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assess the patient’s lung function and track their progression. perform this check to find your actual PEEP. A key limitation
As the patient approaches respiratory collapse, there will be of this ventilator is that it can only deliver a maximum of 27
a decrease in SpO and pH and an increase in PaCO . The liters per minute (LPM) to the patient. To put this in perspec-
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patient will likely also then develop an altered mental status, tive, a healthy adult male breathes between 30–35 LPM. This
generally presenting as confused or “drunk” due to hypercar- and other limitations mean that the SAVE2 should be consid-
bia and may have an SpO below 90%. The decision point for ered only a short-term adjunct, meant to hold a patient until
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sedation, moving to an advanced airway, and placing the pa- evacuation or during movement to a higher level of care with
tient on a ventilator is a pH below 7.25 AND a PaCO greater more advanced ventilators.
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than 50.
In the worst-case scenario of an unexpected PFC problem,
The initial values for the ventilator are TV 7 ml/kg, RR 12, such as a prolonged ground evacuation or a significant delay
PEEP 5, peak inspiratory pressure (PIP) 30 and FiO 40%. in rotary wing MEDEVAC, the SOF medic may have to treat
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TV and PIP should not be changed. The other values should an APC or ARDS patient for a prolonged period with no PFC
be adjusted with the goal of maintaining an SpO between equipment. Guidance for this situation is to continue the treat-
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90–94%. PEEP can be adjusted to a maximum of 10, RR to ment protocol stated above for the TCCC setting. It is import-
a maximum 20 and FiO2 to a maximum of 100%. Carefully ant to understand the limitations of treating a patient like this
monitor plateau and drive pressures as well, ensuring that the with such limited resources. Realistically it is unlikely, even
plateau pressure never exceeds 30 and the drive pressure never with a well-organized team, that a critically injured patient
exceeds 18. Patient positioning is still crucial during mechan- could be successfully held and treated for much longer than
ical ventilation but should be restricted to the prone position several hours with a positive outcome. Management of limited
for a patient on a ventilator. “Proning” the patient is a highly medical supplies and the expectations of team members be-
effective maneuver for most patients that increases alveolar re- come increasingly important tasks in this situation.
cruitment and perfusion, while decreasing overdistention of
the lungs and the chances of causing a ventilator induced lung
injury. Patients should be proned for no longer than 17 hours Conclusion
before being returned to supine for 6–8 hours and must be Returning now to the COP in Eastern Afghanistan and your
monitored closely during and after the move in case they are Service Member suffering from a combination of acute lung
a non-responder or equipment was damaged or shifted during injury. Starting with a least invasive approach, the patient
movement. If the patient continues to deteriorate, another in- is provided 100% O and positioned to provide maximum
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tervention is to inverse the inspiratory:expiratory (I:E) ratio of comfort and oxygenation. You utilize telemedicine early and
the ventilator. This intervention shifts the I:E ratio from 1:2 consult with your senior surgeon/provider to confirm your
to 1:1, prolonging inspiration time in an attempt to allow the treatment plan. Continuing to monitor and position your pa-
maximum amount of perfusion possible in the alveoli. tient, you conduct good PFC basics of padding, establishing a
foley for urine output, conducting hypothermia management,
With appropriate and timely intervention, the patient’s PaO , and organizing and educating your teammates to assist you.
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PaCO and pH levels should return within normal limits. You set up a shift schedule and work with your leadership to
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However, the patient’s trend is more important than the num- convert a vehicle into an improvised critical care ambulance
bers. If the patient is stable but has an SpO in the high 80s in case authorization for ground movement is given. Despite
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and a PaCO between 50–60, that may be the best that can be your best efforts, your patient continues to deteriorate over
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accomplished in the PFC setting. the next 24 hours. Your sedation, airway equipment and ven-
tilator are already prepared when your patient’s ABG levels hit
An important additional consideration for PFC is the differ- the decision point and you move quickly to secure their airway
ent types of equipment SOF medics deploy with depending and place them on the ventilator. Ventilated at an appropriate
on their unit, nationality, and personal training/experience. rate with settings titrated to meet the goal range, your patient
While the above protocol represents an ideal PFC loadout, the stabilizes and is kept within the 90–94% SpO range with min-
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following addresses medics who lack a portable lab capabil- imal adjustments. Fortunately, at around 38 hours the weather
ity and who do not possess a fully adjustable ventilator, such breaks and you are able to hand off your patient to rotary
as the SAVe II (Combat Medical, www.combatmedical.com). wing MEDEVAC for transport to the closest Role 3.
Treatment of the patient still progresses from least invasive
to most invasive, utilizing supplemental O and positioning to Disclosures
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increase oxygenation. If the patient develops an altered men- We have no conflicts of interest.
tal status, generally presenting as confused or “drunk” due to
hypercarbia, AND has an SpO below 90%, then sedate the Disclaimer
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patient and secure their airway in order to assist with posi- Opinions or assertions contained herein are the private views
tive pressure ventilations. The patient should be attached to of the authors and cannot be construed as official or as re-
the ventilator with the initial input based on their height after flecting the views of the United States Department of Defense,
doing alarm checks for disconnect and PIP. This will cause the Verteidigungsministerium der Republik Österreich (Austria),
ventilator to automatically start ventilating the patient at a or their affiliated Services.
preset TV, RR, and PEEP of 0 based on the ideal body weight
of their height. The PIP will read 30 on the monitor, but this is References
misleading as is the stated PEEP. In order to read the true PIP 1. Sweeney RM, McAuley DF. Acute respiratory distress syndrome.
Lancet. 2016;388(10058):2416–2430.
and PEEP, hold down the “confirm” button in the center of the 2. Dries DJ, Endorf FW. Inhalation injury: epidemiology, pathology,
ventilator and it will be displayed. Note that when adjusting treatment strategies. Scand J Trauma Resusc Emerg Med. 2013;
PEEP it may take over a minute to change, so it is important to 21:31.

108 | JSOM Volume 22, Edition 2 / Summer 2022