations from 140 veterans scheduled for major elective procedures requiring nasogastric tubes  , and cultures were obtained of the gastric contents and sputum twice daily after operation . RESULTS PP developed in 26 ( 18.6 % ) of 140 patients . The patients who had PP did not differ from those with no pneumonia after operation except for a history of chronic obstructive pulmonary disease , which was found in 38.5 % of those with PP compared with 20 % of patients with no pneumonia ( p < 0.05 ) . Morbidity was increased in association with PP , because length of stay in the surgical intensive care unit ( 6.2 vs 2.6 days ) , days intubated ( 2.7 vs 0.6 ) , total postoperative days ( 15.3 vs 8.4 ) , and mortality rates ( 19.2 % vs 1.7 % ) were greater than in patients with no pneumonia . Gastric pathogens were present on entry in 38 % of patients , and 32 % of these had PP compared with 13 % whose initial gastric cultures were sterile ( p = 0.01 ) . Colonization of sputum for greater than 24 hours with gastric pathogens occurred in 28 % of patients . These patients had a 40 % incidence of PP compared with 12 % in patients without such evidence of microaspiration ( p < 0.01 ) . CONCLUSIONS PP is a morbid postoperative complication associated with not only chronic obstructive pulmonary disease but also the presence of gastric bacteria during operation and transmission of gastric bacteria to the pulmonary tree after operation In Ontario , Canada , the discrepancy between the high dem and for  coronary artery bypass graft surgery ( CABG )  and the low immediate supply results in waiting lists . In 1990 , a consensus panel of cardiologists and surgeons developed criteria to ensure that high-risk patients were given priority for this procedure ( 1 ) . Each patient receives an acuity score that corresponds to a recommended maximum delay . Aggregated acuity scores of 4 , 5 , 6 , and 7 indicate elective status and represent a waiting time ranging from greater than 14 days to a maximum of 6 months . The mortality rate for patients awaiting CABG  has been shown to be remarkably stableapproximately 0.5 % to 0.6 % per year over the past 10 years ( 2 ) . Despite this , however , evidence shows that patients ' functional and psychological status can deteriorate during the wait for surgery ( 3 - 5 ) . Through its effects on the autonomic nervous system , emotional stress also influences catecholamines , myocardial oxygen dem and , and platelet aggregation ; this may affect morbidity during the waiting period ( 6 - 8 ) . Such factors as preoperative anxiety and little social support have adverse psychological effects during extended preoperative waiting periods and , in addition , have been found to predict poor physical recovery from heart surgery ( 9 ) . Therefore , psychological factors and physical deconditioning , both of which occur during the waiting period ( 10 - 12 ) , may negatively affect patients ' in-hospital course , including length of stay . Because waiting for health services will probably continue to be a reality in publicly funded health care systems that value universal access , careful study of simple , affordable methods to improve patient outcomes during the waiting period is warranted . We examined the effect of a minimum 8-week , multidimensional , preoperative intervention on the presurgery and postsurgery outcomes of patients awaiting elective CABG . We hypothesized that a combination of exercise training , education , and social support would affect patients ' physical and psychological readiness for surgery and thereby reduce postoperative length of hospital stay . We further hypothesized that the effectiveness of the preoperative intervention would be sustained into the first 6 months of the postoperative period . Methods Patients Patients were recruited from the waiting lists of all seven cardiovascular surgeons operating in the Hamilton Health Sciences Corporation surgical center , Hamilton , Ontario , Canada . Each year , approximately 1300 open-heart surgeries are performed in this center . Roughly 60 % of patients awaiting CABG have elective status and are placed on the waiting list . During the time of our study , elective waiting times ranged from 3 weeks to greater than 20 weeks . Approximately 40 % of elective patients are usually awaiting first-time  CABG ( nonvalve replacement ) . Only patients awaiting a first CABG whose surgery date s were at least 10 weeks away were approached to participate in our study . Patients were excluded if they were having combined CABG and valve surgery , if their ejection fractions were less than 0.40 , if they could not attend the exercise classes because of geographic inaccessibility , or if they were unable to participate because of physical limitations . After these inclusion and exclusion criteria were applied , our pool of potential participants was approximately 250 patients per year . We intended to select low-risk patients because it is not common to test an exercise intervention in patients awaiting CABG . Design We design ed a two-group r and omized , controlled trial . Eligible patients were r and omly assigned to 8 weeks of multidimensional preoperative intervention or to usual care . Those assigned to usual care were followed by their primary care physicians , cardiologists , or surgeons . During the waiting period , the intervention group received individualized , prescribed exercise training twice per week in a supervised environment ; education and reinforcement ; and monthly nurse-initiated telephone calls to answer questions and provide reassurance . After surgery , patients in both the treatment and control groups were given the opportunity to join the existing cardiac rehabilitation program ( Append 
    Output:
    
agent
Evidence derived from small trials suggests that preoperative physical therapy reduces postoperative pulmonary complications ( atelectasis and pneumonia ) and length of hospital stay in patients undergoing elective cardiac surgery .
There is a lack of evidence that preoperative physical therapy reduces postoperative pneumothorax , prolonged mechanical ventilation or all-cause deaths
***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: AIMS To compare 19 risk score algorithms with regard to their validity to predict 30-day and 1-year mortality after cardiac surgery . METHODS AND RESULTS Risk factors for patients undergoing heart surgery between 1996 and 2001 at a single centre were prospect ively collected . Receiver operating characteristics ( ROC ) curves were used to describe the performance and accuracy . Survival at 1 year and cause of death were obtained in all cases . The study included 6222 cardiac surgical procedures .  Actual mortality was 2.9 % at 30 days and 6.1 % at 1 year . Discriminatory power for 30-day and 1-year mortality in cardiac surgery was highest for logistic ( 0.84 and 0.77 ) and additive ( 0.84 and 0.77 ) European System for Cardiac Operative Risk Evaluation ( EuroSCORE ) algorithms , followed by Clevel and Clinic ( 0.82 and 0.76 ) and Magovern ( 0.82 and 0.76 ) scoring systems . None of the other 15 risk algorithms had a significantly better discriminatory power than these four . In coronary artery bypass grafting (CABG)-only surgery , EuroSCORE followed by New York State ( NYS ) and Clevel and Clinic risk score showed the highest discriminatory power for 30-day and 1-year mortality . CONCLUSION EuroSCORE , Clevel and Clinic , and Magovern risk algorithms showed superior performance and accuracy in open-heart surgery , and EuroSCORE , NYS , and Clevel and Clinic in CABG-only surgery . Although the models were originally design ed to predict early mortality , the 1-year mortality prediction was also reasonably accurate The role of pre-operative short-term pulmonary rehabilitation in patients with chronic obstructive pulmonary disease who undergo coronary artery bypass graft surgery has been assessed for the first time prospect ively . Forty-five patients posted for coronary artery bypass graft surgery  were r and omised to receive either short-term pulmonary rehabilitation ( group I ) or no such programme ( group II ) . Patients of both the groups were evenly matched with respect to age , sex , body surface area , duration and severity of chronic obstructive pulmonary disease and coronary artery disease . Normal individuals who evenly matched with the study group were assessed for normal respiratory function parameters . Pre-operative and post-operative peak expiratory flow rate , inspiratory capacity , post-operative ventilation time , post-operative pulmonary complication and hospital stay were determined in both the groups . Peak expiratory flow rate ( 220.0 + /- 12.9 and 324.3 + /- 84.3 in group I , 218.0 + /- 16.4 and 260.5 + /- 35.2 in group II ) and inspiratory capacity ( 844.0 + /- 147.4 and 1100.0 + /- 158.1 in group I , 830.0 + /- 117.4 and 1090 + /- 137 in group II ) were significantly lower before and after surgery respectively in both groups compared to normal values . Even though both groups showed a significant rise in post-operative peak expiratory flow rate and inspiratory capacity after surgery , the post-operative peak expiratory flow rate and inspiratory capacity in group I was significantly higher than in group II . In group I , the post-operative ventilation time ( 24.5 + /- 6.00 hours ) , post-operative complications ( n = 4 ) and hospital stay ( 12.4 + /- 3.6 days ) were significantly lower than in group II ( 35.2 + /- 22.3 hours , n = 11 , 18.8 + /- 6.6 days respectively ) . These data suggest that short-term pulmonary rehabilitation is feasible and effective in improving pulmonary functions before and after surgery and in reducing surgical morbidity and cost of medical care significantly CONTEXT Postoperative pulmonary complications ( PPCs ) after coronary artery bypass graft ( CABG ) surgery are a major source of morbidity and mortality , and increase length of hospital stay and re source utilization . The prehospitalization period before CABG surgery may be used to improve a patient 's pulmonary condition . The efficacy of preoperative inspiratory muscle training ( IMT ) in reducing the incidence of PPCs in high-risk patients undergoing CABG surgery has not yet been determined . OBJECTIVE To evaluate the prophylactic efficacy of preoperative IMT on the incidence of PPCs in high-risk patients scheduled for elective CABG surgery . DESIGN , SETTING , AND PATIENTS A single-blind , r and omized clinical trial conducted at the University Medical Center Utrecht , Utrecht , the Netherl and s , with enrollment between July 2002 and August 2005 . Of 655 patients referred for elective CABG surgery , 299 ( 45.6 % ) met criteria for high risk of developing PPCs , of whom 279 were enrolled and followed up until discharge from hospital . INTERVENTION Patients were r and omly assigned to receive either preoperative IMT ( n = 140 ) or usual care ( n = 139 ) . Both groups received the same postoperative physical therapy . MAIN OUTCOME MEASURES Incidence of PPCs , especially pneumonia , and duration of postoperative hospitalization . RESULTS Both groups were comparable at baseline . After CABG surgery , PPCs were present in 25 ( 18.0 % ) of 139 patients in the IMT group and 48 ( 35.0 % ) of 137 patients in the usual care group ( odds ratio [ OR ] , 0.52 ; 95 % confidence interval [ CI ] , 0.30 - 0.92 ) . Pneumonia occurred in 9 ( 6.5 % ) of 139 patients in the IMT group and in 22 ( 16.1 % ) of 137 patients in the usual care group ( OR , 0.40 ; 95 % CI , 0.19 - 0.84 ) . Median duration of postoperative hospitalization was 7 days ( range , 5 - 41 days ) in the IMT group vs 8 days ( range , 6 - 70 days ) in the usual care group by Mann-Whitney U statistic ( z = -2.42 ; P = .02 ) . CONCLUSION Preoperative IMT reduced the incidence of PPCs and duration of postoperative hospitalization in patients at high risk of developing a pulmonary complication undergoing CABG surgery . TRIAL REGISTRATION is rct n.org Identifier : IS RCT N17691887 This study evaluated the efficacy of the relaxation response on the post-operative recovery of 27 cardiac surgery patients r and omly assigned to one of two groups . Thirteen experimental group patients received educational information and practice d eliciting the relaxation response before and after surgery . The 14 patients in the control group received only information . Experimental and control groups were compared before and after surgery on both physiological and psychological recovery variables . There were no initial differences between experimental and control groups on demographic , physiological , and most psychological variables . The experimental group had lower incidence of postoperative supraventricular tachycardia ( SVT ) than the control group ( p = .04 ) despite having had the same occurrence previously . Experimental and control groups did not significantly differ over the course of study on any other physiological variables . Patients practicing the relaxation response had greater decreases in psychological tension ( p = .04 ) and anger ( p = .04 ) than those who received only educational information . The decreases in psychological tension may have been a result of regression to the mean because the experimental group started with elevated tension relative to the control group ( p = .04 ) . We conclude that practicing the relaxation response before and after surgery may reduce SVT , tension , and anger BACKGROUND Postoperative pneumonia ( PP ) is a major complication that has been linked to microaspiration of pathogens originating in the gastrointestinal tract . This prospect i ve study was performed to define the role of gastric bacterial aspiration in the development of PP . METHODS Informed consent was obtained before operations from 140 veterans scheduled for major elective procedures requiring nasogastric tubes  , and cultures were obtained of the gastric contents and sputum twice daily after operation . RESULTS PP developed in 26 ( 18.6 % ) of 140 patients . The patients who had PP did not differ from those with no pneumonia after operation except for a history of chronic obstructive pulmonary disease , which was found in 38.5 % of those with PP compared with 20 % of patients with no pneumonia ( p < 0.05 ) . Morbidity was increased in association with PP , because length of stay in the surgical intensive care unit ( 6.2 vs 2.6 days ) , days intubated ( 2.7 vs 0.6 ) , total postoperative days ( 15.3 vs 8.4 ) , and mortality rates ( 19.2 % vs 1.7 % ) were greater than in patients with no pneumonia . Gastric pathogens were present on entry in 38 % of patients , and 32 % of these had PP compared with 13 % whose initial gastric cultures were sterile ( p = 0.01 ) . Colonization of sputum for greater than 24 hours with gastric pathogens occurred in 28 % of patients . These patients had a 40 % incidence of PP compared with 12 % in patients without such evidence of microaspiration ( p < 0.01 ) . CONCLUSIONS PP is a morbid postoperative complication associated with not only chronic obstructive pulmonary disease but also the presence of gastric bacteria during operation and transmission of gastric bacteria to the pulmonary tree after operation In Ontario , Canada , the discrepancy between the high dem and for  coronary artery bypass graft surgery ( CABG )  and the low immediate supply results in waiting lists . In 1990 , a consensus panel of cardiologists and surgeons developed criteria to ensure that high-risk patients were given priority for this procedure ( 1 ) . Each patient receives an acuity score that corresponds to a recommended maximum delay . Aggregated acuity scores of 4 , 5 , 6 , and 7 indicate elective status and represent a waiting time ranging from greater than 14 days to a maximum of 6 months . The mortality rate for patients awaiting CABG  has been shown to be remarkably stableapproximately 0.5 % to 0.6 % per year over the past 10 years ( 2 ) . Despite this , however , evidence shows that patients ' functional and psychological status can deteriorate during the wait for surgery ( 3 - 5 ) . Through its effects on the autonomic nervous system , emotional stress also influences catecholamines , myocardial oxygen dem and , and platelet aggregation ; this may affect morbidity during the waiting period ( 6 - 8 ) . Such factors as preoperative anxiety and little social support have adverse psychological effects during extended preoperative waiting periods and , in addition , have been found to predict poor physical recovery from heart surgery ( 9 ) . Therefore , psychological factors and physical deconditioning , both of which occur during the waiting period ( 10 - 12 ) , may negatively affect patients ' in-hospital course , including length of stay . Because waiting for health services will probably continue to be a reality in publicly funded health care systems that value universal access , careful study of simple , affordable methods to improve patient outcomes during the waiting period is warranted . We examined the effect of a minimum 8-week , multidimensional , preoperative intervention on the presurgery and postsurgery outcomes of patients awaiting elective CABG . We hypothesized that a combination of exercise training , education , and social support would affect patients ' physical and psychological readiness for surgery and thereby reduce postoperative length of hospital stay . We further hypothesized that the effectiveness of the preoperative intervention would be sustained into the first 6 months of the postoperative period . Methods Patients Patients were recruited from the waiting lists of all seven cardiovascular surgeons operating in the Hamilton Health Sciences Corporation surgical center , Hamilton , Ontario , Canada . Each year , approximately 1300 open-heart surgeries are performed in this center . Roughly 60 % of patients awaiting CABG have elective status and are placed on the waiting list . During the time of our study , elective waiting times ranged from 3 weeks to greater than 20 weeks . Approximately 40 % of elective patients are usually awaiting first-time  CABG ( nonvalve replacement ) . Only patients awaiting a first CABG whose surgery date s were at least 10 weeks away were approached to participate in our study . Patients were excluded if they were having combined CABG and valve surgery , if their ejection fractions were less than 0.40 , if they could not attend the exercise classes because of geographic inaccessibility , or if they were unable to participate because of physical limitations . After these inclusion and exclusion criteria were applied , our pool of potential participants was approximately 250 patients per year . We intended to select low-risk patients because it is not common to test an exercise intervention in patients awaiting CABG . Design We design ed a two-group r and omized , controlled trial . Eligible patients were r and omly assigned to 8 weeks of multidimensional preoperative intervention or to usual care . Those assigned to usual care were followed by their primary care physicians , cardiologists , or surgeons . During the waiting period , the intervention group received individualized , prescribed exercise training twice per week in a supervised environment ; education and reinforcement ; and monthly nurse-initiated telephone calls to answer questions and provide reassurance . After surgery , patients in both the treatment and control groups were given the opportunity to join the existing cardiac rehabilitation program ( Append 
    Output:
    