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Table of Contents
Year : 2017  |  Volume : 7  |  Issue : 1  |  Page : 21-23

Oswal–Hunton metallic endotracheal tubes in pediatric obstructed airway

1 Department of Anaesthesiology, Deenanath Mangeshkar Hospital, Pune, Maharashtra, India
2 Department of Voice Clinic, Deenanath Mangeshkar Hospital, Pune, Maharashtra, India

Date of Web Publication14-May-2018

Correspondence Address:
Dr. Swapna Naik
Department of Anaesthesiology, Deenanath Mangeshkar Hospital, Pune - 411 004 Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jlv.JLV_4_17

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How to cite this article:
Naik S, Kshirsagar J, Gandhi S, Bidaye R. Oswal–Hunton metallic endotracheal tubes in pediatric obstructed airway. J Laryngol Voice 2017;7:21-3

How to cite this URL:
Naik S, Kshirsagar J, Gandhi S, Bidaye R. Oswal–Hunton metallic endotracheal tubes in pediatric obstructed airway. J Laryngol Voice [serial online] 2017 [cited 2022 Dec 4];7:21-3. Available from: https://www.laryngologyandvoice.org/text.asp?2017/7/1/21/232355


We would like to share our experience of securing airway with the all metal Oswal–Hunton tube (OHT) in pediatric patients undergoing CO2 laser excision of airway pathologies.

Pediatric patients present with varying degrees of airway obstruction due to the pathologies such as laryngeal papilloma, epiglottic cysts, or laryngeal webs. Physiological factors such as low functional residual capacity and high oxygen requirement reduce the threshold for hypoxia. Edema sets in early due to breathing against narrowed airway which results in further worsening. These pathologies are best excised by CO2 laser, by microlaryngeal surgery, offering great precision and minimal collateral damage.[1],[2]

CO2 laser limits the use of conventional endotracheal tubes for the fear of fire.[3],[4],[5] Other methods of ventilation in such scenario are use of Venturi, apneic anesthesia with intermittent ventilation, wrapping of conventional tubes with metal tapes, and spontaneous tubeless anesthesia.[6],[7],[8],[9],[10],[11] These methods carry several risks such as barotrauma, inadequate ventilation, hypercarbia, unprotected airway, aspiration, and endotracheal tube fires. Hence, it was proposed by Norton and de Vos to use all metal tubes as a safe device for securing the airway.[12] Prof. Mr. Vasant Oswal, a laryngeal surgeon in the UK, along with anesthetic colleague Prof. Mr. J. Hunton devised a flexible all metal uncuffed endotracheal tube [Figure 1]. The tube was available in three sizes mainly for the pediatric population.[13] The standard sizes available were with an internal diameter of 4 mm and 5 mm. The smallest tube devised for infants consisted of a proximal flexible part which increased ease of intubation and a distal rigid part with an internal diameter of 3.25 mm. The tube being firm in consistency permits negotiation through a narrowed airway. It is biologically inert, autoclavable, and fits the universal connector. The corrugated surface prevents chances of fire and burns by distorting the laser beam getting deflected from it and reducing its intensity. The intubation technique is similar to the conventional tube, and no special training is required.[14] The only disadvantages of this tube are the absence of cuff and also there are no guided markings on the tube surface, so the endobronchial intubation has to be watched for. Considering the pathologies of our patients, followed by a discussion with operating surgeon, it was decided that the OHT was a suitable airway device.
Figure 1: Oswal–Hunton tubes in various sizes

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Our case series consisted of 8 pediatric patients, youngest being a 3-month-old infant with epiglottic cyst to the eldest being a 10-year-old girl with laryngeal papillomatosis. In total, we had 6 cases of papilloma, a case each of laryngeal web and epiglottic cyst. The patients presented with a wide range and severity of symptoms such as change in voice and intermittent stridor. Preoperative preparation with systemic steroid and 4% lignocaine and adrenaline nebulization were completed. Anesthetic induction was started with sevoflurane in oxygen and small doses of propofol. The possibility of worsening of obstruction was always anticipated. Out of 8 cases, 5 patients progressed to stridor with desaturation up to 90% SpO2 and immediate direct laryngoscopy was done and an OHT of appropriate size was used to secure airway after instillation of 10% lignocaine spray [Figure 2] and [Figure 3]. Rest of the three patients got ventilated with face mask and were subsequently intubated after administration of a muscle relaxant. OHT, being semirigid, could negotiate the obstructive legions without trauma. Leakage of gases around the tube was managed by arranging wet cotton pledgets around the laryngeal inlet. The proximal part of the tube was covered with pledgets to prevent ghost burns. High airway pressures due to the small size tubes were compensated with small tidal volume (5 ml/kg) and higher respiratory rate (18–20/min) to maintain adequate minute ventilation which was monitored with end-tidal CO2 (EtCO2) levels. Intraoperatively, pulse rate, noninvasive blood pressure, SpO2, respiratory gas monitor, and EtCO2 were monitored. Average surgical time was 30 min (range - 10–45). At the end of the surgery, peritubal leak was seen indicating a better airway, especially in the case of papilloma excision. Inhalational agent was discontinued, and the muscle relaxant was reversed. After gaining adequate tone and tidal volume, the patients were extubated. The patients were observed in the pediatric intensive care unit for 2 h for the development of postoperative airway edema indicated by signs such as suprasternal retraction, nasal flaring, restlessness, and stridor. The SpO2 monitoring was continued over the next 24 h.
Figure 2: Position of the Oswal–Hunton tubes in the glottis

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Figure 3: Oswal–Hunton tubes in situ - external view

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To conclude, the airway secured with an OHT provides optimal ventilation giving ample time to laryngologist to vaporize the lesion with CO2 laser and widen the airway. While advanced all metal endotracheal tubes such as Laser-Flex are not available in this part of the world, the alternative methods of ventilation are either hazardous or unsuitable in pediatric patients. This situation makes OHT, a valuable alternative in CO2 laser surgeries in pediatric obstructed airway even after 30 years of its invention.

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.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Best C. Anesthesia for laser surgery of the airway in children. Paediatr Anaesth 2009;19 Suppl 1:155-65.  Back to cited text no. 1
Whymark AD, Clement WA, Kubba H, Geddes NK. Laser epiglottopexy for laryngomalacia: 10 years' experience in the west of Scotland. Arch Otolaryngol Head Neck Surg 2006;132:978-82.  Back to cited text no. 2
Roy S, Smith LP. Surgical fires in laser laryngeal surgery: Are we safe enough? Otolaryngol Head Neck Surg 2015;152:67-72.  Back to cited text no. 3
Hunsaker DH. Anesthesia for microlaryngeal surgery: The case for subglottic jet ventilation. Laryngoscope 1994;104(8 Pt 2) Suppl 65:1-30.  Back to cited text no. 4
Sosis MB, Dillon FX. A comparison of CO2 laser ignition of the Xomed, plastic, and rubber endotracheal tubes. Anesth Analg 1993;76:391-3.  Back to cited text no. 5
Werkhaven JA. Microlaryngoscopy-airway management with anaesthetic techniques for CO2 laser. Paediatr Anaesth 2004;14:90-4.  Back to cited text no. 6
Badran I, Jamal M. Pneumomediastinum due to venturi system during microlaryngoscopy. Middle East J Anaesthesiol 1988;9:561-4.  Back to cited text no. 7
O'Sullivan TJ, Healy GB. Complications of Venturi jet ventilation during microlaryngeal surgery. Arch Otolaryngol 1985;111:127-31.  Back to cited text no. 8
Weisberger EC, Emhardt JD. Apneic anesthesia with intermittent ventilation for microsurgery of the upper airway. Laryngoscope 1996;106(9 Pt 1):1099-102.  Back to cited text no. 9
Hunton J, Oswal VH. Metal tube anaesthesia for ear, nose and throat carbon dioxide laser surgery. Anaesthesia 1985;40:1210-2.  Back to cited text no. 10
Quintal MC, Cunningham MJ, Ferrari LR. Tubeless spontaneous respiration technique for pediatric microlaryngeal surgery. Arch Otolaryngol Head Neck Surg 1997;123:209-14.  Back to cited text no. 11
Norton ML, de Vos P. New endotracheal tube for laser surgery of the larynx. Ann Otol Rhinol Laryngol 1978;87(4 Pt 1):554-7.  Back to cited text no. 12
Hunton J, Oswal VH. Anaesthesia for carbon dioxide laser laryngeal surgery in infants. A new tracheal tube. Anaesthesia 1988;43:394-6.  Back to cited text no. 13
Périé-Vintras AC, Donnadieu S, Coste JL, Barrier G. Ventilation with metallic tubes in CO2 laser surgery of the larynx. Ann Fr Anesth Reanim 1989;8:149-52.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3]


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