***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 — Oxygen is commonly administered to patients with ST-elevation – myocardial infa rct ion despite previous studies suggesting a possible increase in myocardial injury as a result of coronary vasoconstriction and heightened oxidative stress . Methods and Results — We conducted a multicenter , prospect i ve , r and omized , controlled trial comparing oxygen ( 8 L/min ) with no supplemental oxygen in patients with ST-elevation – myocardial infa rct ion diagnosed on paramedic 12-lead ECG . Of 638 patients r and omized , 441 patients had confirmed ST-elevation – myocardial infa rct ion and underwent primary end-point analysis . The primary end point was myocardial infa rct size as assessed by cardiac enzymes , troponin I , and creatine kinase . Secondary end points included recurrent myocardial infa rct ion , cardiac arrhythmia , and myocardial infa rct size assessed by cardiac magnetic resonance imaging at 6 months . Mean peak troponin was similar in the oxygen and no oxygen groups ( 57.4 versus 48.0 & mgr;g/L ; ratio , 1.20 ; 95 % confidence interval , 0.92–1.56 ; P=0.18 ) . There was a significant increase in mean peak creatine kinase in the oxygen group compared with the no oxygen group ( 1948 versus 1543 U/L ; means ratio , 1.27 ; 95 % confidence interval , 1.04–1.52 ; P=0.01 ) . There was an increase in the rate of recurrent myocardial infa rct ion in the oxygen group compared with the no oxygen group ( 5.5 % versus 0.9 % ; P=0.006 ) and an increase in frequency of cardiac arrhythmia ( 40.4 % versus 31.4 % ; P=0.05 ) . At 6 months , the oxygen group had an increase in myocardial infa rct size on cardiac magnetic resonance ( n=139 ; 20.3 versus 13.1 g ; P=0.04 ) . Conclusion — Supplemental oxygen therapy in patients with ST-elevation – myocardial infa rct ion but without hypoxia may increase early myocardial injury and was associated with larger myocardial infa rct size assessed at 6 months . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT01272713 BACKGROUND The clinical effect of routine oxygen therapy in patients with suspected acute myocardial infa rct ion who do not have hypoxemia at baseline is uncertain . METHODS In this registry‐based r and omized clinical trial , we used nationwide Swedish registries for patient enrollment and data collection . Patients with suspected myocardial infa rct ion and an oxygen saturation of 90 % or higher were r and omly assigned to receive either supplemental oxygen ( 6 liters per minute for 6 to 12 hours , delivered through an open face mask ) or ambient air . RESULTS A total of 6629 patients were enrolled . The median duration of oxygen therapy was 11.6 hours , and the median oxygen saturation at the end of the treatment period was 99 % among patients assigned to oxygen and 97 % among patients assigned to ambient air . Hypoxemia developed in 62 patients ( 1.9 % ) in the oxygen group , as compared with 254 patients ( 7.7 % ) in the ambient‐air group . The median of the highest troponin level during hospitalization was 946.5 ng per liter in the oxygen group and 983.0 ng per liter in the ambient‐air group . The primary end point of death from any cause within 1 year after r and omization occurred in 5.0 % of patients ( 166 of 3311 ) assigned to oxygen and in 5.1 % of patients ( 168 of 3318 ) assigned to ambient air ( hazard ratio , 0.97 ; 95 % confidence interval [ CI ] , 0.79 to 1.21 ; P=0.80 ) . Rehospitalization with myocardial infa rct ion within 1 year occurred in 126 patients ( 3.8 % ) assigned to oxygen and in 111 patients ( 3.3 % ) assigned to ambient air ( hazard ratio , 1.13 ; 95 % CI , 0.88 to 1.46 ; P=0.33 ) . The results were consistent across all predefined subgroups . CONCLUSIONS Routine use of supplemental oxygen in patients with suspected myocardial infa rct ion who did not have hypoxemia was not found to reduce 1‐year all‐cause mortality . ( Funded by the Swedish Heart – Lung Foundation and others ; DETO2X‐AMI Clinical Trials.gov number , NCT01787110 . Background Postoperative cognitive dysfunction ( POCD ) is a common complication of cardiac surgery . Studies have identified potentially injurious roles for cardiopulmonary bypass ( CPB ) and subsequent reperfusion injury . Cognitive dysfunction has also been linked to the deleterious effects of hyperoxia following ischemia-reperfusion injuries in several disease states , but there has been surprisingly little study into the role of hyperoxia in reperfusion injury after CPB . The potential for tightly regulated intraoperative normoxia to ameliorate the neurocognitive decline following cardiac surgery has not been investigated in a prospect i ve manner . We hypothesize that the use of a protocol ized management strategy aim ed towards maintenance of an intraoperative normoxic level of oxygen , as opposed to hyperoxia , will reduce the incidence of POCD in older patients undergoing cardiac surgery . Methods / Design One hundred patients aged 65 years and older undergoing non-emergency coronary artery bypass grafting surgery on cardiopulmonary bypass  will be enrolled in this prospect i ve , r and omized , controlled trial . Subjects will be r and omized to receive a fraction of inspired oxygen of either 35 % or 100 % while under general anesthesia throughout the intraoperative period . The primary outcome measure will be the incidence of POCD in the acute postoperative phase and up to 6 months . The assessment of neurocognition will be undertaken by trained personnel , blinded to study group , with the telephone Montreal Cognitive Assessment ( t-MoCA ) tool . Secondary outcome measures will include assessment of delirium using the Confusion Assessment Method ( CAM and CAM-ICU ) , as well as time to extubation , days of mechanical ventilation , length of ICU and hospital stay and mortality at 6 months . With the aim of later identifying mechanistic aspects of the effect of oxygen tension , blood , urine , and atrial tissue specimens will be taken at various time points during the perioperative period and later analyzed . Discussion This trial will be one of the first r and omized controlled studies to prospect ively assess the relationship between intraoperative oxygen levels and postoperative neurocognition in cardiac surgery . It addresses a promising biological avenue of intervention in this vulnerable aging population .Trial registration Clinical Trials.gov Identifier : NCT02591589 , registered February 13 , 2015 Although an adverse influence of hyperoxemia during cardiopulmonary bypass is well documented , there is a wide range of oxygen setting s during cardiopulmonary bypass , based mostly on trial and error . The aim of this study was to determine the optimal inspired oxygen fraction during cardiopulmonary bypass . Ninety patients undergoing isolated coronary artery bypass operations were r and omly allocated to one of 3 groups of 30 each . In group 1 , cardiopulmonary bypass was started with an inspired oxygen fraction of 0.40 , increased to 0.60 during rewarming . These setting s were 0.40 and 0.50 in group 2 , and 0.35 and 0.45 in group 3 . Sample s for blood gas analysis were collected at defined time periods during the operation . PaO2 was significantly higher in groups 1 and 2 compared to group 3 . All patients in group 1 and 88 % of patients in group 2 suffered at least one episode of hyperoxemia during cardiopulmonary bypass , compared to 30 % of patients in group 3 . The differences were significant , and we concluded that to avoid hyperoxemia , inspired oxygen fraction should be kept at 0.35 during cardiopulmonary bypass and increased to 0.45 during rewarming Objective : To determine whether higher levels of PaO2 are associated with in-hospital mortality and poor neurological status at hospital discharge in patients treated with mild therapeutic hypothermia after sudden cardiac arrest . Design : Retrospective analysis of a prospect i ve cohort . Patients : A total of 170 consecutive patients treated with therapeutic hypothermia in the cardiovascular care unit of an academic tertiary care hospital . Interventions : None . Measurements and Main Results : Of 170 patients , 77 ( 45.2 % ) survived to hospital discharge . Survivors had a significantly lower maximum PaO2 ( 198 mm Hg ; interquartile range , 152.5–282 ) measured in the first 24 hrs following cardiac arrest compared to nonsurvivors ( 254 mm Hg ; interquartile range , 172–363 ; p = .022 ) . A multivariable analysis including age , time to return of spontaneous circulation , the presence of shock , byst and er cardiopulmonary resuscitation , and initial rhythm revealed that higher levels of PaO2 were significantly associated with increased in-hospital mortality ( odds ratio 1.439 ; 95 % confidence interval 1.028–2.015 ; p = .034 ) and poor neurological status at hospital discharge ( odds ratio 1.485 ; 95 % confidence interval 1.032–2.136 ; p = .033 ) . Conclusions : Higher levels of the maximum measured PaO2 are associated with increased in-hospital mortality and poor neurological status on hospital discharge in patients treated with mild therapeutic hypothermia after sudden cardiac arrest Background The safety of perioperative hyperoxia is currently unclear . Previous studies in patients undergoing coronary artery bypass surgery suggest reduced myocardial damage when avoiding extreme perioperative hyperoxia ( > 400 mmHg ) . In this study we investigated whether an oxygenation strategy from moderate hyperoxia to a near-physiological oxygen tension reduces myocardial damage and improves haemodynamics , organ dysfunction and oxidative stress . Methods This was a single-blind , single-centre , open-label , r and omised controlled trial in patients undergoing elective coronary artery bypass surgery . Fifty patients were r and omised to a  partial pressure of oxygen in arterial blood ( PaO2 ) target of 200–220 mmHg during cardiopulmonary bypass and 130–150 mmHg during intensive care unit ( ICU ) admission ( control group ) versus lower targets of 130–150 mmHg during cardiopulmonary bypass and 80–100 mmHg at the ICU ( conservative group ) . Primary outcome was myocardial injury ( CK-MB and Troponin-T ) at ICU admission and 2 , 6 and 12 hours thereafter . Results Weighted PaO2 during cardiopulmonary bypass was 220 mmHg ( interquartile range ( IQR ) 211–233 ) vs. 157 ( 151–162 ) in the control and conservative group , respectively ( P < 0.0001 ) . During ICU admission , weighted PaO2 was 107 mmHg ( 86–141 ) vs. 90 ( 84–98 ) ( P = 0.03 ) , respectively . Area under the curve of CK-MB was median 23.5 μg/L/h ( IQR 18.4–28.1 ) vs. 21.5 ( 15.8–26.6 ) ( P = 0.35 ) and 0.30 μg/L/h ( 0.25–0.44 ) vs. 0.39 ( 0.24–0.43 ) ( P = 0.81 ) for Troponin-T. Cardiac index , systemic vascular resistance index , creatinine , lactate and F2-isoprostane levels were not different between groups . Conclusions Compared to moderate hyperoxia , a near-physiological oxygen strategy does not reduce myocardial damage in patients undergoing coronary artery bypass surgery .  Conservative oxygen administration was not associated with increased lactate levels or hypoxic events . Trial registration Netherl and s Trial Registry NTR4375 , registered on 30 January Background Valvular heart surgery ( VHS ) utilizing cardiopulmonary bypass ( CPB ) is inevitably associated with ischemic-reperfusion injury , which is known to depend on oxygen tension during reperfusion . The aim of this study was to evaluate the effect of arterial oxygen tension during reperfusion on myocardial recovery in patients undergoing VHS . Methods Fifty-six patients undergoing isolated VHS were r and omly exposed to an oxygen fraction of 0.7 ( hyperoxic group , n = 28 ) or 0.5 ( normoxic group , n = 28 ) during reperfusion . All patients received an oxygen fraction of 0.7 during CPB . In the normoxic group , the oxygen fraction was lowered to 0.5 from the last warm cardioplegia administration to 1 minute after aortic uncl 
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Conclusions Hyperoxia had minimal impact on organ dysfunction , length of stay , and mortality in adult cardiac surgery .
Conclusions L’hyperoxie a eu des répercussions minimes sur le dysfonctionnement des organes , la durée de séjour et la mortalité au cours de la chirurgie cardiaque de l’adulte .