By definition, an algorithm provides a step-by-step approach to solving a problem. Many tasks in EMS are managed using an algorithmic approach, and many local protocols are formatted in an algorithmic, “if you find this, then you do that” fashion.
Airway management is a task well suited to an algorithmic approach, as there are many options, maneuvers, and tools available for use by prehospital providers. The following factors, from simplest to most complex, may be helpful to consider when developing an algorithm for airway management.
First things first
The starting point for any airway management algorithm is an accurate assessment of the patient’s airway status and the identification of any potential airway complications. Identifying current and potential causes of airway compromise allows the provider to select the appropriate positioning, devices, and approach to managing the airway.
The assessment of the airway in a responsive patient can be as simple as listening to the patient speak. A patient who speaks with ease, in a normal sounding voice has an adequate airway. A patient who is conscious, but unable to speak may be choking and require immediate intervention to clear the airway of a foreign body.
For a patient who is conscious, but has a decreased mental status or respiratory difficulty, listen for abnormal sounds as the patient breathes. Stridor, gurgling, and a hoarse voice all indicate potential airway compromise. Unresponsive patients can be evaluated in a similar manner, by listening for any abnormal airway sounds as the patient breathes.
Factors to consider in airway management decisions
Another component of the initial airway assessment is the identification of potential airway management challenges. A quick assessment of the patient’s age, body size, and any special circumstances can allow for quicker management of life threatening airway issues.
For example, patients who are obese are significantly more difficult to ventilate, and may require different positioning and equipment than a normal-sized adult.[1] Pediatric patients require special positioning as well to ensure alignment of airway structures.
Special circumstances such as the presence of dentures, facial and oral trauma, stoma, or potential cervical spine injuries will also influence airway management techniques. Identifying factors that may complicate airway management allows the provider to be adequately prepared to effectively manage the airway.
Getting ready
The final component of the primary assessment is gathering and preparing appropriate equipment for airway management. Often this can be as simple as ensuring the airway bag is nearby. Oxygen delivery equipment, suction, simple adjuncts, and advanced airway equipment should all be quickly gathered and placed close to the patient. This task can often be delegated to another provider, allowing the EMT or paramedic to continue down the airway algorithm.
Identifying and correcting hypoxia
Occurring concurrently with the assessment of airway status is the evaluation of the need for supplemental oxygenation. Hypoxia must be identified quickly and steps taken to adequately oxygenate the patient.
The assessment of hypoxia and administration of oxygen can occur in a fluid and often-simultaneous fashion. For instance, during the initial assessment of the airway the provider may identify the need for supplemental oxygen and delegate the task of administering oxygen to another provider. If the patient is in respiratory failure and requires ventilation with a bag-mask device, or has other signs of airway compromise, the provider can quickly continue the algorithm as another responder is managing oxygen administration.
Positioning and manual maneuvers
Patient positioning is the most basic but perhaps the most important aspect of effective airway management. A properly positioned airway allows for maximum airflow into the lungs, while a poorly positioned airway can inhibit or completely obstruct air movement.
Many conscious patients will automatically assume the most efficient airway positioning on their own. For these patients, providing padding and support to maintain their position of best breathing can ease their work of breathing and keep an adequate airway for as long as possible.
Unresponsive patients require a more thoughtful approach when it comes to positioning. Often BLS providers are taught two options for a manual maneuver to open the airway; the head-tilt chin-lift and the jaw-thrust. Although these maneuvers are considered effective, providers should consider adding other maneuvers to their airway algorithm.
Since the 1940’s, the sniffing position has been considered the ideal position for advanced airway management in the unresponsive patient. [2] Studies have shown that the sniffing position also improves the ease of bag mask ventilations, especially when combined with a jaw thrust maneuver. By bringing the chin forward and tilting the head slightly back, the oral, pharyngeal, and laryngeal axes align to maximize airflow through the upper airway. The jaw thrust maneuver then lifts the tissue of the tongue and soft palate up and away from the back of the throat, providing an unobstructed path through the glottis and into the trachea.
Managing an airway in an obese patient
While the sniffing position aligns the airway structures in a patient of average size, its effectiveness for heavier patients is limited, especially ones who are supine.[3] Patients who are obese may have an excess of soft tissue in the airway and anatomical airway obstruction becomes more likely.
The ramp position may be more successful when positioning the airway of heavier patients in the supine position.[4] Placing padding under the shoulders and head of an obese patient can achieve the same airway alignment as the sniffing position does for a person of average size. The ideal position when using the ramp technique brings the outside of the ear canal forward to the level of the sternal notch. The amount of padding needed and exact angle of the ramp will vary depending on the size of the patient.
For all patients, taking a moment to consider patient positioning and manual maneuvers before beginning more active airway management can help ensure the best possible conditions to maintain the patency of every airway.
Fluid, blood, and mucous
The next step in airway management is identifying the need for suctioning by listening for gurgling sounds during breathing. Fluid, emesis, blood, and mucous are all possible causes of gurgling and should be suctioned from the airway when found. Oral suctioning can be accomplished using a Yankauer rigid catheter. Suctioning the nasopahrynx is accomplished in a similar fashion but is done using a French soft-tip catheter.
Any special circumstances identified in the initial airway assessment should be considered prior to selecting the appropriate suctioning device and technique. Facial trauma, septal defects, and the patient’s age may all influence suctioning decision-making. Significant facial trauma may cause bleeding into the airway, requiring repeated suctioning until an advanced airway is in place. The presence of a perforated or deviated septum may influence the decision to suction the nasal passages. Pediatric patients, especially infants, are at risk for vagal stimulation during oral suctioning, so episodes of suctioning should be performed as quickly and gently as possible.[5]
Fluid, blood, or mucus in the airway may prompt the paramedic to consider placing an advanced airway. BLS providers may wish to request an ALS resource when suctioning is required, as bag mask ventilations are difficult when fluid is present in the airway and the risk of aspiration is significant.[6]
BLS airway adjuncts
Once the patient is positioned appropriately and a patent airway has been achieved, a BLS airway adjunct can be inserted. Oropharyngeal airways (OPA) and nasopharyngeal airways (NPA) help maintain a passage for airflow through an airway opened by manual airway maneuvers. Insertion of an OPA or NPA is especially effective in keeping the tongue and soft tissues from completely obstructing the airway.
OPAs and NPAs are particularly well suited to certain airway scenarios. OPAs work well for patients who are unresponsive with no gag reflex, particularly those who require positive pressure ventilation. When used in combination with positioning and manual maneuvers OPAs increase the ease of bag mask ventilation in unresponsive patients.
An NPA performs a similar function as the oropharyngeal airway, but is designed for use in patients with an intact gag reflex. When inserted into the nare, an NPA creates a small passage for air to move past the tongue and any soft tissue that may be occluding the airway. NPAs must be measured prior to insertion to avoid stimulating a gag reflex or causing trauma to the nasal passages.
NPAs can be used in either nare, or both simultaneously. NPAs may also be an advisable choice in situations where the patient’s mental status is likely to improve quickly, as with diabetic emergencies and narcotic overdoses who receive dextrose or naloxone, respectively.
Considering an advanced airway
The placement of an advanced airway can occur after a BLS airway is established. Supraglottic devices do not require direct laryngoscopy. Endotracheal intubation continues to be the standard when a long-term airway is needed.
Other procedures such as nasal intubation and rapid sequence induction (RSI) also have their place in advanced airway management. Regardless of the advanced airway under consideration, establishing a viable BLS airway using an algorithmic approach ensures the best possible outcome for every patient.
Transport decision
Making an appropriate transport decision is critical when treating a patient with airway compromise. If initial attempts at establishing an airway have failed, the provider must immediately seek advanced resources. Emergent transport of a patient is necessary if an airway cannot be acquired or maintained and a more advanced provider is not immediately available to assist. If an adequate airway has been achieved, either through BLS or ALS procedures, it may be appropriate to transport the patient at a lower priority, assuming that the patient’s vital signs remain within acceptable limits.
Continued reassessment and evaluation
The final step in an airway management algorithm is continued reassessment and evaluation. Recognizing changes in airway status allows the provider to adapt and respond quickly and effectively to new airway challenges. This reassessment may be as simple as using continuous waveform capnography to monitor the placement of an endotracheal tube, or as complex as continually adjusting a mask seal, suctioning the airway, and adjusting patient positioning.
Managing an airway can be a complex and challenging process. Developing an algorithmic approach to airway management allows providers to move smoothly through the decision making process with each and every patient.
References
1. Kristensen, Michael S. “Airway management and morbid obesity.” European Journal of Anaesthesiology (EJA) 27.11 (2010): 923-927.
2. Cattano, Davide. “Airway Management and Patient Positioning: A Clinical Perspective.” Anesthesiology News (2011): 17-23. Anesthesiology News. Web. 10 July 2015.
3. Adnet F, Borron SW, Lapostolle F, Lapandry C. “The three axis alignment theory and the “sniffing position”: perpetuation of an anatomic myth?” Anesthesiology. 1999;91(6):1964-1965
4. Cattano D, Melnikov V, Khalil Y, Sridhar S, Hagberg CA. An evaluation of the Rapid Airway Management Positioner in obese patients undergoing gastric bypass or laparoscopic gastric banding surgery. Obes Surg. 2010;Oct20(10):1436-1441.
5. Walsh, Brian K., Kristen Hood, and Greg Merritt. “Pediatric airway maintenance and clearance in the acute care setting: how to stay out of trouble.” Respiratory care 56.9 (2011): 1424-1444.
6. Nagao, Tomoyuki, et al. “Effects of bag-mask versus advanced airway ventilation for patients undergoing prolonged cardiopulmonary resuscitation in pre-hospital setting.” The Journal of emergency medicine 42.2 (2012): 162-170.
