Learning Objectives
>> Compare and contrast the practice of prehospital airway management between routine single-patient encounters and those situations involving multiple patients.
>> Describe ways to engage laypersons or minimally trained providers in the care of airway management at the scene of a mass casualty incident involving multiple patients requiring airway management.
>> Describe the indications, contraindications and limitations of supraglottic airway management techniques.
>> Describe the indications, contraindications and limitations of subglottic airway management techniques.
Glossary Terms
Epiglottis: Leaf-shaped structure located posterior to the base of the tongue.
Hypopharynx: The laryngeal part of the pharynx extending from the hyoid bone to the lower margin of the cricoid cartilage.
Larynx: The portion of the airway connecting the throat with the trachea.
Nasopharyngeal airway: A basic airway that is inserted via the nose into the posterior oropharynx, behind the tongue.
Oropharyngeal airway: A basic airway that is inserted via the mouth into the posterior pharynx, behind the tongue.
You’re one of the first-arriving units at the scene of a multi-story nursing home fire. A significant fire is being battled by firefighters, and there’s smoke pouring from the building. Patients are arriving at the triage intake area, and it’s obvious numerous patients are in respiratory distress ranging from mild to severe. You’re the senior paramedic and will need to begin the treatment decision making.
Introduction
The ability to rapidly assess the need to provide airway management to a patient is a critical component of the EMS provider’s skill set. Not many decisions in EMS are both time sensitive and critically important. Airway management is a combination of skills that includes the ability to properly assess the patient, followed by the formulation of a plan and then the ability to carry out the psychomotor skills associated with devices and procedures.
When encountering a situation during which multiple patients require active management, our assessment skills won’t change dramatically; however, our decision-making and plan formulation will vary depending on a number of factors, such as expertise, human resource and equipment availability. A discussion of airway management for the individual patient will help to segue into some of the different thought processes, decision making and plans associated with managing a scene that has multiple patients requiring airway management.
Airway Management
Airway management spans a wide variety of potential treatments ranging from the basics of inserting an oropharyngeal airway, providing oxygen and observing, through advanced procedures, such as endotracheal intubation (ETI) and surgical cricothyrotomies. It’s important to remember there’s no “one size fits all” approach to airway management. Avoid a thought process of “airway management equals ETI.” For example, ETI has to be recognized as a time- and equipment-intensive procedure when considered from beginning to end in a mass casualty incident (MCI).
Patients may require airway management for a variety of reasons, including medical, trauma and environmental conditions. Essentially, the need for airway management falls into three broad categories: mechanically opening the airway to facilitate the passage of air/oxygen, facilitating the delivery of positive-pressure ventilation and finally, protecting the airway against potential aspiration and other major contamination of the lower airways.
The need for mechanically opening the airway arises from conditions that prevent the patient from doing so on their own. The most common airway compromise results from depressed mental status leading to a relaxation of the tongue, which falls posteriorly and occludes the airway of the supine patient. Other examples include swelling of the airway, blood and foreign body obstructions, as well as direct and indirect trauma to the airway. Indirect causes include inhalation and ingestion of toxic substances, as well as thermal injuries–all of which can cause significant swelling.
The need to deliver positive-pressure ventilation can arise in any condition during which the patient is suffering from hypoxia and has an impairment of respiratory function. Depressed mental status, pulmonary edema or bronchospasm from asthma, chronic obstructive pulmonary disease or toxic inhalation are common causes of situations that may require positive-pressure ventilation.
Protection against aspiration is needed for patients who are unable to mount protective reflexes that assist in clearing the airway. Often, this patient population has a depressed mental status or unconsciousness. Risk of aspiration may include blood in the airway, as often occurs after traumatic injury, conditions causing excessive salivation and the vomiting of gastric content. In some situations, the entire airway management plan for the patient may revolve around the need for suctioning and mechanically assisting the patient to reduce the aspiration risk.
Anatomy
Pertinent airway anatomy to consider begins with the upper airway structures, including the oral pharynx, tongue and epiglottis. The glottic opening is the opening between the vocal cords, or larynx, which serves as the dividing point between the upper and lower airway structures.
Anterior to the larynx is the thyroid cartilage and the cricoid ring. The latter two prominent structures serve to protect the glottic opening and also provide the palpable landmarks to perform a surgical cricothyroidotomy or transtracheal jet ventilation through the cricithyroid membrane. The lower airway includes the trachea, bronchi and distal to the lungs.
Assessment
The assessment of a patient with a potential need for airway management generally focuses on the patient’s respiratory, neurologic and cardiovascular systems. In general, the assessment begins the moment you see the patient.
A simple assessment of the neurologic exam is important to determine whether the patient has the mental status capacity to maintain airway protective mechanisms. In the unconscious patient, this is assessed by noting the presence or absence of a gag reflex. In the case of patients exhibiting delirium and other forms of altered mental status in which they may be speaking, yelling or screaming during the initial assessment while they have serious underlying injury, it’s likely they won’t require immediate airway assistance other than supplemental oxygen.
Special attention to the respiratory rate and pulse are important when assessing a patient’s vital signs. Oxygen saturations should be measured. You should also observe for additional signs of respiratory distress, such as tachypnea and accessory muscle use. It’s important to remember that in a patient with depressed mental status, the signs of respiratory distress may be blunted or absent–even in the presence of significant hypoxia.
Skin color, temperature and moisture can provide such information as the level of sympathetic nervous system activation. Oxygenation may be important information to consider as well. Pale skin can indicate shock, while cyanotic skin is a critical indicator of severe, systemic hypoxemia.
Auscultation of the lungs can provide valuable information when assessing the patient’s need for airway management. The most important assessment from auscultation is to determine the presence or absence of airflow into the lower airways. Having none, or diminished sounds of air movement, suggests obstruction or lack of respiratory effort on the part of the patient. Once the presence of air movement is established, noting the quantity of air movement, along with sounds indicating obstruction, is the next logical step.
Snoring or sonorous sounds are indicative of a partial obstruction most often caused from the tongue. Stridor is a high-pitched inspiratory sound associated with the obstruction of the upper airway, such as that associated with swelling of the glottis opening.
Wheezing is generally an expiratory sound associated with bronchospasm of the lower airways, but in more severe cases, it may involve an inspiratory component. As bronchospasm worsens, there’s an increase in the overall obstruction of the lower airways and may begin to also include inspiratory wheezing and progress to not hearing any air movement at all in the worst cases.
As a rapid assessment process is being carried out, it’s worth thinking about the categorization described above: 1) Does the patient need their airway mechanically opened; 2) Does the patient require positive-pressure ventilation; and 3) Does the patient need protection for aspiration or some combination of the three situations?
The proper assessment of the patient will assist you in forming an airway management plan. However, formulating airway plans will change when dealing with a MCI during which multiple patients require airway attention.
Treatment Options
Treatment and treatment options will vary significantly based on the resources available in the case of a multi-patient airway encounter. In this context, resources include the availability of personnel, as well as their abilities, and the specialty equipment that may be needed in such a situation. Another consideration in overwhelming multiple patient encounters is the engagement of untrained medical providers and laypersons in realistic tasks that can assist until the situation is stabilized.
After rapid assessment and determination of the need for airway support using the categories suggested, the provider(s) can then begin to implement treatment plans being mindful of the fact that MCI situations may require deviations from typical standard treatment options. One of the biggest differences for MCIs is that we do not use ETI routinely for airway management. In multi-patient airway encounters, this method of securing the airway often isn’t practical due to the extensive amount of needed equipment, setup time, and the skill and expertise level.
In MCI situations, EMS providers should immediately try to determine which patients will need only supplemental oxygen. In the setting of constrained resources, the application of oxygen should be limited to those exhibiting signs of respiratory distress with alterations of their oxygen saturations.
A category of patients who may be treated fairly quickly involve those who require only minor mechanical assistance that can be accomplished by opening their airway. This includes patients with altered mental status or those who are exhibiting excessive salivation or vomiting but are otherwise able to maintain their own airway. These patients can be simply placed on their side in a lateral recumbent position to assist them in clearing their airway. Depending on the availability of resources, a lesser-trained provider–or perhaps even a layperson–can be assigned to the patient with a suction apparatus to assist.
In situations that involve only a single patient, this can be remedied by a number of things: a head tilt chin-lift maneuver, the insertion of an oral or nasal pharyngeal airway or the application jaw thrust with bag-valve mask (BVM) assistance. In situations involving multiple patients for which resources are strained, other forms of treatment may be necessary.
In the formulation of the plan, it’s important to remember that the most common cause of airway obstruction in the unconscious patient is the tongue falling backward to occlude the hypopharynx. In such circumstances, removing an article of clothing from the patient, such as a shoe, may serve as an appropriate prop to place behind the patient’s C-spine to maintain the head in a head tilt-chin lift position that will serve to elevate the tongue from the posterior hypopharynx, thereby creating a patent airway.
Patients who aren’t responding to a mechanical opening of the airway may require more advanced intervention, which may include positive-pressure ventilation to deliver oxygen to avoid hypoxia. In such circumstances, the next logical choice is BVM ventilation as a temporizing measure.
BVM ventilation can be accomplished by one skilled rescuer but many times will require two. In cases for which it’s difficult to maintain a seal with the mask, or for which the patient requires simultaneous application of a jaw-thrust maneuver to maintain a patent airway, a two-person BVM ventilation technique is essential.
When performing two-person BVM, the more experienced person should be maintaining the seal of the mask, and the lesser experienced or even a layperson can perform the part of squeezing the bag.
When BVM ventilation is necessary, it’s often enhanced by an adjunct, such as a nasopharyngeal or oropharyngeal airway. Adjunctive basic airway devices are designed to creative patent passage posterior to the tongue to allow effective exchange of gases for the patient requiring this level of support. It’s important to remember the patients that have an intact gag reflex won’t tolerate an oropharyngeal airway. A nasopharyngeal airway should be avoided with patients who have severe facial trauma and the potential for skull fractures.
Simply opening the airway of the patient who needs positive-pressure ventilation assistance or protection from airway aspiration gastric contents isn’t enough. In these circumstances, more advanced measures of airway care are necessary. In such situations, several options exist.
Advanced airway treatment options can be divided into two broad categories: supraglottic and subglottic–depending on how the device or procedure is designed to function. The decision of which method to use will often be determined by the clinical cause necessitating airway management, along with the presence or absence of a gag reflex and whether local protocols support the use of sedative and paralytic medications to facilitate airway management.
Supraglottic Airways
Supraglottic airways are designed to be used above the vocal cords, or glottis opening. They’re placed using a blind technique and create a seal around the glottic opening but don’t actually cross the vocal cords. Supraglottic devices are contraindicated in situations for which the glottic opening is compromised, threatening the patency of the airway. Examples include laryngeal swelling from thermal burns, anaphylaxis and direct trauma to the neck with an expanding hematoma.
Similar to oropharyngeal airways, supraglottic devices aren’t tolerated in patients with intact gag reflexes. ALS providers should consider use of sedative medications for patients with an intact gag reflex requiring a supraglottic device.
Common supraglottic devices include laryngeal mask airways (LMAs), as well as King airway devices. Advantages of both the LMA and the King tubes include overall ease-of-use, requiring little extra equipment and set up, as well as a rapid insertion time.
When properly inserted, these devices afford some level of airway protection from aspiration. In general, supraglottic devices require only the device itself and a syringe to inflate either the cuff or the balloon of the device.
LMA
LMAs have had a long history of use in airway management in the hospital setting. They have a long track record of being safe and relatively easy to use. During the past several years, they’ve been introduced into the prehospital care setting. The LMA is designed to create a seal around the entire glottic opening by leveraging itself against the posterior pharyngeal wall. An inflatable cuff that surrounds the laryngeal opening creates a seal that facilitates the ability to use positive-pressure ventilation and provide some protection against aspiration.
The size of the LMA is selected on the basis of the patient’s weight. Once the proper size LMA is identified, the device is initially prepared by checking the seal of the mask. Once complete, the air is completely evacuated from the cuff prior to placing the device into the patient. The placement of the LMA is a blind technique assisted by elevating the tongue, often with the blade of a laryngoscope or gloved thumb. The device is placed in and guided into the posterior pharynx anatomically. Once placed, the cuff is inflated with a syringe with the proper amount of air indicated on the packaging of the LMA.
Once the LMA cuff is inflated, a BVM should be connected and ventilation attempted. Observation of chest rise, auscultation of the lung sounds and the presence of end-tidal carbon dioxide (EtCO2) indicate a properly placed device that’s functioning. Assess for the possibility of an air leak by listening during the positive pressure created by the squeezing of the BVM.
If a leak is encountered, place additional air into the cuff and reassess ventilation and seal quality. In some cases, the LMA will need to be removed and replaced to be able to obtain an adequate seal that allows for positive-pressure ventilation and protection. A common cause of an irresolvable leak during the placement of an LMA is the folding of the distal tip of the LMA cuff back onto itself.
King Airway
The King airway has rapidly become a popular device for airway management in the prehospital care setting. Its ease of use, quick setup and insertion are ideal features for this supraglottic device. Newer versions of the tube also facilitate gastric emptying through a suction port that allows a gastric tube to be placed in the stomach through the tube. This is an important consideration for reducing the risk of aspiration during the definitive management of the patient when the King tube will need to be removed.
The device features a high-volume, low-pressure balloon system that creates a seal in the hypopharynx and distally in the esophagus. This effectively isolates the glottic opening and allows for the use of positive-pressure ventilation and provides some protection against aspiration. Unlike its predecessor, the combitube, King tubes are designed to be placed into the esophagus every time. The decision making surrounding the use of the device is also much simpler.
The selection of a properly sized King tube is based on the height of the patient. Once the proper tube is selected, the tongue is lifted, and the device is placed in the patient until reaching the guide marks on the tube, which is similar to the placement of an LMA. Once placed, the balloon is inflated with proper amount of air that’s indicated on the package for the device with a syringe. An assessment of effective ventilation is conducted similar to that described for the LMA.
If a leak is detected, additional air can be placed into the balloon. If an air leak persists after adding additional air to the balloon, the device should be gently pulled back approximately 1—2 cm; that will often create a seal. Studies have shown that the King tube is so easy to use that laypeople were able to successfully place it with instructions given over the phone.
Subglottic Airway Management
Subglottic airway management techniques involve devices or procedures that either cross the vocal cords or are performed below the vocal cords. Most commonly, subglottic airway management is accomplished by ETI. Other forms of subglottic emergent airway treatment include surgical cricothyrotomy and trans-tracheal jet ventilation.
ETI has long been the mainstay of airway management in patients requiring airway opening, positive-pressure ventilation and protection from gastric aspiration. ETI may have a role in multi-patient encounters, but such factors as the amount of equipment required, the setup time and the skill and expertise of the provider must be considered.
Although the intubation is usually accomplished quickly, the amount of setup and equipment required will limit its usefulness in multi-patient encounters. Additionally, ETI requires more aseptic precautions and that the laryngoscope be cleaned between each patient encounter. This becomes another complicating logistic in the setting of multi-patient encounters.
Advantages of ETI include positive control of the airway, affording maximal amount of airway protection against gastric aspiration (although it can still occur) and minimizing problems associated with air leaks that can commonly occur with the use of the supraglottic devices.
During ETI, the tongue is moved in a way that allows access to the vocal cords with a laryngoscope or similar device. Once the view of the vocal cords is obtained, an endotracheal tube is passed across the vocal cords into the trachea. Once inside the trachea, a low-pressure balloon is inflated to create a seal that facilitates being able to use positive-pressure ventilation and protection from aspiration.
Surgical cricothyrotomy may be indicated in the setting of a patient who requires advanced airway management and has a contraindication, or where there’s ineffective use of a supraglottic device and an inability to perform ETI. A cricothyrotomy can be accomplished fairly quickly with a minimum amount of required equipment.
A cricothyrotomy is accomplished by identifying the cricothyroid membrane and making an incision through the skin. Then, through the membrane itself, a tracheal tube, such as a 6.0, is placed directly into the trachea. Once the tube is placed, the cuff of the tube is inflated and an assessment of adequate ventilation is performed.
Potential complications of surgical cricothyrotomy include bleeding, placement of the tube into a false passage in the neck but outside of the trachea, as well as dislodgment of the tube after it’s placed–because they’re notoriously difficult to secure.
In dire emergencies when a patient is suffering from persistent hypoxia in the setting of being unable to otherwise oxygenate them, transtracheal jet ventilation may be considered. This involves performing a needle cricothyrotomy through the cricothyroid membrane and providing oxygen through a catheter via a high-pressure oxygen source.
Summary
Encountering a situation that necessitates the assessment and management of patients requiring airway management can present a significant challenge. It will require a different thought process and set of decision-making skills that vary from the routine practice of airway management during a single patient encounter.
Rapid triaging of the need for airway management is important. Creating a categorization of those patients who simply need supplemental oxygen from those who require assistance with the mechanical opening of the airway, a need for positive-pressure ventilation and those who require protection from aspiration can be a useful starting place for the creation of a treatment plan.
Treatment decisions will depend on the amount of equipment and personnel resources that are available. Non-traditional decision procedures and positioning may need to be implemented, such as placing patients in a lateral recumbent position to use gravity to assist in keeping the airway patent.
In the setting of multiple patient encounters requiring airway management, it’s important to consider the length of time each procedure will take and the amount of equipment that will be required. A rapid securing of the airway by a supraglottic device in suitable patients may be favored over traditional approaches of ETI secondary to the relative complexity of the procedure. JEMS
This article originally appeared in May 2012 JEMS as “Multiple Airways: Rapid assessment is key for managing numerous patients.”
