***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: INTRODUCTION Patients undergoing midline incision for abdominal aortic reconstruction appear to be at greater risk for postoperative incision hernia compared with patients undergoing celiotomy for general surgical  procedures . Controversy exists as to whether incidence of abdominal wall hernia and increased risk for incision hernia is higher in patients with abdominal aortic aneurysm ( AAA ) than in patients operated on because of aortoiliac occlusive disease ( AOD ) . We conducted a prospect i ve multi-institutional study to assess frequency of incision hernia after aortic surgery through a midline laparotomy and of previous abdominal wall hernia . METHODS Patients with AAA ( n = 177 ) or AOD ( n = 82 ) from three major institutions were prospect ively enrolled in the study and examined . Data collected included demographic data , cardiopulmonary risk factors , smoking status , history of previous or current abdominal wall hernia  ( incision , inguinal , umbilical , femoral ) , previous midline incision , suture type , and postoperative complications . At a minimum of 6 months after laparotomy , patients were evaluated clinical ly for a new incision hernia . Differences were tested with the unpaired t test , X(2 ) test , or Fisher exact test , and multiple logistic regression was used to control for confounding variables . RESULTS Mean follow-up of the cohort was 32.8 + /- 2.3 months . Rate of abdominal wall hernia and inguinal hernia in patients with AAA versus AOD was 38.4 % versus 11 % ( P = .001 ) and 23.7 % versus 6.1 % ( P = .003 ) , respectively . Rate of postoperative incision hernia in patients with AAA was 28.2 % , and in patients with AOD was 11.0 % ( P = .002 ) . Adjusting for age , smoking , chronic obstructive pulmonary disease , body mass index , diabetes , bowel obstruction , and suture type , patients with AAA had almost a ninefold risk for postoperative incision hernia formation ( odds ratio [ OR ] , 8.8 ; P = .0049 ) . CONCLUSION Compared with patients with AOD , patients with AAA have a higher frequency of abdominal wall hernia and inguinal hernia , and are at significant increased risk for development of incision hernia postoperatively . The higher frequency of hernia formation in patients with AAA suggests the presence of a structural defect within the fascia . Further studies are needed to delineate the molecular changes of the aorta and its relation to the abdominal wall fascia BACKGROUND Mild perioperative hypothermia , which is common during major surgery , may promote surgical-wound infection by triggering thermoregulatory vasoconstriction , which decreases subcutaneous oxygen tension . Reduced levels of oxygen in tissue impair oxidative killing by neutrophils and decrease the strength of the healing wound by reducing the deposition of collagen . Hypothermia also directly impairs immune function . We tested the hypothesis that hypothermia both increases susceptibility to surgical-wound infection and lengthens hospitalization . METHODS Two hundred patients undergoing colorectal surgery were r and omly assigned to routine intraoperative thermal care ( the hypothermia group ) or additional warming ( the normothermia group ) . The patient 's anesthetic care was st and ardized , and they were all given cefam and ole and metronidazole . In a double-blind protocol , their wounds were evaluated daily until discharge from the hospital and in the clinic after two weeks ; wounds containing culture-positive pus were considered infected . The patients ' surgeons remained unaware of the patients ' group assignments . RESULTS The mean ( + /- SD ) final intraoperative core temperature was 34.7 + /- 0.6 degrees C in the hypothermia group and 36.6 + /- 0.5 degrees C in the normothermia group ( P < 0.001 ) Surgical-wound infections were found in 18 of 96 patients assigned to hypothermia ( 19 percent ) but in only 6 of 104 patients assigned to normothermia ( 6 percent , P = 0.009 ) . The sutures were removed one day later in the patients assigned to hypothermia than in those assigned to normothermia ( P = 0.002 ) , and the duration of hospitalization was prolonged by 2.6 days ( approximately 20 percent ) in hypothermia group ( P = 0.01 ) . CONCLUSIONS Hypothermia itself may delay healing and predispose patients to wound infections . Maintaining normothermia intraoperatively is likely to decrease the incidence of infectious complications in patients undergoing colorectal resection and to shorten their hospitalizations Background : Complications following postmastectomy reconstruction  can cause significant morbidity . The compound effect of individual risk factors on the development of complications following exp and er/implant reconstruction has not , however , been well delineated . This study evaluated the impact of clinical risk factors to predict complications following postmastectomy exp and er/implant reconstruction . Methods : From 2003 through 2004 , 1170 exp and er/implant reconstructions were performed at a single center . A prospect ively maintained data base was review ed . Variables including age , smoking status , body mass index , history of diabetes , hypertension , chemotherapy and /or radiation , as well as timing and laterality of reconstruction were evaluated . The primary endpoint was the development of a complication ; the secondary endpoint was failure of reconstruction . Results : Over the 2 year study period , 1170 exp and er/implant reconstructions were performed in 884 patients . The odds of developing complications was 2.2 times greater in smokers ( p < 0.001 ) and 2.5 times greater in women over 65 ( p = 0.008 ) . Patients who were obese were at nearly two times the odds of having complications ( p = 0.02 ) , as were patients with hypertension ( p = 0.02 ) . Similarly , the odds of reconstructive failure were five times greater in smokers ( p < 0.001 ) . Age was not a significant predictor of reconstructive failure ( p = 0.09 ) ; yet , failure was nearly seven times greater in obese patients ( p < 0.001 ) , and four more times likely in those who were hypertensive ( p = 0.005 ) . Conclusions : Smoking , obesity , hypertension , and age over 65 were independent risk factors for perioperative complications following exp and er/implant breast reconstruction . Smoking , obesity , and hypertension were similarly associated with reconstructive failure . This information can be used to evaluate overall procedural risks and individualize reconstructive options HYPOTHESIS Anastomotic leaks following elective colorectal resections increase morbidity , mortality , and the need for additional interventions . An accurate underst and ing of risk factors would potentially reduce anastomotic leaks and /or allow appropriate selection of patients for diverting stomas . DESIGN Prospect i ve review of patient and operative characteristics that contribute to anastomotic leaks . SETTING Fifty-one sites within the United States ( May 2002-March 2005 ) . PATIENTS Six hundred seventy-two patients who participated in a trial comparing preoperative antimicrobials in elective open colorectal surgery .  MAIN OUTCOME MEASURES Anastomotic leaks were diagnosed using clinical findings and were confirmed with imaging . We examined 20 variables possibly affecting anastomotic healing in univariate and multivariate analyses . RESULTS There were 24  anastomotic leaks in 672 patients ( 3.6 % ) undergoing elective colorectal resection . There were 10 deaths ( 1.5 % ) . A baseline albumin level of less than 3.5 g/dL ( to convert to grams per liter , multiply by 10 ) ( P = .04 ) and male sex ( P = .03 ) were associated with anastomotic leaks in both univariate and multivariate analyses ( adjusted odds ratios , 2.56 and 3.12 , respectively ) . Increased duration of surgery ( SD , 60 minutes ; odds ratio , 1.53 ; 95 % confidence interval , 1.06 - 2.22 ; P = .03 ) and steroid use at the time of surgery ( odds ratio , 3.85 ; 95 % confidence interval , 1.24 - 11.93 ; P = .02 ) were significant in univariate analysis . Surgical procedure with rectal resection ; prophylaxis with ertapenem ( vs cefotetan ) ; or history of obesity , tobacco use , or diabetes was not associated with anastomotic leaks . CONCLUSIONS Significant risk factors for anastomotic leaks include low preoperative serum albumin level , steroid use , male sex , and increased duration of surgery . Appreciation of risk factors provides a rational basis for temporary diversion Background : The authors examined whether the preoperative serum concentrations of cotinine accurately predict the risk of complications in patients undergoing flap reconstruction of head and neck cancer defects . Methods : Patients with incident stage III or IV squamous cell carcinoma of the head and neck undergoing resection with pedicled or free flap reconstruction were selected from an existing data base of 500 patients with squamous cell carcinoma of the head and neck who participated in a prospect i ve epidemiologic study and were review ed retrospectively .  Preoperative serum cotinine concentrations were determined using a competitive microplate immunoassay .  Complications were defined as any adverse postoperative wound outcome at either the donor or recipient site . Results : Eighty-nine patients underwent 101 flap reconstructions . Thirty-seven wound complications occurred in 33 patients . Forty of the 89 patients had a serum cotinine concentration greater than 10 ng/ml ; twenty ( 50 percent ) developed postoperative complications , whereas only 13 of 49 patients ( 27 percent ) with a serum cotinine concentration of 10 ng/ml or less developed complications ( p = 0.028 ) . The relative risk of wound complications for those with a cotinine concentration greater than 10 ng/ml was approximately double that of patients with a lower cotinine concentration ( relative risk , 1.9 ; 95 percent CI , 1.1 to 3.3 ) . Patients with a cotinine concentration greater than 50 ng/ml had a particularly high risk ( relative risk , 2.3 ; 95 percent CI , 1.1 to 16.7 ; p = 0.024 ) . The relative risk of wound complications was not significantly associated with self-reported smoking status or history . Conclusion : A serum cotinine concentration greater than 10 ng/ml may predict an increased risk of wound complication in head and neck flap reconstruction and may serve as an objective , easily measured variable with which to identify patients who may benefit from an aggressive smoking cessation program before surgery Objective : To determine whether an intervention with smoking cessation starting 4 weeks before general and orthopedic surgery would reduce the frequency of postoperative complications . Summary Background Data : Complications are a major concern after elective surgery and smokers have an increased risk . There is insufficient evidence concerning how the duration of preoperative smoking intervention affects postoperative complications . Methods : A r and omized controlled trial , conducted between February 2004 and December 2006 at 4 university-affiliated hospitals in the Stockholm region , Sweden . The outcome assessment was blinded . The follow-up period for the primary outcome was 30 days . Eligibility criteria were active daily smokers , aged 18 to 79 years . Of the 238 patients assessed , 76 refused participating , and 117 men and women undergoing surgery for primary hernia repair , laparoscopic cholecystectomy , or a hip or knee prosthesis were enrolled . Intervention : Smoking cessation therapy with individual counseling and nicotine substitution started 4 weeks before surgery and continued 4 weeks postoperatively . The control group received st and ard care . The main outcome measure was frequency of any postoperative complication . Results : An intention-to-treat analysis showed that the overall complication rate in the control group was 41 % , and in the intervention group , it was 21 % ( P = 0.03 ) . Relative risk reduction for the primary outcome of any postoperative complication was 49 % and number needed to treat was 5 ( 95 % CI , 3–40 ) . An analysis per protocol showed that abstainers had fewer complications ( 15 % ) than those who continued to smoke or only reduced smoking ( 35 % ) , although this difference was not statistically significant . Conclusion : Perioperative smoking cessation seems to be an effective tool to reduce postoperative complications even if it is introduced as late as 4 weeks before surgery Background Smoking is considered to be a risk factor for patients undergoing surgery and anesthesia , but it is unclear whether this is applicable to patients undergoing ambulatory surgery . The aim of this study was to determine the risk of respiratory complications and wound infection among smokers . Methods The authors studied a r and om selection of 489 adult patients undergoing ambulatory surgery .  Smoking status was determined by self-report and confirmed with end-expired carbon monoxide analysis . The risk of respiratory complications ( i.e. , desaturation , cough , laryngospasm , bronchospasm , breath-holding , or apnea ) and wound infection ( i.e. , wound redness or discharge ± positive microbial culture , requiring antibiotic therapy ) in smokers versus nonsmokers was ascert 
    Output:
    
Postoperative healing complications occur significantly more often in smokers compared with nonsmokers and in former smokers compared with those who never smoked .
Perioperative smoking cessation intervention reduces surgical site infections , but not other healing complications