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조영증강흉부전산화단층촬영후발생한대량의공기색전증 1 예 1 충북대학교의과대학내과학교실, 2 영상의학과교실박병출 1, 길호 1, 박찬선 1, 정지인 1, 최은영 1, 신윤미 1, 이기만 1, 김성진 2, 최강현 1 A Case of Massive Air Embolism after Contrast-enhanced Computed Tomography Byeong Chool Park, M.D. 1, Ho Kil, M.D. 1, Chan Sun Park, M.D. 1, Jee In Jeong, M.D. 1, Eun Young Choi, M.D. 1, Yoon Mi Shin, M.D. 1, Ki Man Lee, M.D. 1, Sung Jin Kim, M.D. 2, Kang Hyeon Choe, M.D. 1 1 Department of Internal Medicine and 2 Radiology, College of Medicine, Chungbuk National University, Cheongju, Korea A venous air embolism is a complication of various venous access procedures such as contrast-enhanced computed tomography (CECT). Although most cases of iatrogenic venous air embolisms during CECT involve a few milliliters of air and are asymptomatic, a massive venous air embolism can be fatal. We report a case of a massive intraventricular air embolism after CECT with a review of the literature regarding the pathophysiology and treatment of air embolisms. (Tuberc Respir Dis 2007; 63: 178-182) Key Words: Air embolism, Contrast-enhanced computed tomography, Complication. 서 공기색전증은동맥이나정맥속으로공기가유입되는상태로 1769년 Morgagni 에의해처음알려졌으며, 공기가유입되는부위와우심방과의압력차에의해발생한다 1,2. 전통적으로두경부및골반수술시에공기색전증이주로발생하는것으로알려져있으며, 중심정맥도관삽입, 경피적흉부세침생검, 기계호흡에의한압력손상, 정맥을통한수액주입시등에서도보고되고있다 3,4. 진단및치료를위해방사선조영제를사용하는빈도가많아지고고해상도와고속촬영이가능한 computed tomography(ct) 가발전하면서조영증강 CT 후정맥공기색전증은드물지않게발생되는문제로서두경부조영증강 CT 후 15% 까지 5, 그리고흉부조영증강 CT 후 23% 까지 6 관찰되는것으로보고되었다. 대부분의공기색전은소량으로증상이없어일반적으로치료가필요치않으나대량의공기색전의경 론 Address for correspondence: Kang Hyeon Choe, M.D. Department of Internal Medicine, College of Medicine, Chungbuk National University, 12 Gaeshin-dong, Heungduk-gu, Cheongju, Chungbuk, 361-763, Korea Phone: 82-43-269-6014, Fax: 82-43-273-3252 E-mail: choekh@chungbuk.ac.kr Received: Jun. 14. 2007 Accepted: Jul. 11. 2007 우호흡곤란, 흉통, 빈맥, 저혈압, 의식상태변화, 심폐부전등의다양한임상양상으로발현할수있으며, 유입된공기의양, 공기의유입속도, 체위등에따라치명적일수있다 6,7. 이에저자들은경정맥조영증강 CT 후발생한대량의우심실공기색전증 1예를경험하였기에문헌고찰과함께보고하는바이다. 증례환자 : 남자 47세주소 : 흉부불편감현병력 : 환자는건강검진을위해촬영한흉부방사선사진에서양측폐문비대가관찰되어내원일인근병원에서자동주입기를사용하지않고조영제를가압점적주입하여조영증강흉부 CT 촬영을시행받았으며그후활력증후는안정적이었고가벼운마른기침과흉부불편감이외에뚜렷한증상을호소하지않았다. 그러나촬영된 CT 영상에서대량의공기가우심실과주폐동맥에서발견되어코삽입관으로산소를투여받으며본원으로전원되었다. 과거력 : 특이사항없음흡연력 : 없음사회력및가족력 : 10년전부터가전제품생산공장에서포장일을하고있음. 진찰소견 : 내원당시혈압 150/90 mmhg, 맥박수 178

Tuberculosis and Respiratory Diseases Vol. 63. No.2, Aug. 2007 Figure 1. Simple chest radiograph shows prominent both hili and reticular shadow in both lungs at emergency room. 88회 / 분, 호흡수 22회 / 분, 체온 36.5 로외견상안정적인모습이었다. 의식상태는명료하였으며흉부청진에서천명음이나수포음은들리지않았으며, 심음은규칙적이고심잡음도들리지않았다. 그외전신이학적소견에서특이이상소견은발견되지않았다. 검사실소견 : 코삽입관으로분당 5 L의산소를투여하면서측정한동맥혈가스검사에서 ph 7.44, PaCO 2 36.3 mmhg, PaO 2 107.2 mmhg, HCO 3-25.1 meq/l, SaO 2 98.4% 이었다. 일반혈액검사에서혈색 소 15.3 g/dl, 헤마토크리트 34.2%, 백혈구 8190/ mm 3, 혈소판 216,000/mm 3 이었다. 생화학검사에서나트륨 138 meq/l, 칼륨 4.7 meq/l, 혈액요소질소 11 mg/dl, 크레아티닌 0.9 mg/dl, AST 33 IU/L, ALT 15 IU/L, 총단백 7.2 g/dl, 알부민 4.1 g/dl이었다. 심전도소견은정상동조율이었다. 방사선소견 : 흉부방사선사진에서양측폐문비대와양측폐내에미만성망상형폐침윤이관찰되었고 (Figure 1), 타병원에서시행한조영증강 CT 촬영에서양측폐문부위와기관용골하부위에다발성림프절비대와양측폐내에다발성소결절들이관찰되어종양의폐전이또는유육종증이의심되었으며대량의공기음영이우심실과주폐동맥에서관찰되었으나좌심장에서는보이지않았다 (Figure 2A, 2B, 2C). 임상경과및치료 : 환자는응급실내원시즉시좌측측와위자세에서고농도산소치료를받았다. 경과관찰중활력증후는안정적이었으며가벼운기침과흉부불편감이외에호흡곤란, 흉통등뚜렷한증상을호소하지않았다. 증상발생 8시간후다시촬영한흉부 CT에서전에보이던우심실과주폐동맥내에공기음영은관찰되지않았다 (Figure 3A, 3B). 입원 2일째부터모든증상이호전되었으며대기하평상호흡에서측정한동맥혈가스검사에서 ph 7.47, PaCO 2 39.2 mmhg, PaO 2 72.8 mmhg, HCO 3-29.3 meq/l, SaO 2 95.4% 이었다. 환자는후유증없이회복되었으며입원 16일째흉강경술을시행하여림프절조직을얻었으며유육종증으로진단하였다. 유육종증에대해서는다른장기의침범이없고병기 1로스테로이드치료없이 A B C Figure 2. Contrast enhanced chest CT scans performed at a local hospital show large amount of air in right ventricle (A) and main pulmonary artery (B). Also, enlargement of both hilar and mediastinal lymph nodes (arrow) are seen (C). 179

BC Park et al: A case of massive air embolism after contrast-enhanced computed tomography A B Figure 3. High resolution CT scans obtained after 8 hours show no air in right ventricle (A) and main pulmonary artery (B). 외래에서추적관찰하였고, 공기색전증으로인한후유증없이경과관찰 4개월째환자는연고지관계로타병원으로전원하였다. 고찰공기색전증은우심방과공기가주입되는부위와의압력차에의해발생하는데심장보다공기가주입되는부위가높게위치할경우압력차는증가하게되고실제로좌위자세에서진행되는두경부수술시흔히관찰되며많게는 80% 까지보고되기도하였다 1,4. 최근에조영제사용이보편화됨에따라조영제주입과관련된정맥내공기색전은 CT 영상에서자주접하게되었으며 Woodring 등 6 은점적주입법으로적절하게시행된흉부조영 CT 100예중 23예 (23%) 에서, Groell 등 8 은조영제자동주입기를사용한 677예중 79예 (11.7%) 에서공기색전증을보고하였으며주로주폐동맥, 상대정맥, 우심실, 쇄골하정맥, 우심방등에서공기음영이관찰된다고하였다. Groell 등 8 은정맥공기색전증은주사기에조영제를채운후충분히흔들지않아남아있던기포가유입되거나정맥내삽입된삽입관또는삽입관과주입기의연결관사이에있던소량의공기가유입되어발생하며조영제의종류, 주입속도, 주입양, 주입위치등과는관계가없다고하였다. 대량의공기색전은특히부주의한조영제주입과관련되어일어나는데, Imai 등 9 은자동주입기를사용하여조영제주입시, 조영제가채워지지않은주입기의빈실린지로부터약 100 ml의공기가유입되어발생한대량의우심실색전 1 예를보고하였고, Lee 10 는조영제를신속하게주입하기위해병속에실린지로주입한공기가주입관을통해유입되어발생한우심실색전 2예를보고하였으며이중 1예에서는약 150 ml의공기가주입된것으로추정되며경련및의식소실이발생하였으나고농도산소치료후호전되었다. 공기색전증의발생기전은정맥계내로공기가유입되면중심정맥을거쳐공기가심장내로밀려들어가고심장내로들어온공기는폐순환계로이동하여폐동맥압을상승시키고우심실유출로에저항을증가시켜폐정맥순환 (venous return) 을감소시킨다. 이로인해좌심실로유입되는혈류가감소되고심박출량이저하되어전신성저혈압이발생된다 11. 또한난원공개존증, 심방중격결손과같은기저심장질환이있는경우정맥내공기색전이유발된후우좌단락을통해동맥내공기색전이발생할수있으며이를기이성공기색전증이라부른다 4. 그러나 Gottdiener 등 12 은심초음파에서심장내결손이없는환자에서도기이성공기색전증을증명하였으며, 정맥내로유입된공기가원위폐동맥에밀집되어혈류가차단되면혈역동학적힘에의하여작은공기방울이떨어져나와폐동정맥문합이나폐모세혈관을통하여좌측심장으로이동한다고보고하였다. 180

Tuberculosis and Respiratory Diseases Vol. 63. No.2, Aug. 2007 동맥내공기색전은정맥내공기색전보다더욱치명적일수있으며개를대상으로실험한 Butler 등의보고에의하면적은양의공기색전으로도말초장기의허혈성손상을일으킬수있다고하였다 1. 정맥내공기색전은대부분소량으로증상이없지만다양한임상양상을보일수있는데 6,8, 호흡곤란, 흉통, 빈호흡, 빈맥, 저혈압, 의식소실, 국소적인신경학적이상등을일으키며심한경우사망에이르기도한다 2,3. 정맥내로일반적으로 200 ml의공기가초당 70-100 ml로유입되면치명적인것으로알려져있으며 100 ml의공기만으로도치명적이었다는보고도있으나유입된공기의양, 공기의유입속도, 색전당시의체위, 환자의건강상태등이사망을결정하는중요한인자로보고되고있다 6,7. 대량의정맥내공기색전의경우단순흉부방사선촬영에서주폐동맥혹은심장내에공기음영을관찰할수있으나진단에는경식도심초음파와도플러초음파가사용되며가장민감도가높은방법인경식도심초음파는 5-10 microns 정도의작은공기방울과 0.02 ml/kg 정도의적은양의공기방울을찾아낼수있으며심장내공기방울의위치와좌심장으로공기방울이유입되는것을확인할수도있다 4. 또한흉부조영증강 CT가사용되는데조영제주입과스캐닝사이에시간및위치에따라소량의공기색전을발견하지못할수있으나환자가 CT 검사대에누워검사받는도중에대량의공기색전이발생하는상황에서는흉부 CT를시행하는것이합리적이다 13. 공기색전증의초기치료는우선더이상의공기유입이되지않도록유입경로를차단하며 Durant 자세를취하고고농도및고압산소치료를시행하는것이다 2. Durant 자세란좌측측와위로체위를변경하는것으로, 공기를우심실의심첨부위로모아더이상의페혈관혹은우심실유출로폐쇄를방지하는효과가있다고알려져있다 13. 고농도산소치료는조직에산소를증가시키고공기방울크기를감소시키는효과가있으며고압산소치료는특히뇌공기색전증에효과적으로시기는빠를수록좋다. 고압산소치료는 48시간후에시행하더라도환자의상태를개선시킬수있다는보고가있으나최근의보고에의하면공기 색전발생 6시간이내에치료를시행한경우에서보다좋은예후를보이므로초기고압산소치료가중요하다 14,15. 또한공기가폐동맥유출로를막고있는경우에는공기를더작은폐혈관으로보내기위해체외심압박을시행할수있으며, 비침습적인방법으로치료효과가충분치않고특히중심정맥도관이삽입되어있을경우, 도관을이용하여공기를제거할수도있다. 환자의자세와도관의위치가적절한경우유입된공기의 50% 가량을흡인할수있다고한다 3. 본증례의경우, 자동주입기를사용하지않고조영제를신속하게주입하기위해병속에주사기로주입한공기가, 조영제가모두주입된후에주입관을통해정맥계내로유입되어발생되었고유입된양은약 150 ml로추정되며발생초기에기침및흉부불편감을보였다. 응급실방문즉시좌측측와위자세에서고농도의산소치료를시행하였으며이후 8시간경과후촬영한흉부 CT에서전에보이던우심실과주폐동맥내에공기음영은관찰되지않고흡수된상태로후유증은발생하지않았다. 공기색전증에대한여러가지치료가있으나가장중요한것은예방이라할수있다. 여러보고에의하면주의깊게조영제를주입하여도소량의공기유입 Table 1. Caution for injection of contrast media Make a protocol and follow it correctly First person, prepares the patient and monitors at the patient's side until the injection is complete. Second person, inputs the data to the computer and then performs CT scanning at the control table. Recheck all preparation steps before injection Whether intravenous cannula is adequately inserted into patient's vein, or not Whether contrast media bottle is adequately shaken to remove air bubble, or not Whether air is adequately removed within automated injector, or not Whether air is adequately removed within extension tube, or not Whether extension tube adequately is connected to intravenous cannula and automated injector, or not Pay special attention, in the case as follow In the case of pressurized drip infusion, monitor at the patient's side until the injection is complete. For patient with ventricular septal defect or right to left shunt, observe with attention. 181

BC Park et al: A case of massive air embolism after contrast-enhanced computed tomography 을완전히막을수는없지만임상적으로문제를일으키는대량의공기색전은예방할수있다고한다 3,6-8,13. 따라서조영제를주입시공기색전의가능성을고려하여주의깊은관찰이필요하며 (Table 1) 1,10,13, 공기색전이의심되거나발생이확인되면신속한자세변경과고농도산소투여등적절한치료가시행되어야한다. 요 정맥내공기색전은조영제주입과관련된합병증으로알려져있다. 대부분의경우색전된공기의양이적고증상이없으나대량의공기색전은치명적일수있다. 저자들은흉부 CT 촬영중조영제주입과관련하여발생한대량의우심실내공기색전과보존적치료로후유증없이회복된 1예를경험하였기에문헌고찰과함께보고하는바이다. 약 참고문헌 1. Ie SR, Rozans MH, Szerlip HM. Air embolism after intravenous injection of contrast material. South Med J 1999;92:930-3. 2. van Hulst RA, Klein J, Lachmann B. Gas embolism: pathophysiology and treatment. Clin Physiol Funct Imaging 2003;23:237-46. 3. Muth CM, Shank ES. Gas embolism. N Engl J Med 2000;342:476-82. 4. Sviri S, Woods WP, van Heerden PV. Air embolism: a case series and review. Crit Care Resusc 2004;6:271-6. 5. Sakai O, Nakashima N, Shinozaki T, Furuse M. Air bubbles in the subclavian or internal jugular veins: a common finding on contrast-enhanced CT. Neuroradiology 1998;40:258-60. 6. Woodring JH, Fried AM. Nonfatal venous air embolism after contrast-enhanced CT. Radiology 1988; 167:405-7. 7. Price DB, Nardi P, Teitcher J. Venous air embolization as a complication of pressure injection of contrast media: CT findings. J Comput Assist Tomogr 1987;11:294-5. 8. Groell R, Schaffler GJ, Rienmueller R, Kern R. Vascular air embolism: location, frequency, and cause on electron-beam CT studies of the chest. Radiology 1997;202:459-62. 9. Imai S, Tamada T, Gyoten M, Yamashita T, Kajihara Y. Iatrogenic venous air embolism caused by CT injector: from a risk management point of view. Radiat Med 2004;22:269-71. 10. Lee H. Massive intraventricular air embolism after contrast-enhanced CT: report of two cases. J Kor Radiol Soc 2006;54:349-52. 11. Vesely TM. Air embolism during insertion of central venous catheters. J Vasc Interv Radiol 2001;12: 1291-5. 12. Gottdiener JS, Papademetriou V, Notargiacomo A, Park WY, Cutler DJ. Incidence and cardiac effects of systemic venous air embolism. Echocardiographic evidence of arterial embolization via noncardiac shunt. Arch Intern Med 1988;148:795-800. 13. Pham KL, Cohen AJ. Iatrogenic venous air embolism during contrast enhanced computed tomography: a report of two cases. Emerg Radiol 2003;10:147-51. 14. Kytta J, Tanskanen P, Randell T. Comparison of the effects of controlled ventilation with 100% oxygen, 50% oxygen in nitrogen, and 50% oxygen in nitrous oxide on responses to venous air embolism in pigs. Br J Anaesth 1996;77:658-61. 15.Blanc P, Boussuges A, Henriette K, Sainty JM, Deleflie M. Iatrogenic cerebral air embolism: importance of an early hyperbaric oxygenation. Intensive Care Med 2002;28:559-63. 182