Which groups of patients benefit from helicopter evacuation?

The evacuation of emergency cases by air, usually by helicopter, is controversial because of the cost of the programme, the possibility of an accident (especially in an urban area), and unproven benefit. But such evacuations cannot be studied by a random intervention (eg, air versus ground ambulance). We used an expert-panel approach to estimate the health outcome for patients transferred by emergency helicopter compared with the potential outcome if they had gone by surface ambulance.

The helicopter programme is based at the University Hospital of Tromsø in northern Norway. 370 case-reports of helicopter evacuation from rural areas were screened by anaesthetists for routine and case-specific data. Two expert panels assessed the cases for potential additional health benefit arising from the fact of helicopter evacuation. The panels used a modified Delphi technique to reach consensus in life-years gained. One panel met for cases aged under 15 and pregnant women, the other for older cases.

240 of the 370 cases were male (65%); the age range for both sexes was 0-86 years. The most common diagnosis for the 55 cases aged under 15 was infection (49%); in older patients, cardiovascular disease dominated (50%). Trauma accounted for just under a fifth of cases in both groups. On average, the patients arrived 69 min (range 0-615) earlier in hospital than if they had gone by ground transport. For 283 cases, the initial screening by the anaesthetists indicated no additional benefit compared with that obtainable by ground-ambulance transport. The main reason was that no treatment was given during the flight or early on in hospital that could not have been given otherwise. 90 cases entered the expert panel system. Of these 90, 49 cases were judged to have received no additional benefit. This left 41 (11% of the total of 370 evacuated) who were judged to have benefited, gaining 290.6 life-years. 96% of the total number of life-years gained was achieved in nine patients, six of whom were aged below 7 (four were aged 0-7 months). The life-year-gain per adult patient with cardiovascular disease was 0.54.

We conclude that an emergency helicopter service can provide considerable health benefits for selected patients, at least in this rural setting. Given the costs and risks of such a service, the benefits for most patients are small.