SCCM Resource Library-Military Biocontainment Units and the Transport of Patients with High-Consequence Infectious Diseases

Video Transcription

The 20th century was a time of great invention. Advances in technology brought us new ways to experience life and new ways to protect it.  From the dawn of flight, we saw the opportunity to save lives. The U.S. Army Air Service first converted biplanes into single patient medical transports in 1918.  These early conversions paved the way for the first dedicated aeromedical evacuation aircraft. In 1941, the Army was reorganized and the U.S. Army Air Forces were formed.  David Grant became the first air surgeon and proposed the first air evacuation service. Later that year, the U.S. entered World War II. Demand for aeromedical evacuation grew.  So did our capabilities. So did our airmen. The Air Force was formed as a result of the National Security Act of 1947. Soon after, new conflicts brought new challenges.  We overcame them with innovation, strength, and force.  Today's aeromedical evacuation aircraft employ the latest in health care technology. Providing life-saving care at a moment's notice. Anywhere on earth.  From the first single patient ambulance aircraft to today's airborne hospitals to the inventions of tomorrow.  For 100 years, aeromedical evacuation has provided Air Force trusted care anywhere. This is Lieutenant Colonel Ben Sturmel.  I'm the Chief of Infectious Diseases at Eglin Air Force Base, Florida. And in 2020, I was deployed in support of biocontainment transport operations evacuating  contagious personnel from deployed locations.  This is a standard disclaimer. The views expressed in this presentation are my own. I have no relevant financial relationships to disclose.  During the period from April 2020 through February 2021, I provided specialty support to over 50 missions in four global areas of responsibility, including parts of the Middle  East, Northern Africa, Europe, and the Pacific.  We transported 307 contagious patients, including two children, 37 of those priority for movement, 42 requiring supplemental oxygen, and 10 of those on mechanical ventilation.  This was a deviation from the traditional paradigm of treatment in place for contagious personnel because of the large scale of the global pandemic.  Prior to the COVID-19 pandemic, there were multiple devices that were designed and developed by the Department of Defense in order to transport contagious patients.  But the limitations were primarily the number of patients that could be transported and the provision of care during that transport.  The patient isolation unit was designed to transport a single patient across relatively  short distances and allowed limited capability for support apparatus and care during transport.  The transport isolation system was designed to carry multiple patients of varying acuity and also allow for an antechamber for passage of medical personnel to provide care during  that transport.  During the early stages of the pandemic, the Department of Defense reviewed devices that were used by other agencies as well and found similar limitations.  The aeromedical biocontainment system allowed for provision of care during transport but was also limited to a single patient.  The containerized biocontainment system that was developed by the Department of State was able to take care of four patients and they were able to  provide significant levels of care during transport, but still only four patients.  The need for larger capacity transport drove the rapid development of new container devices,  including the negative pressure connex and the negative pressure connex light.  These devices were able to be loaded onto military airframes. And because of their size, they were able to carry significantly more patients and be  adjustable to provide different levels of care during transport.  These are the three devices that were ultimately used to transport patients during the COVID-19  pandemic, and we will touch on the relative strengths and weaknesses of each platform.  The design of these devices is pretty straightforward. They use a set of blowers to draw air through the antechamber and into the patient care chamber,  and then through multiple sets of HEPA filters in order to scrub the air before it gets returned to  the airframe. The rear doors allow for onloading and offloading of the patients and then sealing  of the patient care chamber. The antechamber allows for the entry and exit of medical personnel and the change of the personal protective equipment.  Comparing the airflow in the devices in air changes per hour to the minimum standard of  the American Institute of Architects, you can see that the devices, even with one blower functioning, perform at least as well as most patient care areas of a hospital.  Comparing the interior of each of the devices, you can see that the space is relatively limited.  In the transport isolation system, the layout is fixed, so you can carry multiple patients on litters, but other patients may have to be seated in aircraft-style seats. If you have  multiple ambulatory patients, then some of those patients may have to lay down on litters for the  duration of the flight. In the negative pressure connects, the negative pressure connects less  In the negative pressure connects, the negative pressure connects light,  those litter stanchions are adjustable, so you can fold them in and you can allow for more seating  for ambulatory patients, or you can fold them outward to allow for more litter patients to be  loaded that may require more significant care, but each of those litter stanchions that open up  take up several seats. The walls of the transport isolation system also are closer to the head and  foot of the litters, which may limit some care provision, especially if you need to do procedures and intubations and patients in flight.  Comparing the capacity for patients, you can see that the TIS can be loaded into a dual  configuration on a C-17, and that doubles your capacity to 14 patients. That's eight on litters,  six of them seated, and then two crew members, one in each device. For the NPC and the NPC light,  you can see that the capacity is, for a single unit, 22 patients for the NPC and 13 for the  NPC light. Every one to two litters that you add, you lose four seats, and so the capacity does go  down. Now, the med crew requirements, we carry a augmented aeromedical evacuation team, as well as  a three-person critical care air transport team. They provide the medical care in flight. We have  an infectious disease physician or an infection control nurse and a public health technician who  work as a team in order to monitor for PPE changes and breaches in PPE, as well as to resolve any  issues that might come up in the transport. And then there's four biomedical support technicians  required for two TIS units, and only two of them required to run a single NPC or NPC light.  Now, because the TIS is flown in dual configuration, you can divide the patients into confirmed patients and persons under investigation.  This is something you would not be able to do when traveling with a solitary NPC or NPC light.  The biggest challenge that we experienced during transport was communication. Between the walls of  the device itself, the noise from the aircraft, and the noise from the blowers, it was very difficult  getting messages from the outside of the unit to the inside. And when only one or two of your crew  members are providing care at a time, it becomes very important to be able to communicate with the  care team outside the device, as well. We tried to use the electronic headsets that we typically use  for aeromedical transport, and unfortunately, those devices kept getting caught up in the personal  protective equipment, and it was difficult to turn them on and turn it off without becoming  contaminated yourself. So, the teams developed systems of using whiteboards and pre-made visual  cues in order to communicate frequent tasks. Now, as you can see here, however, the walls  themselves are not easy to see through, especially once you start loading the amount of equipment  that's needed for patient care, both inside and outside the system. And so, communicating even  with visual cues was sometimes difficult. With the arrival of the negative pressure connects,  some of those issues did improve, and you can see that the windows are much easier to see through,  but because of the size and position of them, they did present some difficulty for those of  us who are more vertically challenged. Now, with the new equipment, we also received some other limitations, and these trash cans seem to be significantly smaller to contain the PPE  and other hazardous materials that were generated by taking care of the larger numbers of patients.  In addition to the issues that we were having with newer equipment, we also had challenges with old  equipment and supplies. A lot of what we were carrying had been purchased in response to the  West African Ebola outbreak years ago, and even the hand sanitizers that we had on hand, a lot of  them had long since expired. The shortages of PPE that were experienced in the United States and  overseas began to affect us as well, leading to some creative trial and error. Obviously, not ideal  when you were trying to do controlled PPE changes in flight. And for the ultimate piece of old equipment, the aircraft themselves presented unique issues due to years of use, abuse,  repair, and maintenance.  One of the more frustrating challenges to me was the level of disbelief that there was in COVID-19  in general, even in the beginning of the pandemic. Now, we went from Ebola, where if anything, there was an irrational fear and stigma associated with that infection  that led to very strong buy-in for PPE and protocols, to COVID-19, where most people felt  that this was a very uncomplicated illness that did not require the level of care that we were  taking for this pathogen. Some challenges presented by patient care. This was early in the  pandemic, so obviously COVID-19 transmission was not fully understood, and if there was any amount  of airborne transmission, then this seems like where it would happen, in an enclosed space with  lots of stagnant air. Now, quarantine requirements for the crews that are being exposed could  potentially limit the number of missions that we could fly or the number of personnel available  in order to do that. If somebody got sick, then prognosis is widely variable, so even the people  that recovered quickly, who knew when they would be ready to fly another mission? Now, for the crew  members and for the patients, treatment was in its infancy. We didn't have vaccines to prevent  transmission. We didn't have treatments that would potentially slow down the progression,  and then for intubation and flight, not ideal, and so if, especially in the transport isolation  system, where space is limited above the head of the litter, we didn't want to take the risk  of exposure of crew members and difficult airways that that might present. Resuscitation would be  worse. There's so little space on the floor there that if you had to take a patient down to do  compressions, there wouldn't be a lot of space to do that and anything else.  Now, on top of that, you really only have what you bring with you, and that's true for  any air medical evacuation mission, but for this one, a lot of the equipment that you have with  you is outside of the isolation unit because if you take it inside, then all of that's contaminated, and so there was a lot of effort to collect, to standardize the approach  in order to have all of the equipment that you need available when you need it.  Now, I do have some cases to present to just kind of demonstrate those challenges in practice. This first case is a case of normal physiology.  And so, for a 36-year-old male soldier presented to a field hospital with sore throat, not really many other symptoms, for about eight days prior to transport.  He tested positive by PCR for SARS-CoV-2. He had no real chronic medical issues and was a nonsmoker. He started off at a pretty high altitude at 6,000 feet.  His respiratory rate was normal. His oxygen saturations are mid-90s on room air.  At cabin altitude, 7,500 feet, he became short of breath and started to drop his saturations down to around 90%, but he had significant variability, which meant that he was dropping  down into the high, maybe the mid-80s.  With only two liters of oxygen by nasal cannula, his symptoms resolved, and his oxygen saturation stabilized at 94%.  And he was able to finish his transport, descend to Ramstein Air Base in Germany at 780 feet, and his oxygen was discontinued with SATs in the mid-90s, again, on ambient air.  So, this patient was transported to Landstuhl Regional Medical Center and placed in an outpatient isolation unit.  Now, this second case is kind of the opposite of that one. And so, this is a 37-year-old male soldier transported to a field hospital after four days  of fever, cough, shortness of breath, and muscle aches.  He also tested positive by PCR, and he has hypertension at baseline on lisinopril, maybe some other comorbidities undiagnosed.  His oxygen saturations at room air at a field clinic were in the mid- to high-80s and improved to 95% in transport.  The chest X-ray on arrival at the hospital showed pneumonia, and he was initially placed in an isolation camp and treated with levofloxacin.  His oxygen saturations dropped to the 80s again, and was reproducible with walking.  He was referred back to the hospital for admission.  After admission to the hospital, his oxygen saturation improved to 97% on two liters nasal cannula.  His chest X-ray showed patchy bilateral pneumonia, which had worsened over the 48 hours. His oxygen saturations then trended down to 90% on four liters nasal cannula.  His antibiotics were changed to ceftriaxone and azithromycin,  and corticosteroids were added.  At that point, they requested routine transfer to L'Ange Tolle Regional Medical Center. Now, at the time of the alert, the critical care transport doctor called the local team  and was notified the patient was on six liters of oxygen by simple mask, maintaining SATs of 98%.  But his respiratory rate had increased to 28, and the patient was beginning to look lethargic.  The critical care doctor and infectious disease doctor provided recommendations,  including changing the corticosteroids, adding remdesivir, adding vancomycin if the cultures or gram stain identified gram-positive cocci, monitoring for drug interactions,  starting low molecular weight heparin for DVT prophylaxis, and also because of the issues that we had known with transport, to potentially intubate the patient in advance,  anticipating that either he would continue to progress or that he would require admission in the air, which would obviously not be ideal.  The patient was intubated eight hours prior to transport due to worsening hypoxia. And you can see in this case that communication between the transport team  and the local care team is definitely important in these cases that have the chance to progress.  Now, unfortunately, there were unanticipated delays with the transport team.  This was a multi-part mission, and at the previous stop,  there were patients that were added en route. And using the TIS at the time, there was a zipper door for loading and unloading patients,  and that zipper had failed and required repair at the previous stop.  The patient was delivered to the flight line by ambulance for tail swap in order to limit ground time and to allow the air crew and the med crew to finish this mission  within time constraints that are restricted.  Now, the patient arrived inadequately sedated, and he was experiencing ventilator asynchrony.  A lot of adjustments were made to the ventilator and to his sedation, and ultimately, he had to be chemically paralyzed.  Now, the cabin altitude, because of simultaneous transport of a traumatic brain injury patient, was restricted to 6,000 feet,  but that was still a significant jump from 500 feet at takeoff.  Once at cruise altitude, the patient stabilized with oxygen saturation in the mid-90s on 80 to 90% FiO2 and pressure control ventilation.  And during flight, his chemical paralysis was able to be weaned to off.  Now, when he was deplaned, he did become asynchronous again with the vent and, again, required continuous adjustment of sedation, reinstitution  of chemical paralysis during transfer to launch to a regional medical center ICU.  Now, this third case occurred quite a bit later in the course of our mission, and we had a bit more experience. We had some more data about COVID and its management and prognosis,  and also we had access to the negative pressure connects. And this is a 62-year-old male contractor, also PCR positive, found during contact tracing after a known exposure.  He initially only had mild fatigue and appetite loss for about six days before transport.  He had no known chronic medical issues and was a nonsmoker.  On presentation, he was satting in the low 90s on room air, but he worsened gradually to 92 to 94% on three liters, and that was awake, proned on the ground.  The nurse reported desaturations down to the high 80s while walking to the bathroom. He was treated with antibiotics, with dexamethasone, with low-malicure weight heparin,  and they requested a routine evacuation.  He was delivered to the plane via AMBUS, which is an ambulance bus, exactly what it sounds like.  His oxygen saturations en route were 93% on three liters nasal cannula.  Due to mechanical issues with the plane, unfortunately, the ramp would not open, and he had to be in-plane walking through the crew door, which is a pretty steep set of steps.  His oxygen saturations dropped down to 87%.  He was placed on a litter in prone position.  His oxygen saturations improved to 94% on five liters, but he was comfortable with no distress.  At cabin altitude of 7,200 feet, baseline around 5,000,  his oxygen saturations were in the mid-90s on five liters still. After three hours, the patient was returned to a supine position due to back pain. He is 62 years old.  His oxygen saturations dropped to 87%, but improved to 95% on eight liters simple mask.  The aeromedical evacuation crew director contacted command and requested upgrade to priority. Now, for the duration of the flight, the patient was encouraged to side position,  but was often supine because he was uncomfortable in the litter. After descent back to Ramstein, his oxygen was titrated to six liters nasal cannula with oxygen saturations of 95%.  He was transported to Longitudinal Regional Medical Center, and then subsequently admitted to the ICU. Now, some important points and lessons learned.  Mechanical and operational difficulties can play a major role in success of these missions. Patients who appear stable on the ground might still be challenging when you get them  to altitude because of the pressure differential. Intubation of patients, however, can worsen outcomes in patients with COVID-19, even on the ground.  The stress on the ventilated patients during transport may also make sedation and mechanical ventilation more difficult.  The newer containment modules, like the negative pressure connects, may allow sedation and mechanical ventilation to be more difficult.  The negative pressure connects may allow us flexibility in managing respiratory failure and allow us to avoid intubation and to perform intubation in flight.  But awake prone positioning was also found to improve oxygenation for that third case. Now, these lessons learned are specific to COVID-19 and may not apply to other illnesses.  And it may be tempting to apply some of these to future transportation of patients with other hemorrhagic fevers or other unrelated conditions.  And the caution is that each of those should be approached with the same level of caution and thoughtfulness that this mission was.  Thank you for listening and I appreciate your time.

Video Summary

The video transcript discusses the challenges and lessons learned from aeromedical evacuations during the COVID-19 pandemic. It highlights the various devices used for transporting contagious patients, such as the patient isolation unit, transport isolation system, aeromedical biocontainment system, and containerized biocontainment system. The limitations and strengths of each device are discussed, including their capacity for patients and the challenges of communication and equipment shortages during the pandemic. The transcript also presents three case studies, illustrating the physiological challenges faced during transport, such as fluctuating oxygen saturations and the need for intubation in-flight. The importance of communication between transport teams and local care teams is emphasized, as well as the need for operational readiness and adapting to mechanical difficulties. The transcript concludes with important lessons learned for future aeromedical evacuations.

Asset Subtitle

Crisis Management, Infection, 2022

Asset Caption

Military medical teams uniquely need to be able to manage the transport of critically ill patients, regardless of the nature of their illness, over great distances to receive definitive care. These teams must be able to deploy at a moment's notice and care for patients with complex polytrauma, acute respiratory failure, highly infectious diseases, and possibly children as well as adults. This session will review the capabilities and experiences of the U.S. military's critical care air transport (CCAT) teams, as well as lessons from their work that may be broadly applicable to "earthbound" critical care.

Meta Tag

Content Type Presentation

Knowledge Area Infection

Knowledge Area Crisis Management

Knowledge Level Intermediate

Knowledge Level Advanced

Membership Level Select

Tag Disaster

Tag Infectious Diseases

Year 2022

Keywords

aeromedical evacuations

COVID-19 pandemic

patient isolation unit

transport isolation system

aeromedical biocontainment system

case studies

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