It is worth repeating: BLS before advanced life support (ALS). This means that an advanced airway adjunct should be attempted only when any of the following conditions are met:
Before deciding to move to an advanced airway, evaluate the patient and anticipate and prepare for a difficult airway. If assessment reveals it will be difficult to successfully intubate the patient or current ventilation efforts are successful with minimal difficulty, sometimes it may be best to stay with what is working, rather than risk a bad outcome for the patient. A good mnemonic to assess for a difficult airway is LEMON, as follows:
The crowning achievement of any paramedic is walking into the emergency department with a successful intubation. Nothing feels better than when the resident or attending looks into the mouth and declares, “Yup! It’s in!” That sense of accomplishment can last the rest of the tour at least. To be successful at this, prepare for the procedure completely before making an attempt. Set out all the necessary equipment, including laryngoscope blades, the stylet, the water-based lubricant, the ETT, a 10 mL syringe, and suction. Put on gloves; because blood or bodily fluid splashing is possible, wearing a surgical mask with a face shield also is recommended.
Indications:
Contraindications:
Procedure:
Other methods of intubation exist and are frequently taught during paramedic classes. Because none of these methods or techniques have been tested, only their indications and contraindications will be discussed. A step-by-step procedural outline as done with other procedures that have been tested is not included here.
Nasotracheal intubation, where the ETT is inserted through the nostril, is an alternative to orotracheal intubation when it would be extremely difficult for oral intubation. The patient must be breathing to perform this skill, unlike orotracheal intubation. Indications for this procedure include trismus, intractable seizures, mandibular fractures or wiring, or any oral pathology that would inhibit oral intubation. This technique is contraindicated in patients who have facial trauma, who are not breathing, or who have anatomic abnormalities such as a deviated septum or a history of cocaine abuse. Nasal trauma and bleeding are the most common problems associated with this procedure.
Digital intubation involves the rescuer inserting his or her fingers into the patient’s mouth and feeling for the epiglottis. Next, direct the ETT over the fingers along the middle finger and into the glottic opening. This should be attempted only in extreme circumstances, such as when a laryngoscope has malfunctioned or is not available, the patient is in an extremely confined space, or when other techniques have failed. When performing this skill, ensure that the patient is either deeply unconscious or apneic. If the patient seizes or goes into trismus, the patient may bite down hard enough to actually cut off the fingers. Using a bite block in these situations is highly recommended. A misplaced ETT is the most common complication of this procedure. Because of the availability of alternative airway devices, such as the Combitube or King LT, among others, digital intubation is rarely performed and not typically recommended.
Other less commonly used intubation methods also exist in certain systems. Local protocols will indicate whether other alternate forms of intubation are available. First, a lighted stylet that illuminates the trachea internally and is visible through the skin externally when correct placement is achieved may be an intubation option. A 2nd
option may be retrograde intubation, which involves inserting a large-bore intravenous catheter into the cricothyroid membrane in a cephalic direction and threading a guide wire through it until it is visible in the pharynx. The guide wire is then pulled out through the mouth, and an ETT is placed over it and slid directly into the trachea blindly. This very complex procedure should be performed only under the strictest of sterile techniques.
While direct laryngoscopy is still currently the preferred method of securing an airway, other devices can be used in the event that orotracheal intubation is not possible or proves extremely difficult. In many cases, these devices and procedures should be used before attempting alternative intubation techniques, such as those discussed previously in this chapter because placement of and successful ventilation with these techniques is often quicker than digital, nasal, or retrograde intubation will be.
The Combitube is a preformed dual lumen plastic tube that is blindly inserted into a patient’s mouth and can be used for ventilation regardless of whether it is inserted into the esophagus or the trachea. This tube is expected to enter the esophagus but occasionally will enter the trachea, so, essentially, it cannot be misplaced.
Indications: The patient is older than 16 years old and has a height of 5 feet 7 inches (4 feet 5 inches for the Combitube SA); an ETT cannot be placed for any reason.
Contraindications: Esophageal trauma, alcoholism (esophageal varicies)
Procedure:
The laryngeal mask airway (LMA) is designed to wedge itself into the hypopharynx and cover the entire glottic opening. Ventilation is then directed into the trachea after the cuff is inflated, sealing off the entire hypopharynx. Insertion for these types of airways is blind, similar to the Combitube. LMAs come in a variety of sizes and are not limited based on height, like the Combitube. A drawback for these devices, compared with the Combitube or the ETT, is that they do not completely prevent vomiting or aspiration.
Indications: An alternative to BLS airway when an ETT cannot be placed
Contraindications: Morbid obesity because the seal for these patients is not as tight as for others; patients with COPD may require higher airway pressures, which is not accomplished well with the LMA.
Procedure:
The King LT is very similar to the Combitube, except that it is only a single lumen and must be inserted into the esophagus to work. Similar to the Combitube, it has a distal cuff that seals the esophagus and a pharyngeal cuff that seals the oropharynx; however, it has only 1 tube for ventilation. Unlike the Combitube, it comes in a variety of sizes and can be used in children as small as 12 kg.
Indications: Inability to place an ETT for any reason
Contraindications: Esophageal trauma, alcoholism (esophageal varicies)
Procedure:
The surgical airway is not something that should be performed in the field. Severe bleeding during the incision of the trachea may occur if the thyroid gland is inadvertently lacerated. Because this procedure would be performed only if all the previously described procedures to establish an airway fail, it can safely be presumed that the airway in question is extremely difficult and could be made worse with excessive thyroid bleeding. In addition, this procedure should be performed only with operating room quality sterility, which is nearly impossible to effectively establish in the back of an ambulance or a helicopter. The nonsurgical or needle cricothyrotomy, on the other hand, is possible to successfully perform in the field and is the recommended method for establishing an airway when all else fails.
The needle cricothyrotomy is a life-or-death last resort for establishing airway patency. Ensure that local protocols allow this procedure to be performed; in many cases, online medical control needs to be contacted first to verify permission. This procedure is much quicker than a surgical airway and carries with it significantly less chance for bleeding or failure.
Indications: Inability to ventilate by any other method; severe facial trauma and severe oral bleeding
Contraindications: Complete obstruction superior to the needle insertion point (prevents effective exhalation, leading to hypercarbia, and increases the risk for barotrauma to the lungs); be prepared to treat pneumothorax if overinflation of the lungs occurs from high pressure ventilations.
Procedure:
Some patients have a stoma or a tracheostomy tube and are in need of O2 or ventilatory assistance. Many of these patients need to be suctioned frequently and will sometimes have a sudden onset of severe respiratory distress until they are suctioned. Simply inserting a soft-suction catheter until resistance is felt but no more than 12 cm and suctioning only on the way out as described previously should clear up most respiratory issues. The patient will cough as the suction catheter is inserted, so use caution in case of airborne mucus.
Any ventilation that is necessary for this patient population must be performed through the stoma or the tracheostomy tube. If the patient has only a stoma, using a pediatric mask attached to an adult BVM should work to get an adequate seal for ventilation through the stoma. Tracheostomy tubes are manufactured with the same size connector as ETTs, which means the BVM can be connected directly to it. Then ventilate as usual.
Occasionally, it may be necessary to insert an ETT through the stoma to facilitate ventilations. In this case, take a tube that just fits the lumen of the stoma, usually a 6.0 ETT, but try not to go an ETT <5.0. Insert it 1–2 cm beyond the cuff and inflate the cuff. Ventilate normally. Cut the ETT so that only 3–4 cm protrudes from the neck to make it a little less unwieldy.
After ensuring a patent airway, preferably by ensuring the patient can talk to you, evaluate and treat any breathing problems. Before exploring the variety of respiratory emergencies, this section reviews all the O2 administration methods that are available to the paramedic in the field. In addition, ventilatory support methods, including BVM techniques and continuous positive airway pressure (CPAP) will be presented. Finally, the section will conclude with a discussion on special patient populations who may present a challenge with breathing problems.
Designed for low concentrations of O2, nasal cannulas are typically used to deliver O2 to a breathing patient at a flow of 1–6 L per minute (LPM), providing a fraction of inspired oxygen (FiO2) of 24% to 45%. Remember, each liter per minute of supplemental O2 delivers 3% more O2 to the patient over the atmospheric concentration of 21%, so the equation to estimate FiO2 is FiO2 = 21 + (3 * liter flow). This can be used when a patient is unable to tolerate a non-rebreathing or simple face mask or does not require high concentrations of O2 to maintain adequate perfusion. It also is highly recommended that the patient be placed on nasal cannula O2 at 6 LPM during intubation attempts.
Simple face masks fit over the patient’s mouth and nose and are used to deliver moderate levels of O2, typically 6–10 LPM. The mask allows atmospheric air to mix with O2 and will deliver between 35% and 60% FiO2.
The non-rebreathing mask is used to deliver high concentrations of O2 to a spontaneously and adequately breathing patient. At liter flows between 10 and 15 LPM, the non-rebreathing face mask can reliably deliver a FiO2 of 90% to 100%. Use of this mask is indicated in any patient who requires high concentrations of O2, such as a person in shock or hypoxia. This mask has a bag—the O2 reservoir—attached to it which should be filled prior to placing it on the patient. The liter flow should be increased to the point that when the patient takes a breath, the bag does not deflate. This will help ensure that the patient is getting the maximal flow of O2 with each breath.
The Venturi mask is not typically initiated by the paramedic; however, it may be used during interfacility transfers, where the sending provider wants to strictly control FiO2 for the patient. This mask is designed to mix pure O2 and atmospheric O2 to obtain specific concentrations. The liter flow for this device is either 3 LPM or 6 LPM, depending on the desired concentration. It should be maintained for the duration of patient contact unless the patient’s condition deteriorates and higher concentrations or an alternate delivery device (i.e., BVM) is warranted.
The tracheostomy mask is specifically designed to fit over a stoma or a tracheostomy tube and may not be available in the emergency setting. A tracheostomy mask may be improvised using a simple face mask or a non-rebreather mask to cover the stoma.
O2 humidifiers are designed to add moisture to the O2 being delivered to the patient. O2 delivered to a patient from a concentrator or a sealed bottle or cylinder is completely devoid of any moisture or humidity. Delivering dry O2 to a patient for extended periods can dehydrate the patient and the mucous membranes, which becomes an issue with long transport times, such as those on interfacility transfers, but not during a typical emergency where patient contact time is limited.
As mentioned earlier in this chapter, normal ventilation is accomplished by creating negative pressure in the chest when the diaphragm contracts and descends into the abdominal cavity and the intercostal muscles contract and the rib cage raises anteriorly and superiorly to increase the volume of the thoracic cavity. This is important to the circulatory system as well. During the creation of negative pressure, not only is air drawn in but also blood is pulled up from the extremities and head, returning it in greater quantity to the heart. When artificial ventilation methods must be employed, however, the enhanced venous return is not only lost but also actually reduced because of the now positive pressures used to push air into the lungs. Finally, because positive pressures are used, the air that is squeezed into the chest enters the lungs; occasionally, if too much force is provided to deliver the breath, air will enter the stomach, a condition known as gastric insufflation or gastric distension.
As a patient’s breathing worsens, before the patient stops breathing
altogether, the paramedic should begin assisting the patient’s existing respiration using a BVM device. This is a very difficult skill and requires almost complete concentration on the part of the paramedic to do it successfully. Losing concentration while assisting ventilations will inadvertently make the patient’s breathing and their already high anxiety worse.
Indications: Inadequate breathing based on fast rate or shallow depth
Contraindications: Patient’s increased anxiety when hands and the BVM are on the face
Procedure:
Multiple ways can be used to deliver a breath to a patient once he or she has stopped breathing; however, the most effective way is with 2 rescuers using a BVM. Mouth to mask with supplemental O2, as is taught in most CPR classes, is 2nd. Once a patient has stopped breathing, or is in respiratory arrest, paramedics need to breathe for them entirely. This is arguably the most important skill any prehospital provider can master at any level. There are no contraindications to this skill; even when there is massive facial trauma, still attempt to establish a seal with the mask to the face to deliver ventilations.
Procedure:
CPAP is essentially the same as the assisted ventilations described previously; however, it is controlled by a machine and does not require the provider to hold the mask to the face of the patient. It uses straps that fasten to the mask and wrap around the head. It has been shown to decrease the morbidity and mortality of patients with severe respiratory distress who, prior to the use of CPAP, would have been intubated. CPAP provides continuous pressure into the lungs and opens collapsed alveoli while preventing further atelectasis. It is not uncommon for patients who are found with respiratory rates in the 40s and oximetry readings <80% to dramatically improve with CPAP application to having a slowed respiratory rate and pulse oximetry reading approaching 100%.
Indications: Patients in severe respiratory distress caused by congestive heart failure (CHF), exacerbation of COPD, or asthma; patients also need to be breathing and generating enough force to start the delivery of O2 through the device and need to be able to exhale forcefully enough to stop the flow.
Contraindications: Respiratory arrest, bradypnea, chest trauma, altered mental status and unable to follow verbal commands, excessive facial hair or facial deformities such that the mask does not have a tight, complete seal
Procedure:
Any time artificial ventilation is used in the absence of an ETT, it is very likely that air enters the stomach in addition to the lungs, resulting in gastric distension. This presents the very real possibility of projectile vomiting as the stomach suddenly and spontaneously decompresses, further complicating the airway and respiratory problem at hand, not to mention creating a nightmare of a cleanup. Furthermore, as the stomach expands and pressure within it builds, it will become increasingly more difficult to ventilate the patient because the lungs can no longer expand into the abdominal cavity as they normally would.
Minimize the development of gastric distension by positioning the airway correctly and hyperextending the neck, delivering breaths slowly over 1–2 seconds, and allowing full exhalation before delivering the next breath. Even observing these suggestions will likely result in some distension. To relieve it, the paramedic can insert a nasogastric tube or an orogastric tube if protocols allow. The nasogastric tube is contraindicated in patients with facial fractures because the tube can enter the cranium through a fractured basal skull. The orogastric tube should be used only in the cases of facial fractures and in patients who are unresponsive and do not have a gag reflex. Because the orogastric tube is used only during these conditions, it is nearly always inserted after ETT placement and cannot be placed if any other advanced airway device is used. (It can be used with a Combitube if it was placed in the esophagus and the patient is being ventilated through blue tube number 1.)
Nasogastric tube placement procedure:
Orogastric tube placement procedure: