|Air ambulance transportation with capabilities to provide advanced life support
|Moga C, Harstall C
This review compared transport by helicopter ambulance with ground ambulance transport. Although patients transported by helicopter seemed to show benefits overall, most included studies appeared methodologically weak and the authors concluded that decisions about which form of transport to use were complex and needed to take account of many factors. The cautious conclusions appropriately reflected the limitations of the evidence.
To evaluate the efficacy/effectiveness, safety and efficiency of air ambulance transportation with on-board capabilities to provide advanced life support (ALS).
The authors searched The Cochrane Library, PubMed, CRD databases, Web of Science, CINAHL, BIOSIS Previews, EMBASE and Scopus in July 2007. Search terms were reported. Additional searches were made of library catalogues, guidelines, regulatory agencies, grey literature sources, other HTA resources and search engines. Searches were limited to studies published in English in 2000 or later.
Studies comparing helicopter transport with fixed wing (aeroplane) and ground transport were eligible for the review. All forms of transport had to be capable of providing ALS. Studies of patients with trauma or medical or surgical conditions were eligible. Outcomes of interest included mortality during transport or in hospital, morbidity associated with preparing the patient for transport, time required for transport, hospital length of stay and outcomes of interventions applied during transport. Safety and cost outcomes were also included. Included studies involved both trauma and medical patients being transported from the scene of an incident to a healthcare facility or between facilities. All included studies compared helicopter with ground transport. Study selection was performed by one reviewer.
Assessment of study quality
The authors did not state that they assessed validity.
Data were extracted by one reviewer using a standardised form and checked by a second reviewer.
Methods of synthesis
Studies were discussed in a narrative synthesis classified by type of transfer (on-scene or interfacility) and type of patient involved.
Results of the review
Sixteen studies were included, all but one of which were retrospective. The authors stated the results were subject to bias because of weak study designs. The total number of patients included was not clear; sample size ranged from 60 to 16,699. Study results varied according to the type of patient and the distance they had to be transported. Most of the review findings were based on only one or two studies. There were no studies comparing helicopter with fixed wing aeroplane transport. Overall, patients transported by helicopter showed a benefit in terms of survival, time to reach a healthcare facility, time to definitive treatment and outcomes of treatment compared with those using ground transport.
Cost information was retrieved from eight studies, one of which found air transport to be cost-effective for acute stroke patients requiring thrombolysis. A study in Alberta found that ground transport to a trauma centre from rural areas cost a median $494 compared with $1,254 for helicopter transport. For transfer from a rural healthcare facility to the trauma centre, median costs were $1,157 (ground) and $2,118 (helicopter).
Both air and ground transportation have a role in the healthcare system. Decisions about the appropriate mode of transport are complex and need to take account of various factors, including access to the scene, the patient's condition, availability of different forms of transport, safety of transport, location and availability of financial resources.
This review addressed a clear question and had clear inclusion criteria for interventions, participants and outcomes. Inclusion criteria for study designs were broad and most included studies were retrospective. The authors searched a wide range of sources, although the limitation to English language could have introduced language bias to the review. Study selection was performed by one reviewer, which could be a source of errors or bias in the review. Validity of included studies was not formally assessed, but the authors stated that most were at high risk of bias. Hence, these studies and any synthesis derived from them may not have been reliable. The use of a narrative synthesis was appropriate in view of the wide range of patients, outcomes and study designs included. The authors' cautious conclusions appropriately reflected the limitations of the evidence presented.
Implications of the review for practice and research
Practice: the authors did not state any implications for practice.
Research: the authors stated that a registry or database covering both medical and trauma patients should be implemented to evaluate different forms of patient transport in Alberta.
Alberta Health and Wellness
Moga C, Harstall C. Air ambulance transportation with capabilities to provide advanced life support. Edmonton, AB, Canada: Institute of Health Economics. 2008
Subject indexing assigned by CRD
Advanced Cardiac Life Support; Air Ambulances; Emergency Medical Technicians; Rescue Work; Transportation of Patients
Database entry date
This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.