Algorithm
The "Non-Intubating Airway Management Algorithm" (Figure 21-3) is entered at the top with the assumption that an assessment is complete and the patient is in need of further airway or respiratory support and management. The next three interventions should all be automatic. The first and most important intervention is to minimize or prevent hypoxia. Hypoxic brain death occurs within 6 to 10 minutes of apnea or significant hypoxia.
Therefore, immediate application of high-flow oxygen is mandatory to provide as much of a time margin as is possible. Ideally, since the patient is at least in ventilatory failure and at worst is apneic, the oxygen will be applied through a bag-valve-mask (BVM) device or, if the patient is apneic, with an automatic transport ventilator (ATV). This may be delegated to another provider so the Paramedic can continue down the algorithm.
The second automatic task is to assemble airway management equipment. The equipment will depend on what skills the Paramedic is able to perform, but should ideally be available in a single bag or box and be organized, complete, and up-to-date.
Figure 21-3 Non-intubating airway management algorithm.
Once these tasks have been accomplished, the next step is to begin supporting the patient. Opening the airway and providing ventilation is the first step in supporting the patient. If the patient is spontaneously but ineffectively breathing, then supported ventilations with a BVM is the most appropriate intervention.
If the patient is apneic, then either a BVM or an automatic transport ventilator attached to a mask can be used. If the Paramedic is successful at opening the airway and providing ventilation, then a rapid assessment of the intervention’s adequacy is performed (auscultation, observation). Either an oropharyngeal or a nasopharyngeal airway is inserted depending on the absence or presence of a gag reflex, respectively. Finally, the patient is transported.
Note that in both the intubating and non-intubating algorithms, there are distinctions made between transport and transport emergently. These differences are based on a specific list of conditions (Table 21-2), which require emergent transport (the assumption being that for all other conditions, the risks of emergent transport may outweigh any benefits).
If a patient’s vital signs are otherwise stable and the airway and ventilation adequately managed, the risk-to-benefit ratio for emergent transport may be too high. In that case, the Paramedic should consider non-emergency transport. If the patient’s airway cannot be managed, however, then the patient should be transported emergently. This approach is taken by the "intubating" and "non-intubating" algorithms. In reality, the decision will be made based on local protocols, local standard of care, and medical direction.
Table 21-2 Conditions Requiring Emergency Transportation
|
• |
Abnormal vital signs that cannot be corrected/do not respond to |
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treatment |
|
|
• |
Unmanageable airway |
|
• |
Ischemic compromise of an extremity |
|
• |
Complicated delivery |
|
• |
Uncontrollable bleeding |
|
• |
Cardiac arrest reversal with abnormal vital signs |
|
• |
Cardiac arrest without defibrillation/medications available |
There will be times when a patient’s airway cannot be established or the patient cannot be ventilated on the first attempt. If this is the case, the Paramedic must quickly troubleshoot. Immediate actions should include repositioning the patient’s head and, if needed, suctioning the airway and performing obstructed airway skills.
Once these interventions are performed, the Paramedic should make a second attempt to open the airway and ventilate the patient. If the second attempt is successful, then, as before, the Paramedic should assess the adequacy of ventilation, insert an oropharyngeal (OP) or nasopharyngeal (NP) airway, and transport the patient.
If, after the second attempt, the Paramedic is unable to establish a patent airway or ventilate the patient, an obstruction should be assumed. The appropriate obstructed airway management skills (Heimlich maneuver, unconscious patient abdominal thrusts, chest thrusts, or back blows) should be performed and another attempt should be made to ventilate the patient. If this attempt is successful, then the Paramedic should assess the adequacy of ventilation, place an OP or NP airway, and transport the patient. If, however, the third attempt at ventilation fails, then a change in tactics must be made. An analysis of the actions performed gives insight into why, after three ventilation attempts, the Paramedic should change tactics.
When the first attempt is made to ventilate the patient, it is assumed that the patient has normal anatomy and that "normal" (not including foreign body obstruction) causes of respiratory and airway failure have occurred. In most of these patients, a head-tilt, chin-lift or jaw thrust, in combination with BVM or ATV ventilation, will be adequate to open the airway and provide ventilation.
If these interventions fail, the next intervention is to rapidly troubleshoot and correct easily identifiable problems, including inadequate performance of skills, on the first ventilation attempt. Therefore, when the second attempt is made at ventilation, the Paramedic will still assume the patient has normal anatomy and "normal" causes of the airway and respiratory failure. In most of the remaining patients, these few corrections will open the airway and allow adequate assisted ventilation.
If the second attempt at ventilation fails, however, the Paramedic must consider abnormal conditions. Therefore, between the second and third ventilation attempts, the Paramedic performs all of his skills to correct or compensate for anatomical issues, airway obstruction, and physiological defects. The Paramedic corrects all the variables for which he is able to compensate. The third attempt at ventilation, therefore, is an optimized attempt.12 If this attempt fails, there is little else the Paramedic can do. Therefore, after the third attempt, a different tactic must be taken.
The failure of the third ventilation attempt signifies that the Paramedic has no additional changes in care to offer. Therefore, the patient must be transported immediately to another provider capable of offering additional, advanced care. These are critically unstable patients and should be transported emergently. During that transport, the Paramedic should continue to perform obstructed airway skills and attempt to ventilate. If it will shorten the time to access advanced care, ALS providers should intercept the transport.
CULTURAL/REGIONAL DIFFERENCES
In some regions, prehospital physician intercepts are possible and, if available, should be requested at this time as well. If these intercepts will increase the time to definitive care (e.g., physician, emergency department, or operating room), then they should not occur and the patient should be emergently and safely transported. The Paramedic should not wait on-scene for an EMS Physician to arrive.
Intubating Airway Management Algorithm
As with the Non-Intubating Airway Management Algorithm, a patient enters the Intubating Airway Management Algorithm by virtue of having met one of the five criteria for airway and respiratory management and by having a Paramedic capable of intubating and performing other advanced airway skills. The top of the algorithm (Figure 21-4) is the entrance point and assumes that the patient needs to be intubated. As will be recalled, other non-intubated ventilatory support modalities should have been tried by this point. The algorithm directs the Paramedic toward a goal: a secure airway with adequate ventilation.
The Paramedic places the patient on high-flow oxygen or ventilates the patient with a BVM. At this point, if possible, the most experienced Paramedic should be performing or directly supervising the patient’s care. While the Paramedic is doing this, the least experienced Paramedic on the scene, who is capable of preparing the intubation and airway management equipment, should be doing so. Having the most experienced providers directly managing the patient’s care will optimize that care.
While there is some debate as to the definition of an intubation attempt, the National Association of EMS Physicians (NAEMSP) developed a standardized reporting tool (Table 21-3). As each unsuccessful intubation attempt will cause edema, bleeding, and patient deterioration, it is important that the first intubation attempt be the best intubation attempt.13 Conditions must be optimized through proper, working equipment and, if used, drug selection. The patient must be correctly positioned, the Paramedic must be correctly positioned relative to the patient, and lighting should be controlled as much as possible. The proper route must be selected. In short, everything that can be controlled should be so as to make the first attempt most likely to succeed.
Once the equipment is prepared and conditions are optimized, the route must be selected. For a breathing patient, particularly one with a primary respiratory disease such as CHF or a COPD exacerbation, nasal intubation is an excellent choice.14-18 These patients are likely to become hypoxic rapidly if medications are used to sedate or paralyze them as they have no reserve capacity. If the patient is not breathing, however, or has evidence of a basilar skull fracture, then an attempt at oral intubation is the next step.
Figure 21-4 Intubating airway management algorithm.
Table 21-3 NAEMSP Definition of Intubation Attempt
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1. |
Insertion of laryngoscope blade into mouth (for orotracheal methods) |
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2. |
Insertion of tube through nares of nose (for nasotracheal methods) |
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3. |
Insertion of rescue airway device into mouth (for Combitube, LMA, and other oral rescue airway devices) |
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4. |
Insertion of rescue airway devices through the neck (for cricothyroidotomy, needle jet ventilation, retrograde ETI, and other "surgical" methods of airway management) |
H.E. Wang, R.M. Domeier, D.F. Kupas, M.J. Greenwood, R.E. O’Connor, "Recommended guidelines for uniform reporting of data from out-of-hospital airway management: position statement of the National Association of EMS Physicians," Prehospital Emergency Care 8, no.1 (2004): 58-72.
After the endotracheal tube is passed, tube position is confirmed by auscultation and another confirmation device.
First, auscultate over the epigastrium while the patient is ventilated. If the endotracheal tube is correctly placed in the trachea, there should be an absence of gastric sounds. Next, auscultate over both the left and right lung fields for presence of equal breath sounds. If the right lung sounds are louder than the left, the endotracheal tube is likely in the right mainstem bronchus. Check depth of endotracheal tube placement and withdraw the tube by 1 or 2 cm, reinflate the balloon, and reassess lung sounds. If the lung sounds remain unequal, then assess the patient for a pneumothorax, as discussed in later topics.
The two commonly accepted additional methods of confirming tube placement are esophageal detector devices and colorimic end-tidal carbon dioxide measurement.19-21 Each of these methods has benefits and drawbacks. Using two or three tend to cancel out the problems inherent in each method.
Once the endotracheal tube is confirmed to be in a tracheal position, it must be secured using either a commercial device or tape. Additionally, the use of a cervical immobilization collar and cervical immobilization device (head blocks) will minimize tube movement and the potential for displacement. The use of waveform capnography in the intubated patient can provide an additional layer of safety as endotracheal tube dislodgement can be identified and corrected almost immediately. The Paramedic must continue to monitor the patient for changes in respiratory status and transport the patient.
If the first intubation attempt fails, however, then the Paramedic must reconsider his actions and determine the best course to increase the chances of success on the second attempt. Sometimes it is possible to identify a single item that caused the intubation attempt to fail, such as laryngoscope light failure, insufficient suction, or the need for sedation and/or paralysis. Other times, the Paramedic simply recognizes that a different approach must be tried without being completely sure why the first approach failed. Therefore, if the first intubation attempt failed, the patient must be ventilated as needed and the Paramedic must attempt to optimize the subsequent intubation attempt. The changes made to optimize the second attempt should be based on the findings of the first attempt.
Once the Paramedic is ready to reattempt intubation, no more than two more attempts should be made to intubate the patient. If, after a total of three attempts, the patient is not intubated and no clearly correctable problem is identified, then a different approach to the specific patient is required. By the time the third attempt has been made, the Paramedic should have maximized conditions. In all likelihood, further attempts will result only in more bleeding and edema and a more difficult airway to manage. The greater the number of attempts at endotracheal intubation, the lower the chance of success.22
If the second or third intubation attempt is successful, then the tube should be confirmed with three methods, it should be secured, and the patient should be monitored and transported. If these two additional attempts are not successful, however, then the airway manager must move on with his management plan. The patient should be ventilated as needed.
The next class of devices that are likely to succeed in at least partially securing the airway are devices designed for blind insertion into the upper portion of the airway above the glottis. Several terms have been used to describe these devices, including supraglottic airway devices, non-visualized airway devices, and blind insertion airway devices (BIADs). For the remainder of this discussion, we will use the term BIADs when referring to these airways. The BIADs commonly used include the King LTS-D airway, laryngeal mask airway (LMA), and the esophageal tracheal Combitube. Each of these devices has its strengths and weaknesses. In general, the esophageal obturator airway (EOA) and esophageal gastric tube airway (EGTA) should rarely be considered as they have a history of high complication rates and both require maintenance of a mask seal during use. Although they are still the BIADs of choice for some agencies, standard of care is moving away from the EOA and EGTA and toward one of the other devices.
It is rare that a blind insertion airway device will not provide at least some ability to effectively ventilate a patient. Although the airway may not be secure in the sense of having a tube beyond the vocal cords with direct access to the trachea, it is more secure than with simple face-mask ventilation. There will be occasions when these devices will not provide adequate ventilation. For example, in a patient with an inhalation burn and vocal cord edema, none of these devices can guarantee that air will pass through the cords to adequately ventilate the patient. However, as noted before, failure to provide some improvement in ventilation is rare.
Once the BIAD is in place, it needs to be confirmed. In this case, auscultation and end-tidal carbon dioxide measurement can be utilized. Esophageal detection devices will not necessarily work with any of the BIADs. Therefore, monitoring the patient’s condition over time becomes the third method of confirming device placement. Once the placement has been confirmed, the BIAD must be secured in the manner recommended by the manufacturer and the patient should be monitored and transported. If the patient has no other concurrent issues and the BIAD is allowing for adequate oxygenation and ventilation, then a non-emergency mode transport may be appropriate.
If the BIAD will not pass (for anatomical reasons, injuries, etc.) or does not seem to be providing adequate ventilation, then the Paramedic must fall back on the fundamentals of airway management. The objective of airway management is to allow adequate oxygenation and ventilation.
Therefore, if all previous methods of securing the airway have failed, then face-mask ventilation with a BVM or ATV and an oropharyngeal or nasopharyngeal airway is appropriate. There will be patients whose airways cannot otherwise be managed due to injury or anatomy who will do well with face-mask ventilation. If the patient can be adequately ventilated by these interventions, then the patient should be monitored and transported. These patients with clearly difficult airways will usually qualify for emergent transport. If the patient improves and remains stable with face-mask ventilation alone, however, non-emergent transport can be considered.
If all other airway management modalities have failed and the patient still cannot be ventilated, then the Paramedic must assume that there is a pathological obstruction of the airway. This obstruction may be visualized during an intubation attempt or assumed from either the patient’s disease process or simply from the failure to ventilate. If basic and advanced obstructed airway skills do not clear the airway, then the Paramedic is left to attempt to establish a surgical airway. If the pathology is at the level of the thyroid cartilage or above, a surgical airway will allow ventilation and oxygenation. If the obstruction is at or below the level of the trachea, however, a surgical cricothyrotomy will most likely fail.
If the surgical airway succeeds, the patient should be monitored and transported emergently. If, however, the surgical airway fails, then the patient must be transported emergently while the Paramedic attempts to oxygenate and ventilate the patient. If available, the Paramedic may consider a physician intercept or an intercept with a more experienced Paramedic while en route to the hospital.
Conclusion
Airway management can be one of the most life-saving tasks a Paramedic can perform for a patient. As has been demonstrated in the cardiopulmonary resuscitation arena, algorithms can greatly enhance consistent and correct task performance during life-threatening emergencies.
The value of an algorithmic approach to airway management has been recognized by professional organizations. Although the use of algorithms can greatly facilitate airway management, it is important to recognize that the algorithm is written for the majority of situations and that algorithms are not "one size fits all." Therefore, the Paramedic must recognize that an algorithm is simply one more tool to improve the quality of patient care. While it does not replace clinical judgment in a specific situation, it allows a systematic approach that will enhance patient care.
key points:
• The algorithm is a form of preplanning in an emergency situation.
• Emergency airway algorithms all begin with a patient in need of airway and ventilation management.
• The Paramedic must determine what degree of airway management and respiratory support is needed for every patient.
• Active airway or respiratory management is required for each of the following:
■ Non-patent airway
■ Inability to maintain patient’s own airway
■ Failure to oxygenate
■ Failure to ventilate
■ Anticipated deterioration of the patient’s status or the airway status
• If, on primary assessment, a patient does not have a patent airway, the first intervention is the use of a head-tilt, chin-lift or jaw-thrust maneuver to open the airway. If the patient has a patent airway but is unable to maintain that airway, the Paramedic should determine the cause of the disability.
• Hypoglycemia or narcotic overdose should be considered when presented with patients who are typically thought of as "unresponsive" but not in cardiac or respiratory arrest.
• Despite having a patent airway, it is possible that the patient may still not be effectively oxygenating or ventilating.
• If the patient with a patent airway is maintaining that airway, is oxygenating and ventilating normally, and is not expected to deteriorate, then the Paramedic has completely assessed the patient’s airway and respiratory status. She should continue monitoring for effect.
• The "Non-Intubating Airway Management Algorithm" addresses the need for airway or respiratory support and management, which is the first and most important automatic intervention to minimize or prevent hypoxia.
• The second automatic task is to assemble airway management equipment appropriate to the Paramedic’s skill level.
• The Paramedic should support the patient with ineffective breathing or apnea by opening the airway and providing ventilation.
• The following conditions require emergent transport:
■ Abnormal vital signs that cannot be corrected/ do not respond to treatment
■ Unmanageable airway
■ Ischemic compromise of an extremity
■ Complicated delivery
■ Uncontrollable bleeding
■ Cardiac arrest reversal with abnormal vital signs
■ Cardiac arrest without defibrillation/medications available
If the patient’s airway cannot be managed, the patient should be transported emergently.
• The Paramedic should consider suctioning and repositioning the head as initial interventions for a patient who cannot be ventilated.
• If a second attempt is successful, the Paramedic should consider an OPA or NPA along with patient transport.
• If a second attempt is unsuccessful, an obstruction should be assumed. The Paramedic should perform the appropriate obstructed airway management skills (Heimlich maneuver, unconscious patient abdominal thrusts, chest thrusts, or back blows) and make another attempt to ventilate the patient.
• Continued failure to ventilate is an abnormal circumstance requiring all measures available to obtain a patent airway, including transporting the patient to a provider capable of offering an advanced level of airway care.
• Conditions prior to the first intubation attempt must be optimized by first selecting the proper provider, equipment, medications, and route. The Paramedic and patient must also be in proper positions with sufficient lighting.
• Nasal intubation is an excellent choice for the spontaneously breathing patient with a respiratory disease history.
• Oral intubation is a good choice for an apneic patient or one with a suspected basilar skull fracture.
• After the endotracheal tube is passed, tube position is confirmed by auscultating first over the epigastrium, then over the left and right lung fields for presence of equal breath sounds.
• The Paramedic confirms placement with at least one additional method. Waveform capnography is required in many EMS systems.
• The Paramedic should note the depth of the endotracheal tube placement and secure the endotracheal tube with tape or a commercial device.
• The Paramedic should use a cervical immobilization device to minimize tube movement and potential for displacement.
• The Paramedic should continue monitoring the patient for effect.
• If the first intubation attempt fails, the patient must be ventilated. No more than two more attempts should be made to intubate the patient.
• Blind insertion airway devices (BIADs) are likely to succeed in at least partially securing the airway and are designed for blind insertion into the upper portion of the airway above the glottis.
• Once the BIAD is in place, the Paramedic should confirm it by auscultation, end-tidal carbon dioxide measurement, or simply monitoring the patient’s condition over time.
• An obstruction may be visualized during an intubation attempt or assumed from either the patient’s disease process or the failure to ventilate.
• A surgical airway is often considered the last course of action that may allow ventilation and oxygenation.
