***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 and Objectives : This is a small pilot study to compare hemodynamic stability during carotid endarterectomy performed with either regional anesthesia or combined regional/general anesthesia . Methods : Twenty‐eight patients undergoing elective carotid endarterectomy were r and omly assigned to : ( 1 )  superficial cervical plexus block  ( n = 14 ) ; or ( 2 )  superficial cervical plexus block plus general anesthesia ( n = 14 ) . The primary outcome measure was hemodynamic stability as indicated by blood pressure changes . Mean arterial pressure was recorded at different times ( T0 , T1 , T2 , T3 ) . Surgery duration , carotid cross‐clamping time , time to recovery of consciousness , perioperative complications , requirement for antihypertensive or antihypotensive drugs , and lidocaine supplementation were recorded . Patients were asked to grade their intraoperative comfort . Results : In group 1 , mean arterial pressure was higher at T1 and T2 compared with group 2 ( P < .001 ) . Hedges ' g effect size was 2.47 ( 95 % confidence interval [ CI ] , 1.48‐3.45 ) at T1 ( very large effect ) and 1.36 ( 95 % CI , 0.54‐2.18 ) at T2 ( large effect ) . Surgery duration was 106 ± 28 minutes in group 1 versus 91 ± 16 in group 2 ( P = .1026 ) . Carotid cross‐clamping time was 45 ± 14 minutes in group 1 versus 36 ± 9 in group 2 ( P = .0503 ) . Comfort and analgesia were better in group 2 ( 1.43 ± 0.65 ) than in group 1 ( 2.21 ± 0.7 ) ( P = .0053 ) . Conclusions : This pilot study suggests that combined regional/general anesthesia provides greater hemodynamic stability and patient comfort  compared with regional anesthesia during carotid endarterectomy . Further studies are warranted before conclusions can be drawn as to the efficacy and safety of the technique To compare the use of  r and omized controls ( RCTs ) and historical controls ( HCTs )  for clinical trials , we search ed the literature for therapies studied by both methods . We found six therapies for which 50 RCTs and 56 HCTs were reported . Forty-four of 56 HCTs  ( 79 percent ) found the therapy better than the control regimen , but only 10 of 50 RCTs ( 20 percent ) agreed . For each therapy , the treated patients in RCTs and HCTs of the same therapy was largely due to differences in outcome for the control groups , with HCT control patients generally doing worse than the RCT control groups . Adjustment of the outcomes of the HCTs for prognostic factors , when possible , did not appreciably change the results . The data suggest that biases in patient selection may irretrievably weight the outcome of HCts in favor of new therapies . RCTs may miss clinical ly important benefits because of inadequate attention to sample size . The predictive value of each might be improved by reconsidering the use of p less than 0.05 as the significance level for all types of clinical trials , and by the use of confidence intervals around estimates of treatment effects OBJECTIVE to examine the effects of type of anaesthesia on cerebral blood flow during  carotid endarterectomy ( CEA ) .  DESIGN prospect i ve r and omised study . METHODS thirty-four CEA procedures under local anaesthesia ( LA ) are compared to 33 procedures under general anaesthesia ( GA ) .  Mean middle cerebral artery velocity ( MCAV(mean ) ) was monitored using Transcranial Doppler ( TCD ) and mean arterial pressure ( MAP ) assessed by continuous intra-arterial blood pressure transducer . RESULTS pre-op MCAV(mean ) and MAP were similar in both groups . Pre-clamp MCAV(mean ) was similar in both groups and did not differ from pre-op values . With carotid clamping the MCAV(mean ) significantly dropped in both groups . The post-clamp MCAV(mean ) was significantly less in the GA group ( p < 0.05 ) , and the percentage reduction in MCAV(mean ) significantly more for GA procedures ( p < 0.05 ) . Pre-clamp MAP was significantly elevated in LA procedures and significantly lowered in GA procedures . Pre-clamp MAP was significant less for GA procedures ( p < 0.001 ) . Post clamp MAP did not differ from pre-clamp levels in either group . There was no correlation between MCAV(mean ) and MAP . Complication rate , combined death/stroke rates were similar in each group . CONCLUSION LA CEA is associated with better preservation of the ipsilateral cerebral circulation and increased tolerance of the effects of carotid clamping . Changes in MCAV(mean ) can not be explained by variations in blood pressure between the two techniques BACKGROUND To evaluate the influence of anesthetic technique on perioperative neurological and cardiopulmonary complication rates in patients undergoing carotid endarterectomy .  PATIENTS AND METHODS 186 patients with symptomatic internal carotid artery ( ICA ) stenosis > 70 % or asymptomatic ICA stenosis > 80 % were prospect ively r and omized for either locoregional ( LA ) or general anesthesia ( GA ) . RESULTS Neurological complication rates were similar in both groups ( GA 2 % vs. LA 2 % ) . Cardiopulmonary complication rates were not significantly different ( GA 4 % vs LA 1 % ) . There were no stroke-related deaths , but one patient from the GA group died from severe postoperative pneumonia . Thus , a significant difference in combined stroke/cardiopulmonary related death between the two groups ( GA 1 % vs LA 0 % ) could not be found . However , perioperative cardiopulmonary monitoring showed that significantly more patients operated under general anesthesia had hypertensive events , with systolic blood pressure values greater than 180 mmHg on postoperative day one . There were no differences in the number of postoperatively hypotensive episodes ( systolic blood pressure values < 100 mmHg ) between the two groups . CONCLUSIONS Significant differences in the perioperative neurological and cardiopulmonary complication rates between general and locoregional anesthesia in patients undergoing carotid endarterectomy could not be observed A prospect i ve study was undertaken to determine the efficacy of performing carotid endarterectomy without an intraluminal shunt . During a two-year period , 240 patients , ranging in age from 36 to 89 years , underwent 309 consecutive carotid endarterectomies .  The indication for operation was transient ischemic attacks in 151 ( 63 % ) patients , asymptomatic carotid bruit in 67 ( 28 % ) , and previous stroke in 22 ( 9 % ) . Internal shunts were not used in any patients and all arteriotomies were patched with a preclotted knitted Dacron@ velor patch . Systemic heparinization was used during the procedure . The early postoperative mortality was 0.64 % ( 2/309 ) . Both deaths were caused by myocardial infa rct ion . The incidence of stroke after operation was 1.29 % ( 4/309 ) . Neither carotid clamp time nor the presence of contralateral disease correlated with the occurrence of postoperative stroke . According to results of angiography , 22 patients had total occlusion of the contralateral internal carotid artery with satisfactory intracranial circulation . No postoperative strokes occurred in this subgroup . Results of this study revealed that equally good or superior results may be obtained without a temporary shunt in performing carotid endarterectomy Because of controversies in the cerebrovascular literature regarding the use of an intraluminal shunt in carotid endarterectomy , we report a r and omized prospect i ve study of 118 consecutive symptomatic patients receiving surgery within a single neurosurgical practice . Over 4 years , 138 carotid endarterectomies were performed in the 118 patients , 63 operations with intraluminal shunting  and 75 without .  St and ard rationale for surgery included ipsilateral cerebral infa rct ion in 38 % of the operations and ipsilateral transient ischemic attacks in 36 % . Unilateral angiographic stenosis of greater than 90 % was seen in 58 % of the operations ; there were no ipsilateral occlusions . Surgery was performed under general anesthesia with barbiturate induction and mild blood pressure elevation . The 30-day complication rate included a mortality rate of 0.7 % with a 5.1 % incidence of postoperative neurologic deficit and a 1.4 % rate of myocardial infa rct ion . In the 24 hours after surgery there were no cerebral infa rct ions in the shunted group and six in the unshunted group . This 8 % rate in the unshunted group compared with 0 % in the shunted group was significant at p = 0.023 with a power of 0.95 by Fisher 's exact test and chi 2 analysis . This suggests that in our neurosurgical practice ( resident training program ) the use of an intraluminal shunt during carotid endarterectomy significantly reduces the risk of intraoperative neurologic deficit without increasing the incidence of other complications Background The aim of this study was to compare the influence of either general ( GA ) or local ( LA ) anesthesia on the postoperative neurocognitive outcome in patients undergoing carotid endarterectomy ( CEA ) in a r and omized study . Therefore , we performed a subgroup analysis of the multicenter GALA study . Methods A total of 40 patients were enrolled and r and omized to receive either LA ( n = 17 ) or GA ( n = 23 ) anesthesia .  The indication for intraoperative shunting was based on the intraoperative cognitive performance in the LA group and on the clinical experience of the surgeon in the GA group . Outcome measurements included patient performance on a neuropsychological Trail Making Test , evaluation of patients mood using the self-report inventory BSKE , and serum levels of the neurobiochemical marker S100ß . The data were analyzed for each variable using a t-test and were presented as the mean ( SD ) . Differences in shunt frequency were analyzed performing a chi-squared test . Group differences in the Trail Making Test , BSKE evaluation , and S100ß concentrations were derived from the analyses of covariances with repeated measurements using preoperative values as covariates . Results Compared to baseline , the S100ß concentrations increased significantly in the GA group [ 0.086 ( 0.038 ) vs. 0.061 ( 0.024 ) μg/l ; p < 0.001 ] before unclamping of the carotid artery , whereas there were no changes in the LA group [ 0.068 ( 0.024 ) μg/l , p = 0.09 vs. 0.061 ( 0.021 ) μg/l , p = 0.09 ) . Furthermore , we detected significant group differences after surgical intervention ( GA 0.087 ( 0.031 ) μg/l ; LA 0.06 ( 0.021 ) μg/l ; p = 0.006 ) . The postoperative neurocognitive performance in the Trail Making Test decreased significantly in the GA group , whereas there were no significant changes in the LA group . The self-report inventory BSKE evaluation revealed no significant group differences . Conclusions We concluded that performing local anesthesia in patients undergoing CEA positively influenced early postoperative neurocognitive outcomes . Significant group differences in postoperative S100ß concentrations confirmed the beneficial effect of local anesthesia Background Diagnostic accuracy studies of neuromonitoring devices during carotid endarterectomy in awake patients are limited by the question of the transferability to anesthetized patients . This study was design ed to compare the different neuromonitoring parameters in patients under regional and general anesthesia with stump pressure as the primary endpoint and the courses of cerebral blood flow velocity ( Vmca ) measured by transcranial Doppler sonography , regional cerebral oxygen saturation ( rSO2 ) measured by near-infrared spectroscopy , and the amplitude of somatosensory evoked potentials ( SEP ) as the secondary endpoints . Material s and Methods Ninety-six patients undergoing carotid endarterectomy were r and omized to regional ( n=48 ) or sevoflurane/fentanyl anesthesia ( n=48 ) group . Absolute and relative changes of Vmca and rSO2 and the SEP amplitude were recorded at baseline , during carotid artery clamping , and after declamping . Intergroup differences ( ß ) were calculated by generalized estimation equations and linear regression analysis . Results Mean arterial pressure ( P<0.001 ) and heart rate ( P<0.001 ) were significantly higher in the regional anesthesia group . SP did not differ between both the groups ( ß=−1.6 ; P=0.71 ) . Vmca ( ß=9.2 ; P<0.01 ) and rSO2 ( ß=4.1 ; P<0.01 ) values were higher in the awake patients . After adjustment for mean arterial pressure , the differences of Vmca remained consistent ( ß=9.3 ; P<0.01 ) whereas these of rSO2 during clamping ( ß=2.9 ; P=0.105 ) and during reperf 
    Output:
    
There was no statistically significant difference in the incidence of stroke within 30 days of surgery between the local anaesthesia group and the general anaesthesia group .
AUTHORS ' CONCLUSIONS The proportion of patients who had a stroke or died within 30 days of surgery did not differ significantly between the two types of anaesthetic techniques used during carotid endarterectomy  .
This systematic review provides evidence to suggest that patients and surgeons can choose either anaesthetic technique , depending on the clinical situation and their own preferences