Special Reprint: Ambulance Report

Occupant Protection for Ambulance Passengers: An Overview

      Ambulances, revered for their role in saving lives, present risks to crew and patients that have attracted increased interest recently. This is due largely to the individual research efforts of Nadine Levick, M.D., an emergency physician at Harlem Hospital in New York City, and Marilyn Bull, M.D., a developmental pediatrician at Riley Children’s Hospital, Indianapolis, Ind. Dr. Levick’s work, supported in part by the PED-SAFE-T EMSC targeted issues grant, has been publicized through a number of recent papers and articles. Dr. Bull was awarded the “Out of Hospital Care Award” by the American Academy of Pediatrics Section on Emergency Medicine in October of this year.
      Recently, the American Ambulance Association, which had been instrumental in supporting Dr. Levick’s vehicle crash tests, established a special task force to address EMS transport safety issues. It is developing a clearinghouse of EMS transport safety information to be available via its web page. Meanwhile, more and more EMTs and medics are becoming trained in child passenger safety and aware of the problems of occupant protection for themselves and patients.

The problem
      Ambulance crash data have recently revealed the risks for EMTs and paramedics as well as patients being transported by ambulance. There are an estimated 5000 ambulance crashes annually, causing approximately one fatality per week (25 percent to ambulance occupants, often EMTs or paramedics) and many serious injuries daily. Intersection crashes of ambulances, both frontal and lateral, are most commonly associated with serious injures.
      Emergency vehicles are very different from passenger vehicles and have unique functions. Occupants sit facing in various directions and have specific actions to perform during transport. There are no safety standards for providing care in a moving ambulance, although such standards exist for air-ambulance transport. While an emergency physician at Johns Hopkins, Dr. Levick studied how a group of patients under age 14 were actually transported in ambulances. She found that 76 of 206 children (37 percent) were unrestrained on the bench or a person’s lap. More than half were on the gurney, and over 10 percent of these were not restrained while others were using the one of the two sets of adult straps. (SRN, July/Aug. 2000)

Sled and crash tests of patient compartments
      Dr. Levick’s focus has been on the emergency vehicle as a system. She emphasizes that unless all occupants and equipment are properly restrained, risks are high to properly restrained individuals. She conducted sled tests of the intact rear ambulance patient compartment with adult dummies and a restrained child dummy in 1999 (1,2).
     In 2000, Levick ran vehicle-to-vehicle ambulance crashes with instrumented dummies in the patient compartment (3). Frontal and side impacts were used to show the effects of common real-world scenarios. A 3-year-old child dummy was secured in a convertible child restraint anchored to the gurney via two belt paths with the gurney back semi-upright at about 45 degrees. In addition, male and female adult dummies were in the patient compartment; one unrestrained in each test and the other two lap-belted. Two dummies were on a side-facing bench seat and the other in the rear-facing attendant’s seat. Medical equipment was included make the environment as realistic as possible.
     The dangers of unrestrained occupants and/or unrestrained equipment striking other occupants was demonstrated clearly in these tests. For example, the child dummy was struck head-first by a 80 kg (176 pound) dummy. Recommendations included increased vehicle padding and attendant head protection in addition to the use of restraints by all occupants and for all equipment. Data from these tests were used to develop crash pulses to be used in further testing.

Child restraint use modes tested
     Over a number of years, Dr. Bull and her colleagues have conducted sled tests of various child restraints and isolettes on ambulance gurneys at the University of Michigan. The anchors for the gurneys failed in the early tests.
     In the most recent tests (2000), redesigned gurney anchors performed significantly better. A convertible CR installed facing the rear and a Cosco Dream Ride car bed performed well (SRN, Sept./Oct. 2001) (4). Both restraints were secured using two belts that are standard equipment on gurneys. The Dream Ride Car Bed was positioned laterally and equipped with a second set of belt loops to enable belts to be attached on either side of it. In the convertible restraint, both an infant and a toddler would be positioned facing the rear.

Transporting children
      EMS providers who are involved in child passenger safety as technicians and educators have many questions specifically about transporting children. In 1999, the Emergency Medical Services for Children (EMSC) Program of NHTSA and DHHS issued general guidelines for transporting children: Do’s and Don’ts of Transporting Children in an Ambulance (SRN, Fall 1999). The guidelines were developed by a team led by Dr. Levick. They were intended to be interim guidelines pending the availability of more specific technical data and methods of anchoring child restraints such as those outlined in the recent publications by Drs. Bull and Levick. So far, it has not be updated.
      There remain many questions about effective restraint designs and operational protocols for the crew. The most crucial and immediate take-home messages from the tests so far are:
      • Ambulance drivers should use caution and avoid unnecessary speed.
      • Restraints should be used by all occupants.
      • All equipment should be fastened down securely.
SRN will publish a follow-up article on real-world activities to protect children in ambulances in an upcoming issue. NOTE: Since the methods of anchoring CRs used by both Dr. Levick and Dr. Bull are unorthodox, manufacturers must be consulted before using their products in this way.

References
1) “Biomechanics of the patient Compartment of Ambulance Vehicles under crash conditions: Testing countermeasures to mitigate injury,” Levick NR, Li G, Yannaccone J, Society of Automotive Engineers Technical Paper 2001-01-1173; www.sae.org/servlets/index (search by paper number)

2) “Development of a dynamic testing procedure to assess crashworthiness of the rear patient compartment of ambulance vehicles,” Levick NR, Li G, Yannaccone J, Enhanced Safety of Vehicles Technical Paper # 454, May 2001.

3) “Ambulance crashworthiness and occupant dynamics in vehicle-to-vehicle crash tests: Preliminary report,” Levick NR, Donnelly BR, Blatt A, et al. Enhanced Safety of Vehicles, Technical Paper # 452, May 2001

4) “Crash Protection for Children in Ambulances,” Bull, MJ, Weber, K, Talty, J, Manary, M, 45th Annual Proceedings, Assoc. for the Advancement of Automotive Medicine, 2001; http://www.carseat.org/Resources/Bull_Ambulance.pdf