The impact of a physician-staffed helicopter on outcome in patients admitted to a stroke unit: a prospective observational study

Kamilia S Funder, Lars S Rasmussen, Nicolai Lohse, Rasmus Hesselfeldt, Volkert Siersma, Jesper Gyllenborg, Sandra Wulffeld, Ole M Hendriksen, Freddy K Lippert, Jacob Steinmetz, Kamilia S Funder, Lars S Rasmussen, Nicolai Lohse, Rasmus Hesselfeldt, Volkert Siersma, Jesper Gyllenborg, Sandra Wulffeld, Ole M Hendriksen, Freddy K Lippert, Jacob Steinmetz

Abstract

Background: Transportation by helicopter may reduce time to hospital admission and improve outcome. We aimed to investigate the effect of transport mode on mortality, disability, and labour market affiliation in patients admitted to the stroke unit.

Methods: Prospective, observational study with 5.5 years of follow-up. We included patients admitted to the stroke unit the first three years after implementation of a helicopter emergency medical services (HEMS) from a geographical area covered by both the HEMS and the ground emergency medical services (GEMS). HEMS patients were compared with GEMS patients. Primary outcome was long-term mortality after admission to the stroke unit.

Results: Of the 1679 patients admitted to the stroke unit, 1068 were eligible for inclusion. Mortality rates were 9.04 per 100 person-years at risk (PYR) in GEMS patients and 9.71 per 100 PYR in HEMS patients (IRR = 1.09, 95% CI 0.79-1.49; p = 0.60). The 30-day mortality was 7.4% with GEMS and 7.9% with HEMS (OR = 1.02, CI 0.53-1.96; p = 0.96). Incidence rate of involuntary early retirement was 6.97 per 100 PYR and 7.58 per 100 PYR in GEMS and HEMS patients, respectively (IRR = 1.19, CI 0.27-5.26; p = 0.81). Work ability after 2 years and time on social transfer payments did not differ between groups. We found no significant difference in mean modified Rankin Scale score after 3 months (2.21 GEMS vs. 2.09 HEMS; adjusted mean difference = -0.20, CI -0.74-0.33; p = 0.46).

Discussion: The possible benefit of HEMS for neurological outcome is probably difficult to detect by considering mortality, but for the secondary analyses we had less statistical power as illustrated by the wide confidence intervals.

Conclusion: Helicopter transport of stroke patients was not associated with reduced mortality or disability, nor improved labour market affiliation compared to patients transported by a ground unit.

Trial registration: The study was registered at ClinicalTrials.gov ( NCT02576379 ).

Keywords: Disability; Helicopter emergency medical services; Labour market affiliation; Mortality; Stroke.

Figures

Fig. 1
Fig. 1
Flowchart of included patients. GEMS: ground emergency medical services; HEMS: helicopter emergency medical services
Fig. 2
Fig. 2
Cumulative risk of death in patients admitted to the stroke unit. GEMS: ground emergency medical services, HEMS: helicopter emergency medical services

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