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| SPECIAL ARTICLE |
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| Year : 2009 | Volume
: 53
| Issue : 5 | Page : 567-574 |
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Transoesophageal Echocardiography Related Complications
SK Mathur1, Pooja Singh2
1 Head, Divison of Cardiothoracic Anaesthesia, Division of Cardiothoracic Anaesthesia,Department of Anaesthesiology,Institute of Medical Sciences,Banaras Hindu University,Varanasi 221005, India
2 PDCC Student, Division of Cardiothoracic Anaesthesia,Department of Anaesthesiology,Institute of Medical Sciences,Banaras Hindu University,Varanasi 221005, India
| Date of Web Publication | 3-Mar-2010 |
Correspondence Address:
S K Mathur
Department of Anaesthesiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005
India
 Source of Support: None, Conflict of Interest: None  | Check |
PMID: 20640107 
The application of transesophageal echocardiography (TEE ) has been continuously increasing over past several decades. It is usually considered a very safe diagnostic and monitoring device. Though the complications are rare, but these complications must be known to the operators performing TEE. The goal of this article is to encapsulate the potential complications associated with TEE. The complications are primarily related to gastro intestinal, cardiovascular and respiratory systems along with some miscellaneous problems related to probe insertion, drugs and inexperience of the operator. Strategies for the prevention of these complications are also analyzed in order to avoid the risk.
Keywords: Transesoph ageal echocardiography, Complications, Prevention
How to cite this article:
Mathur S K, Singh P. Transoesophageal Echocardiography Related Complications. Indian J Anaesth 2009;53:567-74 |
 Introduction | |  |
Transesophageal echocardiography (TEE) is a semi invasive monitoring and diagnostic modality of immense utility. The practical clinical use of TEE was first described in 1976 when a modified rigid endoscopic probe with single M-mode crystal was used. Since thattime, TEE technology has evolved rapidly with developments in flexible endoscopic probe technology, phased-array ultrasound systems, and crystal miniaturization. Presently, TEE is being used widely in operation theatres, intensive care units, cardiac catheterization laboratory and day care units. Although the technique is quite safe, if conducted by a skilled person, it is important to overview the procedure related complications, considering its widespread use. In the following article, we are trying to give a deep insight regarding the complications of TEE examinations.
| Gastrointestinal Complications | | |
1. Injuries of Gastrointestinal Tract:
Dental traumas [1] , submucosal hematoma of pharyngeal area [2],[3] jawsubluxation [4],[5] and tonsillar bleeding are related to probe insertion in upper gastrointestinal(GI)tract. Esophageal perforations mostly occur in the abdominal followed by intrathoracic and cervical portions of the esophagus. They are caused by anatomic variations like GI abnormalities, extrinsic compression of esophagus from enlarged left atrium, [6],[7] calcified lymph node [8] and cervical spur. Other causes are poor patient cooperation and inadequate technical skill or mucosal damage due to movement, is chemia, heat and pressure generated by the probe (TEE probe can generate a pressure of 60 mmHg ).
The hypopharynx and upper esophagus are most prone to perforation [3] caused by neck extension with or without prominent anterior vertebral osteophytes and by stretching ofmucosaandmuscular fibres. Shearing forces, prolonged flexion of probe tip and probe mobilization in a locked position can lead to tearing of oesophagus. [9]
Non pulsatile flow, prolonged cardio pulmonary bypass [10] , distended atrium [11] , mechanical compression [12]and excessive heat are the factors which can cause ischaemic esophageal wall injury.
In conscious and sedated patient, perforations are evident from signs of subcutaneous emphysema, dyspnoea and pain. But under general anaesthesia, esophageal intubation is easy and perforation usually goes unnoticed, ultimately resulting in mediastinitis, sepsis and multi organ failure. [13] Diagnosis can be confirmed radiologically by computedtomography and chest radiographs and may include findings like pneumothorax, au fluid level, mediastinal shift, subcutaneous emphysema, pleural effusion and empyema.
2. Gastroesophageal Lesions and Anatomic Variations
Lesions such as neoplasm, diverticulum [4] , cervical spine [2],[14] orinflammatorymucosal changes are risk factors for complications associated with TEE probe insertion. As there is no direct visualization of esophagus during TEE probe insertion and manipulations, it requires more attention compared to conventional optical gastroscopy. Esophageal intubations most often fail at the level of cricopharynx due to prominence of cricoid muscle. Schatzki's ring and prior cervical surgery [15] can lead to esophageal narrowing and can cause complications during TEE. Disorders like esophageal achalasia, barrett's esophagus, chemical esophagitis, late scleroderma, Chagas disease and benign and malignant esophageal tumors can reduce esophageal lumen. Peptic ulcer and gastroesophageal reflux disease(GERD) can lead to strictures which ultimately can cause erosion and bleeding of esophagus. Probe of TEE can easily slip into Zenkers diverticulum and can cause perforation. [16]
Normal anatomical variations like aortic impression, large left atrium and left mainbronchus orpathological variations such as mediastinal tumours' and esophageal duplication cyst compress esophagus and hamper esophageal intubations. [17]
Vascular abnormalities like esophageal varices due to portal hypertension can cause bleeding during TEE. [18] Cervical spine abnormalities due to trauma or subluxation at C 1 and C2 vertebrae may make esophageal intubation difficult and can also lead to neurological deficit. [19]
3. Unsuccessful Esophageal Intubation
Factors contributing to this problem are lack of cooperation from patients and inexperience of operatoras well as anatomic abnormalities like double aortic arch [20] , cervical osteophytes [21] and mucosal abnormalities such as prior radiation exposure, decreased saliva production and prior tracheostomy. Mallory-Weiss syndrome which is associated with forceful vomiting efforts has been reported during'' EE which leads to failed intubations. [21]
4. Bleeding of Esophageal Tract
Risk factors associated with upper GI bleeding due to 'FEE include previous ulcerative process, vasoactive drugs and failure to use H2 antagonist drugs in the perioperative period. [22] Long bypass period, reoperation [23] , emergency surgery, aspirin [24] and anticoagulant [25] use are other factors which are associated with GI bleeding.
5. Changes in Esophgeal Integrity
TEE exposes the esophageal mucosa to ultra sound waves and pressure for long periods. Mucosal edema, erosion, hematomas and petechiae can be produced specially in small children. [26]
6. Injure to Other Solid Organs & Oral Injuries
Splenic laceration can occur due to deep insertion of the probe into the stomach for transgastric imaging . [27] Dysphasia can occur due to local compression from probe insertion which affects pharyngoesophageal tissue and laryngeal nerve especially in female and paediatric patients. [28],[29],[30] Dysphagiais also associatedwith pulmonary aspiration. TEE in sitting position can cause dysphasia which is due to local effect of probe, combined with extreme flexion of head. [31] Tongue swelling [32] and necrosis [33] may also occur due to prolonged placement of TEE probe.
7. Probe Tip Buckling
Probe tip buckling is caused due to tip flaccidity in an old TEE probe, improper insertion, general anaesthesia and inexperience. It can cause injury when withdrawn hastily: [31],[34]
8. Other Foreign Bodies in Esophagus
Breakage and dislodgement of temperature probe and esophageal stethoscope during TEE are reported. [35],[36] Nasogastric tube and feeding tube share the same space and thus may lead to shearing, dislodgement of the spur and poor TEE imaging.
| Respiratory Complications | | |
TEE examinations in sedated patient may be associated with small reduction of 0 2 saturation. Incidence of oxygen desaturation and aspiration increases with obesity [37] and during emergency procedures. [38] To avoid this complication, oxygen supplementation is advocated in sedated patient. In awake patients, problems such as bronchospasm, laryngospasm, posterior pharyngeal wall hematoma, supraglottic hematoma and stenosis may occur along with pulmonary edema, atelectasis and airway obstruction. [39],[40],[41],[42],[43],[44] TEE probe placement, motion and removal may lead to displacement or accidental extubation of endotracheal tube particularly in children. [45] Compression of pulmonary tree or endotracheal tube may hamper ventilation. [44],[45],[46],[47],[48]
| Cardiovascular Complications | | |
Esophageal intubation can induce vagal and sympathetic reflexes such as hypertension or hypotension, tachyarrhythmias orbradycardia and even myocardial infarction. [49],[50],[51] Anhythmias are manifested as non-sustained ventricular and supra ventricular tacky arrhythmias, atrial fibrillation and 3 rd degree heart block. [52] It can also induce angina and myocardial ischemia. Risk factors like sedation along with fasting, patient on anti-hypertensioe drugs and also hypoxemia may precipitate heart failure and fatal arrhythrnias. [53],[54]
Valsalvamaneuver associated with retching and coughing leads to increase in intrathoracic, central venous and pulmonarypressures and release is associated with abrupt decrease of systemic pressure. Large intrathoracic pressure and associated hemodynamic changes resulting from retching may cause fatal pulmonary embolisation from right atrium mass, [55],[56] mitral vegetation and left intracardiac thrombus [57] resulting in stroke, aortic dissection and cardiac tamponade. [58]
| Infections | | |
Risk of bacteremia is associated with TEE and may lead to morbid infections such as endocarditis. The most common organisms responsible for bacteremia after TEE intubation include á-hemolytic streptococcus, staphylococcus aureus  and staphylococcus epidermidis. [59]
Use of prophylactic antibiotic therapy during TEE, though controversial, is suggested forpatients who are immuno suppressed, have prosthetic valves, cyanotic congenital heart disease, surgically constructed shunts and previous history of endocarditis. [60] Contaminated TEE probe and the lubricating jelly are the sources of infection. [61],[62] Aproperly cleaned probe with glutaraldehyde can reduce the incidence of post TEE infections.
| Medication Related Complications | | |
Sedation:
Sedation improves patients' tolerance to TEE probe insertion and reduces coughing, vomiting and pain. Benzodiazepines, propofol and short actingnarcotics are most commonly used for sedation. Side effects of these drugs like respiratory depression, hypotension, agitation and allergy may occur and must be treated promptly.
Local Anaesthetic Medication:
Local anaesthetic used systemically to blunt the hemodynamic effects of TEE, for superior laryngeal nerve block and in j elly can cause anaphylactic or overdose reactions. Congenital absence of methemoglobin reductase enzyme and topical local anaesthetics like prilocaine , lidocaine and benzocaine can lead to meth emoglobinemia. [63],[64],[65] It can be diagnosed by central cyanosis and low Hb saturation unresponsive to oxygen therapy. Dyspnoea, confusion, dizziness, coma and death may occur.
| Miscellaneous complication | | |
Probe contamination:
Disruption ofprotective probe sheath can create a lumen between core and sheath which can get filled with fluids and contaminants such as glutaraldehyde and which can be ingested during TEE. [66]
Location related complication:
TEE in emergency unit, especially intrauma patients, leads to more complications such as death, respiratory insu$iciency, hypotension, emesis, agitation and cardiac dysrhythmias. These are the patients which present with compromised hemodynamic and respiratory conditions and unstable cervical spine damage. These patients are with full stomach and altered sensorium andthus are at increased risk of aspiration. Therefore, endotracheal intubation is highly recommended in these patients.
Effect of ultrasound waves on tissues:
Powerful ultrasound beam can cause vibration of gas filled structures leading to hemorrhage and hemolysis. [67] It can also produce excessive heat and damage of surroundingtissues. But in TEE, low intensityof SMHz is used which is devoid of any harmful effects. [68],[69]
Relative Contraindications of TEE
History
Dysphagia
Odynophagia
Mediastinal radiation
Recent upper gastrointestinal surgery
Recent esophagitis
Thoracic aortic aneurysm
Esophageal pathology
Stricture
Tumour
Diverticulum
Varices Esophagitis
Prevention of TEE complications
Evaluation and surveillance of patients:
1. Informed consent must be obtained.
2. Careful medical history.
- Allergyy
- Bleeding disorder:
- Dysphagiato solid and liquid.
- Esophageal varices, diverticulum, esophageal web, upper GI bleeding, peptic ulcer, GERD& hiatal herniaa
- Previous gastric, esophageal and neck surgeries.
- Radiation therapy.
- Cervical arthrosis.
- Use of antacid, salicylates, anticoagulants and antiplatelet agents.
3. Physical Examination.
- The oral and dental hygiene and loose teeth.
- Assessment ofneck mobility, stability and arthritic changes.
- Assessment of airway.
4. Endocarditis prophylaxis for high risk patients.
5. Fasting for 6 hr before an elective procedure.
6. Surveillance and monitoring of vital signs at baseline
and throughout the procedure.
7. 02 supplementation and venous access should be established.
Suction device and resuscitation equipments must be kept ready.
8. In emergency settings, rapid sequence induction with orotracheal intubation is performed while in elective procedures, TEE can be performed on awake or mildly sedated patient with 6 hr fasting.
9. Dentures should be removed and bite guard should be placed to protect instrument and fingers.
10. TEE probe should be lubricated and kept in unlocked control-wheel position. It should never be forced into the passage. TEE probe must be inspected for mechanical dysfunction and damage of outer sheath causing electrical and thermal injuries leading to anhythmias anddeath. [70]
11. Awake patient is asked to swallow while under general anesthesia probe can be placed under direct latyngoscopy which reduces the trauma.
12. Insertion of probe only upto 40-50 cm from incisors is advocated. Anynasogastric orfeedingtube ortemperature probe should be removed to avoid potential, kinking, knotting or gastric migration and prevent intetference during imaging.
13. During cardiac surgery special care is taken as the probe is used for longer duration and anticoagulation during cardiopulmonary bypass and hypothermia leave the mucosa more vulnerable to pressure necrosis and ischemia.
14. Patient should be monitored until fully awake and eating and drinking is allowed once the effect of local anesthetic is dissipated.
Transesophageal echocardiography provides better imaging of cardiac anatomy and function but since it is more invasive than ttansthoracic echocardiography, operators should be aware of the likely complications, minimize the risk factors and take measures to prevent the complications.
| References | | |
| 1. | Rafferty T, LaMantia KR, Davis E, et al. Quality assurance for intraoperative transesophageal echocardiography monitoring: a report of 846 procedures. Anesth Analg 1993; 76: 228-32.  |
| 2. | Bettex D, Chassot PD. Echographie Transoesophagienne en Anesthesia-Reani nation. Masson, Williams& Williams; 2002:1-12. |
| 3. | Saphir JR. Cooper JA, Kerbavez RJ, Larson SF, Schiller NB. Upper airway obstruction after transesophageal echocardiography. JAm Soc Echocardiogr 1997;10:977-8. |
| 4. | Vignon P, Gueret P, Chabemaud JM, et al. Failure and complications of transesophageal echocardiography. Apropos of 1500 consecutive cases (French). Arch Mal Coeur Vaiss 1993; 86: 849-55. |
| 5. | Chee TS, Quek SS, Ding ZP, Chua SM. Clinical utility,safety, acceptability and complications of transoesophageal echocardiography (TEE) in 901 patients. Singapore Med J 1995; 36:479-83 |
| 6. | Massey SR, Pitsis A, Mehta D, Callaway M. Oesophageal perforation following perioperative transoesophageal echocardiography. Br J Anaesth 2000; 84: 643-6. |
| 7. | Dewhirst WE, Stragand JJ, Flaming BM. Mallory-Weiss tear complicating intraoperative transesophageal echocardiography in a patient undergoing aortic valve replacement. Anesthesiology 1990; 73:777-8. |
| 8. | Pong MW, Lin SM, Kao SC, Chu CC, Ting CK, Tsai SK. Unusual cause of esophageal perforation during intraoperative transesophageal echocardiography monitoring for cardiac surgery-a case report. ActaAnaesthesiol Sin 2003; 41: 155-8. |
| 9. | St-Pierre J, Fortier LP, Couture P, Hebert Y Massive gastrointestinal hemorrhage after transoesophageal echocardiography probe insertion. Can JAnaesth 1998; 45: 1196-9. |
| 10. | Kharasch ED, Sivarajan M. Gastroesophageal perforation after intraoperative transesophageal echocardiography. Anesthesiology 1996; 85: 426-8. |
| 11. | Han YY, Cheng YJ, Liao WW, Ko WJ, Tsai SK.Delayed diagnosis of esophageal perforation following intraoperative transesophageal echocardiography during valvular replacement-a case report. Acta Anaesthesiol Sin 2003;41: 81-4. |
| 12. | Fujii H, Suehiro S, Shibata T, Aoyama T, Ikuta T.Mallory - weiss tear complicating intraoperative transesophageal echocardiography. Circ J2003; 67:357-8. |
| 13. | Soong W, Afifi S, McGee EC. Delayed presentation of gastric perforation after transesophageal echocardiography for cardiac surgery. Anesthesiology 2006;105:1273-4. |
| 14. | Tam JW Burwash IG, Ascah KJ, et al. Feasibility and complications of single-plane and biplane versus multiplane transesophageal imaging: a review of 2947 consecutive studies. Can J Cardio11997; 13: 81-4. |
| 15. | Dougherty Thomas B. The difficult airway in conventional head and neck surgery. In: Benumof J (Ed.).Airway Management Principles and Practice. St. Louis :Mosby; 1996: 688 |
| 16. | Fergus I, Bennett ES, Rogers DM, Siskind S, Messineo FC. Fluoroscopic balloon-guided transesophageal echocardiography in a patient with Zenker's diverticulum. JAm Soc Echocardiogr 2004;17:483-6. |
| 17. | Carerj S, Paola TM, Oddo A, Lucisano V, Oreto G.Esophageal duplication cyst: a rare obstacle to transesophageal echocardiography. Echocardiography 1998;15: 601-2. |
| 18. | Suriani RJ, Cutrone A, Feierman D, Konstadt S. Intraoperative transesophageal echocardiography during liver transplantation. J Cardiothorac Vasc Anesth 1996;10: 699-707. |
| 19. | Riazi J. The difficult pediatric airway. In: Benumof J (Ed.). Airway Management Principles and Practice. St. Louis: Mosby; 1996. |
| 20. | Stevenson JG. Role of intraoperative transesophageal echocardiography during repair of congenital cardiac defects. Acta Paediatr Suppl 1995; 410: 23-33. |
| 21. | Badaoui R, Choufane S, Riboulot M, BacheletY Ossart M. Esophageal perforation after transesophageal echocardiography (French). Ann Fr Anesth Reanim 1994;13: 850-2. |
| 22. | Norton ID, Pokomy CS, Baird DK, Selby WS. Upper gastrointestinal haemorrhage following coronary artery bypass grafting. AustN Z J Med 1995; 25: 297-301. |
| 23. | Leitman IM, Paull DE, Bane PS, Isom OW, Shires GT. Intra-abdominal complications of cardiopulmonary bypass operations. Surg Gynecol Obstet 1987;165:251-4. |
| 24. | Kallmeyer IJ, Collard CD, Fox JA, Body SC,Shernan SK. The safety of intraoperative transesophageal echocardiography: a case series of 7200 cardiac surgicalpatients. AnesthAnalg 2001; 92: 1126-30. |
| 25. | MassaN, MorrisonM. Transesophageal echocardiography: an unusual case of iatrogenic laryngeal trauma. Otolaryngol HeadNeck Sub 2003;129: 602-4. |
| 26. | Green MA, Alexander JA, Knauf DG, et al. Endoscopic evaluation of the esophagus in infants and children immediately following intraoperative use of transesophageal echocardiography. Chest 1999; 116: 1247-50. |
| 27. | Olenchock SA Jr, Lukaszczyk JJ, Reed Jill, ThemanTE. Splenic injury after intraoperative transesophageal echocardiography. Ann Thorac Surg 2001; 72:2141-3. |
| 28. | Rousou JA, Tighe DA, Garb IL, et al. Risk of dysphagia after transesophageal echocardiography during cardiac operations. Ann Thorac Surg 2000; 69: 486-90. |
| 29. | Sakai T, Terao Y Miyata S, Hasuo H, Haseba S,Yano K. Postoperative recurrent laryngeal nerve palsy following a transesophageal echocardiography (Japanese). Masui 1999; 48: 656-7. |
| 30. | Kohr LM, Dargan M, Hague A, et al. The incidence of dysphagia in pediatric patients after open heart procedures with transesophageal echocardiography. Ann Thorac Surg 2003; 76:1450-6. |
| 31. | Cucchiara RF, Nugent M, Seward JB, Messick SM. Air embolism in upright neurosurgical patients: detection and localization by two-dimensional transesophageal echocardiography. Anesthesiology 1984; 60: 353-5. |
| 32. | Yamamoto H, Fujimura N, Namiki A. Swelling of the tongue after intraoperative monitoring by transesophageal echocardiography (Japanese). Masui 2001; 50:1250-2. |
| 33. | Sriram K, KhorasaniA, Mbekeani KB, Patel S. Tongue necrosis and cleft after prolonged transesophageal echocardiography probe placement. Anesthesiology 2006;105: 635. |
| 34. | Kronzon I, Cziner DG, Katz ES, et al. Buckling of the tip of the transesophageal echocardiography probe: a potentially dangerous technical malfunction. J Am Soc Echocardiogr 1992; 5:176-7. |
| 35. | Yasick A, Samra SK. An unusual complication of transesophageal echocardiography. AnesthAnalg 1995; 81:657-8. |
| 36. | Benedict PE, Foley K. Transesophageal echocardiography not without pitfalls. J Cardiothorac VascAnesth 1997;11: 123. |
| 37. | DhariwalA, Plevris JN, LoNT, FinlaysonND,Heading RC, Hayes PC. Age, anemia, and obesity associated oxygen desaturation during upper gastrointestinal endoscopy. GastrointestEndosc 1992; 38:684-8. |
| 38. | Gendreau MA, Triner WR, Bartfield J. Complications of transesophageal echocardiography in the ED.Am J EmergMed 1999; 17:248-51. |
| 39. | ChanKL, Cohen GI, Sochowski RA, Baird MG Complications of transesophageal echocardiography in ambulatory adult patients: analysis of 1500 consecutive examinations. JAm Soc Echocardiogr 1991; 4:577-82. |
| 40. | Khandheria BK, Seward JB, Bailey KR. Safety of transesophageal echocardiography: experience with 2070 consecutive procedures. J Am Coll Cardiol 1991; 17: 20A |
| 41. | Liu JH, Hartnick CJ, Rutter MJ, Hartley BE,Myer CM 3rd. Subglottic stenosis associated with transesophageal echocardiography. Int J Pediatr Otorhinolaryngol 2000; 55:47-9. |
| 42. | Stienlauf S, Witzling M, Herling M, Harpaz D.Unilateral pulmonary edema during transesophageal echocardiography. JAm Soc Echocardiogr 1998;11:491 3. |
| 43. | Lam J, Neirotti RA, Hardjowijono R, Blom-MuilwijkCM, Schuller JL, Visser CA. Transesophageal echocardiography with the use of a four-millimeter probe. JAm Soc Echocardiogr 1997;10:499-504. |
| 44. | Phoon CK, Bhardwaj N. Airway obstruction caused by transesophageal echocardiography in a patient with double aortic arch and truncus arteriosus. J Am Soc Echocardiogr 1999;12: 540. |
| 45. | Stevenson JG. Incidence of complications in pediatric transesophageal echocardiography: experience in 1650 cases. JAm Soc Echocardiogr 1999;12: 527-32. |
| 46. | Gilbert TB, Panico FG, McGill WA, Martin GR,Halley DG, Sell JIB. Bronchial obstruction by transesophageal echocardiography probe in a pediatric cardiac patient. AnesthAnalg 1992; 74: 156-8. |
| 47. | Stevenson JG, Sorensen GK. Proper probe size for pediatric transesophageal echocardiography. Am J Cardiol 1993;72:491 2. |
| 48. | Zestos MM Chehade 1V1, Mossad E. A transesophageal echocardiography probe causes airway obstruction in an older child. J Cardiothorac VascAnesth 1998; 12: 65-6. |
| 49. | Stoddard MF, Longaker RA. The safety of transesophageal echocardiography in the elderly. Am Heart)1993;125:1358-62. |
| 50. | Al Moussarih A, Douard H, Lafitte S, Broustet JP,Roudaut R. Acute myocardial infarction during transesophageal echocardiography. Echocardiography 1999;16: 579-80. |
| 51. | Suriani RJ, TzouN. Bradycardia during transesophageal echocardiographic probe manipulation. J Cardiothorac VascAnesth 1995; 9:347. |
| 52. | Daniel WG, Erbel R, Kasper W, et al. Safety of transesophageal echocardiography. A multic enter survey of 10,419 examinations. Circulation 1991; 83: 817-21. |
| 53. | Khandheria BK. The transesophageal echocardiographic examination: is it safe? Echocardiography 1994; 11:55-63. |
| 54. | Goland S, Shimoni S, Attali M, et al. Fatal ventricular arrhythmia as a complication of transesophageal echocardiography.Eur J Echocardiogr 2005; 6: 151-3. |
| 55. | Shah CF Thakur RK, Ip JH, Xie B, Guiraudon GM. Management of mobile right atrial thrombi: a therapeutic dilemma. J Card Surg 1996;11: 428-31. |
| 56. | Cavero MA, Cristobal C, Gonzalez M, Callego JC, Oteo JF, Artaza M. Fatal pulmonary embolization of a right atrial mass during transesophageal echocardiography. JAm Soc Echocardiogr 1998;11: 397-8. |
| 57. | Black IW, Cranny GB, Walsh WF, Brender D. Embolization of a left atrial ball thrombus during transesophageal echocardiography. J Am Soc Echocardiogr 1992; 5:271-3. |
| 58. | Kim CM, Yu SC, Hong SJ. Cardiac tamponade during transesophageal echocardiography in the patient of circumferential aortic dissection. J Korean Med Sci 1997; 12:266-8. |
| 59. | Rey JR. Axon A, Budzynska A, Kruse A, Nowak A. Guidelines of the European Society of Gastrointestinal Endoscopy (E.S.GE.) antibiotic prophylaxis for gastrointestinal endoscopy. European Society of Gastrointestinal Endoscopy. Endoscopy 1998; 30: 318-24. |
| 60. | Wilson W, Taubert KA, Gewitz M, et al. Prevention of infective endocarditis: guidelines from the American HeartAssociation: a guideline from the American Heart Association Rheumatic Fever, Endocarditis,and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation 2007;116:1736-54. |
| 61. | Webb SF. Outbreak of Serratia marcecens associated with flexible fiberbronscope. Chest 1975; 68:703-8. |
| 62. | Anonymous. Infection control during gastrointestinal endoscopy. Guidelines for clinical application. Gastrointest Endosc 1988; 34(3 Suppl) : 37S-40S. |
| 63. | Grauer SE, Giraud GD. Toxic m ethem oglobinemia after topical anesthesia for transesophageal echocardiography.JAm Soc Echocardiogr 1996; 9: 8746. |
| 64. | Ho RT, Nanevicz T, Yee R, Figueredo VM. Benzocaineinduced in ethemoglobinemia-two case reports related to transesophageal echocardiography premeditation. Cardiovasc Drugs Ther 1998; 12: 311-2. |
| 65. | Vidyarthi V; Manda R, AhmedA, Khosla S, Lubell DL. Severe methem oglobinem ia after transesophageal echocardiography. Am J Ther 2003; 10: 225-7. |
| 66. | Venticinque SG, Kashyap VS, O'Connell RJ. Chemical burn injury secondary to intraoperative transesophageal echocardiography. Anesth Analg 2003;97:1260-1. |
| 67. | Baggs R, Penney DP, Cox C, et al. Thresholds for ultrasonically induced lung hemorrhage in neonatal swine. UltrasoundMedBiol 1996; 22: 119-28. |
| 68. | Carstensen EL, Duck FA, Meltzer RS, Schwarz KQ,Keller B. Bioeffects in echocardiography. Echocardiography 1992; 9: 605-23. |
| 69. | Miller MW, Brayman AA. Biological effects of ultrasound. The perceived safety of diagnostic ultrasound within the context of ultrasound biophysics: a personal perspective. Echocardiography 1997;14:615-28. |
| 70. | SwitzDM, ClarkeAM, Longacher JW Jr. Electrical malfunction at endoscopy. Possible cause of arrhythmia and death. JAMA 1976; 235: 273-5. |
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