Stridor is a high-pitched extra-thoracic breath sound resulting from turbulentair flow in the larynx or lower in the bronchial tree. It is different from a stertor which is a noise originating in the pharynx. Stridor is a physical sign which is caused by a narrowed or obstructed airway. It can be inspiratory, expiratory or biphasic, although it is usually heard during inspiration. Inspiratory stridor often occurs in children with croup. It may be indicative of serious airway obstruction from severe conditions such as epiglottitis, a foreign bodylodged in the airway, or a laryngeal tumor. Stridor should always command attention to establish its cause. Visualization of the airway by medical experts equipped to control the airway may be needed.
Stridor is mainly diagnosed on the basis of history and physical examination, with a view to revealing the underlying problem or condition. Chest and neck x-rays, bronchoscopy, CT-scans, and/or MRIs may reveal structural pathology. Flexible fiberoptic bronchoscopy can also be very helpful, especially in assessing vocal cord function or in looking for signs of compression or infection.
Treatments
The first issue of clinical concern in the setting of stridor is whether or not tracheal intubation or tracheostomy is immediately necessary. A reduction in oxygen saturation is considered a late sign of airway obstruction, particularly in a child with healthy lungs and normal gas exchange. Some patients will need immediate tracheal intubation. If intubation can be delayed for a period, a number of other potential options can be considered, depending on the severity of the situation and other clinical details. These include:
Use of dexamethasone 4–8 mg IV q 8 - 12 h in cases where airway edema may be the cause of the stridor; note that some time may be needed for dexamethasone to work fully.
Use of inhaled Heliox ; the effect is almost instantaneous. Helium, being a less dense gas than nitrogen, reduces turbulent flow through the airways. Always ensure an open airway.
In obese patients elevation of the panniculus has shown to relieve symptoms by 80%.
