Checklists and acronyms are used to support quality care and as an aide to providers who do not perform these procedures in their daily practice.  In preparation for an advanced procedure (including securing an airway) using an acronym or other checklist can prove invaluable.  One such acronym is presented: the SOAP ME acronym (Suction, Oxygen, Airway, Pharmacy, Monitors/Machine, ETCO₂ and other Equipment) which has been adopted to “clean up” and organize the preparation for airway management.

The patient’s condition dictates the available time for a provider to consider all items on this checklist. 

A rapidly deteriorating patient with airway compromise may need the airway procedure first and follow-on considerations later.  If a patient can be more appropriately classified as semi-urgent (e.g., gradually worsening respiratory status) the provider will have more time to consider the algorithm and prepare.  Recommendations follow the “minimum, better, best” format.

SUCTION

• Minimum: Improvised suction (i.e., syringe + nasopharyngeal airway [NPA]) and patient positioning if not contraindicated
• Better: Manual suction bulb with adapter
• Best: Powered commercial suction with oral tip and in-line endotracheal tube suction adapter

Suction should be available when establishing and maintaining an airway to remove excessive secretions or blood.  It is particularly important to utilize suction to facilitate view of the vocal cords during endotracheal intubation.  In addition, suction should be available for routine and emergency follow-up care for any intubated patient.  Suction may need to be utilized as needed to remove secretions, mucous or blood from the airway.  In the event of high airway pressures, suction may be used to remove mucus/mucus plugs or to clear obstructions.  In the case of thick secretions, a saline flush of 1-2 mL followed by in-line suctioning of the endotracheal tube may be useful.

NOTE: During in-line suctioning of tubes, the suction should only be applied when withdrawing the catheter and not upon initial insertion.

OXYGEN

• Minimum: Standard nasal canula at 15L/min. Head of the bed elevated if not contraindicated.  
• Better: Standard reservoir face mask with flow rate as high as possible.
• Best: If adequate respirations, standard reservoir face mask set with flow rate as high as possible augmented with nasal cannula at 15L/min oxygen in preparation for apneic oxygenation, leave in situ throughout procedure. If inadequate respirations Bag-Valve-Mask (BVM) with positive end-expiratory pressure (PEEP) valve and flow rate as high as possible.

Preoxygenation prolongs tolerance of the apneic period.  The goal is 3 minutes of tidal volume breathing at 90% Fraction of Inspired Oxygen (FiO2).  For those with inadequate respirations BVM ventilation may be necessary.  Though it appears to be relatively simple, the procedure requires preparation, training and skill to perform correctly.  Care should be taken to ensure proper volume and rate of bag-delivered breath.  One hand should provide moderate pressure to the bag for no more than 50% of the volume of an adult bag or just enough to see the chest begin to rise at a rate of 12-16 breaths per minute (one breath every 4-5 seconds) initially. The resuscitation bag should be no larger than 1000ml (For reference, the pocket BVM is 1600ml, 50% is 800 ml TV). It is important to avoid hyperventilation through large or rapid breaths. If able, use a two-handed technique to ensure a proper mask seal, with assistant squeezing the bag along with use of oropharyngeal or nasopharyngeal airway. See Appendix C: Bag-Valve-Mask Technique for a detailed description.

AIRWAY

Airway  management

Airway management should follow a stepwise assessment, followed by: 

• Basic interventions are recommended if it addresses the airway obstruction/respiratory insufficiency: Nasopharyngeal airway, oropharyngeal airway, BVM with PEEP valve (if available), patient positioning if not contraindicated.
• If the patient continues to decompensate, perform intermediate interventions: Supraglottic airway.
• If the patient requires emergent surgical intervention due to severe obstruction/respiratory insufficiency despite interventions above, obtain an advanced airway: oral endotracheal tube or via a surgical airway.

Positioning of the patient to help clear airway obstruction should be considered first, when possible.  The simple option of placing the patient in a sitting position, placing the patient in the lateral “recovery” position, or head tilt-chin lift/jaw thrust maneuver may be enough to ensure adequate respirations.  While beneficial, a jaw thrust or chin lift maneuver is difficult to maintain as it dedicates one individual solely to opening the airway. Likely more practical is placing a patient with their chin away from chest (whether its supine or recovery), when possible and not contraindicated. Simple adjuncts such as a nasal or oropharyngeal airway (NPA/OPA) may be utilized in addition to proper positioning to help ensure a clear airway.⁴  Of note, there are multiple sizing challenges with an NPA that can actually cause further obstruction if not measured precisely, therefore, remain vigilant. Oropharyngeal airway insertion can present a considerable noxious stimulus and may not be tolerated by conscious or even some semiconscious patients.  BVM ventilation is the next step. 

For those patients requiring prolonged active respiratory support or airway protection, a definitive airway is preferred.  A definitive airway requires control of the patient’s airway with an inflated cuff in the trachea. Definitive airway placement requires considerable skill and sustainment training. If not current and practiced, or if encountering difficulty securing a definitive airway consider other airway adjuncts such as supraglottic airways.

Furthermore, intubation and providing mechanical ventilation are not without risk.  The benefits should outweigh the attributable cost and risk of managing the mechanically ventilated patient, especially within the austere/battlefield setting.  Pathology associated with failure to oxygenate and failure to ventilate will most often require definitive airway interventions and appropriate mechanical ventilator support.  At times, it may only serve as a temporizing measure while seeking definitive critical care.  Initiation of mechanical ventilation must be guided by clinical suspicion of underlying pathophysiology and clear criteria.  A definitive airway is required for effective mechanical ventilation and these patients require sedation – both mechanical ventilation and sedation may make a hypotensive patient more hypotensive and could result in hemodynamic instability.  Thoughtful consideration for whether the patient requires mechanical ventilation must occur.  In patients with hemorrhagic shock requiring intubation and mechanical ventilation, remember the general principle of “resuscitation before intubation.” Utilize airway adjuncts if the patient’s airway can be maintained adequately during initial resuscitation efforts with blood products. In an under-resuscitated patient, cardiac arrest can occur when induction and paralytic medications are given during rapid sequence intubation.

Airway management in the tactical setting requires a different conceptual approach than airway management in the hospital, or even the civilian prehospital environment.  Differences in epidemiology, injury patterns, equipment and environment must be considered if airway management is to be optimized.  First, most military casualties requiring a prehospital airway have trauma to the head, face or neck.  Surgical airway is often the final common pathway due to bleeding or distorted anatomy. When reliable suction and oxygen delivery are not available, personnel are not experienced in rapid sequence intubation or using neuromuscular blockade, a definitive airway will often mean a surgical airway. (see Appendix E: cricothyroidotomy procedure checklist for a detailed description).

PHARMACY

A definitive airway is required for effective mechanical ventilation and these patients require sedation – both mechanical ventilation and sedation may make a hypotensive patient more hypotensive and could result in hemodynamic instability.  In an under-resuscitated patient, cardiac arrest can occur when induction and paralytic medications are given during rapid sequence intubation.

Be cautious with sedation, advanced airway placement and positive pressure ventilation in patients who are hypotensive or under-resuscitated.  Blood pressure can fall rapidly during airway management due to a variety of mechanisms.

Active resuscitation with blood products especially in the hypotensive patient is recommended.  Be prepared to support blood pressure with additional fluids and vasopressors (e.g., norepinephrine/epinephrine bolus or drip) if trained or under direct telemedicine guidance.

In all cases, monitor blood pressure (BP) closely (every 1-2 minutes during the procedure, every 3 minutes post-procedure).  A BP drop may be brief (if due to vagal effects of epiglottis stimulation during ETT placement) or sustained (if due to loss of sympathetic drive secondary to pain and sedation medications, and/or positive pressure ventilation).

IV/IO  Access

• Minimum: If (IV) / intraosseous (IO) attempts fail or when unavailable: medication may be given intramuscularly or intranasally for immediate sedation to facilitate surgical cricothyroidotomy. Continue attempts at IV/IO access after airway has been controlled
• Better: 2 patent IV/IO
• Best: 2 patent IV/IO and if appropriately trained large bore central venous access

Flow is directly proportional to the fourth power of the catheter radius and inversely proportion to the length of a catheter (R4 /Length).  Prior to administering medications and providing positive pressure ventilation two 16 gauge or larger angiocatheters should be placed. If continued massive transfusion is required, consideration should be given to placement of a 9 French central venous line so that rapid transfusion can be maintained.  Ultrasound may be used to help identify deep veins. 

Airway  Placement

• Minimum: Local anesthetic for cricothyroidotomy (superficial skin anesthesia plus 1-2 mL injected through the cricothyroid membrane); or placement without medications in unconscious patient. **Note: most sedating agents can be given an intramuscular (IM) if IV/IO has not been established
• Better: Any IV/IO sedating agent (opioid, benzodiazepine: reference the JTS Analgesia and Sedation Management During Prolonged Field Care CPG. for procedural doses of such agents).⁸
• Best: Procedural dose ketamine (1-2 mg/kg IV push) for ETT or cricothyroidotomy placement + local anesthetic (lidocaine) for cricothyroidotomy placement.

Post-Airway  Placement 

• Minimum (without IV access): Ketamine (sedation dose), 3-4mg/kg IM
• Better: IV/IO pushes of ketamine, opioid, and/or midazolam (alone or in combination as per the individual’s scope of practice, experience, and availability of medications)
• Best: Ketamine IV/IO Drip. Hydromorphone or alternate opioid IV/IO push for breakthrough pain and midazolam IV/IO push as needed for sedation

(Reference JTS Analgesia and Sedation Management During Prolonged Field Care CPG for details and drug doses).⁸

Neuromuscular blockade (succinylcholine, rocuronium, vecuronium, etc.) is only recommended for use by those trained and practiced in its use.  Though these are standard medications to use in rapid sequence intubation and ventilator management, their potential lethality in inexperienced hands does not justify routine use.  If trained and/or under direct supervision of telemedicine support, the use of neuromuscular blockade may be considered, subject to local medical direction and protocols.

MONITORS/MACHINE

Monitor

• Minimum: Pulse oximeter (SpO2), portable Capnometry (ETCO₂)/capnography assistant to monitor respirations and record manual vital signs. Trending vital signs using a flow sheet is recommended. Refer to the JTS Documentation in Prolonged Field Care CPG.⁹  Voice or data connections to perform telemedicine communication
• Better: Transmit photographs from smartphones or personal devices to augment telemedicine communications.
• Best: Automatic vital signs monitor with SpO2, ETCO₂/waveform capnography, +/- electrocardiogram (EKG); Synchronous (real-time continuous) telemedicine using video or remote patient monitoring systems

Monitoring is the active process of assessing the patient throughout a procedure.  It involves the gathering, documenting and interpretation of vital signs and other data, and the continuous assessment of their clinical status.  Telemedicine can be an important adjunct and critical capability to employ when monitoring a patient undergoing complex procedures.

Machine

• Minimum: Bag-Valve-Mask (BVM) with positive end-expiratory pressure (PEEP) valve
• Better: Automated portable ventilator (preferably with PEEP); oxygen concentrator
• Best: Full-feature portable ventilator (e.g., several ventilatory modes, PEEP); supplemental oxygen if available

Managing ventilators or advanced equipment unfamiliar to a provider presents challenges.  Initiate telemedicine consultation for best guidance at 833-ADVSRLN (833-238-7756)/DSN: 312-429-9089..

PEEP is important for prolonged ventilation. PEEP is the pressure in the airway at the end of the expiration which prevents the alveoli of the lung from completely collapsing.  In a spontaneously breathing person, this pressure is maintained by closing the glottis, clearing the throat, coughing, sighing, etc. With an invasive airway, the glottis is bypassed with the tube and “natural” PEEP is lost. PEEP should therefore be introduced into the ventilated patient using a PEEP valve on the BVM or using the PEEP setting on a ventilator. When using BVM or ventilator, provide PEEP. (Recommended initial setting is 5cm H2O.)¹⁰

ETCO2  &  Other  Equipment

Airway  Confirmation  Equipment  (ETCO₂)

• Minimum: Visualization of the tube through the cords and auscultation of breath bilateral sounds
• Better: Colorimetric capnography
• Best: Continuous end-tidal carbon dioxide (ETCO₂)

Regardless of how an endotracheal tube is placed, a verification of correct tube placement must be performed every time as incorrect tube placement may be fatal.  The right mainstem and hypopharynx are the most common locations of incorrect placement of ETT.  Visualization of the tube passing through the vocal cords (in the case of endotracheal intubation) should be assured.  Esophageal intubation is also common.  Auscultate, if possible, to verify bilateral breath sounds and absence of gurgling in the epigastric region.  When performing a cricothyroidotomy subcutaneous placement of the tube may occur.  For both oral and surgical airways colorimetric capnography and endotracheal detection devices should be considered to verify correct tube placement as tube misplacement can be fatal. Continuous ETCO₂/wave capnography is the gold standard for initial detection of and monitoring for appropriate tube placement. (See Appendix G: Waveform Capnography & Pulse Oximetry Interpretation for a detailed description)

Other  Equipment

Supraglottic airways are most commonly placed blindly.  They are also not considered definitive airways in that they do not provide an inflated cuff in the trachea.  Without an inflated cuff in the trachea, the airway is not protected against aspiration.  Nonetheless, supraglottic airways can provide a conduit for oxygenation and ventilation.  If definitive airway is required, an endotracheal tube may be placed through the supraglottic airway or a bougie may be threaded to allow for endotracheal exchange. (See Appendix D: Supraglottic Airway Placement for a detailed description.)

Repeated attempts at endotracheal intubation are associated with worse outcomes. Visualization of the vocal cords is vital for endotracheal intubation.  Direct laryngoscopy traditionally has been used for endotracheal intubation.  Although there are shortcomings described regarding the use of video laryngoscopy, including fogging especially in airways with heavy secretions, video laryngoscopy is associated with a higher first attempt intubation rate and should be considered the best option especially in those with limited experience.  Nonetheless, given its limitations, airway providers must maintain competency with both techniques. 

An important adjunct to passing an endotracheal tube whether trans orally or through a cricothyroidotomy, is the use of a bougie (sometimes also referred to as an Eschmann Stylet).  This device is simple, rugged and can be used to guide tube placement.  The bougie is placed in the trachea before the endotracheal tube and may be used first to confirm proper positioning. The bougie will provide tactile feedback against the tracheal rings confirming proper placement, or by encountering a hard stop when abutted against a distal bronchus.  An endotracheal tube is then introduced over the bougie into the trachea, while the laryngoscope is maintained in place to lift the laryngeal structures.  Lastly, the bougie is removed.  A bougie may also be used to change tubes in the case of a tube malfunction.  This may be accomplished by placing a bougie in a tube or SGA that is currently positioned, remove the tube over the bougie (ensuring the bougie remains in the proper position within the airway lumen), and replacing a new tube over that bougie.  Remove the bougie, leaving the new tube in place.

Placement of a nasogastric or orogastric tube should be considered following intubation of a patient in order to reduce the risk of pulmonary aspiration and prevent gastric distention.  If only supraglottic airway access is available, consider using a supraglottic device that incorporates an orogastric tube port.  Always measure the distance from nose to stomach and note the distance prior to insertion, then verify epigastric sounds.  Always reassess tube position prior to putting anything into stomach to ensure proper gastric placement.