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  Table of Contents 
Year : 2016  |  Volume : 17  |  Issue : 2  |  Page : 65-66

Armored tubes: An unusual chink in armor!

Department of Anaesthesia, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India

Date of Web Publication16-Dec-2016

Correspondence Address:
Dr. Shagun Bhatia Shah
H. No: 174-175, Ground Floor, Pocket-17, Sector-24, Rohini, New Delhi - 110 085
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0973-0311.195968

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How to cite this article:
Shah SB, Bhargava AK, Goyal P. Armored tubes: An unusual chink in armor!. Indian Anaesth Forum 2016;17:65-6

How to cite this URL:
Shah SB, Bhargava AK, Goyal P. Armored tubes: An unusual chink in armor!. Indian Anaesth Forum [serial online] 2016 [cited 2023 Jun 1];17:65-6. Available from: http://www.theiaforum.org/text.asp?2016/17/2/65/195968


Armored tubes or flexometallic cuffed endotracheal tubes (FMCETTs) have a metallic or nylon spiral reinforcing wire enclosed on both interior and exterior by rubber, polyvinyl chloride (PVC), latex, or silicone.[1],[2],[3] The most common reported cause of FMCETT obstruction is kinking caused by loosening of reinforcing spiral due to ethylene oxide sterilization/reuse and tube bite.[2],[3],[4] We report an unusual leak in the armored tube whose timely detection saved a 60-year-old female posted for right maxillectomy and pectoralis major myocutaneous flap reconstruction for carcinoma right retromolar trigone, from airway catastrophe. All her incisors were extremely loose and were secured with sterile silk thread knotted around each tooth and firmly taped to the cheek. She had a short neck with a receding mandible. Her mentohyoid distance was 4 cm. An irremovable gold nose pin adorned her left nostril. Her nostrils were prepared with xylometazoline drops. Anesthesia was induced with intravenous fentanyl 100 μg, propofol 70 mg, and atracurium 40 mg. A C-Mac D-blade videolaryngoscope[5] was utilized anticipating a difficult airway. A 7 mm internal diameter FMCETT was inserted endotracheally through the left nostril. Rotating maneuvers, FMCETT cuff inflation, and neck flexion failed to facilitate intubation. A Bodecker's forceps were used to grasp the FMCETT and negotiate it through the glottis. After auscultatory and capnographic confirmation of FMCETT placement, a nasogastric tube was inserted through the right nostril and oropharyngeal packing was done. Anesthesia was maintained with bispectral index-guided propofol infusion, desflurane 2%-4%, oxygen 40%, medical air 60%, morphine 6 mg, fentanyl in hourly boluses of 20 μg, and a peripheral nerve stimulator-guided atracurium infusion.

After maxillary resection when the head and neck were repositioned for a radical neck dissection (RND), a circle leak of 180-200 ml appeared and it became difficult to ventilate the patient. FiO2 was increased to 100%, external circuit was checked for leaks and disconnections, and the flow rates and set tidal volume were increased in an attempt to deliver adequate tidal volume. Hand ventilation with an Ambu bag too yielded similar results. Finally, the FMCETT was changed with a PVC Portex cuffed tube (6.5 mm internal diameter) under C-MAC D-blade videolaryngoscopy inserted through the right nostril. The nasogastric tube was allowed to remain in the right nostril; there was no leakage thereafter. Anesthesia was reversed, and the patient was extubated the next morning over a bougie after overnight retention of PVC tube. After extubation, we submerged the FMCETT in a bucket of water, injected methylene blue dye through the pilot balloon and the dye leaked out into the water bucket [Figure 1]. The site of the leak was the chink in the embedded portion of the connecting tubing of the cuff adjacent to the avulsed leaflet. The sharp edge of the bolt of the patient's nose pin had damaged the endotracheal tube (ETT). The external PVC coating of the tube was avulsed from the underlying metallic spiral like a leaflet [Figure 1]. This leaflet was on the medial side of the tube while the nose pin touched the lateral side. We realized that the chink was created during the 180° rotation maneuver[4] of the FMETT while attempting to negotiate the glottis. This conclusion was also supported by the depth at which the chink appeared (17 cm from the patient end). The narrow tubing connecting the pilot balloon to the FMETT cuff had also been damaged by the nose pin at the same level adjacent to the avulsed leaflet. This second chink was responsible for the blood in the ETT cuff as well as blood in the pilot balloon. The oral pack provided some seal, and the FMETT was relatively snugly fitting, but the leak appeared once the pack was dislodged due to repositioning of head and neck for RND.
Figure 1: From left to right: Left ala of patient's nose showing the nose pin; leaflet-like avulsion of the external polyvinyl chloride coating of flexometallic nasotracheal tube; methylene blue dye leaking out from the chink in the cuff inflation tubing into a bucket of water

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Overuse/repeated sterilization of reusable FMCETTs can result in complications.[1],[3] The FMCETT used in this case was new, disposable, and of good quality (Mallinckrodt Medical, Athlone, Ireland) and the cause of complications was not reused. A routine check for cuff and pilot balloon integrity was also performed before intubation.

We conclude that as a protocol, all nose pins should be removed before nasotracheal intubation to prevent damage to the tube.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Dorsch JA, Dorsch SE, editors. Tracheal tube and associated equipment. In: Understanding Anesthesia Equipment. 5 th ed. Philadelphia: Lippincott Williams and Wilkins; 2008. p. 561-628.  Back to cited text no. 1
Chalkeidis O, Kalakonas A, Chaidutis C, Chotoumanidis C. Endotracheal tube cutting during neurosurgical operation. Eur J Anaesthesiol 2009;26:533-4.  Back to cited text no. 2
Azim A, Matreja P, Pandey C. Desaturation with flexometallic endotracheal tube during lumbar spine surgery - A case report. Indian J Anaesth 2003;47:48-9.  Back to cited text no. 3
  Medknow Journal  
Balakrishna P, Shetty A, Bhat G, Raveendra U. Ventilatory obstruction from kinked armoured tube. Indian J Anaesth 2010;54:355-6.  Back to cited text no. 4
[PUBMED]  Medknow Journal  
Shah SB, Hariharan U, Bhargava AK. C Mac D blade: Clinical trips and tricks. Trends Anaesth Crit Care 2016;6:6-10.  Back to cited text no. 5


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