• 1) Minimize viral aerosol formation and direct exposure of medical personnel.
• 2) Use the best available PPE for high risk procedures like endotracheal intubation. (See Appendix B.)
• 3) Gauge the need for inserting an advanced airway on the patient work of breathing. COVID-19 patients decompensate rapidly – a low threshold for intubation allows more time for preparation and may prevent complications.
• 4) If the COVID attending provider does not feel comfortable with placing an advanced airway, consider teleconsultation and/or waiting for arrival of more experienced personnel (e.g., evacuation team). Never try to place an advanced airway unless you know how to do it.
• 5) One assistant is sufficient during intubation in most cases; however, an additional assistant can be standing by in the “warm” zone at least 2 meters away wearing appropriate PPE.
• 6) Passively pre-oxygenate with 100% O₂ for at least 5 minutes. Consider placing a surgical mask on the patient (over top of nasal cannula or non-rebreather mask).
• 7) Utilize strict rapid sequence intubation technique – avoid BVM ventilation if possible. If available, place viral filter in-line during use of BVM.
• 8) Utilize video laryngoscopy (i.e. GlideScope) if available for intubation to limit direct exposure. If unable to intubate or obtain adequate vocal cord visualization on the first pass, consider the placement of a laryngeal mask airway (LMA) with viral filter.  Ventilate with the BVM and PEEP valve until oxygenation is adequate.  Then, re-attempt the procedure.
• 9) Chest X-Ray may not be available or feasible to confirm tube placement. Utilize end-tidal carbon dioxide (EtCO₂) monitoring and auscultation to confirm placement.
• 10) General guide for tube size and depth is as follows: for males use 8.0 endotracheal tube (ETT) inserted to 25cm at the incisors; for females use 7.0 ETT inserted to 23cm at the incisors. In general, place as large an ETT as possible since secretions may be an issue.
• 11) If available, place heated humidification device (e.g., Hamilton H900) or heat and moisture exchanger (HME) in the INHALATION circuit of the ventilator tubing. If available, place a HEPA filter (microbiological filter) or HME-F (HME plus microbiological filter) in the EXAHALTION circuit of ventilator tubing.

Cricothyroidotomy for definitive airway management:

• 1) Many medics and other providers operating independently in far-forward environments are trained to use cricothyroidotomy as their primary definitive airway. While the use of a surgical airway first line is appropriate in patients presenting in-extremis or with the loss of an airway (e.g., severely injured trauma patients with facial or neck trauma), patients with COVID-19 generally present with gradually progressive symptoms and intact native airways.
• 2) Early intra-theater transfer to a facility with advanced capabilities is preferable to early cricothyroidotomy whenever possible.
• 3) Laryngeal mask airway or other supraglottic airway placement may be a sufficient bridge to definitive airway placement. Placement of a mask over the LMA (hole cut in the middle of the mask for the LMA) will minimize aerosol spread from any air leak.  PEEP above 10 cm H₂O via LMA may not be effective and may exacerbate any leak around the LMA.  Sedation and analgesic requirements for an LMA may be slightly more than with a cricothyroidotomy.
• 4) Cricothyroidotomy without the ability to provide mechanical ventilation consumes significant resources (manpower required to bag-ventilate the patient with PEEP, inefficient delivery of oxygen via bag-ventilation, and significant aerosol risk to those providing care).

Systemic Corticosteroids

Professional societies recommend using systemic corticosteroids in the treatment of severe and critical COVID-19 (see the DoD COVID-19 PMG for more details).  If unfamiliar with corticosteroid treatment regimens, discuss with advanced provider via telehealth prior to initiating therapy.

Antimicrobial Therapy (to treat possible bacterial pneumonia co-infection)

• 1) Consider early use of azithromycin (500mg PO or IV daily for a minimum of 5 days) to treat mild to moderate community acquired pneumonia (CAP) in patients with lower respiratory tract symptoms and fever.
• 2) If azithromycin is not available, doxycycline (100mg PO or IV q12h) can be substituted for empiric treatment of bacterial pneumonia.
• 3) For patients with severe symptoms, recommend adding ceftriaxone (IV 2gm q24h is the best option) or ampicillin-sulbactam (3gm IV q6hr is a good alternative) or ertapenem (1g IV or IM q24h if it is the only available option).
• 4) Levofloxacin (750mg PO or IV q24h) is another reasonable option for empiric treatment of severe community-acquired pneumonia.

Fever Management

Fever management with acetaminophen every 6 hours (1000mg IV or 975mg PO or PR) as needed for temperature over 38°C.

Sedation and Analgesia

• 1) Sedation goal is Richmond Agitation and Sedation Scale (RASS) -1 to -2 (comfortable, transiently responsive to verbal stimulation) and synchronous with the ventilator. Increase sedation and/or add narcotics to improve patient-ventilator synchrony.  Use of paralytics may be required for very severe cases (as discussed below).
• 2) Ketamine may cause increased secretions which may require more frequent suctioning. If medication options are limited, consider more frequent dosing of midazolam to decrease the dose of ketamine required and potentially decrease the secretion burden.
• 3) A reference guide for starting and titrating a ketamine drip along with useful adjuncts is provided in JTS Analgesia and Sedation Management during Prolonged Field Care CPG.
• 4) Combined use of multiple sedatives (i.e. propofol, dexmedetomidine and/or midazolam) may act synergistically to decrease the total sedative dose and help to mitigate the hypotensive effects of propofol, however multiple continuous drips is not recommended outside of an ICU setting. A ketamine drip may be combined with bolus doses of additional medications.
• 5) Caution should be used with combining propofol and dexmedetomidine, especially in younger patients with higher vagal tone due to increased risk of bradycardia and hypotension.
• 6) Intermittent or doses of fentanyl or hydromorphone may be useful for analgesia and optimizing ventilator synchrony.
• 7) Low dose vasopressors may be necessary to support hemodynamics in the face of deeper sedation and higher PEEP. (See Appendix D.)

Bronchodilation

• 1) Use of metered-dose-inhalers (MDIs) over nebulized bronchodilators to treat wheezing will help to minimize risk for infectious aerosol.
• 2) If the ventilator tubing does not have a capped inlet for medication administration (aka MDI adapter) -- 1) clamp the ETT, 2) disconnect the ventilator, and 3) administer the MDI (6 puffs) directly into the INHALATION circuit. Then, reconnect the ventilator and unclamp ETT to insufflate the medication.
• 3) Magnesium Sulfate 2gm IV over 20 minutes (similar to treatment of an asthma exacerbation) may be a safer alternative for treatment of bronchospasm given the risks of disconnecting the circuit.

Lung-protective ventilation

• 1) Initiate lung-protective ventilation strategy.
  • Tidal volume 6mL/kg ideal body weight (IBW)
    • Ÿ IBW – Men = 50 kg + (2.3 kg x (height in inches - 60))
    • Ÿ IBW – Women = 45.5 kg + (2.3 kg x (height in inches - 60))
      • Maintain peak pressure less than 35 mm Hg
      • Maintain SpO₂ 88-95% or PaO₂ 55-80 mm Hg
      • Permit Hypercarbia (but keep arterial pH > 7.30)
      • Use ARDSnet protocol. (See Appendix E)
• 2) If ETT must be disconnected from the ventilator for ANY reason, clamp the ETT to prevent decruitment and minimize viral aerosol formation.
• 3) If in-line suction devices are not available, de-recruitment will likely occur with suctioning. Salvage recruitment maneuvers may be necessary.
• 4) On the EMV+ 731 (mode AC-V) a recruitment maneuver can be done as follows:
  • Change upper limit of Peak Inspiratory Pressure (PIP) alarm to 50 cm H₂0.
  • Decrease tidal volume as low as possible (50mL).
  • Increase PEEP to 30-40 cm H₂0.
  • Hold for 40 seconds (if signs of hemodynamic instability develop, stop the recruitment maneuver, and resume prior settings).
  • Increase PEEP to 2 cm H₂0 ABOVE prior PEEP setting.
  • Increase tidal volume back to prior setting.
  • Return upper limit of PIP alarm to prior setting.
  • Monitor for any persistence of hemodynamic instability or persistently high PIP (Although rare, the high PIP encountered during RMs can cause pneumothorax).
• 5) Dry Lung. The mantra “a dry lung is a happy lung” still applies in severe COVID-19 care; over resuscitation is likely to be harmful.  Fluid resuscitation should be guided by assessment of volume responsiveness.  If available and evacuation is significantly delayed, loop diuretics can be used to attain a net even volume status, providing the patient is hemodynamically stable (i.e. not requiring vasopressor support).

Management of Oxygenation

• 1) Escalate PEEP to 12 cm H₂0 as aggressively as possible as hemodynamics allow to optimize oxygenation, minimize FiO₂ needs, and extend oxygen supply.
• 2) Use the ARDSNet Protocol LOW PEEP table as a guide for further titration of PEEP. Refer to JTS Acute Respiratory Failure CPG.
• 3) Be prepared to start vasopressors and judicious use of IVF to support pre-load in the face of high PEEP (aka PEEP tamponade).
• 4) Consider a combination of paralysis and prone positioning early to lengthen duration of available oxygen supply.
• 5) Consider Inverse Ratio Ventilation (IRV) once patient reaches PEEP 18 cm H₂0 on the LOW PEEP table.

Management of Ventilation

• 1) If blood gas analysis is not available, a general EtCO₂ goal of 35 mm Hg +/- 5, is adequate. However, if blood gas analysis is available (i.e. i-STAT), recommend obtaining a baseline PCO₂ and correlate with EtCO₂, especially since the gradient between the two is much wider in patients with significant lung disease (i.e. an EtCO₂ of 40 may actually represent a PCO₂ of 60 with a pH around 7.24).
• 2) The manual breath button on the bottom left of EMV+ 731 allows for manual measurement of plateau pressure (Pplat). The Pplat goal is less than 30 cm H₂O with a secondary goal of maintaining driving pressure (Pplat minus PEEP) below 15 cm H₂  In the absence of Pplat, a PIP target of less than 35 cm H₂0 is also reasonable.
• 3) If Pplat is greater than 30 cm H₂0, decrease set tidal volume by 1 mL/kg steps (about 50-80 mL). Titrate set respiratory rate (RR) up increments of 2 bpm to maintain pH and EtCO₂ at goal.  Avoid RR above 35 bpm given significant risk for breath stacking and auto PEEP (which will eventually make the patient hemodynamically unstable).
• 4) If i-STAT with blood gas cartridges are available, consider serial blood gas evaluation (adjusting frequency depending on patient stability).

Reverse Trendelenburg

Reverse Trendelenburg positioning (head of bed up, spine straight) can help offload abdominal pressure contributing to increased thoracic pressure.  This can be extremely helpful maneuver to improve pulmonary compliance in obese patients and/or those with intra-abdominal hypertension.

Secretion Management Considerations

• 1) Increased secretions and mucous plugging of the bronchial tree are extremely common causes for increased oxygen requirement and difficulty with ventilation in patients with severe respiratory failure from lung infections.
• 2) Anecdotal evidence regarding COVID-19 patients suggests that secretions are problematic in some patients. Additionally, in-line suction (closed system) devices that minimize aerosol formation and de-recruitment are not usually available in austere settings.
• 3) Heated humidification prevents desiccation (drying out) of secretions and promotes ciliary clearance.
  • Ÿ Heated-humidification devices are designed to be used along with ventilators (e.g., Hamilton H900).
  • Ÿ Heat-Moisture Exchangers (HME) are supplies that fit in-line with the ventilator tubing and trap heat and moisture within the circuit.
  • Ÿ HME Filters (HME-F) are supplies that fit in-line with the ventilator tubing and provide HME and microbiologic filtration.
• 4) Pharmacologic treatment for secretions generally falls into one of three categories: mucolytics (break up mucous), bronchodilators, or anti-sialagogues (anti-salivation).
  • Ÿ Mucolytics:
    • ž Pre-treat with for 10-15 minutes.
    • ž 20% N-acetylcystine (Mucomyst) as 1-2mL direct instillation into ETT every 6 hours as needed for secretion control.
    • ž 3% Saline (Hypertonic Saline) as 5mL direct instillation into the ETT every 6 hours as needed for secretion control.
  • Ÿ Bronchodilators: Albuterol will help dry up secretions.  While ultimately decreasing secretion volume, bronchodilators may also increase the risk of a mucous plug formation.  Use with caution.
  • Ÿ Anti-Sialagogues: Has the greatest effect on oral secretions with modest effect on pulmonary secretions (and therefore not routinely recommended for COVID-19 patients).  However, antisialagogues such as scopolamine and glycopyrrolate are often effective at attenuating the increased secretions caused by high dose ketamine.
• 5) Percussive chest physiotherapy is often provided by respiratory therapists in Role 3 facilities to facilitate secretion clearance. Manual (with hands) or mechanical (with percussive physical therapy devices) can be used to create the same effect.

Adjunctive Strategies for Severe ARDS

• 1) There is no single right answer as to which strategies should be used in severe ARDS. Each approach may or may not be feasible due to the resource constraints of the austere environment.  If unfamiliar with these techniques, obtain teleconsultation.
• 2) Pressure Control – may include Inverse Ratio Ventilation (PC-IRV):
  • EMV+ 731 with the most recent software package has the capability to do PC-IRV. While using AC-P mode, PC-IRV is achieved by increasing the Inspiratory-to-Expiratory (I:E) ratio above 1:2 (i.e. 1:1, 2:1, 3:1 and higher).
  • PC-IRV cannot fully approximate Airway Pressure Release Ventilation (APRV), but is still the best available salvage mode using EMV+ 731.
  • Once PEEP is maximized (or limited by peak inspiratory pressure) and oxygenation is still not yet at goal, increase the I:E ratio incrementally.
  • Tidal volume goal remains the same as with conventional ventilation; adjust cycle time (60/RR) to optimize minute ventilation.
  • Higher I:E ratios are not physiologic, so PC-IRV will likely require increased depth of sedation for patient comfort and synchrony.
• 3) Paralysis for Patient-Ventilator Synchronization
  • Adequate depth of sedation is essential prior to starting a paralyzing medication; recommend RASS greater than -2.
  • SCCM and DoD COVID-19 Practice Management Guide recommend intermittent paralytics over continuous infusions, if possible. Continuous infusion can result in prolonged paralysis if not closely monitored, especially if muscle twitch monitor is not available.
  • Paralysis with Vecuronium:
    • Ÿ Bolus: 5mg to 10mg every 60-90 minutes as needed.
    • Ÿ Infusion: 0.8 to 1.2mcg/kg/min (approx. 80mcg/min for 80kg).
    • Ÿ Without pump: 40mg vecuronium in 250mL bag (50mL wasted) of normal saline yields 40mg/250mL = 160mcg/mL. For 80mcg/min = 0.5mL/min ~ 1gt every 12 seconds in 10gt tubing.
  • Monitoring Goal:
    • Ÿ Absence of muscle movement and no evidence of spontaneous breathing on the ventilator. If possible, titrate to 2/4 TOF (testing device likely only available for surgical teams).
    • Ÿ Increased HR and BP may suggest inadequate sedation and should be empirically treated by increasing sedation.
    • Ÿ Once the patient is stabilized, consider holding the paralytic at least once every 24 hours to provide for assessment of sedation depth.
    • Ÿ DO NOT hold sedation until paralytic wears off unless absolutely necessary (e.g., sudden hypotension).
• 4) Prone Positioning
  • “Awake Self-Proning” with high flow nasal cannula devices has been successfully used in patients with moderate to severe COVID-19 lung disease. If patients are unable to tolerate prone positioning (i.e. strong desire to remain in a tripod position), DO NOT force them into the prone position.
  • Reference DoD COVID-19 Practice Management Guide for full details on prone positioning precautions and procedures.
  • Placement of either a central line or additional peripheral access is strongly encouraged PRIOR to prone positioning.
  • Have push-dose vasopressor medication available during the process of prone positioning and un-positioning, as hypotension frequently occurs.
  • Proning cycle is generally 16 hours of prone positioning each 24 hours. Match the proning cycle to the daily care plan as much as possible.
  • Prone positioning may not be feasible or safe during evacuation.

Anticipate Complications

• 1) Pneumothorax can occur with higher PIP. Sudden increases in PIP and/or hemodynamic instability may indicate pneumothorax.
• 2) Pneumomediastinum with subcutaneous emphysema can also develop with the use of high PEEP (typically from dissection of air into the adventitia of small bronchi/bronchioles). The development of crepitus across the chest, neck, and/or upper extremities suggests the presence of this condition.  Tension physiology from pneumomediastinum is EXCEEDINGLY rare and usually no intervention is needed.
• 3) Acute kidney injury leading to renal failure is a genuine threat to seriously ill COVID-19 patients. Patients unable to make urine can develop fatal arrhythmias from electrolyte abnormalities and acidotic blood.  They need to be evacuated to a location capable of renal replacement therapy as soon as possible.
  • Oliguria is defined as less than 0.5 mL/kg/hour of urine output (UOP).
  • Oliguric patients should receive a bolus of 500 cc crystalloid. This may be repeated once if UOP does not improve.  If the patient remains oliguric after a 1L bolus, consider the onset of acute tubular necrosis (ATN), especially if UOP remains low for more than 6 hours. 
  • As formal creatinine testing for acute kidney injury (AKI) is not likely to be available, consider urine dipstick testing with attention to specific gravity, proteinuria, and hematuria:
    • Ÿ An abnormally low (dilute) specific gravity in the setting of oliguria suggests tubular damage and the inability to concentrate urine.
    • Ÿ Significant proteinuria can be seen in ATN; however, this is not specific and can be seen in a variety of acute medical conditions.
    • Ÿ Hematuria may suggest the presence of myoglobinuria – consider rhabdomyolysis as a cause of acute kidney injury.
  • If UOP suddenly declines or stops, flushing the Foley and/or performing a bladder ultrasound scan can help determine if the problem is mechanical (Foley blockage) or organic (true kidney injury).
  • Once ATN sets in, do not aggressively fluid resuscitate or diurese simply to meet UOP goals. Use alternative markers of fluid responsiveness (like blood pressure response to passive straight leg raise) to help determine the need for further fluids and vasopressor medications.
  • Monitor closely for the development of electrolyte disturbances, specifically metabolic acidosis and hyperkalemia. Use medical management of hyperkalemia as appropriate.  The JTS CPG on Hyperkalemia and Dialysis in the Deployed Setting describes field-expedient techniques for peritoneal dialysis; however, this should be done in concert with teleconsultation.

• 1) An IV pump is recommended over dial-a-flow and drip-chamber titration (if available).
• 2) When outdoors, place the monitor, ventilator, and IV pumps upwind and as far away as possible from the patient to minimize contamination of caregivers.
• 3) Establish arterial line monitoring early when possible for patients with severe COVID-19 disease as they often become hemodynamically unstable.
• 4) If possible, establish central access early in anticipation of the need for continuous vasopressors. Multiple peripheral IVs may also be needed for infusions of sedatives, analgesia, antibiotics, etc.
• 5) A conventional central venous catheter can be placed through an introducer catheter (i.e. Cordis) to expand the number of available infusion ports. This should be done during the initial insertion under sterile technique, if possible.
• 6) Some severely ill COVID-19 patients may develop dilated cardio-myopathy with florid cardiogenic shock. This may be secondary to systemic inflammation, stress, or a direct viral myocarditis.  Patients may also develop arrhythmias.  Manage arrhythmias following Red Cross advanced life support guidelines.
• 7) An unexpected change in the vital sign trends or hypotension out of proportion to sedation and PEEP should merit evaluation for additional causes of shock. Limited transthoracic echocardiography may be useful in discriminating between hypovolemic, cardiogenic, and distributive shock (in personnel trained to perform the assessment).
• 8) Utilize dynamic parameters (i.e. skin temperature, capillary refilling time, pulse pressure variation, blood pressure response to passive straight leg raise, and/or serum lactate measurement) over static parameters to help guide the need for further fluid resuscitation (Surviving Sepsis Campaign COVID-19 Guidelines).
• 9) Norepinephrine is the first line vasopressor for most causes of shock. Fixed rate vasopressin infusion (0.04 units/min) is useful as an early adjunct in non-cardiogenic shock; start vasopressin when norepinephrine reaches doses above 12mcg/min.  Epinephrine is sometimes the only option available in remote locations. 
• 10) Vasopressors should be titrated to a MAP goal of 60- 65 mm Hg. (Surviving Sepsis Campaign COVID-19 Guidelines.)

• 1) Nasogastric or orogastric tube (NG/OGT) should be placed early for gastrointestinal decompression. If medical evacuation is significantly delayed (greater than 24-48 hours), consider starting enteral nutrition.
• 2) Enteral nutrition is contraindicated in hemodynamically unstable patients (i.e. those on high or increasing doses of vasopressors). Low volume tube feeding on patients with stable low doses of vasopressors is generally safe.
• 3) At a minimum, confirm position of gastric tube placement with auscultation over both lung fields and the abdomen along with aspiration of gastric contents. Urinalysis test strips for pH may provide an addition method for NG/OGT placement confirmation in patients not on acid suppressive therapy.
• 4) Goal 25-30 kcal/kg/day + 1-1.2 gm/kg protein; however, this might be difficult, especially in the absence of formal concentrated tube feeds.
• 5) Meal supplement drinks are not sufficient. For example, one Muscle Milk Light bottle contains only 150 kcal and 28 gm protein in 500 mL, which is extremely dilute compared to most tube feeding formulations.  This potentially increase extra-vascular lung water (especially in the setting of critical illness) with minimal benefit to nutritional status.
• 6) A more concentrated alternative is to use commercially available protein powder (with similar caloric/protein content per scoop) at 1/4 the recommended concentration and mix in a blender until no clumps are visible. Administer in small volume boluses (e.g., 60mL via Toomey syringe) as tolerated every 2 to 4 hours to a goal of 1 gm/kg/day protein content.
• 7) Further recommendations for enteral nutrition can be found in JTS CPG for Nutritional Support Using Enteral and Parenteral Methods.
• 8) If possible, blood sugar checks should be obtained at least every 6 hours, particularly for those with known diabetes mellitus.
• 9) Venous Thromboembolism (VTE) prophylaxis should be given as long as there are no contraindications. Patients with COVID have demonstrated and increase risk of the formation of thrombus formation, therefore it is recommended to administer Lovenox 30 mg SQ twice daily (avoid if evidence of renal failure) or 7,500 units heparin SQ every 8 hours.
• 10) If pharmacologic prophylaxis is not available, manual ankle plantar/dorsi-flexion range of motion exercises and lower extremity massage every two hours. Consider applying compression stockings if available. DO NOT use ACE wraps.
• 11) Stress-Ulcer Prophylaxis should be given to all intubated patients as long as there are no contraindications. Famotidine 20 mg IV every 12 hours or 20 mg via NG/OGT twice daily, or consider and a proton pump inhibitor, if available (i.e. pantoprazole 40 mg IV daily or omeprazole via NG/OGT daily).
• 12) Ventilator Associated Pneumonia prevention bundle applied to the limitations of an austere environment includes:
  • Ÿ Head-of-bed elevation to 30 degrees
  • Ÿ Suction the oropharynx as needed
  • Ÿ Brush teeth every 12 hours, ideally with commercially prepared Chlorhexidine oral care if available.
• 13) The JTS CPG for  Nursing Interventions in Prolonged Field Care provides in-depth discussion of the nursing tasks that may be required if medical evacuation is significantly delayed.

Cardiopulmonary arrest is a difficult topic.  Generally speaking, in cases of cardiac arrest, Cardiopulmonary Resuscitation (CPR) in an austere environment may not be a wise use of resources unless the etiology for the arrest is rapidly reversible.  Additionally, significant aerosol generation will invariably occur during CPR of a COVID-19 patient.  It is reasonable during a pandemic to establish medical rules of engagement that discourage providers from performing CPR on infected patients.  If CPR is performed, efforts should focus on reducing provider exposure to COVID-19 and prioritizing strategies with lower aerosol formation risk. (See DoD Covid-19 PMG.)