Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 53 9 2015 10 06 590 592 EN Nima Hosseinzadeh School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Shahram Samadi Department of Anesthesiology and Intensive Care, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Mihan Jafari Javid Department of Anesthesiology and Intensive Care, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Alireza Takzare Department of Anesthesiology and Intensive Care, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 06 Reinforced tubes are commonly used to minimize the opportunity of upper airway obstruction in patients at risk. There are a few reports of the airway obstruction resulted from kinked reinforced tubes. This report describes the obstruction of a reinforced tube in an adult patient who underwent tonsillectomy. Under general anesthesia; an armoured endotracheal tube was inserted into the trachea uneventfully. A few minutes after starting the surgery, the anesthesia machine detected a high airway pressure and an increased ETCO2 (end-tidal CO2) up to 50 mmHg.  Further evaluation showed spiral wire damage resulted from Mouth Gag device that led to airway obstruction. Early anticipation of the complications leads to proper management of such critical and life threatening complications and prevention of hypoxia, hypercapnia, pneumothorax, and pulmonary edema. Based on our experience using an armoured endotracheal tube in tonsillectomy does not guarantee a safe airway and intensive monitoring is necessary. https://acta.tums.ac.ir/index.php/acta/article/view/4300 https://acta.tums.ac.ir/index.php/acta/article/download/4300/4255