• Journal of Chest Surgery
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• v.34 no.6
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• pp.465-471
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• 2001

Background: Hypothermia protects the brain by suppressing the cerebral metabolism and it is performed well enough before the total circulatory arrest(TCA) in the operation of aortic disease. Generally, TCA has been performed depending on the rectal or nasopharyngeal temperatures; however, there is no definite range of optimal temperature for TCA or an objective indicator determining the temperature for safe TCA. In this study, we tried to determine the optimal range of temperature for safe hypothermic circulatory arrest by using the intraoperative electroencephalogram(EEG), and studied the role of EEG as an indicator of optimal hypothermia. Material and Method: Between March, 1999 and August 31, 2000, 27 patients underwent graft replacement of the part of thoracic aorta using hypothermia and TCA with intraoperative EEG. The rectal and nasopharyngeal temperatures were monitored continuously from the time of anesthetic induction and the EEG was recorded with a ten-channel portable electroencephalography from the time of anesthetic induction to electrocerebral silence(ECS). Result: On ECS, the rectal and nasopharyngeal temperatures were not consistent but variable(rectal 11$^{\circ}C$ -$25^{\circ}C$, nasopharynx 7.7$^{\circ}C$ -23$^{\circ}C$). The correlation between two temperatures was not significant(p=0.171). The cooling time from the start of cardiopulmonary bypass to ECS was also variable(25-127min), but correlated with the body surface area(p=0.027). Conclusion: We have found that ECS appeared at various body temperatures, and thus, the use of rectal or nasopharyngeal temperature were not useful in identifying ECS. Conclusively, we can not fully assure cerebral protection during hypothermic circulatory arrest in regards to the body temperatures, and therefore, the intraoperative EEG is one of the necessary methods for determining the range of optimal hypothermia for safe circulatory arrest. :

• Journal of Chest Surgery
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• v.41 no.2
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• pp.229-238
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• 2008

Background: Protection of the brain is a major concern during thoracic aortic surgery using hypothermic circulatory arrest (HCA). This study compares the surgical outcomes of two different cerebral protection methods in thoracic aortic surgery using HCA: retrograde cerebral protection (RCP) and antegrade cerebral protection (ACP). Material and Method: We retrospectively reviewed data on 146 patients who underwent thoracic aortic surgery from May 1995 to February 2007 using either RCP (114 patients, Group 1) or ACP (32 patients, Group 2) during HCA. There were 104 dissections (94 acute and 10 chronic) and 42 aneurysms (41 true aneurysms and 1 pseudoaneurysm), and all patients underwent ascending aortic replacement. There were 33 cases of hemiarch replacement, 5 of partial arch replacement, and 21 of total arch replacement. Result: The two groups were similar in preoperative and operative characteristics, but Group 2 had more elderly (over 70 years old) patients (34.4% vs. 10.5%), more coronary artery diseases (18.8% vs. 4.4%), more total arch replacements (46.9% vs. 5.3%) and longer HCA time ($50{\pm}24$ minutes vs. $32{\pm}17$ minutes) than Group 1. The operative mortality was 4.4% (5/114) and 3.1% (1/32), the incidence of permanent neurologic deficits was 5.3% (6/114) and 3.1% (1/32), and the incidence of temporary neurologic deficits was 1.8% (2/114) and 9.4% (3/32) in Groups 1 and 2, respectively. There were no statistical differences between the two groups in operative mortality, postoperative bleeding, or neurologic deficits (permanent and temporary). Conclusion: The early outcomes of aortic surgery using HCA were favorable and showed no statistical difference between RCP and ACP. However, the ACP patients endured longer HCA times and more extended arch surgeries. ACP is the preferred brain protection technique when longer HCA time is expected or extended arch replacement is needed.

• Journal of Chest Surgery
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• v.30 no.5
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• pp.501-505
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• 1997

It was reported that use of aprotinin in elderly patients undergoing hypothermic circulatory arrest was associated with an increased risk of renal dysfunction, and myocardial infarction as a result of intravascular coagulation. We reviewed 20 patients who received high-dose aprotinin under deep hypothermic circulatory arrest with(NP group, n= 11) or without selective cerebral perfusion(SP group, n=9). The activated clotting time was exceeded 750 seconds in all but 1 patient. After opening aortic arch, retrograde low flow perfusion was maintained through femoral artery to prevent air embolization to the visceral arteries. Four patients among 20 died during hospitalization'due to bleeding, coronary artery dissection pulmonary hemorrhage and multiple cerebral infarction. Postoperatively, cerebrovascular accidents occurred in two patients; one with preoperative carotid artery dissection and the other with unknown multiple cerebral infarction. In conclusion, use of aprotinin in young patients undergoing hypothermic circulatory arrest did not increase the risk of renal dysfunction or intravascular coagulation if ACT during circulatory arrest is maintained to exceed 750 seconds with low-flow perfusion.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.108-111
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• 2004

Reoperation on the recurrent aortic aneurysm adjuvent to sternum remains a challenging problem in regard to the risk of the massive hemorrhage at the time of resternotomy resulting from inadvertent entry into the aneurysmal sac. The cardiopulmonary bypass technique of femoral cannulation and deep hypothermic circulatory arrest can provide a safe resternotomy. The left ventricle is likely to distend due to lack of contraction with ventricular fibrillation during core cooling. To prevent ventricular distention during core cooling, sufficient venous drainage is mandatory, We report a technique in which deep hypothermic circulatory arrest is achieved before resternotomy without left ventricular distention by active venous drainage using centrifugal pump.

• Journal of Chest Surgery
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• v.31 no.6
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• pp.553-559
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• 1998

Introduction: The most dramatic application of hypothermia in cardiac surgery is in deep hypothermic circulatory arrest(DHCA). Because man in natural circumstances is never exposed to this extreme hypothermic condition, one of the controversial aspects of clinical hypothermia is appropriate acid-base management($\alpha$-stat versus pH-stat). This study aims to compare $\alpha$-stat with pH-stat for: (1) brain cooling and re-warming speed during hypothermia induction and re-warming by cardiopulmonary bypass (CPB); (2) cerebral perfusion, metabolism, and their coupling; and (3) the extent of development of cerebral edema after circulatory arrest, in young pigs. Materials & Methods: Fourteen young pigs were assigned to one of two strategies of gas manipulation. Cerebral blood flow was measured with a cerebral venous outflow technique. After a median sternotomy, CPB was established. Core cooling was initiated and continued until nasopHaryngeal temperature fell below $20^{\circ}C$. The flow rate was set at 2,500 ml/min. Once their temperatures were below $20^{\circ}C$, the animals were subjected to DHCA for 40 mins. During cooling, acid-base balance was maintained according to either $\alpha$-STAT or pH-STAT strategies. After DHCA, the body was re-warmed to normal body temperature. The animals were then sacrificed, and their brains measured for edema. Cerebral perfusion and metabolism were measured before the onset of CPB, before cooling, before DHCA, 15 mins after re-warming, and upon completion of re-warming. Results & Conclusion: Cooling time was significantly shorter with $\alpha$-stat than with pH-stat strategy, while there were no significant differences in rewarming time between the two groups. Nosignificant differences were found in cerebral blood flow, metabolic rate, or flow/ metabolic rate ratio between two groups. Temperature-related differences were significant in cerebral blood flow, metabolic rate, and flow/metabolic rate ratio within each group. Brain water content showed no significant differences between two groups.

• Journal of Chest Surgery
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• v.30 no.5
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• pp.471-478
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• 1997

Introduction: The use of rabbits as a cardiopulmonary bypass(CPB) animal model is extremely dif%cult mainly due to technical problems. On the other hand, deep hypothermic circulatory arrest(CA) is used to facilitate surgical repair in a variety of cardiac diseases. Although steroids are generally known to be effective in the treatment of cerebral edema, the protective effects of steroids on the brain during CA are not conclusively established. Objectives of this study are twofold: the establishment of CPB technique in rabbits and the evaluation of preventive effect of steroid on the development of brain edema during CA. Material '||'&'||' Methods: Fifteen New Zealan white rabbits(average body weight 3.5kg) were divided into three experimental groups; control CA group(n=5), CA with Trendelenberg position group(n=5), and CA with Trendelenberg position + steroid(methylprednisolone 30 mglkg) administration group(n=5). After anesthetic induction and tracheostomy, a median sternotomy was performed. An aortic cannula(3.3mm) and a venous ncannula(14 Fr) were inserted, respectively in the ascending aorta and the right atrium. The CPB circuit consisted of a roller pump and a bubble oxygenator. Priming volume of the circuit was approximately 450m1 with 120" 150ml of blood. CPB was initiated at a flow rate of 80~85ml/kg/min, Ten min after the start of CPB, CA was established with duration of 40min at $20^{\circ}C$ of rectal temperature. After CA, CPB was restarted with 20min period of rewarming. Ten min after weaning, the animal was sacrif;cod. One-to-2g portions of the following tissues were rapidly d:ssected and water contents were examined and compared among gr ups: brain, cervical spinal cord, kidney, duodenum, lung, heart, liver, spleen, pancreas. stomach. Statistical significances were analyzed by Kruskal-Wallis nonparametric test. Results: CPB with CA was successfully performed in all cases. Flow rate of 60-100 mlfkgfmin was able to be maintained throughout CPB. During CPB, no significant metabolic acidosis was detected and aortic pressure ranged between 35-55 mmHg. After weaning from CPB, all hearts resumed normal beating spontaneously. There were no statistically significant differences in the water contents of tissues including brain among the three experimental groups. Conclusion: These results indicate (1) CPB can be reliably administered in rabbits if proper technique is used, (2) the effect of steroid on the protection of brain edema related to Trendelenburg position during CA is not established within the scope of this experiment.

• Journal of Chest Surgery
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• v.35 no.10
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• pp.755-759
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• 2002

A 64-year-old man was admitted for gross hematuria. Preoperative study revealed right renal cell carcinoma with inferior vena cava(IVC) tumor thrombus. Right radical nephrectomy was performed, and deep hypothermic circulatory arrest(DHCA) with retrograde cerebral perfusion(RCP) was used for extraction of tumor thrombus in the IVC. The thrombus originated from the right kidney, which extended the orifice of the gonadal vein in the left renal vein laterally, the hepatic vein superiorly, and 3cm below the right renal vein inferiorly. The thrombus was removed completely without caval wall injury under DHCA with RCP, and the postoperative course was uneventful. He received immunotherapy with interferon, and followed up without any surgical problem.

• Journal of Chest Surgery
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• v.39 no.1 s.258
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• pp.12-17
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• 2006

Background: Circulatory arrest under deep hypothermia is an important auxiliary means for surgical correction of total anomalous pulmonary venous connection (TAPVC), However, cardiac operations under deep hypothermic circulatory arrest are associated with the risk of post-arrest neurologic abnormalities. The purpose of this study is to evaluate the results of the surgical correction of total anomalous pulmonary venous connection without the total circulatory arrest. Materiai and Method: Between April 2000 and October 2004, hospital records of 10 patients were reviewed retrospectively. Result: The locations for abnormal anatomical connections were supracardiac in 7 cases, cardiac in 1 case, and infracardiac in 2 cases. The mean cardiopulmonary bypass time and aorta cross clamp time were 116.8$\pm$40.7 and 69.5$\pm$24.1 minutes. There was no surgical mortality. Postoperative complications were post-repair pulmonary venous stenosis in 1 case, pneumonia in 1, pneumothorax in 1, wound infection in 1,and diaphragmatic paralysis in 1. All patients without pulmonary venous stenosis were in NYHA class I at mean follow-up of 16.6 months (3$\∼$49 months) Conclusion: We could obtain excellent results by repair without the total circulatory arrest for total anomalous pulmonary venous connection.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.43-49
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• 2004

Background: Acute thoracic aortic dissections involving the aortic arch differ in diagnosis, surgical procedures, and operative results compared to those that do not involve the aortic arch. In general cerebral perfusion under deep hypothermic circulatory arrest (HCA) is performed during the repair of the aortic arch dissection. Here, we report our surgical results of the aortic arch dissection repair using retrograde cerebral perfusion (RCP) and its safety. Material and Method: Between January 1996 and June 2002, 22 consecutive patients with aortic arch dissection underwent aortic arch repair. In 20 of them RCP was performed under HCA. RCP was done through superior vena cava in 19 patients and by systemic retrograde venous perfusion in 1, in whom it was difficult to reach the SVC. When the patient's rectal temperature reached 16 to 18$^{\circ}C$, systemic circulation was arrested, and the amount of RCP amount was 481.1 $\pm$292.9 $m\ell$/min with perfusion pressure of 20∼30 mmHg. Result: There were two in-hospital deaths (4.5%) and one late death (9.1%). Mean circulatory arrest time (RCP time) was 54.0$\pm$ 13.4 minutes (range, 7 to 145 minutes). RCP time has no correlation with the appearance of consciousness, recovery of orientation, or ventilator weaning time (p=0.35, 0.86, and 0.92, respectively). Ventilator weaning was faster in patients with earlier recovery of consciousness and orientation (r=0.850, r=926; p=0.000, respectively). RCP of more than 70 minutes did not affect the appearance of consciousness, recovery of orientation, ventilator weaning time, exercise time, or hospital stay (p=0.42, 0.57, 0.60, 0.83, and 0.51, respectively). Conclusion: Retrograde cerebral perfusion time under hypothermic circulatory arrest during repair of aortic arch dissection may not affect recovery of orientation, ventilator weaning time, neurologic complications, and postoperative recovery.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.279-284
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• 1998

Deep hypothermic circulatory arrest(DHCA), in which systemic temperatures of 2$0^{\circ}C$ or less are used to allow temporary cessation of the circulation, is an useful adjunct in cardiac surgery. Because man in natural circumstances is never exposed to the extreme hypothermic condition, however, one of the controversial aspects is appropriate blood gas management($\alpha$STAT versus PH-STAT) during DHCA. This study aims to compare $\alpha$STAT with PH-STAT management for control of blood gases in experimental cardiopulmonary bypass(CPB) circuits with a membrane oxygenator. Fourteen young pigs were assigned to one of two strategies of gas manipulation. After a median sternotomy, CPB was established. Core cooling was initiated and continued until nasopharyngeal temperature fell below 2$0^{\circ}C$. The flow rate was set at 2,500 ml/min. Once their temperatures were below 2$0^{\circ}C$, the animals were subjected to circulatory arrest for 40mins. During cooling, blood gas was maintained according to either $\alpha$$\alpha$STAT or pH-STAT strategies. After DHCA, the body was rewarmed to normal body temperature. Arterial blood gases were measured before the onset of CPB, before cooling, before DHCA, at the point of 27$^{\circ}C$ during re-warming, on completion of re-warming. Cooling time was significantly shorter in $\alpha$-STAT than PH-STAT strategy, while there was no significant differences in rewarming time between two groups. Carbon dioxide was added between 5.5 and 3.0% in PH-STAT, while no carbon dioxide was added in $\alpha$STAT management. Amounts of oxygen administration were gradually lowered as temperature decreased. In this way, criteria of PH, PaCO, and PaO adjustments were satisfied in both $\alpha$STAT and PH-STAT management groups.