the data of 10 consecutive patients among 176 patients who underwent surgery for the management of carotid body tumor at antalya training and research hospital , antalya , turkey between 2013 and 2016 were retrospectively examined , and included in the analysis . the patients who underwent throat surgery or carotid artery surgery for indications other than cbt , and those with missing file data were excluded from the study . demographic data of the patients , their comorbidities , side , and duration of operation , hospital , and intensive care unit stays , intraoperative blood pressure , variations in heart rates , inotropic drug use , amounts of blood , and blood products used , and complications were recorded . all patients were operated under general anesthesia . for premedication 0.05 mg / kg midazolam was administered . the patients were brought into operating room , and underwent 3-channel electrocardiography , monitorization using pulse oximetry , and arterial monitorization via radial artery cannulation . then anesthetic induction was applied . following routine anesthetic induction , contralateral unoperated subclavian vein was cannulated to monitor central venous pressure . then appropriate colloid , and crystalloid infusions were performed so as to maintain central venous pressure , and mean arterial blood pressure at 810 mmhg , and 5560 mmhg , respectively . sudden drops in blood pressure were managed with 5 mg bolus doses of ephedrine . in patients whose adequate blood pressure levels could not be achieved despite adequate fluid infusion , and admisistration of ephedrine , inotropic support infusions were initiated . , irvine , california , usa ) , and at the termination of the operation , the patients were extubated in the operating room . for the purpose of postoperative observation , the patients were brought into intensive care unit of cardiovascular surgery . when they had brought into intensive care unit of cardiovascular surgery , the patients were awake , and cooperated , and they could maintain their hemodynamic stability without the need for inotropic support , in addition absence of respiratory distress , and persistence of the blood gas analysis results within normal limits ( po2>70 mmhg , and pco2<50 mmhg ) , and based on the criteria of vas scores of 5 , they were discharged from the intensive care unit . through a parallel skin incision made on the sternocleidomastoid muscle , cervical region was explored . following exploration of common carotid artery , and its branches , n. vagus , and n. hypoglossus were accessed , and protected . dissection was started from the bifurcation of carotid artery , and advanced up to the upper edge of the tumor . in all patients , spss version 21 statistical software ( spss inc . , chicago , il , usa ) program was used for the analysis of statistical data of the patients . all patients were operated under general anesthesia . for premedication 0.05 mg / kg midazolam was administered . the patients were brought into operating room , and underwent 3-channel electrocardiography , monitorization using pulse oximetry , and arterial monitorization via radial artery cannulation . then anesthetic induction was applied . following routine anesthetic induction , contralateral unoperated subclavian vein was cannulated to monitor central venous pressure . then appropriate colloid , and crystalloid infusions were performed so as to maintain central venous pressure , and mean arterial blood pressure at 810 mmhg , and 5560 mmhg , respectively . sudden drops in blood pressure were managed with 5 mg bolus doses of ephedrine . in patients whose adequate blood pressure levels could not be achieved despite adequate fluid infusion , and admisistration of ephedrine , inotropic support infusions were initiated . intraoperative cerebral monitorization was achieved using cerebral oxymetre ( masimo rds7a , masimo corp . , irvine , california , usa ) , and at the termination of the operation , the patients were extubated in the operating room . for the purpose of postoperative observation , the patients were brought into intensive care unit of cardiovascular surgery . when they had brought into intensive care unit of cardiovascular surgery , the patients were awake , and cooperated , and they could maintain their hemodynamic stability without the need for inotropic support , in addition absence of respiratory distress , and persistence of the blood gas analysis results within normal limits ( po2>70 mmhg , and pco2<50 mmhg ) , and based on the criteria of vas scores of 5 , they were discharged from the intensive care unit . through a parallel skin incision made on the sternocleidomastoid muscle , cervical region was explored . following exploration of common carotid artery , and its branches , n. vagus , and n. hypoglossus were accessed , and protected . dissection was started from the bifurcation of carotid artery , and advanced up to the upper edge of the tumor . in all patients , spss version 21 statistical software ( spss inc . , chicago , il , usa ) program was used for the analysis of statistical data of the patients . a total of 10 patients ( male , n=4 ; 40% , and female , n=6 ; 60% ) were operated at antalya training and research hospital with the diagnosis of cbt between the years 2013 , and 2016 . seven of these patients applied with the complaints of painless neck mass , while the remaining 3 patients were discovered incidentally during cervical ultrasonograms obtained for various indications demographic data of the patients are shown in table 1 . demographic data are indicated as meanstandard deviation , and numbers ( percentages ) asa : american society of anaesthesiologists ; ef : ejection fraction ; copd : chronic obstructive pulmonary disease ; cad : coronary artery disease ; pad : peripheral artery disease ; sd : standard deviation . right ( n=6 , 60% ) , and left ( n=4 ; 40% ) sided tumors were detected . based on shamblin classification , the patients were evaluated as type 1 ( n=3 ; 30% ) , and type 2 ( n=7 , 70% ) . during tumor resection bleeding was observed on carotid bifurcation , and controlled with primary suturing , mean tumor diameter was detected as 3.91.6 cm . cross - clamping was used in one patient , and intraluminal shunt was not employed in any patient . hypertension , and tachycardia developed in one patient during tumoral excision . in four patients hypotension , and bradycardia were observed during tumoral excision ( figure 1 ) . three patients of these 4 cases were treated with bolus doses of ephedrine . since the remaining patient did not respond adequately to bolus doses of ephedrine , infusion of inotropic support was started . a significant difference was not detected between preoperative , intraoperative , and postoperative peak heart rates . cerebral oximetry values estimated at five different timepoints ( pre - induction baseline , postinduction , before , and after tumor excision , and at the termination of the operation ) were compared . in none of the patients a drop of more than 25% did not occur relative to baseline values . mean vas score at postoperative 0 ( entrance into intensive care unit ) , and 1 . intra- , and post - operative data as expressed as meanstandard deviation or number ( percentage ) vas : visual analogue scale during postoperative period permanent neurological damage , and mortality were not seen in none of the cases . cbt is localized on superolateral regions of the throat , posteroinferior part of the corner of the lower jaw , and it can yield symptoms as solid , painless swelling increasingly growing within years occasionally , these tumors can be discovered incidentallly . their incidence rates have been reported between 0.06 , and 3.3:100000 , and they are seen more frequently in women when compared with men . they can be seen at any age , however they are observed most frequently between 4 . and 5 . computed tomography ( ct ) , magnetic resonance ( mr ) imaging , and mr angiography yield information about the composition of the tumor , and the relationship between the tumor , and soft tissue , bone , and surrounding vasculature . diagnostic accuracy , and sensitivity of computed tomographic angiography in the detection of carotid body tumors have been reported as 100 percent . according to shamblin classification , carotid body tumors are classified into 3 types based on the severity of internal carotid artery involvement . in type 1 carotid artery is minimally involved , and it is seen in 26% of the cases with cbt . this type of tumors can be easily removed . in type 2 , internal carotid artery it completely invades arterial structures , and so its dissection is not possible . in the treatment of these types , internal and/or external carotid arteries should be also removed . in our series , all patients were classified as type 1 , and type 2 . carotid body tumors has a tendency to accompany head and neck paragangliomas , malignant tumors of lungs , breast , and larynx , and they are bilateral or multiple . therefore during preoperative evaluation the existence of other tumors should be carefully investigated . when literature is reviewed , mostly preference for general anesthesia for cbt surgery is noted . however in some cases cited in the literature local , and regional anesthesia were applied . in a series consisting of 4 cases reported by toktas et al . local anesthesia had been used , and any surgical complication was not seen . in the literature a case with cbt operated under cervical plexus block has been reported . a patient who had been considered to have a higher risk for general anesthesia because of eisenmenger syndrome had been operated under continuous cervical plexus block , and any complication had not been encountered . cervical plexus block is a preferred anesthetic method for carotid artery surgery [ 12 , 13 ] . cbt is frequently localized on carotid bifurcation , and during regional applications , because of the hypervascularity of the tumor , unwanted punctures of the tumoral mass may be encountered . because of risk of bleeding , needle or open biopsy is containdicated in these tumors . since part from bleeding this condition may cause catecholamine release from the tumor , hemodynamic instability is a possibility . during application of nerve block , in order to refrain from perforation of the tumor with the needle , regional applications under ultrasound guidance may have higher procedural safety . in patients with cbt carrying higher risk for general anesthesia , preference for regional anesthesia will be more appropriate . since we had nt any patient with higher risk for general anesthesia , so as to refrain from complications of regional anesthesia , we preferred general anesthesia in all of our patients . knowing functional status of the tumor is important during preoperative evaluation for anesthetic technique . presence of excessive cathecolamine release should be investigated during preoperative period using urinary metanephrine , and vanillylmandelic acid measurements . during surgery for functional tumors , alpha - adrenergic blocker drugs should be at hand so as to prevent hypertensive episodes due to excessive cathecolamine discharge . therefore , central venous pressure should be monitored , and required resuscitation with fluid replacement should be readily available . invasive arterial monitorization , close follow - up of hemodynamic state is absolutely necessary for maintenance of blood pressure during specific intervals , and blood gas analyses . because of the presence of potential ischemic areas , and already dilated vessels , normocapnic state should be preferred during anesthesia hypercapnia may result in dilation of vessels outside ischemic areas , and blood flows through these dilated vessels leading to bleeding is one of the most important intraoperative complications . especially during excision of the tumors which invaded carotid artery , substantial amount of blood loss can occur , and sudden hemodynamic changes can be observed . based on shamblin classification tumor types , cbts of type ii , and iii have been found to be associated withgreater amounts of blood loss , longer operation times , higher incidence of nronal damage , more severe vascular injury , and frequent need for repair [ 17 , 18 ] . excessive blood loss during excision of the tumor , and potential complications can be predicted based on preoperative classification , and preparation of preoperative blood supply should be made accordingly . blood loss requiring blood transfusion occurred in only one of our cases this case was type 2 cbt according to stamblin classification this bleeding occurring on the carotid bifurcation was stopped with primary suturing . especially in stamblin type 3 group where tumor invaded carotid artery , cross - clamping should be applied to preclude excessive bleeding during excision of the tumor . especially in cases with stenosis of the contralateral carotid artery detected during clamping neurologic monitorization conveys importance . for the monitorization of neurologic status , electroencephalography , measurement of somatosensory evoked potentials , transcranial doppler us , measurement of carotid stump pressure   and cerebral oxymetre   can be used . the superiority of one method over another has not been demonstrated exactly . during clamping of the carotid artery , if stenosis of the contralateral carotid artery was detected , use of a shunt can be a proper alternative . during shunting , it has been revealed in many studies that during cross - clamping , maintenance of mean blood pressure values at nearly 20% higher levels higher than the baseline values has a protective effect on the preservation of cerebral perfusion . it has been already known that barbiturates used during this period contribute to redistribution , and protect the tissues against focal ischemia . brain edema is associated with cytotoxic , and vasogenic edema , and it usually follows an ischemic process . use of mannitol is useful in the reduction of this type of edema . in our series we did nt use a shunt in this patient , while cross - clamping procedure lasted for 8 minutes , and bleeding was stopped using primary suturing . during postoperative period lack of any control group was the main limitation of this study which prevented comparison of data . cerebral monitorization , and preservation of cerebral perfusion are important issues especially during tumoral resection , and cross - clamping . during preoperative period , performing necessary preparations , being prepared for excess amounts of blood loss , and maintenance of optimal blood pressure levels against sudden hemodynamic changes are among the basic components of anesthetic management .
objective : carotid body tumors ( cbt ) are benign tumors that originate from neural non - chromaffin cells that are typically localized near carotid bifurcation . surgical removal of the tumor is the most appropriate treatment . 
 general anesthesia is preferred anesthetic technique for cbt surgery . 
 basic elements of anesthetic management are protection of hemodynamic stability and maintaining cerebral perfusion pressure ( cpp ) . 
 the aim of this study was to evaluate anesthetic management of cbt surgery and present the literature knowledge.methods:the study included 10 consecutive patients with diagnosis of cbt who underwent surgery at antalya training and research hospital , in antalya , turkey , between 2013 and 2016 . 
 preoperative demographic details ; comorbidities ; side of surgical site ; duration of operation ; length of intensive care unit ( icu ) and hospital stay ; change of intraoperative blood pressure ; use of inotropic drugs , blood products , and analgesics ; postoperative visual analogue scale ( vas ) pain score ; and complications were recorded.results:according to shamblin classification , 3 tumors were type i and the remaining 7 were type ii . 
 tumors were located on right side in 6 patients , and on left in 4 . 
 blood loss sufficient to require transfusion was observed in 1 patient . 
 average intraoperative blood loss was 28768 ml . 
 tachycardia and hypertension were observed in 1 patient ; bradycardia and hypotension were seen in 4 patients . 
 infusion for inotropic support was administered to 1 patient . 
 mean duration of operation was 10920 minutes . 
 mean vas score was 41 , mean icu tramadol consumption was 8025 mg . 
 duration of stay in icu and hospital were 2.41.1 hours and 3.80.7 days , respectively . 
 mortality and neurological complications were not seen in postoperative period.conclusion:cbt surgery requires close and complex anesthesia management . 
 protection of hemodynamic stability against sudden hemodynamic changes , monitoring , and maintaining cpp are the most important aspects of anesthetic management .