How We Built a Better Ambulance

We knew it would be a challenge to design new specialty-care transport ambulances that were both efficient for medical teams and safe for patients and crews. Engaging in a free flow of ideas with vendors and stakeholders while working to remain fiscally responsible complicated the effort further. But we were able to do all this and more to achieve our operational goals for The Children’s Hospital of Philadelphia’s Emergency Transport Team.

In developing the vehicles, we blended the latest technology with a safety package that provides all occupants with a safe operating environment both internally and externally. The design team and ambulance manufacturer, American Emergency Vehicles (AEV), worked together to create three new specialty-care transport units for the hospital (known as CHOP) and American Medical Response. Over the past five years, CHOP and AMR have shared a unique partnership providing advanced critical care to a diverse neonatal and pediatric population. Three ambulances are equipped to provide care to patients from neonates through adults, and they meet EMS licensure requirements for Pennsylvania and New Jersey.

Getting Started

We reviewed crash data testing from Objective Safety and concluded many ambulance crashes cause catastrophic injuries and deaths due to design flaws within the patient compartment. Around 22 people die every month in ambulance crashes. Objective Safety provided video crash-testing using dummies in scenarios common to the transport and 9-1-1 environments. AEV also has done crash-testing of its design and demonstrated maintenance of box integrity through multiple 40-mph T-bone-type impacts. AEV defined safety zones that required attention and made design recommendations to minimize occupant injury potential. We took that information and worked closely with AMR and AEV to design the vehicles.

The CHOP Emergency Transport Team (ETT) transports approximately 3,000 patients every year by ambulance, helicopter and fixed wing. The team averages 2,500 ground transports annually. Its ambulances average approximately 7,500 miles a month. Important among our needs was a dependable chassis that could withstand the rigors of constant urban/suburban use. Up to this point the industry has utilized mostly Ford E-350 Super Duty diesel ambulance chassis. These have 7.3-liter diesel engines coupled to robust transmissions to handle the torque required for propulsion. This causes a lot of front-end weight issues that require increased vigilance by maintenance personnel. The diesel engines also require extra care to keep running efficiently. CHOP and AMR encountered several major engine failures over their five-year working period that led to significant out-of-service intervals. AMR’s fleet management team noted these events and suggested CHOP consider the Ford E-450 Super Duty chassis with the V-10 Triton gas engine. Several of AMR’s operational hubs in the Midwest use them with great success. We decided to mount them on the Ford gas chassis based on out-of-service data and AMR’s recommendations.

The Patient Care Area

The next challenge was to design a patient care area that was both safe and efficient, blending ergonomics with functionality. One big concern was rider comfort. A normal CHOP ground transport can range between 2–5 hours depending on the destination and traffic. We knew having a comfortable ride would reduce stress and fatigue on providers, allowing them to maintain focus during patient care. CHOP, AEV and EVS (Emergency Vehicle Seating) Ltd. held a conference call to discuss our concerns. This helped EVS engineers understand our unique needs, which allowed them to design and build one-of-a-kind custom seating for the transport team. The seats provide the rider with comfort for long trips as well as a crashworthy design.

The finished product is constructed with an integrated five-point restraint harness in high-visibility yellow. The harnesses have pretensioners built in that allow the occupant to move freely in the seat but lock when stressed by G-forces. The seats adjust forward and aft and are on a swivel base that locks in various attitudes to allow the crew to get close the patient and remain seated while the vehicle is in motion.

The Interior

We planned the interior crew area to maintain function and diminish the potential for injury. Head strikes and projectiles are two of the major causes of injuries to crew members in the patient care area. By padding and protecting corners, we reduced the risks associated with head strikes during a crash. We integrated a full LED lighting package with technology to make the atmosphere bright as well as functional. The LED task lighting above the crew seats can be switched from white to red to allow crews to acclimate during nighttime operations. To decrease the potential for projectile injury, we carved out space for all our gear to fit in specific spaces. All cabinets are backlit to illuminate stock. We moved our spare gas cylinders to an outside compartment to further enhance the team’s safety.

We incorporated crash mounting for our equipment in the crew area to decrease our risk of injury in a crash. We utilized TMS Medical Technologies mounts for our defibrillator/monitors. These are rated for high-G-force crashes. AMR equips each vehicle with the Road Safety vehicle monitoring system, which monitors vehicle operating parameters and provides active feedback to the operator. The EMTs utilize an electronic PCR on Panasonic Toughbooks that link them to their base via on-board gateways through the Road Safety system. The Toughbooks are mounted in Havis-Shields docking stations to keep them secure during transport.

A camera in the patient compartment allows the EMT and parent to view the team in the back during transport. We lowered the curb entry step to allow for safer entry and exit. The vehicle contains dual environmental control systems; one functions only when the vehicle is plugged in to shore power and allows us to maintain a constant internal temperature. Patient comfort was just as important; we worked closely with CHOP’s Child Life, Education and Creative Arts Therapy team to provide a transport that is safe and kid-friendly. We incorporated an AM/FM/TV/DVD system with a 17-inch flat-panel high-definition monitor built into the rear overhead panel. The system also has integrated surround sound.

Compartment space is limited, so accommodating all the gear we’re required to carry and the additional gear used in daily operations was challenging. We raised the roof 4 inches to gain compartment space and allow us to stand upright when entering and exiting the vehicle. AMR packaged all the required equipment in clear sealed bags with inventory and expiration dates. This helped condense and secure everything. The rest of the space stores all our operational gear. Each compartment is backlit for easy visualization of stock, and we added electrical power to compartments that house equipment that requires power to charge.

We transport a wide range of patients with many types of medical issues, including trauma. We incorporated the Smithworks fluid warmer to carry two one-liter bags of normal saline solution. The fluid temperature is maintained at a constant 104ºF. We also have a Norcold refrigerator to transport medications and mother’s milk. Backup and redundancy is important in transport medicine. We specified two Vanner 1,800-watt inverters and one 3-kw gas-powered Kohler generator. Each unit can handle the entire electrical load and back the other up.

The Exterior

The vision and concept for the exterior of the vehicles was shared by AMR and CHOP. The goal was to provide a vehicle that was aesthetically pleasing and projected robust lighting and reflectivity to other vehicles. We worked for several weeks with AEV’s graphics design team on renderings that met our visual needs and could be approved by CHOP public relations and the Pennsylvania and New Jersey offices of EMS. The final graphics package is completely reflective on all sides. Additionally the DOT striping and outline striping allow for optimum visualization at night. The transport team occasionally stops at accident scenes while responding to referring facilities and provides EMS care until emergency providers arrive. We added an arrow stick above the rear doors to provide visual guidance to oncoming traffic during highway operations. Additionally each crew member has a DOT-compliant reflective vest to use during roadway incidents.

The external lighting package is completely LED. This is brighter and reduces amperage draw on the electrical system. We specified the Opticom traffic control system for traffic lights and requested a dual siren system that projects sound in two modes. AEV offered a great option to meet our needs: The primary siren is enhanced by the Whelen Howler system. These work together to provide sound projection and coverage. The system is equipped with two 1,000-watt subwoofers mounted in the bumper. They project sound down and out in the lower decibel range, which penetrates the sound protection of newer vehicles. Traffic now not only hears us but can feel the sound of our vehicle as we approach.

The Northeastern U.S. encounters weather patterns that concerned us as we planned. We get frequent rain, sleet and snow in the winter, but do not always require chains. AEV and AMR allowed us the flexibility to use chains as the weather dictates. We specified automatic tire chains that let us navigate roads in up to 4 inches of snow. This gives us operational capability in most conditions. Our emergency communications center utilizes real-time weather tracking and closed-circuit survellience of our roadways to provide a regional snapshot of flight and ground conditions.

The design process was a great learning experience. The trucks have been operational for about four months now with minimal issues. We have added a few small things to customize our work areas. The patients, team and clinicians we interact with are impressed by the level of thought and safety put into our vehicles. The gas engines are holding up well. They do, however, require a more aggressive preventive maintenance schedule due to mileage and the difference in how much oil the gas engine requires (6 quarts vs. 16).

We spent many hours planning to maximize the safety and efficiency of our design and remain finincially responsible. Utilizing a team approach allowed all stakeholders to have their voices heard and was instrumental in the planning, building and delivery of three great critical care vehicles for CHOP. We have enjoyed the openness and flexibility of AMR and AEV to help us create state-of-the-art vehicles to help our kids.

Louis Bellace, RN, BSN, MS, PHRN, CEN, CMTE, is a senior nursing leader on the Critical Care Transport Team of The Children’s Hospital of Philadelphia. He has been a critical care nurse for 25 years, and has extensive clinical and administrative experience in fire and EMS operations. He has consulting expertise in ambulance research and design, and remains active in this field. His areas of interest are equipment technology and prehospital care. He provides logistics expertise to the team in several clinical areas including ground and flight EMS operations. He is a reserve officer in the United States Air Force where he served in Iraq and Afghanistan as a flight nurse airlifting wounded soldiers.