الفهرس 
Development of the larynx and tracheaOnly 14 pages are availabe for public view
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Abstract
The trachea or windpipe is a cartilaginous and membranous tube, extending from the lower part of the larynx, on a level with the sixth cervical vertebra, to the upper border of the fifth thoracic vertebra, where it divides into the two bronchi, one for each lung.
The most common cause of laryngotracheal stenosis is trauma, which can be internal (eg. resulting from prolonged endotracheal intubation, tracheotomy, surgery, irradiation and endotracheal burns) or external (eg. blunt or penetrating neck trauma). Of these causes, it has been reported that prolonged endotracheal intubation is the leading cause of laryngotracheal stenosis.
Laryngeotracheal stenosis is diagnosed by a thorough history and physical examination; radiologic, and endoscopic evaluation. Other investigations such as pulmonary function tests may also be helpful.
The most important method of evaluation is by direct Iaryngoscopy and rigid bronchosopy. The length and severity of the stenosis is assessed directly, and a determination is made whether the stenosis is soft or hard.
A variety of methods for providing adequate oxygenation and elimination of carbon dioxide have been used during tracheal resection. These methods can be divided into five approaches:
1- Standard orotracheal intubation.
2- Insertion of a tube into the opened tra¬chea distal to the area of resection.
3- High frequency jet ventilation (HFJV) through the stenotic area.
4- High frequency positive pressure ventilation (HFPPV).
5- Cardiopulmonary bypass.
Blind anesthesia induction and intubation can depress the patient’s auto-compensation, which could result in severe consequence of cardiac and respiration arrest, especially in patients who have had hypoxia because of the increase in oxygen consumption. Cardiopulmonary bypass could allow gas exchange and good surgical access for the tracheal operations and avoid aggravating hypoxia and carbon dioxide accumulation which may result in cardiac arrest during normal anesthesia and tracheal intubation.
After surgery, all patients stay under close supervision in the intensive care unit. Broad-spectrum antibiotics are given to all patients for 10 days starting from the day of surgery, whereas corticosteroids are given only to nontracheostomized patients on the day of extubation and on the following days if necessary.
Tracheostomy-dependent patient may return to a routine care unit as soon as frequent cleansing of the cannula is no longer necessary. All patients without tracheostomy are sedated and kept intubated for a minimum of 5 to 7 days. Extubation is carried out under general anesthesia with a control endoscopy.