***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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    ***EXAMPLES*** 
    Input: OBJECTIVE We aim ed to evaluate the efficacy of low dose N-acetylcysteine ( NAC ) against myocardial ischemia-reperfusion damage in coronary artery bypass surgery accompanied by cardiopulmonary bypass ( CPB ) . METHODS Thirty patients operated due to triple coronary artery disease were enrolled into this prospect i ve r and omized study ( control group -n=15 and NAC group - n=15 ) . N-acetylcysteine was added to induction cardioplegia solution in dose of 4 mmol/l and in dose of 2 mmol/l to maintenance cardioplegia solution in the NAC group . Hemodynamic measurements were performed before and after anesthesia with different intervals . Creatine kinase-MB ( CK-MB ) levels were analyzed during 24 hours postoperatively . Blood sample s were obtained from coronary sinus before CPB ( T1 ) , just before the cross-clamp removed ( T2 ) and 30 minutes later ( T3 ) . Malondialdehyde ( MDA ) , glutathione peroxidase ( GSH-Px ) , nitric oxide ( NO ) levels and neutrophil percentage were determined . Statistical analysis was performed using student 's t test , Chi-square and two-way ANOVA tests . RESULTS There were no significant differences between the two groups with regard to the hemodynamic parameters , and CK-MB levels . The MDA levels were significantly lower in NAC group than in control group during reperfusion period ( 0.75 nmol/l vs 0.88 nmol/l , p<0.05 ) . Neutrophil percentage in coronary sinus blood was significantly lower in NAC group than in control group during the reperfusion period ( 77.6 % vs 82.7 % , p<0.05 ) . The GSH-Px and NO levels were also not statistically different between groups . CONCLUSION Low dose NAC as an adjunct to cardioplegic solutions effectively reduces myocardial oxidative stress in coronary bypass surgery with cardiopulmonary bypass , but may not restore the myocardial injury Background / Aims : There are controversial data about renal function following  off-pump coronary artery bypass grafting ( CABG ) .  The present study aim ed to evaluate renal function changes 24 h after on- and off-pump CABG , as well as renal function correlated with high-sensitivity C-reactive protein ( hs-CRP ) and tumor necrosis factor-α ( TNF-α ) . Methods : Ninety patients with coronary artery disease referred to our center for CABG from July 2006 to November 2007 were enrolled in the study . Patients were equally and r and omly divided in two groups , on- and off-pump .  Serum levels of creatinine ( Cr ) , blood urea nitrogen , creatinine clearance ( CrCl ) , hs-CRP , and TNF-α were determined immediately before and 24 h after surgery . Results : Cr and CrCl changes after surgery were not significantly different between the two groups ; however , blood urea nitrogen levels after surgery were significantly higher in the on-pump group ( p = 0.035 ) . No statistically significant difference was noted between the two groups in terms of changes in levels of hs-CRP and TNF-α ( p = 0.350 and 0.805 , respectively ) . The changes in CrCl levels had no significant correlation with hs-CRP and TNF-α . Conclusions : The early Cr and CrCl levels after surgery are not significantly different in on- and off-pump groups . The early renal function after on- or off-pump CABG is not correlated with the levels of inflammatory markers including hs-CRP and TNF-α STUDY OBJECTIVES Comparison of pulmonary outcomes after  off-pump coronary artery bypass ( OPCAB ) vs on-pump coronary artery grafting with cardiopulmonary bypass ( CABG/CPB ) .  STUDY DESIGN We examined preoperative and postoperative respiratory compliance , fluid balance , hemodynamics , arterial blood gases , chest radiographs , spirometry , pulmonary complications , and time to extubation in a prospect i ve trial of 200 patients r and omized to OPCAB vs CABG/CPB performed by one surgeon . RESULTS One CABG/CPB patient and two OPCAB patients required mitral valve repair or replacement and were withdrawn . After three crossovers from CABG/CBP to OPCAB and one crossover from OPCAB to CABG , 97 CABG/CPB patients and 100 OPCAB patients remained . There were no significant preoperative demographic differences between groups .  Postoperative compliance was reduced more after OPCAB than after CABG/CPB ( - 15.4 + /- 10.7 mL/cm H(2)O vs - 11.2 + /- 10.1 mL/cm H(2)O [ mean + /- SD ] ; p = 0.007 ) , associated with rotation of the heart into the right chest to perform posterolateral bypasses ( p < 0.001 ) and the concomitant increased fluid requirements necessary to maintain hemodynamic stability during rotation of the heart . In addition to higher intraoperative fluid intake ( 4,541 + /- 1,311 mL vs 3,585 + /- 1,033 mL , p < 0.0001 ) ,  OPCAB patients had higher intraoperative fluid balance ( 3,903 + /- 1,315 mL vs 1,772 + /- 1,373 mL , p < 0.0001 ) , and higher postoperative pulmonary arterial diastolic pressure ( 15.0 + /- 5.5 mm Hg vs 11.8 + /- 5.2 mm Hg , p < 0.0001 ) and central venous pressure ( 10.4 + /- 4.5 mm Hg vs 8.4 + /- 4.7 mm Hg , p < 0.0001 ) . Despite lower compliance , immediate postoperative Pao(2 ) on fraction of inspired oxygen of 1.0 ( 275 + /- 97 torr vs 221 + /- 92 torr , p = 0.001 ) was higher after OPCAB and extubation was earlier ( p = 0.001 ) . Postoperative chest radiographs , spirometry , mortality , reintubation , or readmission for pulmonary complications were not different between groups . CONCLUSIONS Compared to CABG/CPB , OPCAB was associated with a greater reduction in postoperative respiratory compliance associated with increased fluid administration and rotation of the heart into the right chest to perform posterolateral grafts . OPCAB yielded better gas exchange and earlier extubation but no difference in chest radiographs , spirometry , or rates of death , pneumonia , pleural effusion , or pulmonary edema Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Objective : When used to prevent perioperative inflammation and ischemia – reperfusion injury , N-acetylcysteine may inadvertently impair hemostasis . We , therefore , performed a post hoc analysis of a recent r and omized controlled trial in cardiac surgery to determine whether N-acetylcysteine was associated with increased blood loss and blood product transfusion . Design : Blinded ( patients , caregivers , outcome assessors ) placebo-controlled parallel group r and omized trial ( www . Clinical Trials.gov ID NCT00188630 ) . Setting : Tertiary care hospital in Toronto , Ontario , Canada ( September 2003 to October 2005 ) . Patients : A total of 177 patients with preexisting moderate renal insufficiency ( estimated glomerular filtration rate ≤60 mL/min ) and undergoing cardiac surgery . Interventions : Eighty-nine patients were r and omized to receive intravenous N-acetylcysteine ( 100 mg/kg bolus ; 20 mg·kg−1·hr−1 infusion until 4 hours after cardiopulmonary bypass ) , and 88 were r and omized to receive placebo . Measurements and Main Results : We used laboratory markers ( hemoglobin , platelets , coagulation ) , chest-tube blood loss , and blood product transfusion to evaluate hemostasis . Compared with placebo , patients who received N-acetylcysteine arm experienced a mean 24-hour chest-tube blood loss that was 261 mL higher ( 95 % confidence interval [ CI ] 93–488 mL , p = 0.008 ) , and were transfused 1.6 more units of red blood cells ( 95 % CI 0.4–3.1 units , p = 0.02 ) during hospitalization . The risk of receiving ≥5 units of red blood cells within 24 hours of surgery was significantly higher with N-acetylcysteine ( relative risk 1.85 , 95 % CI 1.06–3.21 , p = 0.03 ; adjusted relative risk 2.09 , 95 % CI 1.24–3.83 , p = 0.005 ) . Conclusions : In patients who have preexisting moderate renal insufficiency and are undergoing cardiac surgery  , N-acetylcysteine was associated with important effects on blood loss and blood product transfusion . Clinicians and research ers should , therefore , consider the potential for impaired hemostasis when using N-acetylcysteine in the perioperative setting . Further research is needed to eluci date mechanisms by which N-acetylcysteine may impair hemostasis , and the risk – benefit profile of N-acetylcysteine for perioperative organ protection Objective : To assess the preventive effect of the antioxidant N-acetylcysteine on postoperative acute renal failure  in patients with renal insufficiency undergoing cardiac surgery . Design : R and omized , placebo-controlled , prospect i ve study . Setting : University cardiology center . Patients : Two hundred fifty-four consecutive patients with chronic renal insufficiency ( estimated creatinine clearance ≤60 mL/min ) undergoing elective cardiac surgery . Interventions : Patients were r and omized to receive N-acetylcysteine ( n = 129 ) or placebo ( n = 125 ) . Patients of the N-acetylcysteine group received four boluses of intravenous N-acetylcysteine ( 1200 mg every 12 hrs , starting immediately before cardiac surgery ) . Measurements and Main Results : The incidence of postoperative acute renal failure ( > 25 % increase in serum creatinine from baseline ) and the in-hospital clinical course were evaluated . Acute renal failure occurred in 46 % of patients and was associated with increased in-hospital mortality ( 7 % vs. 0.7 % ; p = .024 ) . It occurred in 52 % of control patients and 40 % of N-acetylcysteine-treated patients ( p = .06 ) . In-hospital mortality and need for renal replacement therapy were not affected by N-acetylcysteine , but a lower percentage of N-acetylcysteine-treated patients required mechanical ventilation prolonged for > 48 hrs ( 3 % vs. 18 % ; p < .001 ) and had an intensive care unit stay > 4 days ( 13 % vs. 33 % ; p < .001 ) . Conclusions : Intravenous administration of N-acetylcysteine does not clearly prevent postoperative acute renal failure in patients with renal insufficiency undergoing cardiac surgery Abstract Isoflurane is a volatile halogenated anesthetic used especially for anesthesia maintenance whereas propofol is a venous anesthetic utilized for anesthesia induction and maintenance , and reportedly an antioxidant . However , there are still controversies related to isoflurane-induced oxidative stress and it remains unanswered whether the antioxidant effects occur in patients under propofol anesthesia .  Taking into account the importance of better underst and ing the role of anesthetics on oxidative stress in anesthetized patients , the present study was design ed to evaluate general anesthesia maintained with isoflurane or propofol on antioxidant status in patients who underwent minimally invasive surgeries .  We conducted a prospect i ve r and omized trial in 30 adult patients without comorbidities who underwent elective minor surgery ( septoplasty ) lasting at least 2 h admitted to a Brazilian tertiary hospital . The patients were r and omly allocated into 2 groups , according to anesthesia maintenance ( isoflurane , n = 15 or propofol , n = 15 ) . Peripheral blood sample s were drawn before anesthesia ( baseline ) and 2-h after anesthesia induction . The primary outcomes were to investigate the effect of either isoflurane or propofol anesthesia on aqueous plasma oxidizability and total antioxidant performance ( TAP ) by fluorometry as well as several individual antioxidants by high-performance liquid chromatography . As secondary outcome , oxidized genetic damage ( 7,8-dihydro-8-oxoguanine , known as 8-oxo-Gua ) was investigated by the comet assay . Both anesthesia techniques ( isoflurane or 
    Output:
    
Conclusions The addition of NAC during cardiac surgery did not result in a statistically significant reduction in clinical outcomes .