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There are a number of different artificial airways; each one has its own criteria for use based on the clinical circumstances. The artificial airways that you see most often relates to the unit you work in. If you’re in the ER, you’ll see the temporary airways frequently; if in ICU, you’ll see endotracheal tubes (ETT) and tracheostomies; if in long-term care, you’ll see a lot of tracheostomies; and if in the OR, you’ll see a little of everything. We’ll start with the temporary airways, which should only be used for a few hours, and progress to those that can be used for longer time periods.
A combitube is often used by paramedics in field resuscitation. It contains two lumens, one that intubates the esophagus, and one that intubates the trachea. The combitube is easy to insert quickly, and it eliminates the risk of intubating the esophagus rather than the trachea. The manual resuscitation bag is attached to the lumen that inflates the lungs, and the esophageal balloon is inflated to decrease the risk of aspiration. The combitube should only be used for emergency intubation, and should be replaced with an ETT as soon as possible.
A laryngeal mask airway (LMA) is used for emergent intubation or in situations where ETT intubation has failed. The LMA looks like an ETT with an inflatable, silicone rubber collar at the bottom end. This collar surrounds and covers the supraglottic area, providing a continuous upper airway. The LMA does not protect the patient from aspiration, thus it can only be used as a short-term measure until another type of airway is established. An advantage of the LMA is that it maintains an open airway, while allowing ETT intubation to be done through it. This is particularly beneficial in patients in whom previous ETT intubations attempts have failed.
Oropharyngeal
The goal of an oropharyngeal airway is to keep the tongue from obstructing the upper pharynx. It will cause an alert patient to gag, thus it should only be used in an unconscious patient with a diminished gag reflex. Before inserting the airway, explain the procedure to the patient (even though they’re unconscious) and use universal precautions as necessary. Place the patient in the supine position if possible, suction the mouth, and remove any dentures. To estimate the appropriate size, hold the airway next to the patient’s upper jaw, with the front even with the patient’s teeth. The end of the airway should reach the angle of the jaws. In general, a small airway is used for children, a medium for average-sized adults, and a large for large adults. Size is important since an airway that’s too large can contribute to the obstruction and cause the patient to gag, vomit, and aspirate, whereas an airway that’s too small may push the tongue further back into the oropharynx. The airway is inserted into the mouth upside down, then rotated it is placed over the tongue. Care should be taken to avoid scraping the palate or exerting pressure on the upper teeth. The airway should be rotated down slightly as it approaches the posterior wall of the oropharynx, so it follows the natural curvature of the oral cavity. It’s recommended that oropharyngeal airways not be taped in place. Complications of oropharyngeal airway insertion include oral trauma, obstruction of the airway, laryngospasm, gagging, and vomiting. After insertion, the patient’s lungs should be auscultated, and the patient placed on his or her side to decrease the risk of aspiration. Most patients don’t have an oropharyngeal airway in place for long periods of time, since they will either be intubated if they continue to have a compromised airway, or else will recover to the point of not needing it. However, here are some tips for those instances when you may have to care for a patient with an oropharyngeal airway.The position of the airway in the patient’s mouth and breath sounds should be assessed frequently. The oral cavity should be suctioned as needed. Mouth care should be done every two to four hours and as needed. Mouth care can be done with a moistened swab. If the airway is coated with secretions, it can be removed and cleaned if the patient’s respiratory status is stable. Remove the airway by pulling it out and downward, following the curvature of the mouth. Immediately insert a clean airway before cleaning the soiled one with hydrogen peroxide and water. This airway can be kept for future use with the same patient. If the patient has the oropharyngeal airway as a long-term measure, the airway should be cleaned and replaced at least once every eight hours.
Nasopharyngeal
The function of a nasopharyngeal airway is similar to that of the oropharyngeal, except that it’s lubricated and inserted through a nostril into the posterior pharynx. Conscious patients tolerate this better than the oropharyngeal airway. Another benefit of a nasopharyngeal airway is that it provides easy access for sterile suctioning of the patient’s pharynx and trachea. Before inserting the airway, explain the procedure to the patient and position him or her in the supine position, if possible. Nasopharyngeal airways are available in sizes from #28 to #34 French. To select the correct size, hold the airway next to the patient’s cheek and compare the diameter of the airway to the diameter of the nostril. The airway diameter must be slightly smaller. The airway should also be slightly longer than the distance from the tip of the nose to the edge of the jaw. Lubricate the airway with water-soluble lubricant and insert it into the selected nostril. Gently slide it along the floor of the nose while pushing the tip of the nose up with your non-dominant hand. Once inserted, it should follow the natural curvature of the nasopharynx. If you encounter resistance, carefully twist the airway as you insert it, but don’t force it. If there’s still resistance, try the other nostril or use a smaller airway. If you can feel air moving through the airway opening, it’s placed properly. You should also be able to see the tip of the airway behind the uvula when you look into the patient’s mouth. Lung sounds should also be auscultated. Complications of nasopharyngeal airway insertion include trauma to the nares, airway obstruction, laryngospasm, gagging, and vomiting. Some patients may have a nasopharyngeal airway in place for a few days. Care of the airway is similar to that of an oropharyngeal airway. The airway should be removed once every eight hours. Explain the procedure to the patient and use universal precautions. If you encounter resistance while removing the airway, apply water-soluble lubricant around the nares and the nasal end of the tube, then gently rotate the tube until it can be removed. Immediately insert another nasopharyngeal airway into the patient’s other nostril, unless contraindicated. Then clean the soiled tube with hydrogen peroxide and water, and store it for future use with the same patient. Assess the patient’s nares for irritation and ulceration.
Endotracheal Tube
The endotracheal tube (ETT) is the most common artificial airway used for short-term (up to three weeks) airway management or mechanical ventilation. Insertion of an ETT is indicated for airway maintenance, secretion control, oxygenation and ventilation, and administration of emergency medications during cardiopulmonary arrest. The tube may be inserted either nasally or orally, however, the oral route is preferred during emergency placement because insertion is easier and a larger-diameter tube can be used. The nasal route is used if the patient has a jaw fracture, a history of recent oral surgery, or trauma to the mouth or lower face. This route also provides greater patient comfort. Nasal intubation is contraindicated if the patient has a nasal obstruction, a fractured nose, sinusitis, or a bleeding disorder. Extreme caution should be used if the patient has a basal skull fracture. ETT's are available in a variety of sizes, based on the inner diameter. For adults, this generally includes tubes with an inner diameter of 6 mm - 8.5 mm. It’s recommended that at least a size 7 tube be used in adults to decrease the work of breathing when the patient is weaning from the ventilator. Breathing spontaneously through an ETT has been compared to breathing through a straw. Obviously, a smaller tube may have to be used for nasal intubation, but most patients can tolerate tube sizes between 6 - 7.5 for this.
A tracheostomy (trach) tube is the preferred artificial airway for patients requiring long-term mechanical ventilation (longer than three weeks). It’s also indicated for other conditions such as upper airway obstruction or malformation, failed or repeated intubations, complications from endotracheal intubations, glottic incompetence, sleep apnea, or chronic inability to clear secretions. Resistance to airflow is less with a trach tube than an ETT because it is wider, shorter, and less curved. This reduces the work of breathing for the patient, and allows easy removal of secretions. Some trach tubes also allow eating and talking (if the patient’s respiratory status is stable), and are more comfortable than an ETT. Trach tubes come in the same sizes as ETT's, based on the inner diameter. Most adults require a size 7, 7.5, or 8. Trach tubes are made of either disposable plastic or metal. Plastic tubes are generally changed two times per week, and are thrown away after one-time use. Metal tubes are left in place for longer periods of time, and are reinserted after cleaning. Trach tubes can be either single-lumen or double-lumen tubes. Single-lumen tubes have a cuff around the tube that is inflated with air to hold it in place, and an obturator, which is used during tube insertion. Double-lumen tubes contain the same components as the single-lumens, along with an additional inner cannula that can be removed. Many inner cannulas are disposable and are simply thrown away and replaced once every eight hours. Cannulas that are not disposable can be reinserted after removal for cleaning. Single-lumen tubes have a larger internal diameter that is less restrictive to airflow, which reduces the work of breathing for the patient. Double-lumen tubes are safer for patients with copious secretions because the inner cannula can be quickly removed if it becomes obstructed. Removing the cannula essentially converts the double-lumen tube to a single-lumen. Disposable, plastic trach tubes have an adaptor on the outer end that can connect to a manual resuscitation bag, providing for easy manual ventilation in the event of respiratory arrest. The adaptor also fits with ventilator tubing, making it simple to mechanically ventilate a patient with a trach who is experiencing respiratory distress. Tracheostomy tubes are inserted either surgically or percutaneously. Complications of insertion include hemorrhage, pneumothorax, laryngeal nerve injury, pneumomediastinum, tracheoesophageal fistula (opening between trachea and esophagus), and cardiopulmonary arrest. Wound infection, subcutaneous emphysema (air in subcutaneous tissue), tube obstruction, and tube displacement may also occur. Long-term complications include tracheal stenosis (narrowing), tracheoesophageal fistula (opening between the trachea and esophagus), tracheoinnominate artery fistula (opening between trachea and innominate artery, causing hemorrhage), and tracheocutaneous fistula (opening between trachea and skin). Finally, if there is no artificial airway in place and the patient is being ventilated with a manual resuscitation bag without an artificial airway in place, there are some important points to remember. First, there is no limit to the length of time that a patient can be manually ventilated, as long as the procedure is done correctly. “Bagging” seems such a simple procedure but many health care professionals do it incorrectly. The following are guidelines to keep in mind.
Here’s a review of the advantages and disadvantages of each artificial airway.
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