Upper airway obstruction how is it recognized and solved

The term 'obstructed upper airway' is used in anaesthesia to describe a variety of clinical situations with varying degrees of airway compromise. The upper airway has a framework of bones and cartilages, beginning at the nose and lips and ending at the level of first tracheal ring. The upper airway is normally kept transience by muscles which pull the soft palate, tongue and epiglottis away from posterior pharyngeal wall. Obstruction results when the activity of those muscles is diminished (e.g. unconsciousness, general anaesthesia), or when increased negative pressure is generated within upper airway during inspiration (laryngeal spasm, oedema). Other mechanisms are due to mechanical obstruction (internal or external) due to altered anatomy in the airway (e.g. benign and malignant tumours). A careful history and clinical examination including detailed assessment of the airway should be undertaken when possible to determine the site, severity and cause of obstruction including the usual tests to predict difficulty in intubation.The symptoms and signs of airway obstruction are due to increased work of breathing, ineffective ventilation and secondary effects of hypoxia/hypercapnia. Stridor suggests that the airway diameter is reduced by 50%. The respiratory phase during which stridor occurs may indicate the site of obstruction: inspiratory stridor indicates obstruction in and above vocal cords: expiratory stridor indicates obstruction below the vocal cords. It is important to understand the principles of safe airway management when the upper airway is compromised, especially when associated with a difficult airway. Each patient has to be considered according to the level and nature of the obstruction and individual clinical circumstances and every anaesthetist should have in mind a plan for failed intubation/ventilation. Maintenance of oxygenation and making definitive control of the airway take a priority over everything else.