MACHINE, SUCTION, MONITOR, AIRWAY, INTRAVENOUS ACCESS, DRUGS

Checklists are commonly used in medical practice. In preparation for an advanced procedure (including securing an airway) using an acronym or other checklist approach will prove invaluable. One such acronym, originally developed as a simple pre-operative anesthesia checklist, is presented. The MSMAID acronym (Machine, Suction, Monitor, Airway, Intravenous access, Drugs) organizes an approach to preparation for airway management and may also prove useful in preparation for other procedures.

The patient’s condition dictates the available time for a provider to consider all items on this checklist. A rapidly deteriorating patient with airway disruption or compromise will need the airway procedure first and follow-on considerations later. If a patient can be more appropriately classified as semi-urgent (e.g., worsening respiratory status due to an underlying pulmonary cause) the provider will have more time to consider the algorithm and prepare. Logistic considerations, and sometimes considerable time constraints, will affect preparation for advanced procedures. Recommendations follow the “minimum, better, best” format.

Machine

(Equipment required post-intubation)

- 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.

PEEP is important for prolonged ventilation. PEEP is the pressure in the airway at the end of the expiratory phase 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).6

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 patient care and maintenance requirement for any intubated patients. Suction should be utilized as needed to remove secretions, mucous or blood from the airway device or oropharynx. 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.

Monitor

(Monitoring and telemedicine support)

- Minimum: Pulse oximeter (SpO2), assistant to monitor respirations and record manual vital signs. Trending vital signs documentation. PFC flow sheet is recommended. Refer to PFC Documentation CPG.7 Voice or data connections to perform telemedicine communication
- Better: Portable Capnometry (ETCO2)/capnography in addition to SpO2. 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.

Airway

- Minimum: Medic is prepared for a ketamine cricothyroidotomy.
- Better: Add ability to provide continuous sedation.
- Best: Add a responsible rapid-sequence intubation capability (to include chemical paralysis) with airway maintenance (to include suction) and continuous sedation.

Per the PFC Capabilities Position Paper, a definitive airway requires control of the patient’s airway with an inflated cuff in the trachea. In addition, sedation is needed to keep the patient comfortable and sustain the airway.8

A proposed algorithm was developed by Mabry RL et al for an awake surgical airway (Figure 1).9 This algorithm incorporates the skills recommended for Tactical Combat Casualty Care and presents the decision process deemed adequate (minimum standard) for definitive airway control in PFC. The airway algorithm is presented in its published form and surgical airway is synonymous with cricothyrotomy. As noted above, the indications for surgical airway include disrupted face or neck anatomy, as well as a need for prolonged positive pressure ventilation in a resource constrained PFC environment. Consider temporizing, if possible, with basic airway maneuvers or other airway adjuncts (e.g.; NPA, SGA). Please see Table 1.

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. Simple adjuncts such as a nasal or oropharyngeal airway (in an unconscious patient) may be utilized in addition to proper positioning to help ensure a clear airway.

For those patients requiring active airway assistance, the first step should be inserting an NPA to open the airway. BVM ventilation is the next step in the algorithm and though it appears to be relatively simple, the procedure requires preparation, training and skill to perform correctly. A spontaneously breathing patient may prove challenging, but properly delivered, synchronous breaths may be the only requirement to assist a patient’s respirations. 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. It is important to avoid hyperventilation through large or rapid breaths, particularly with traumatic brain injury (TBI) casualties, therefore ETCO2 monitoring is indicated for all patients requiring assisted ventilation and all patients with altered mental status (including both TBI casualties and sedated patients). BVM is an important airway management skill (see Appendix C: Bag-Valve-Mask Technique for a detailed description). It is highly recommended that all PFC training on airway skills cover BVM skills and techniques.

OP and SGA insertion can present a considerable noxious stimulus and may not be tolerated by conscious or even some semiconscious patients. Additionally, the dyssynchronous use of BVM ventilation may lead to poor patient cooperation, abnormal tidal volumes, gastric insufflation (and resultant regurgitation/aspiration), or other complications.

The decision to perform a cricothyroidotomy is one that is sometimes difficult. When possible, in urgent but not emergency situations, a telemedicine call should be considered to help with medical decision making.

An important adjunct to passing an endotracheal tube, either via the cricothyroid membrane or the oropharynx, is the use of a gum elastic bougie (sometimes also referred to as an Eschmann Stylet or, simply bougie). This device is simple, rugged and should 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 by either tactile discrimination (feeling the tube bump against the tracheal rings on introduction), or by encountering a hard stop when abutted against the carina. An endotracheal tube is then introduced over the bougie into the trachea. 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 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. Confirmation procedures discussed below must be repeated once the new tube is in place.

Consistent with TCCC guidelines, the routine use of orotracheal intubation is not recommended as the minimum standard in PFC. This procedure requires considerable skill and sustainment;10 and requires appropriate sedation for both rapid sequence intubation and post-intubation management. If a provider is appropriately trained, current and practiced in the procedure, and has the required support equipment and medications, then orotracheal intubation may be considered. Although preferred when possible, training in orotracheal intubation is not required to obtain a definitive airway in the PFC operational setting. Consider basic measures first before proceeding to either type of invasive airway. Additional details on orotracheal intubation are included in the JTS Airway CPG.

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. In comparison, most airways in the civilian prehospital environment are placed in elderly people for cardiac arrest. When reliable suction and oxygen delivery are not available, or personnel are not experienced in rapid sequence intubation using neuromuscular blockade, a definitive airway will often mean a surgical airway.

Proper Tube Placement

- Minimum: Visualization of the tube passing through the vocal cords (in the case of endotracheal intubation); auscultation of epigastric region (should be silent) and bilateral lung sounds (should be present). Colorimetric capnography + endotracheal detection device (EDD). Easy bilateral rise and fall of the chest + misting of the tube + no signs of gastric insufflation. (Reassess frequently and have another medic double check if unsure.)
- Better: Minimum plus portable capnometer. Ultrasound if trained/available to guide and/or verify placement
- Best: Continuous ETCO2/waveform capnography

Verification of correct tube placement must be performed every time as incorrect tube placement may be fatal. The REACH study5 showed that right mainstem and hypopharynx placement are the most common locations of incorrect placement of ETT. Esophageal intubation is also common. Subcutaneous placement of cricothyroidotomy tube may occur. Use capnography to verify correct tube placement as tube misplacement can be fatal. Auscultate, if possible, to verify bilateral breath sounds. If ultrasound is available, this can be used to further verify placement in the correct position.11

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: 1-2 patent IV/IO
- Best: 2-3x patent intravenous IV/IO with additional IO device on standby

Though an important consideration to administer medications and fluids, do not delay an emergent airway to obtain IV/IO access in the instance you are the sole provider.

Ultrasound may be used to help identify small or deep veins. Ultrasound guided IV access may be attempted if trained. Other sites to consider for superficial IV attempts include the external jugular and saphenous veins. If appropriately trained, consider central venous access or venous cutdown.

Drugs

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 IM if IV/IO has not been established
- Better: Any IV/ IO sedating agent (opioid, benzodiazepine: reference the Analgesia and Sedation Management for PFC CPG for procedural doses of such agents).12
- Best: Procedural dose ketamine (1-2 mg/kg IV push) for ETT or cricothyroidotomy placement + local anesthetic (lidocaine) for cricothyroidotomy placement

Prolonged Sedation

(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 Analgesia and Sedation Management in PFC CPG for details and drug doses).12

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.

In all cases, monitor BP closely (every 1-2 minutes during the procedure, every 3-5 minutes for 15 minutes post-procedure). A BP drop may be brief (if due to vagal effects of epiglottis stimulation during ETT placement) or sustained (due to positive pressure ventilation, increased intrathoracic pressure and decreased venous return to the heart). Loss of sympathetic drive secondary to pain and sedation medications, and/or continued hypovolemia can also result in hypotension. Continue resuscitation with blood products (trauma patients) or crystalloid (non-trauma patients) if a hypotensive patient requires immediate airway interventions. Be prepared to support blood pressure with vasopressors (e.g. epinephrine bolus or drip) if trained or under direct telemedicine guidance.

Neuromuscular blockade (succinylcholine, rocuronium, vecuronium, etc.) is NOT recommended for use by the average practitioner of PFC. Though these are standard medications to use in rapid sequence intubation and ventilator management, their potential lethality in inexperienced hands does not justify routine recommended 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.