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Endobronchial blocker placement in small children
- Anthony M-H Ho (18 November 2008)
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Limitation of use of bronchial blocker via Murphy eye of the endotracheal tube to prevent its dislod
- Rakesh Garg, Anju Gupta, Nishkarsh Gupta (16 November 2008)
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Anthony M-H Ho
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To the Editor: We thank Drs. Garg, Gupta, and Gupta for their interest in our work and for their thoughtful comments. We were aware of the safety issues raised. In the end, it came down to weighing the theoretical risks mentioned against the problem of a misbehaving endobronchial blocker balloon and the consequences. Clinicians who have had the misfortune of dealing with a blocker that would not stay in place in the middle of surgery would appreciate how challenging the problem can be. We inserted the lubricated endotracheal tube preloaded with the lubricated blocker with the same degree of care (plus apprehension) as inserting a relatively bulky double-lumen tube with a much stiffer and angulated tip in an adult. As for the trimming in the case of a small tube, we took special care to ensure that there were no sharp edges or points. We were also wary of the possibility of over-inflation of any balloon in the paediatric airway, irrespective of the technique used. During withdrawal of the balloon, if it was necessary, we never used excessive force and were prepared to remove the whole airway conduit en bloc if necessary. Fortunately, from our limited experience, withdrawal of the endobronchial blocker was not difficult. We had no problem inflating or deflating or sliding the balloon after the blocker catheter had been slightly bent. Neck movements do change tube and blocker positions and we were careful that if they did occur, we checked the ventilation and tube and blocker positions carefully afterwards. Dr. Garg et al’s experiment with the red rubber tube is enlightening but there are insufficient details for us to evaluate and respond to. We appreciate that additional stress could be caused by a foreign body near the carina but feel that that is not a particular difficult problem to overcome. After all, most of us have had to deal with worse problems such as foreign body aspiration, airway stent insertions, rigid bronchoscopy, double-lumen tube and endobronchial blocker placement, etc., all of which probably involve even higher stress levels. Whether our technique eventually proves superior or otherwise remains to be seen. The comments by Dr. Garg et al serve as a reminder that extreme care must be exercised when anaesthetising small children for major thoracic surgery. Anthony M.-H. Ho, MD, FRCPC, FCCP Department of Anaesthesia and Intensive Care The Chinese University of Hong Kong Shatin, NT Hong Kong SAR Conflict of Interest:None declared |
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Rakesh Garg, Anaesthesiologist and Intensivist Department of Anaesthesiolgy and Intensive Care, All India Institute of Medical Sciences, Ansari Nag, Anju Gupta, Nishkarsh Gupta
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Title: Limitation of use of bronchial blocker via Murphy eye of the endotracheal tube to prevent its dislodgement. Author: Rakesh Garg, MD, DNB, Anju Gupta, MD; Nishkarsh Gupta, MD,DNB Institute: Department of Anaesthesiolgy and Intensive Care, All India Institute of Medical Sciences, Ansari Nagar, NewDelhi-110029, India. Corresponding Author: Dr Rakesh Garg, MD, DNB, MNAMS, FCCS Address: 58-E, Kavita Colony, Nangloi, Delhi-110041, India. Email: drrgarg@hotmail.com Phone no. : 91-11-9810394950 Fax No. – 00-91-11-26588031 Conflict of interest: None Source of Funding: None Short Title: Limitation of inserting blocker via Murphy eye. To the Editor: We read with interest the novel technique of preventing endobronchial blocker (EBB) dislodgement by Ho and collagues1 but we have a few concerns regarding use of such technique. The authors mentioned of bending the tip of blocker prior to insertion. This may cause mucosal injury during the insertion especially at cricoid potion (narrowest part) of trachea. It would have been more informative if data of tracheal morbidity including mucosal injury may have been noted postoperatively during removal of endotracheal tube. The author mentions about trimming of the bevel of the endotracheal tube (ETT). Many aspects of the ETT including angle and direction of the tip bevel are specified by standards and modification should be evaluated prior to its use.2 We have apprehension regarding the sharp edges, (created by such trimming) which may cause injury to tracheal mucosal especially during insertion and near the carina. Moreover the risk of rupture of pilot balloon of EBB during inflation and its accidental tear and dislodgement into the distal airway cannot be ruled out. Complete shearing of balloon has been reported when removing it from the Tuohy- Borst valve after the surgery.3 The sharp angulation at the exit of blocker through Murphy’s eye of a well fitted ETT may obstruct the inflating lumen of the balloon and can create problems in its inflation and deflation. The concern of stress response due to close proximity of ETT to carina has not been thought of by the authors. We also want to highlight the importance of avoiding any neck movements when such blocker is in situ. Weiss and collagues have demonstrated by radiological assessment that in paediatric patient, head-neck flexion consistently results in a movement of the ETT tip towards the carina, and head-neck extension moves the ETT tip away from the carina. 4 Yoo and collagues and Ritz and collagues have also reported that the ETT migrated upward to the vocal cords during neck extension and downward to the carina during neck flexion in children in their study by bronchoscopic examination.5, 6 So, extension or rotation of the head and neck moves tip of ETT in cephalad direction7 and may cause dislodgement of the blocker as it is attached snugly with the endotracheal tube. Similarly, because of its close proximity to carina, any caudal movement of the tube during flexion of neck may lead to difficulty in ventilation and may also traumatize to tracheal mucosa at carina. We also have an apprehension regarding the positioning of the blocker as with authors technique the blocker cannot be moved manually or using FOB. We have passed size 4 ETT preloaded with Fogarty catheter through an size 8 red rubber tube (shortened to 10 cm length) ten times each with both type of assemblies (intraluminal and extrluminal) as described by the author. We observed that there was difficulty in inflating the balloon in one of the case and relatively more pressure was required to inflate the balloon in another case, in the intraluminal group (group in which fogarty was inside the ETT and came out of the Murphy eye). All the red rubber tubes were slit opened after inserting and withdrawing the assembly. We observed that the scratch mark were present on inside of the tubes in 12 of the 20 tubes used. Moreover the movement of the blocker to and fro required much greater force as compared to when the blocker is either completely intraluminal or extra luminal of the ETT. The author’s technique may prevent dislodgement of the EBB but the potential disadvantages of tracheal morbidity, difficulty in balloon inflation and repositioning of blocker and limitation of modification of the endotracheal tube, limits its clinical relevance. References: 1. Ho AMH, Karmakar MK, Critchley AH, Ng SK, Wat CY. Placing the tip of the endotracheal tube at the carina and passing the endobronchial blocker through the Murphy eye may reduce the risk of blocker retrograde dislodgement during one-lung anaesthesia in small children. Br J Anaesth 2008;101:690-3. 2. Jaeger JM, Durbin CG. Special purpose endotracheal tubes. Respir Care 1999;44:661-683. 3. Prabhu MR, Smith JH. Use of the arndt wire guided endobronchial blocker. Anesthesiology 2002;97:1325. 4. Weiss M, Knirsch W, Kretschmar O, Dullenkopf A, Tomaske M, Balmer C, stutz K, Gerber AC, Berger F. Tracheal tube-tip displacement in children during head-neck movement – a radiological assessment. Br J Anaesth2006;96:486-491. 5. Yoo SY, Kim JH, Han SH, Oh AY. A comparative study of endotracheal tube positioning methods in children: safety from neck movement. Anesth Analg 2007;105:620-625. 6. Ritz EMJ, Ungern-Stenberg BSV, Keller K, Frei FJ, Erb TO. The impact of head position on the cuff and tube tip position of preformed oral tracheal tubes in young children. Anaesthesia 2008;63:604-609. 7. Olufolabi AJ, Chariton GA, Spargo PM. Effect of head posture on tracheal tube position in children. Anaesthesia 2004;59:1069-1071. Conflict of Interest:None declared |
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