- Clinical science
Airway management is the evaluation, planning, and use of medical procedures and devices for the purpose of maintaining or restoring ventilation in a patient. These procedures are indicated in patients undergoing general anesthesia and in patients with respiratory failure or acute airway obstruction.
In endotracheal intubation, a tube is inserted orally into the trachea to provide oxygen via mechanical ventilation during general anesthesia. The tube should be placed under direct visualization with the help of a laryngoscope. Correct placement is established based on measurement of exhaled CO2 and evidence of bilateral breath sounds on auscultation. Complications of endotracheal intubation include dental damage, esophageal misplacement of the tube, infections, and tracheal stenosis. If long-term intubation is expected, a tracheostomy is usually performed. This procedure involves the creation of a reversible or permanent stoma below the cricoid cartilage. Cricothyrotomy is an airway of last resort and performed in emergency situations, such as acute obstruction of the airway by blood, edema or a foreign body. An incision is made in the membrane between the thyroid and cricoid cartilage to obtain airway access.
Once access to an airway has been established by any of the above mentioned routes, mechanical ventilation is used to assist or replace spontaneous breathing. The breathing rate, amount of oxygen per breath, applied pressure, and other parameters can be adjusted to achieve best possible ventilation and oxygenation. Complications of mechanical ventilation include barotrauma (e.g., pneumothorax, pneumomediastinum) and ventilator-induced lung injury, which clinically resembles ARDS. Once patients show sufficient spontaneous breathing, they are weaned off ventilation support.
- Definition: orotracheally or nasotracheally placement of a cuffed tube below the vocal cords
- Preoxygenation: administration of 100% oxygen via face mask prior to intubation to ensure sufficient time to perform intubation.
- Sedation (e.g., propofol)
- Muscle relaxation (e.g., succinylcholine)
- Positioning of patient with mild cervical flexion (sniffing position)
- Placement of the endotracheal tube with the help of a laryngoscope: observe the tip of the tube passing into the larynx through the vocal cords (direct visualization).
- Signs of proper tube placement
- Inflate the cuff to secure the tube if proper placement is ensured.
Rapid sequence intubation
- A method of endotracheal tube intubation used for emergency airway management that involves rapid induction of unconsciousness followed by administration of a paralytic agent.
- Differs from traditional intubation in that it uses weight-based doses of short-acting medications (rather than gradually titrating the dose) in order to forego bag-valve-mask ventilation and achieve more rapid intubation.
Complications of intubation
- Early complications
- Late complications after intubation: vocal cord injuries, vocal cord granuloma
- Complications of long-term intubation
- Suction airways prior to extubation to minimize risk of aspiration (e.g., of fluids, foreign material)
- Extubation criteria
- Definition: : Permanent or temporary opening (stoma) in the cervical trachea created through surgical incision below the cricoid cartilage for the placement of a tracheal tube
- Definition: emergency procedure in which an incision is made through the skin and median cricothyroid ligament (cricothyroid membrane) to obtain airway access
- Indications: 'cannot-intubate-cannot-ventilate' (CICV) scenario (if orotracheal intubation has failed or is contraindicated)
- Complications: See section on complications of tracheostomy above.