In 2014 Southern California, like many areas of the United States, intensified planning and response to deal with potential Ebola patients arriving from affected West African countries, where more than 11,000 people eventually died. These efforts were tested in real life by 10 persons under investigation who were transported and/or evaluated over nine months, causing significant impacts to emergency departments, public health agencies, and the private and public components of the 9-1-1 system.
County EMS and public health agencies, local hospitals, and prehospital providers found that improvised efforts to isolate these patients during transport by wrapping the interiors of (often older, less reliable) ambulances with duct tape and plastic sheeting caused slip and trip hazards and dangerous overheating of the patient compartments due to the plastic covering floors and air conditioning vents. Furthermore, the vehicles’ drivers, unable to wear extensive PPE for safety reasons, had to hope for their safety that the patient compartment had been adequately sealed off using tape and plastic. The counties of Los Angeles, Orange, and Ventura came together to create a multifaceted regional solution to the challenge of treating and transporting highly infectious patients—using high-risk ambulances (HRAs).
While agencies may choose not to build dedicated high-risk ambulances, the innovations implemented for this project—isolating the patient compartment from the driver’s area and installing separate air conditioning systems for each; HEPA filtration/UV light disinfection; the creation of a negative-pressure environment; and including decontamination methods during design/construction—should be considered when purchasing new ambulances for day-to-day use. These innovations could address the infection-control and cross-contamination problems EMS has struggled with for years.
There are three main elements to the Southern California regional emerging infectious disease (REID) response.
First personnel had to be trained and equipped with specialized personal protective equipment: powered air-purifying respirators (PAPRs), suits, boots, and heavy gloves. Few EMTs/paramedics, nurses, and physicians have used PAPRs, nor are many familiar with a technical PPE donning and doffing procedure to prevent contamination. Most PAPRs have a battery life of 6–8 hours or so, so there may be a need for hydration, bathroom breaks, etc.
Los Angeles, Orange, and Ventura counties partnered with CARE, AMR, and McCormick ambulance companies, which each trained 30–40 personnel and agreed to host and operate the ambulances, which remained the property of Los Angeles County. Three area hospitals (Cedars Sinai, Kaiser Los Angeles, and Ronald Reagan UCLA Medical Center) have been designated by the California Department of Public Health as Ebola treatment centers, and the ambulance companies have been exercising with them at least twice a year.
Second, using Los Angeles/Long Beach Urban Area Security Initiative (UASI) grant funds, Los Angeles County EMS convened a multidisciplinary team to design the six HRAs. The team included ambulance, EMS, hospital, public health, epidemiology, risk management, and fleet personnel. The goal was to create vehicles that were easy to decontaminate, had separate AC systems for the driver and patient compartments, and achieved negative-pressure status for the treatment area. The team considered van and modular-type ambulances but opted against them due to cost and because they units would not be used for standard patient transports.
New design elements included a welded and caulked steel bulkhead behind the driver’s and passenger’s seats that sealed off the patient compartment. When the vehicles were deployed, several older paramedics noted they were uncomfortable not being able to see into the rear of ambulance. To address this we installed an intercom (which could be kept permanently on) between the two areas. Sealed windows were also a possibility.
Two air conditioning systems were built into each unit: one for the driver’s area and one for the patient compartment, with a high-capacity AC unit (as personnel in PAPRs can easily become overheated) with integrated HEPA filtration and HEPA filter exposed to UV light disinfection. Similarly, the exhaust fan near the rear doors has HEPA filtration and UV disinfection so any air discharged from the unit is filtered. The AC unit was placed above the patient’s head in the bulkhead wall, ensuring head-to-foot airflow patterns to better protect treatment personnel in case of a suit breach. Design specifications exceeded both ambulance and hospital isolation room air exchange and negative-pressure airflow requirements.
After a bidding process Leader Emergency Vehicles, a local manufacturer, was chosen as the vendor to build six units. Specialized testing equipment (borrowed from a hospital) was needed to check the negative-pressure status of the vehicles during construction. They achieved twice the standard of negative-pressure rooms.
The interior of the patient compartment was constructed with no shelves or compartments and finished with a white laminate material that would easily show contamination and be decontaminated. Instead of a bench seat there are two chairs, which swivel 270 degrees, across from the stretcher and a captain’s chair at its head. The chairs are made from light-colored molded plastic foam without sewed seams, and the seat belts are bright yellow, again to show contaminants/ease decontamination. The ambulance has space for onboard oxygen, but all other medical equipment will be brought in, including suction.
The light-colored floor of the treatment area has high-strength tie-down brackets and carabiners to secure the equipment and bags in case of rollover. Besides the oxygen, only a folding backboard (to assist in lifting incapacitated patients) and body-fluid spill kit are kept permanently in each unit. Local and state authorities waived minimum equipment requirements for these special vehicles. The total cost for each ambulance was approximately $90,000 without stretchers, equipment, etc.
Patient privacy during these (possibly high-profile) transports is a concern. The side and rear windows of the patient compartment received the darkest possible interior and external tint coatings. Despite this, at night when the interior is fully illuminated, there is still more visibility than the design team would like. We continue to look for solutions, including taping paper drapes inside the windows.
A tablet mount was installed inside over the rear door, overlooking the stretcher. During exercises the treatment team live-streamed the entire patient transport to the receiving facility using a HIPAA-compliant Internet application. Due to the difficulty of spoken communications while wearing PAPRs, the EMTs held up a whiteboard with written updates. This was very useful to the receiving practitioners.
As the third element of the response, we considered several methods for patient compartment decontamination. Removing visible contaminants and wiping down all compartment surfaces with an approved solution is always the first step. Ambulances in Europe have been constructed with UV disinfection lights in the ceiling above the stretcher, and crews are expected to turn them on (via timer) as they leave the vehicle. This allows an unattended disinfection process. However, as UV light exposure can cause eye injury, the bulbs contain heavy metals that might be released during an accident, and because the HRAs are not expected to be used in 24/7 operations, no integrated decontamination system was installed. A hanging UV disinfection light, operated by remote control, was purchased for use in the ambulances.
Los Angeles County EMS is also in the process of purchasing handheld decontamination misters to complement this. With hindsight, the design team might have had integrated decontamination mister ports/valves installed in the compartments. Integrated ports would allow EMS personnel without PPE to simply attach a mister externally to the patient or driver’s compartment and fill it with the disinfectant mist.
Other crucial questions remain, especially for highly lethal diseases like Ebola. Who completes and certifies the decontamination process? Would your agency personnel perform an initial wipe-down and/or the final back-in-service decontamination? Would you hire a private vendor or ask local public health or environmental health to assist? Would other patients/crews be safe and feel comfortable using that ambulance the next shift?
There are several ways to check decontamination, including disposable tabs that change color when exposed to sufficient cleaning solution, DNA testing, and swabbing/culturing for viruses and bacteria. These processes are highly technical and will need support from local authorities and equipment vendors.
Operationally there are numerous issues to consider when dealing with highly infectious disease patients (or potential patients). These include the level of care that can be provided in PAPRs (BLS/ALS/CCT) and the equipment needed to do so; whether to send more than one ambulance per patient in case of suit breach/vehicle failure; employee monitoring after a transport; who will accept the medical waste; how will confirmation of patient death be performed if needed; decedent management; whether to use patient isolation pods; suit breach and team injury/illness protocols; and sending nurses/doctors/technicians into homes to evaluate low-acuity patients and draw blood, among others.
The new SoCal high-risk ambulances have been used successfully in multiple exercises, including the federal multistate air-transport exercise Tranquil Terminus. And while the units are arguably overkill for patients who have or are suspected to have COVID-19 or similar diseases, we have already transported one high-risk coronavirus passenger using them.
Protection of the ambulance personnel who rode up front and communicated by intercom and ease of decontamination were both cited as reasons to utilize a high-risk ambulance. Southern California health/EMS authorities will also consider them for other scenarios, such as patient contaminated by nerve agents or other chemical/radiological exposures.
Finally, while it’s likely only a few large jurisdictions can afford dedicated highly infectious disease ambulances, we believe the innovations implemented for this project should be considered by all agencies as they design and purchase new vehicles. A bulkhead wall (with or without sealed window) and separate HEPA-filtered AC systems would protect the driver and passenger; creating a negative-pressure environment enhances those protections; and minimizing cabinets, compartments, and difficult-to-clean areas and considering vehicle decontamination (integrated UV lights/mister ports) from the beginning would protect our personnel, our patients, and our communities from both these novel diseases and the ones we’ve been battling for decades.
Sidebar: What About Coronavirus?
As the COVID-19 situation evolves, use of the high-risk ambulances in Southern California is growing but controversial even among the agencies that host them. They have already been used to transport passengers at high risk of having COVID-19, due to their ease of cleaning/decontamination and the fact that the crew can ride up front without PPE due to the separate air conditioning system. The passenger communicates with the crew via intercom. Use of the ambulances on actual COVID- 19 patients is anticipated. For a (relatively) low-mortality airborne-transmissible disease with high likelihood of community spread, these ambulances can be seen as overkill. However, we believe the concepts of separating the driver compartment, making disinfection easier, and having filtered air in the patient compartment will help protect patients, personnel, and the public during disease outbreaks such as COVID-19.
Michael Noone, NRP, has been a paramedic for 24 years and works for the Los Angeles County EMS Agency handling regional disaster medical health mutual aid coordination. This has included incidents such as the 2015 San Bernardino terrorist attack, 2017 Thomas fire, 2019 Woolsey fire, and COVID-19. He has deployed to natural disasters in Haiti, the Philippines, Nepal, and the United States, directed emergency management exercises in Ethiopia for USFS-IP/USAID, and published on international disaster volunteering.