Airway Obstruction due to Abutting of the Distal Tip of the Microcuff Endotracheal Tube with the Tracheal Wall in an Infant Undergoing Cardiac Surgery

Dear Editor, Infants undergoing surgery for complex congenital heart disease usually require postoperative invasive ventilation. Evidence shows that introducing pediatric microcuff endotracheal tubes (ETTs) provides an adequate seal with fewer intubation attempts.[1] However, when used for prolonged ventilation, the absence of Murphy eye can hamper ventilation when the distal end of the tube is not patent.[2] This letter highlights the airway obstruction due to abutting of the microcuff ETT tip with the tracheal wall. A 3-month-old male child with Scimitar syndrome and juxta-ductal coarctation of the aorta underwent corrective repair. He had an eventful postoperative course in the intensive care unit with two episodes of extubation failure due to severe pulmonary hypertensive crisis. Pulmonary vasodilators were started to control the pulmonary hypertension. The child developed dystonic episodes, and the trachea was reintubated for the third time with a 4 mm microcuff ETT. After 1 hour of reintubation, the child developed severe bronchospasm, with a silent chest on auscultation, and a peak airway pressure of 34 cm H2O. The child was sedated, paralysed, and treated with a broad spectrum of bronchodilators. Despite extensive treatment, the child had recurrent episodes of a rise in peak airway pressures and a silent chest when the effect of muscle relaxants wore off. On retrospective evaluation of serial chest radiographs, it was noted that the tip of the microcuff ETT was abutting the tracheal wall and causing airway obstruction [Figure 1a and b]. Also, we noticed the plateau pressure on the ventilator remained low during the episodes of silent chest. Fibreoptic bronchoscopic examination of the trachea confirmed the abutting of the microcuff ETT tip against the tracheal wall [Figure 1c and Video 1]. We replaced the microcuffed ETT with a 4.5 mm uncuffed ETT having a Murphy eye. Chest radiograph showed the tip of the uncuffed ETT at the T1-T2 level [Figure 1d and e] and away from the tracheal wall. All the bronchodilator medications were weaned off, and there were no further episodes of airway obstruction. The child was extubated uneventfully after recovering from the neurological disease.Figure 1: (a) Chest radiograph showing abutting of the distal tip of microcuff endotracheal tube with the tracheal wall (yellow arrow); (b) Illustrative sketch showing the distal opening of the microcuff endotracheal tube abutting the tracheal wall causing airway obstruction; (c) Fibreoptic bronchoscopic image showing the abutting of the tip of microcuff endotracheal tube on the tracheal wall; (d) Chest radiograph after exchange of microcuff endotracheal tube with uncuffed endotracheal tube showing tip of the uncuffed endotracheal tube in the center of the tracheal lumen (red arrow); (e) Illustrative sketch showing the distal tip of the uncuffed endotracheal tube with Murphy’s eye in the center of the tracheal lumen {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1.","caption":"","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_kgdjkqip"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} A microcuff ETT provides adequate sealing through an ultra-thin cuff placed distal to the sub-glottic area.[1] The distal location of the cuff at the tip and absence of the Murphy eye in pediatric microcuff ETT help to position the cuff-free segment of ETT between the vocal cords and cricoid cartilage, thus decreasing the risk of airway edema and stridor after tracheal extubation.[2] Also, the microcuff ETTs decrease the risk of aspiration and allow for improved control of ventilation and oxygenation in neonates and infants.[3] In our case, the other possible causes for the problem are blockade of the microcuff ETT due to secretions, mucous plugs, and blood clots. Also, due to the small length of the airway in infants, a minimal flexion or extension of the neck may cause ETT malposition in the airway. Although the microcuff ETTs have several advantages over the conventional uncuffed ETTs, the absence of a Murphy eye in microcuff ETT was deleterious if the distal end of the tube gets abutted with the tracheal wall. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.