General aspects
This is a prospective analysis performed with approval of the Regional Ethical Review Board in Umeå, Sweden (diary number 2012-95-31 Ö). Predetermined and specific time points for consecutive intensive care transports by road, helicopter and fixed-wing transports were recorded by the intensive care ambulance medical personnel for the following periods: October 2008 – January 2009 for fixed-wing as part of an internal prospective review, and then June 2012 to January 2013 for road and helicopter ambulances as part of an expanded study protocol. Time points were recorded in order to measure the time intervals for the preparatory, actual transport (time with patient), and system restoration phases, and this was done in order to establish ‘templates’ for each of the individual steps in the process. For the preparatory phase, the times that were measured included the following: telephone contact from ambulance dispatch center to physician on call, time from telephone contact to decision (to go) time, time from decision until at ambulance site and mission-ready, and other preparation time. These ‘preparation’ times were added together and combined to a category which was then called pre-transport time. Times with the patient were recorded for the following events: report and handover from ICU team to transport team, transport within hospital and loading in ambulance (these times not included in the calculation since they were the same for all systems), time until pick-up by connecting local ambulance and time for local ambulance transport to local airport (both specific for fixed-wing and helicopter), time for loading from local ambulance to FW, flight time (defined as lift-off and landing times for air-ambulances) or driving time (from ambulance hall to ambulance hall), time for report and hand-over, time for loading into the ambulance, and time after completed handover, and total time with patient for medical crew. Finally, times were noted for ground transfer between FW and road ambulance without patient, back to ambulance station for cleaning/resetting/refilling in order to be mission-ready again (restoration times).
The fixed-wing aircraft employed in the air ambulance role was a two-engine turboprop with pressurized cabin (Beech 200 Super King Air), represented as FW1. The helicopter (rotor wing, RW) types employed included the following: Eurocopter AS 365 N3 Dauphin (RW1) and Eurocopter AS 365 N2 Dauphin (RW2 and RW3), which both have the same cruising speed, though different lift capacities. The transit travel speed (template) for the FW was 500 km/hr (310 miles/hr), for RW was 270 km/hr (167 miles/hr), and for road ambulance (RA) 70 km/hr (42 miles/hr). The local RA speed for moving FW-transported patients from the airfield to the receiving hospital was set at 50 km/hr (31 miles/hr).
Cost estimations for each of the ambulance systems were based on information provided by the hospital administrator responsible for the regional ambulance contracts with the private ambulance vendor, and were based on the ambulance contract itself, and are provided in Swedish kronor (SEK). The costs for medical crews are the costs reported by each of the county councils for the medical crew cost (for year 2012). Annual flying hours for the FW and RW systems were based on the averages from the previous two years. For the RW1, measured for the Norrbotten county, Gällivare city system with two pilots as aircrew, the total operating costs per hour (hr) were derived from an estimated annual activity of 750 flying hours, fixed costs of 37,000 SEK/hr, operating costs of 12,800 SEK/hr, personnel costs of 11,000 SEK/hr (one specialist physician and one specialist nurse as medical crew), administrative costs of 900 SEK/hr. This lead to a total hourly mission cost of 61700 SEK/hr.
For the RW2, measured for the Västerbotten county, Lycksele city system with two pilots as aircrew, and for an estimated annual activity of 700 flying hours, fixed costs of 25,714 SEK/hr, hourly operating costs of 8,000 SEK/hr, personnel costs 7,895 SEK/hr (one specialist physician and one specialist nurse as medical crew), administrative hourly 71 SEK/hr, this allowed us to derive an hourly mission cost of 41,610 SEK/hr.
For the RW3, measured for the Jämtland county, Östersund city system, and for an estimated annual activity of 737 flying hours with one pilot and one pilot assistant (helicopter emergency medical service crew/HEMS) for aircrew, fixed costs of 24,483 SEK/hr, hourly operating costs of 9,500 SEK/hr, personnel costs 3,053 SEK/hr (one specialist nurse alone as medical crew), administrative hourly 814 SEK/hr, this allowed us to derive an hourly mission cost of 37,850 SEK/hr.
For the FW system, measured for the Northern Sweden region, operating with two pilots and a specialist nurse for aircrew, and for an estimated annual activity of 2,400 flying hours (based on previous 2 years activity), fixed costs of 0 SEK/hr, hourly operating costs of 21,301 SEK/hr, personnel costs 4,430 SEK/hr (specialist physician and specialist nurse as medical crew), administrative hourly 100 SEK/hr, this allowed us to derive an hourly mission cost of 25,831 SEK/hr.
For the RA system, the estimation was based on a per-kilometer cost, from the county council’s own estimation of costs based on approximately (nationally) 8,200,000 SEK per ambulance per year, and 100,000 kilometers, leading to an estimation of 82 SEK per km. This was converted to an hourly cost of 5,740 SEK/hr, based on average transit speed of 70 km/hr (43 miles/hr). For the RA system, there was typically an additional nurse from the ‘sending’ hospital accompanying the patient. These cost estimations were simplified to the following, to ease further calculations: RW1 60,000 SEK/hr, RW2 and RW3 40,000 SEK/hr, FW 25,000 SEK/hr, and och RA 6,000 SEK/hr.
Cost-distance is defined as the cost per km patient transportation with the given ambulance system. This was calculated from the cost per hour of operation for each ambulance system using the template for travel speed during transit for each of the systems: RA = 70 km/hr, RW 270 km/hr and FW 500 km/hr. For FW, the road ambulance connections between airport and hospital (template distance 10 km, 50 km/hr, medical crew plus RA costs for this segment which add up to 9,970 SEK for both sending and receiving hospital/airport connections) were included in the time and speed assessment.
Cost estimates for each ambulance system are based on reports from each of the county councils (Table
1), and consist of ‘costs’ in the contracts with the private air ambulance companies for operational support for public hospital missions, as well as different county council contracts and medical crew salaries. The FW fixed costs are not presented separately in the contracts, but are rolled into hourly costs, and these are presented. Only the helicopter systems here present fixed costs. These different RW systems include one (with HEMS) and two pilot (no HEMS) helicopter aircrew configurations. Medical staffing in the ambulance is shown for each system (Table
1), and was either 2 nurses, or a physician and nurse. Physician and nurse costs are presented as an hourly mission cost, and these were collected for each county and ambulance system. Medical crew costs included ‘on-call’ availability costs.
Table 1
Ambulance system cost estimations
RA | 6,040 SEK/hr | included | | included | | 82, SEK/km 57,740 SEK/hr | 95% | 300 SEK/hr | 5% | included | |
RW 1 | 61,700 SEK/hr | 37,000 SEK/hr | 60% | 12,800 SEK/hr | 21% | 50,700 SEK/hr | 82% | 11,000 SEK/hr | 18% | 900 SEK/hr | 1% |
RW 2 | 41,610 SEK/hr | 25,714 SEK/hr | 62% | 8,000 SEK/hr | 19% | 33,715 SEK/hr | 81% | 7,895 SEK/hr | 19% | 71 SEK/hr | < 1% |
RW 3 | 37,850 SEK/hr | 24,483 SEK/hr | 65% | 9,500 SEK/hr | 25% | 34,947 SEK/hr | 92% | 3,053 SEK/hr | 8% | 814 SEK/hr | < 1% |
FW | 25,831 SEK/hr | none in this contract | | 21,301 SEK/hr | 100% | 21,301 SEK/hr | 82% | 4,430 SEK/hr | 18% | 100 SEK/hr | < 1% |
In addition to the distance-cost estimation (based on the above schematized average speeds for each system), there was added a schematized start-cost based on time on the ground with patient. For all the RW systems, the time in the helicopter before and after flying was estimated to be 4 minutes total (aircraft start-up and shut-down): RW-1 4,000 SEK, RW-2 and RW-3 2,667 SEK. For the FW system, the patient time in the aircraft before flying was estimated to be 10 minutes before take-off and 10 minutes after landing, for a total of 20 nonflying minutes in the aircraft, and this was added to the 12 minutes (times 2) for each ground ambulance transport from or to hospital. This resulted in 9,970 SEK standing ground costs for each FW transport mission. The RA system reported a start-up cost of 1,640 SEK, which was the standing start cost for all RW transport missions.