thyroid carcinoma is the most common endocrine malignancy . among women , it is the fifth most common malignancy . the global incidence of thyroid carcinoma has been growing rapidly in recent years . as a result , there is an exponential increase in number of operations performed to treat thyroid carcinoma globally . thus , the postoperative complications of these operations have attracted the attention of researchers all over the world . the most common complications of thyroid operations are as follows : hypoparathyroidism , damage to the laryngeal nerves , and postoperative hemorrhage . according to the data of our center , moreover , 88.7% cases of cervical hematoma occurred within 12 hours postoperatively . however , most of these postoperative hemorrhages were not too acute to threaten patients life in a short time . among patients whose primary site was in the hypopharynx or oropharynx , the incidence of life - threatening cervical bleeding was more common postoperatively . to the best of our knowledge , among the patients who underwent thyroid surgery , life - threatening bleeding occurred in very cases postoperatively . in this study , we came across 7 patients who suffered life - threatening bleeding after undergoing thyroid surgery . we have retrospectively analyzed the clinical histories and documents of these 7 patients in order to summarize the causes of life - threatening bleeding that occurred postoperatively . thereafter , we have described the steps that must be taken to prevent life - threatening bleeding in patients undergoing thyroid surgery . 2014 , 15 764 patients underwent thyroid surgery at our hospital . among them , 13 485 patients were diagnosed with thyroid cancer . after undergoing thyroid surgery , 167 patients ( 1.06% ) developed postoperative bleeding , so debridement was performed on these patients . however , only 7 patients ( 4.2% of postoperative bleeding , 0.44 of patients who underwent thyroid surgery ) developed acute life - threatening hemorrhages . this group of 7 patients consisted of 2 males and 5 females in the age group of 3568 years . out of these 7 patients , 4 cases were pathologically diagnosed with thyroid papillary carcinoma ( ptc ) ; 1 case was diagnosed with poorly differentiated follicular carcinoma ; and the remaining 2 patients were diagnosed with poorly differentiated carcinoma . 5 cases had undergone operations ; 2 cases had received radioiodine treatment , while 2 cases had been treated with external beam radiotherapy ( table 1 ) . out of the 7 patients , 1 patient developed hemorrhage in the superior thyroid artery , while 5 patients developed carotid blowout syndromes ( cbs ) . only 1 patient had been diagnosed with tracheo - innominate artery fistula ( tif ) . interestingly , in patients with cbss , all the bleeding sites were located in the lower segment or the root of the right carotid artery . the hemorrhage of the superior thyroid artery was detected in the patient who started coughing severely about 1 hour after undergoing surgery . the remaining 6 patients developed hemorrhages within 3 to 21 days after undergoing thyroid operations . before developing massive hemorrhages , 2 patients suffered herald bleeding that stopped spontaneously . out of the 7 patients , 4 patients developed obvious signs of hemorrhages , such as severe cough , defecation , and sputum - sucking nursing . one patient developed severe cough that acted as an external force and blew off the ligature . the remaining 6 patients were diagnosed with massive hemorrhages , which were caused by surgical wound infection that developed due to various reasons . this included opening the surgical wound , keeping the airway open , and compressing suspicious bleeding site . six patients were immediately sent to the operating room ( or ) . under the effect of general anesthesia , debridement was performed on these patients . however , the fifth patient died before reaching the or . the superior thyroid artery of the first case was ligated once more to control bleeding . in the remaining 5 patients with cbs and tif , the treatment measures were as follows : the ruptures of carotid arteries were sewn and mended in 2 cases ; the carotid artery was ligated in 1 case ; and innominate , carotid , and subclavian arteries were ligated in 2 cases . to cover the large arteries all the hemorrhages of these 5 patients were under control as they received emergency treatment in or . among the 5 patients who were rescued successfully , moreover , there was 1 patient who suffered hemorrhages 3 times . to control bleeding of these recurrent hemorrhages , we resected the head of the clavicle of 1 patient . the sternum of the other patient was split to gain adequate access to the vessel . table 4 shows the various treatments and their corresponding outcomes in these patients . among the 5 patients who finally survived , 3 patients underwent innominate artery ligation . one patient suffered from a short - term delirious state , while another patient developed muscle weakness in the lower left limb within in a few days after the operation . although these 2 patients recovered gradually , 1 patient suffered from mild muscle weakness of the left lower extremity ( grade 4 ) 2 months after the surgery . there is no exact definition for life - threatening bleeding that occurs postoperatively . in this study , the postoperative bleeding is defined as life - threatening bleeding under any of the following 2 conditions : i ) the patient bleeds more than 500 ml within 5 minutes after the surgery ; and ii ) the hemorrhage would become life - threatening if emergency treatment is not provided within a few minutes . the life - threatening bleeding usually occurs postoperatively in patients who have undergone operations for treating head and neck squamous cell carcinomas , such as laryngeal carcinoma , hypopharyngeal carcinoma , and cervical esophageal carcinoma . postoperative cervical hemorrhages occur in some patients who have undergone thyroid surgery . in these patients , there is minimal bleeding due to hematomas , which are generally not life - threatening with timely treatment ( usually several quarters ) . the post - operative bleeding becomes life - threatening in very few cases after undergoing thyroid surgery . in general , these patients have undergone multiple treatments as they are diagnosed with thyroid carcinoma at an advanced stage . , 5 patients had undergone various treatments , including multiple operations , radioiodine treatment , and external beam radiotherapy . after being subjected to multiple operations and radiation , the tissue of the surgical wound lacked proper blood circulation . as a result another important risk factor was the advanced stage of this disease . in our group , there were 5 cases with t4 disease . in these patients , we not only resected the thyroid gland but also performed partial or total resection of the following organs : hypopharynx , larynx , cervical trachea , and cervical esophagus . the surgical wound was easily contaminated by the bacteria residing in the upper respiratory and digestive tract , which were also opened while performing the surgery . owing to the incidence of anastomotic fistula after surgery , the operative wounds , where the great arteries lost the protection of their surrounding connective tissue , were totally contaminated by the resident bacteria . in some cases , the tumor surrounded the carotid sheath , so it had to be scraped carefully while performing surgery . therefore , patients with multiple treatments and advanced diseases should be treated carefully to prevent the occurrence of life - threatening bleeding postoperatively . previous studies have reported that after undergoing thyroid surgery , patients have to be monitored for the first 24 hours , especially the first 12 hours . in this high - risk period , patients are quite prone to hemorrhage . the most frequent bleeding sites are the surface of the strap muscle , superior thyroid vessel , and the end of the recurrent laryngeal nerve . in patients treated with thyroid surgery , however , the case diagnosed with hemorrhage in the superior thyroid artery was an exception as life - threatening bleeding occurred just 1 hour after the surgery . in the other 6 cases , hemorrhages occurred within 321 days after the operations . five hemorrhages occurred at common carotid artery , while 1 hemorrhage occurred at an innominate artery . interestingly , in patients with cbss , all the bleeding sites were located in the lower segment or the root of right carotid artery , so they were clinically similar to the case with tifs . in this group , 1 patient experienced herald bleeding 4 days before suffering life - threatening bleeding postoperatively . another patient also experienced herald bleeding 8 days before developing life - threatening bleeding postoperatively . infection is the major reason for life - threatening bleeding that occurs postoperatively in patients who undergo thyroid operations . at the same time , unreliable ligation of arteries could also be another cause of this life - threatening bleeding . in our group , the first case suffered from a hemorrhage in the superior thyroid artery 1 hour after undergoing the surgery . this patient developed severe cough , which blew off the ligature ; this observation was confirmed while performing debridement of the surgical wound . the superior thyroid artery is the major artery that supplies blood to the thyroid gland . its hemorrhage caused the wound to become swollen within seconds ; the hemorrhage of this artery also oppressed the trachea within seconds . however , this serious phenomenon has been seldom reported in previous studies . in the remaining 6 cases , cervical and pharyngoesophageal anastomotic fistula were the causes of infections in the third and seventh cases , respectively . tracheal anastomotic fistula and subcutaneous pneumatosis were the causes of infection in fourth and fifth cases , respectively . however , while being subjected to radical radiation therapy , the surgical wound of the sixth case underwent continuous necrosis , exposing the carotid artery . total thyroidectomy was performed along with central and ipsilateral neck dissection on the second patient in this group . but , owing to preoperative leukopenia and postoperative chylous leakage , infection finally developed in the second case . six days after the surgery , we detected the infection in the second patient after draining the necrotic material from the tube . on the 8 day after surgery , this patient developed massive hemorrhage . in this study , we have easily figured out the measures that can be used to prevent this severe complication . the high - risk patients must be prescribed antibiotics to prevent pre - operative infection . then , during the operation , superior thyroid arteries should be ligatured firmly and checked over to prevent hemorrhage . while resecting the tracheal sleeve , we must ensure proper blood supply in anastomosis . if anastomotic fistula or wound infection is detected after surgery , the surgical wound should be opened immediately . then , the necrotic materials should be removed to prevent it from infiltrating the great arteries and causing bleeding . this would help in arresting the life - threatening bleeding that occurs in some patients after undergoing thyroid surgery . the emergency treatment at bedside is provided to stabilize the patients , who are then immediately transferred to or . the patient develops life - threatening bleeding in any of the following conditions : rapid - progressing hematoma , massive hemorrhage from incision , and tracheostoma . the life - threatening bleeding that occurs postoperatively is totally different from the common hemorrhage that occurs in patients after undergoing thyroidectomy . the emergency treatment provided at bedside includes the following features : ( 1 ) airway protection ; ( 2 ) temporary control or reduction in the bleeding by compressing ; ( 3 ) transfer of the patient to or ; and ( 4 ) setting up venous channels to correct hemorrhagic shock . the first thing to do at bedside is keep the airway unobstructed . with this objective , we hyperinflate the cuff of the tracheostomy tube ; this has been a successful measure in 85% of the cases as it prevents blood aspiration temporarily . if tracheotomy had not been performed , then the surgical incision would have opened without hesitation and the trachea would have got suppressed , thereby limiting airflow . utley   has reported that when the artery is compressed against the posterior surface of the manubrium by a finger , hemorrhage is controlled and reduced . at this stage , we have adequate time for transferring these patients into or . however , vein access should be set up simultaneously . the mortality rate of patients provided with emergency treatment at bedside is very high ; jones   have reported that only 31% cases with tracheo - innominate artery fistula could be successfully handled by providing emergency treatment at bedside . in our group , 6 patients successfully revived after receiving emergency treatment at bedside ; however , 1 patient died of respiratory and circulatory failure even after receiving emergency treatment at bedside . furthermore , the life - threatening bleeding of these 6 patients was controlled within a short span when they were shifted to or . therefore , although the success rate of emergency treatment provided at bedside is low , it is extremely necessary in such cases . to control bleeding in the superior thyroid artery , we once again ligated the artery . in the first case , we first enlarged the incision to explore and confirm the bleeding site of these cases . in the 5 cases with cbs , all the hemorrhage sites were located at the root or lower segment of carotid artery . as a result in the single case with tif , we again encountered some difficulties while exposing the bleeding site . in some of these cases , median sternotomy or clavicular head resection previous studies have described various methods to control cbs or tif , including direct suture , resection , and ligation of innominate artery . in addition , endovascular stent graft or endovascular embolization has been successfully performed on cases with cbs or tif in previous studies [ 10,14,1618 ] . traditionally , there have been 2 broad approaches to tackle the erosion of innominate and carotid artery : i ) interrupting the blood flow through the artery and ii ) maintaining the blood flow . in case of tif , the survival rate of patients whose blood flow was interrupted through the innominate artery was greater than that of patients treated by maintaining the blood flow . in a review by jones   et al . , the survival rates of cases treated by interrupting the blood flow was significantly higher ( 77% survival ) than that of patients whose blood flow was maintained ( 6% survival ) . in our research , the fourth case developed tif after undergoing thyroid surgery ; we performed ligation of both proximal and distal innominate artery of this patient . the ends of the carotid and subclavian arteries were also sewn . at the same time , the wound was repeatedly washed , and the infected necrotic tissues were debrided thoroughly . luckily , the hemorrhage was controlled effectively , and there was no recurrence of bleeding in this case . traditionally , open surgery is the main treatment for patients with cbs . the conventional open surgery approaches include direct suture , resection , and ligation . in the mid-1980s , however , in the 5 patients with cbs , all the hemorrhage sites were located in the root or the lower segment of the carotid artery , which was close to the innominate artery . as a result , the chances of developing furcation were high . therefore , endovascular intervention was more challenging and unreliable . the use of any synthetic materials in the infected area would have easily led to life - threatening bleeding of fatal nature . in our group , all the 4 patients with cbs underwent open surgery in or after receiving emergency treatment . the ligation of carotid artery was carried out in the second and third cases , while the crevasse was directly sutured in sixth and seventh cases . the bleeding of sixth case was successfully controlled as there was no recurrence of bleeding . however , there was recurrence of bleeding in the second and seventh case 29 hours after undergoing open surgery . furthermore , ten days after receiving first aid , the second case suffered bleeding once more . finally , to control the bleeding , we ligated the innominate , carotid , and subclavian arteries of second and seventh cases . our outcome suggests that ligation of innominate artery must be carried out to stop life - threatening bleeding that occurs postoperatively in patients who develop cbs or tif complications after undergoing thyroid surgery . viable adjacent tissues , such as pectoralis major myocutaneous flap and sternocleidomastoid muscle flap should be used to cover and protect the blood vessels . because of collateral flow through the external carotid artery , thyrocervical trunk , and vertebral vessels , ligation of the innominate artery was recommended in the management of tif . researchers were of the view that this approach would not lead to significant neurological or vascular complications . jones et al .   have reported that 22 patients survived the initial operation , and only 1 patient developed neurological deficits . neurological events may be reduced by adequately replacing blood perioperatively . at the same time , the intraoperative and postoperative blood pressure should be maintained at a slightly higher level to overcome cerebral ischemia . in our group , after the ligation , they were administered intravenous fluids to increase blood volume and improve microcirculation . the second case developed a short - term delirious state after receiving first aid ; however , this patient recovered from that state within 2 months . the fourth case developed grade 2 muscle weakness in the left lower limb , and the mri scan revealed multiple cortical infarctions in his right frontal lobe , temporal lobe , parietal , and occipital cortex ( figures 1 , 2 ) . after 2 months , this patient s left lower extremity recovered greatly and the patient showed grade 4 muscle weakness , which was milder than the original grade 2 muscle weakness . the life - threatening bleeding does occur in some patients after undergoing thyroid surgery . in general , these patients have undergone multiple treatments as they are diagnosed with thyroid carcinoma at an advanced stage . the pathologic differentiation is quite poor in these cases . in this study , 5 patients had undergone various treatments , including multiple operations , radioiodine treatment , and external beam radiotherapy . after being subjected to multiple operations and radiation , the tissue of the surgical wound lacked proper blood circulation . as a result , it was difficult to heal the surgical wound of these patients . another important risk factor was the advanced stage of this disease . in our group , there were 5 cases with t4 disease . in these patients , we not only resected the thyroid gland but also performed partial or total resection of the following organs : hypopharynx , larynx , cervical trachea , and cervical esophagus . the surgical wound was easily contaminated by the bacteria residing in the upper respiratory and digestive tract , which were also opened while performing the surgery . owing to the incidence of anastomotic fistula after surgery , the operative wounds , where the great arteries lost the protection of their surrounding connective tissue , were totally contaminated by the resident bacteria . in some cases , the tumor surrounded the carotid sheath , so it had to be scraped carefully while performing surgery . therefore , patients with multiple treatments and advanced diseases should be treated carefully to prevent the occurrence of life - threatening bleeding postoperatively . previous studies have reported that after undergoing thyroid surgery , patients have to be monitored for the first 24 hours , especially the first 12 hours . in this high - risk period , patients are quite prone to hemorrhage . the most frequent bleeding sites are the surface of the strap muscle , superior thyroid vessel , and the end of the recurrent laryngeal nerve . in patients treated with thyroid surgery , however , the case diagnosed with hemorrhage in the superior thyroid artery was an exception as life - threatening bleeding occurred just 1 hour after the surgery . in the other 6 cases , hemorrhages occurred within 321 days after the operations . five hemorrhages occurred at common carotid artery , while 1 hemorrhage occurred at an innominate artery . interestingly , in patients with cbss , all the bleeding sites were located in the lower segment or the root of right carotid artery , so they were clinically similar to the case with tifs . in this group , 1 patient experienced herald bleeding 4 days before suffering life - threatening bleeding postoperatively . another patient also experienced herald bleeding 8 days before developing life - threatening bleeding postoperatively . infection is the major reason for life - threatening bleeding that occurs postoperatively in patients who undergo thyroid operations . at the same time , unreliable ligation of arteries could also be another cause of this life - threatening bleeding . in our group , the first case suffered from a hemorrhage in the superior thyroid artery 1 hour after undergoing the surgery . this patient developed severe cough , which blew off the ligature ; this observation was confirmed while performing debridement of the surgical wound . the superior thyroid artery is the major artery that supplies blood to the thyroid gland . its hemorrhage caused the wound to become swollen within seconds ; the hemorrhage of this artery also oppressed the trachea within seconds . however , this serious phenomenon has been seldom reported in previous studies . in the remaining 6 cases , life - threatening bleeding occurred postoperatively due to surgical wound infection . cervical and pharyngoesophageal anastomotic fistula were the causes of infections in the third and seventh cases , respectively . tracheal anastomotic fistula and subcutaneous pneumatosis were the causes of infection in fourth and fifth cases , respectively . however , while being subjected to radical radiation therapy , the surgical wound of the sixth case underwent continuous necrosis , exposing the carotid artery . total thyroidectomy was performed along with central and ipsilateral neck dissection on the second patient in this group . but , owing to preoperative leukopenia and postoperative chylous leakage , infection finally developed in the second case . six days after the surgery , we detected the infection in the second patient after draining the necrotic material from the tube . in this study , we have easily figured out the measures that can be used to prevent this severe complication . the high - risk patients must be prescribed antibiotics to prevent pre - operative infection . then , during the operation , superior thyroid arteries should be ligatured firmly and checked over to prevent hemorrhage . while resecting the tracheal sleeve , we must ensure proper blood supply in anastomosis . if anastomotic fistula or wound infection is detected after surgery , the surgical wound should be opened immediately . then , the necrotic materials should be removed to prevent it from infiltrating the great arteries and causing bleeding . this would help in arresting the life - threatening bleeding that occurs in some patients after undergoing thyroid surgery . the emergency treatment at bedside is provided to stabilize the patients , who are then immediately transferred to or . the patient develops life - threatening bleeding in any of the following conditions : rapid - progressing hematoma , massive hemorrhage from incision , and tracheostoma . the life - threatening bleeding that occurs postoperatively is totally different from the common hemorrhage that occurs in patients after undergoing thyroidectomy . the emergency treatment provided at bedside includes the following features : ( 1 ) airway protection ; ( 2 ) temporary control or reduction in the bleeding by compressing ; ( 3 ) transfer of the patient to or ; and ( 4 ) setting up venous channels to correct hemorrhagic shock . the first thing to do at bedside is keep the airway unobstructed . with this objective , we hyperinflate the cuff of the tracheostomy tube ; this has been a successful measure in 85% of the cases as it prevents blood aspiration temporarily . if tracheotomy had not been performed , then the surgical incision would have opened without hesitation and the trachea would have got suppressed , thereby limiting airflow . utley   has reported that when the artery is compressed against the posterior surface of the manubrium by a finger , hemorrhage is controlled and reduced . at this stage , we have adequate time for transferring these patients into or . the mortality rate of patients provided with emergency treatment at bedside is very high ; jones   have reported that only 31% cases with tracheo - innominate artery fistula could be successfully handled by providing emergency treatment at bedside . in our group , 6 patients successfully revived after receiving emergency treatment at bedside ; however , 1 patient died of respiratory and circulatory failure even after receiving emergency treatment at bedside . furthermore , the life - threatening bleeding of these 6 patients was controlled within a short span when they were shifted to or . therefore , although the success rate of emergency treatment provided at bedside is low , it is extremely necessary in such cases . to control bleeding in the superior thyroid artery , we once again ligated the artery . in the first case , we first enlarged the incision to explore and confirm the bleeding site of these cases . in the 5 cases with cbs , all the hemorrhage sites were located at the root or lower segment of carotid artery . as a result , we could not easily expose the bleeding site in these 5 cases . in the single case with tif , we again encountered some difficulties while exposing the bleeding site . in some of these cases , median sternotomy or clavicular head resection previous studies have described various methods to control cbs or tif , including direct suture , resection , and ligation of innominate artery . in addition , endovascular stent graft or endovascular embolization has been successfully performed on cases with cbs or tif in previous studies [ 10,14,1618 ] . traditionally , there have been 2 broad approaches to tackle the erosion of innominate and carotid artery : i ) interrupting the blood flow through the artery and ii ) maintaining the blood flow . in case of tif , the survival rate of patients whose blood flow was interrupted through the innominate artery was greater than that of patients treated by maintaining the blood flow . in a review by jones   et al . , the survival rates of cases treated by interrupting the blood flow was significantly higher ( 77% survival ) than that of patients whose blood flow was maintained ( 6% survival ) . in our research , the fourth case developed tif after undergoing thyroid surgery ; we performed ligation of both proximal and distal innominate artery of this patient . the ends of the carotid and subclavian arteries were also sewn . at the same time , the wound was repeatedly washed , and the infected necrotic tissues were debrided thoroughly . luckily , the hemorrhage was controlled effectively , and there was no recurrence of bleeding in this case . traditionally , open surgery is the main treatment for patients with cbs . the conventional open surgery approaches include direct suture , resection , and ligation . in the mid-1980s , however , in the 5 patients with cbs , all the hemorrhage sites were located in the root or the lower segment of the carotid artery , which was close to the innominate artery . as a result , . the use of any synthetic materials in the infected area would have easily led to life - threatening bleeding of fatal nature . in our group , all the 4 patients with cbs underwent open surgery in or after receiving emergency treatment . the ligation of carotid artery was carried out in the second and third cases , while the crevasse was directly sutured in sixth and seventh cases . the bleeding of sixth case was successfully controlled as there was no recurrence of bleeding . however , there was recurrence of bleeding in the second and seventh case 29 hours after undergoing open surgery . furthermore , ten days after receiving first aid , the second case suffered bleeding once more . finally , to control the bleeding , we ligated the innominate , carotid , and subclavian arteries of second and seventh cases . our outcome suggests that ligation of innominate artery must be carried out to stop life - threatening bleeding that occurs postoperatively in patients who develop cbs or tif complications after undergoing thyroid surgery . viable adjacent tissues , such as pectoralis major myocutaneous flap and sternocleidomastoid muscle flap should be used to cover and protect the blood vessels . because of collateral flow through the external carotid artery , thyrocervical trunk , and vertebral vessels , ligation of the innominate artery was recommended in the management of tif . researchers were of the view that this approach would not lead to significant neurological or vascular complications . jones et al .   have reported that 22 patients survived the initial operation , and only 1 patient developed neurological deficits . neurological events may be reduced by adequately replacing blood perioperatively . at the same time , the intraoperative and postoperative blood pressure should be maintained at a slightly higher level to overcome cerebral ischemia . in our group , after the ligation , they were administered intravenous fluids to increase blood volume and improve microcirculation . the second case developed a short - term delirious state after receiving first aid ; however , this patient recovered from that state within 2 months . the fourth case developed grade 2 muscle weakness in the left lower limb , and the mri scan revealed multiple cortical infarctions in his right frontal lobe , temporal lobe , parietal , and occipital cortex ( figures 1 , 2 ) . after 2 months , this patient s left lower extremity recovered greatly and the patient showed grade 4 muscle weakness , which was milder than the original grade 2 muscle weakness . life - threatening bleeding is a rare and serious complication that develops in some patients after undergoing thyroid surgery . it is often encountered in thyroid carcinoma patients with any of the following complications : history of multiple treatments , advanced stage of disease , and poor pathological differentiation . this life - threatening bleeding that occurs in patients after undergoing thyroid operation can be classified as superior thyroid artery hemorrhage , cbs , and tif . the bleeding site of cbs is always located at the root or lower segment of the artery , making it clinically similar to tif . hemorrhage of the superior thyroid artery occurs several hours after the surgery , and its development is related to the unreliable ligation and patient movement after surgery . the complications of cbs and tif usually occur several days after the surgery , and both are related to the surgical wound infection , which is induced by events such as chylous leakage , cervical esophageal fistula , and tracheal anastomotic fistula . once the hemorrhage is detected , emergency aid at bedside helps in stabilizing the patients . then , they are safely transferred immediately to the or . to control the life - threatening bleeding , ligation of the innominate artery was performed in cases complicated with tif or cbs ; with this approach , the patients did not develop any significant neurological or vascular complications . thereafter , the patients were given intravenous fluids to increase blood volume and improve microcirculation . thus , we prevented the development of neurological complications , such as hemiplegia and mental disorders .
backgroundfew reports have discussed life - threatening bleeding that occurs postoperatively in patients who have undergone thyroid surgery . in this article , we discuss the causes , treatment measures , and possible ways of preventing this severe complication.material/methodsfrom jan 2002 to dec 2014 we retrospectively analyzed 7 patients who developed life - threatening bleeding after undergoing thyroid surgery at our center.resultsamong the group of 7 patients , there was 1 case of superior thyroid artery hemorrhage ( stah ) , 5 cases of carotid blowout syndrome ( cbs ) , and 1 case of tracheo - innominate fistula ( tif ) . 
 the stah was caused by unreliable ligation . 
 all the cases of cbs and tif were caused by surgical wound infection . 
 six patients were transferred to the operating room immediately ; open surgical treatment was performed on these 6 patients . out of these 6 patients , 1 
 patient did not survive the operation , and hemorrhage was successfully controlled in 3 patients . 
 the remaining 2 patients again experienced bleeding even after undergoing open surgery . 
 only 1 patient developed long - term neurological complications.conclusionsinfection is the most common cause of life - threatening bleeding that occurs postoperatively in some patients who have undergone thyroid surgery . 
 early surgical intervention can save the lives of these patients without causing any severe neurological complications .