This clinical review feature article is presented in conjunction with the Department of Emergency Medicine Education at the University of Texas Southwestern Medical Center, Dallas.
- Differentiate between oxygenation and ventilation.
- Apply various assessment components for oxygenation, ventilation and airway protection.
- Describe each airway management role when three rescuers assist ventilations with a bag-valve mask.
- Identify potential negative systemic effects of artificial airway management and the precautions needed to prevent them.
- Be aware of techniques and principles that increase the effectiveness of airway equipment, oxygenation and ventilation.
- Ataxic breathing: A type of breathing associated with damage to the respiratory centers in the medulla that’s characterized by unpredictable, irregular, rapid, short breaths with pauses of several seconds; also known as Biot’s breathing.
- Breath stacking: Rapid, artificial respirations that don’t allow for complete expiration, resulting in residual air added to the volume of the next inspiration and eventual over-inflation of the lungs. This can lead to high-intrinsic, positive end-expiratory pressure within the airways and high-intrathoracic pressure, decreasing venous return to the right heart.
- Capnography: The measurement of exhaled CO2 levels.
- Gastric insufflations: Substances inhaled into a body cavity, such as the air that inadvertently enters the stomach with the use of a bag-valve mask.
- Gastric regurgitation: The return of swallowed food into the mouth. In patients with altered mental status, any regurgitated food also has great potential to inadvertently enter the airway.
- Grunting: Audible, short, grunt-like breaks during exhalation. Grunting occurs when the glottis briefly stops air flow in an attempt to generate positive pressure and keep the lower airways open. It suggests lower respiratory tract obstruction and is often associated with pneumonia, atelectasis and respiratory distress syndrome in newborns.
- Transtentorial herniation: Downward displacement of the brain, typically from increased intracranial pressure through the tentorial notch. This causes pressure on underlying structures, including the brainstem.
- Stridor: An abnormal, high-pitched respiratory breath sound caused by partial blockage of the airway.
- Vagal response: Stimulation of the vagus nerve, causing a parasympathetic response of bradycardia and vessel dilation.
Basic airway management is a fundamental skill that all EMS professionals should master. Its principles and practices transcend all departments, ranks and certification levels, and it’s the absolute priority during every patient contact you have. Often, the difference between life and death—your chance to make a difference for a patient—lies in your ability to aggressively and effectively manage their airway. Your patients depend on your competence and deserve nothing less than excellent airway management.
Managing an airway can be a challenge, even for the most experienced health-care professionals. Traditionally, basic airway management instruction falls into the old “see one, do one, teach one” approach to medicine. The problem with this approach is that, in reality, basic airway management is one of the most difficult skills to acquire and teach. One reason for this is the emphasis placed on manikin instruction, due to a lack of actual patients. The majority of manufactured manikins are fairly easy to hand ventilate with a bag-valve mask (BVM) because it’s easy to make a seal with the BVM, and the manufactured lungs inflate with minimal effort. As a result, some instructors and students become complacent with respect to airway learning.
The fact is that all providers involved with airway management need a reality check. With so many intermediate and advanced airway skills being practiced, such basic skills as BVM ventilation are deteriorating. It must be understood that these fundamental airway skills will perish over time if not routinely practiced. In addition, we must realize there’s been a sea change with respect to airway management in the field. After years of resuscitation research, we now realize less may actually be more.
Uninterrupted chest compressions with little emphasis placed on ventilation is the latest cardiocerebral resuscitation skill. Advanced procedures, such as intubation, central line placement and administration of all of those “wonder drugs,” may not be best for our patients. In fact, many experts now feel that basic EMTs could do more good for the airway than paramedics. To help you understand these concepts and make that difference for your patients, we’re revisiting the “must-know” basics to make you a better airway manager.
Five Basic Tips
1. Know the hallmarks of good airway management. Oxygenate. Ventilate. Protect the airway. These are the three principles and goals of airway management from which all of your airway actions should stem.
When managing an airway, you should recognize that you’re attempting to accomplish two separate and equally important physiological tasks: oxygenation and ventilation. Oxygenation is the process of delivering oxygen to our patient’s lungs via the BVM reservoir so that oxygen is picked up by blood flowing past the alveolar membrane. Ventilation occurs as a result of gas exchange at the alveolar-capillary membrane, thus allowing carbon dioxide to be removed from the blood by exhalation. For oxygenation and ventilation to occur, the airway must be patent and clear from secretions or blood, which is why the principles include airway protection.
2. Conduct a thorough assessment. This is instrumental in supporting your patient’s oxygenation, ventilation and airway protection needs. Your airway assessment should begin before you ever talk to a patient. Use visual and auditory clues to your advantage. Cyanosis, stridor or any similar abnormality during your initial encounter should be diagnostic of a compromised airway. Be vigilant for early signs of respiratory insufficiency or failure.
Check your patient’s level of consciousness as a measure of airway patency. A patient with a Glasgow Coma Scale (GCS) score of less than or equal to 8 is someone you should be more aggressive with, because the patient has an inability to protect their own airway. In general, we know that if someone can’t open their eyes, speak, cry or make purposeful movements in response to pain, they have a significant central nervous system derangement.
Assess the adequacy of their breathing. Are they breathing too fast or too slow? Are their respirations shallow or deep? Are their breath sounds absent, diminished or unequal? Do you hear any abnormal sounds, such as grunting, snoring, wheezing or stridor? Have you noticed any nasal flaring, accessory muscle use or pursed lips? Is the patient in a tripod position or refusing to lie down? Are they cyanotic or listless?
Conduct a physical exam of the patient’s face, neck and chest. This exam will help you identify current and potential problems, as well as determine what equipment you should (and shouldn’t) consider using. Do you see any active bleeding from their oropharynx or hear any gurgling? If so, use suction.
Note if they’re missing any teeth. Do they have a fractured or otherwise anatomically deformed mandible? If so, using a BVM by yourself may be challenging, and you should anticipate the need for additional help. Do they have raccoon eyes, battle’s sign, active bleeding and/or cerebrospinal fluid leaking from their nose or ears? If so, you should suspect a basilar skull fracture and not place a nasal airway. Mid-facial fractures should also preclude you from placing a nasal airway.
Observe and palpate their chest. Do they have equal rise and fall? Do you note any signs of injury that may explain their current condition? If there’s paradoxical movement indicative of a flail chest, some simple pressure on the affect side may immediately improve the patient’s ability to breathe.
Obtain a respiratory rate, pulse rate and blood pressure. Furthermore, you should obtain their oxygen saturation and, if able, use capnography to further assess their ventilation and perfusion.
3. It’s OK to ask for help. Traditionally, it was taught that one-person BVM ventilation was acceptable and adequate. It’s likely no surprise that this philosophy must be changed. Our patients are getting older and sicker, and the anatomy (and size) of our patient population is changing for the worse. Generally speaking, most of our adult patients are overweight, and many are considered obese. Add a beard that interferes with your ability to get a mask seal, and you have a recipe for disaster with respect to managing their airway. Gone are the days of a single provider in the back of the rig managing an airway, with an “ambulance driver” up front driving with lights and sirens to the emergency department. With a changing population and science, we too must change as basic airway managers.
Ideally, three experienced EMS providers should be utilized to manage a patient’s airway in the field. The first provider would open the airway using either a head-tilt chin lift or a modified jaw thrust (if cervical spine injury is suspected) with two hands, while effectively “pulling” the face into the mask. This is to ensure a proper seal of the mask against the patient’s face. The second provider then squeezes the reservoir bag while watching for chest rise and listening for leaks around the mask. The third provider applies adequate cricoid pressure to prevent gastric insufflations and passive gastric regurgitation. If vomiting occurs, remember to release the cricoid pressure, logroll the patient and suction.
4. Your airway management actions have systemic effects. As is the case with most advanced treatments, some basic skills have potential systemic physiological effects. It was long taught that aggressive “bagging” of patients all the way to the hospital was of paramount importance for saving lives. In reality, we’re doing more harm than good with overly aggressive ventilation of our patients. Therefore, when assisting a patient with their respirations, it’s important to understand the physiology of artificial ventilations and their systemic effects.
Advanced level providers should understand that many patients in the field with airway problems aren’t necessarily candidates for intubation. Excellent basic airway skills can usually be just as effective. Further, it’s just as important to have good judgment during your assisted ventilations as it is to have sharp and refined airway skills. You must understand that patient encounters won’t all be the same, and you must tailor your approach to each situation. However, for most patients you’ll treat in the field, the following guidelines will suffice.
Adequately assisted respirations should be comprised of slow, controlled ventilations (10–12 breaths/min for the apneic adult; 20 breaths/min for children less than or equal to eight years), while looking for chest rise with each tidal volume delivered. Each adult tidal volume should be 400–600 mL or approximately 6–7 mL/kg over 1–2 seconds for adults, with adequate chest rise for children. This should be followed by complete exhalation so that lung overdistention, breath stacking and gastric insufflation are prevented.
Current American Heart Association guidelines for CPR state that lungs should be inflated 8–10 times per minute without pausing for chest compressions, and the inflation volume should be delivered in one second.1 It’s crucial to understand that overly aggressive ventilation of a patient can result in very high intrathoracic pressures, which impedes venous return to the right side of the heart and causes a fall in cardiac output, blood pressure and coronary perfusion pressure.1,2 Because the high rates of “bagging” and/or high tidal volumes can result in the physiological problems discussed above, it’s extremely important to use the correct size BVM and airway adjunct for the patient you’re caring for.
In addition to these common problems encountered with assisted ventilations, the provider must also have a solid understanding of the physiological changes that occur in patients with traumatic brain injury (TBI) and/or multiple trauma with hypovolemia.
When caring for a patient with a known or suspected TBI, hypoventilation, aggressive hyperventilation and hypoxia must all be avoided. For adults with severe TBI (GCS less than or equal to 8), the assisted ventilatory rate should be 12 breaths/min (one breath every five seconds). For children eight years or younger with severe TBI (GCS less than or equal to 8), the assisted ventilatory rate should be up to 20 breaths/min (one breath every three seconds).
A slightly higher ventilatory rate may be considered in a select group of patients. If active seizures, or such signs of transtentorial herniation as fixed or asymmetric pupils, neurologic posturing (decerebrate or decorticate), Cushing’s reflex (hypertension and bradycardia), abnormal breathing pattern (Cheyne-Stokes, central neurogenic and ataxic breathing) or neurologic deterioration are present, mild hyperventilation may be considered with ventilatory rates increased to 20 breaths/min in adults and to 25 breaths/min in children.
These increased ventilations result in a lower partial pressure of CO2 (pCO2). This lower CO2 level causes a slight cerebral vasoconstriction, thus lowering intracranial pressure. However, as one might suspect, if the patient is overventilated, the pCO2 can become so low that intense cerebral vasoconstriction ensues, worsening brain ischemia.
When caring for a trauma patient in shock, or any hypovolemic patient for that matter, the same principles of good assisted ventilation apply. As with TBI patients, aggressive assisted ventilations can lead to increased intrathoracic pressure, which impairs venous return to the heart and worsens an already compromised blood pressure and cardiac output.
Therefore, a provider can actually harm a patient in shock if care isn’t taken to deliver slow, controlled ventilations with adequate chest rise.
5. Master the use of your equipment. The use of your equipment should be driven by and supportive of the principles of airway management. In essence, your equipment should keep a patient’s airway open and clear to support oxygenation and ventilation. To ensure this, BVMs, oral and nasal airways, suction devices and various other adjuncts, all appropriately sized and in proper working order, will be needed. Please refer to “Airway Equipment Perals of Wisdom” below for a few tips and tricks regarding your equipment.
EMS is continually evolving as age-old techniques and equipment are refined and updated through research and solid outcome data. This constant transformation is important, as is your willingness to change and adapt to recommendations for improved airway management.
The next time the tones sound, respond with the confidence of a master airway manager. Your understanding and application of airway management principles, in addition to sharp airway skills, will make you the best advocate for your patient and will help you save many lives. Never let your basic skills deteriorate.
Be proud of what you do and take pride in your ability and commitment to make a difference—one airway at a time.
1. 2005 American Heart Association. Guidelines for cardiopulmonary resuscitation and emergency cardiovascular care part 4: Adult basic life support. Circulation. 2005;112:IV19–IV34.
2. Aufderheide TP, Lurie KG. Death by hyperventilation: A common and life-threatening problem during cardiopulmonary resuscitation. Crit Care Med. 2004;32:S345–S351.
Airway Equipment Pearls of Wisdom
- Don’t keep your BVMs jammed together in a precarious location. Keep them readily available. EMS providers are notorious for storing 10 lbs. of equipment in a five-pound bag. Murphy’s Law of EMS Equipment states, “lifesaving equipment will not fail until it is needed to save a life.”1 To that end, take care of your equipment and your equipment will take care of you.
- Measure an oral airway from the corner of the mouth to the corner of the earlobe. Oral airways that are either too big or too small can cause or become airway obstructons.2
- Use the correct size mask and apply it appropriately. Correctly sized masks help to ensure an adequate seal. Be careful not to cover patients’ eyes with the mask, due to the risk of corneal abrasion or a vagal response (bradycardia) that can be caused by the pressure you exert on the eyes while trying to maintain a seal.3 Additionally, when pulling the patient’s jaw up into the mask with your middle, ring and pinky fingers, use care to ensure your fingers stay on the bony prominence of the mandible and not primarily on the soft tissues of the neck.
- Remember that suctioning removes fluids and particles, as well as oxygen. Try to suction adults for no more than 15 seconds, children for no more than 10 seconds and infants for no more than five seconds before providing two minutes of ventilations.2
- While suctioning, use an appropriate tip. We’ve all heard the saying, “don’t bring a knife to a gun fight.” The same rule applies here. Don’t expect a 6F soft-tip suction catheter to clear an airway occupied by thick soupy remnants of a partially digested meal.
- Let gravity help you remove copious fluids. Logroll your patient and suction.
- Turn your suction on every day and briefly clamp the tubing to check its true “power.” Also, ensure that you have adequate tubing length to reach your patient. Don’t forget to check the portable suction. The “it’s there” check doesn’t suffice.
- Don’t be afraid of new equipment. Continuous positive airway pressure devices, impedance threshold devices, and such supraglotic airway devices as the Easy Tube, laryngeal mask airway and King Airway, are becoming a standard for providers across the country. In some regions, the use of these devices by BLS providers is still controversial; however, thorough training, competency checks and sound medical oversight can allow for these devices to be safely and effectively used by all levels of providers.
1. Murphy’s EMT laws. (n.d.) Murphy’s Laws Site. Retrieved September 12, 2017, from www.murphys-laws.com/murphy/murphy-EMT.htm
2. American Academy of Orthopaedic Surgeons. Emergency Care and Transport of the Sick and Injured, Ninth Edition. Jones & Bartlett Publishers: Sudberry, Mass., 2005.
3. King C, Henretig F, King B, et al. Textbook of Pediatric Emergency Procedure, Second Edition. Lippincott, Williams & Wilkins: Philadelphia, 2008.
This article originally appeared in October 2010 JEMS as “Airway Basics: Five tips for better respiratory management.”