title: The evolving role of helicopter emergency medical services in the transfer of stroke patients to specialized centers.
abstract: BACKGROUND
  In 1996, when the Food and Drug Administration (FDA) approved use of thrombolytic therapy for ischemic stroke, interfacility transport of stroke patients assumed increasing urgency.
  
  
  OBJECTIVE
  To describe one helicopter emergency medical services (HEMS) program's 15-year experience with interfacility transport of patients with suspected stroke, with emphasis on reporting changing patterns seen after the advent of thrombolytic therapy for stroke.
  
  
  METHODS
  This was a retrospective study of patients undergoing HEMS transport, during 1985-1999, with a pre-transport diagnosis of suspected ischemic stroke. Data collected included patient demographics and times of symptom onset, community hospital arrival, community hospital request for HEMS, and receiving hospital arrival. Patients were divided into pre-thrombolysis era (1985-1995) and thrombolysis era (1996-1999). Group characteristics were compared using Pearson chi-square, Fisher's exact, rank-sum, and logistic regression analysis.
  
  
  RESULTS
  There were 192 total transports, 76 (40%) pre-thrombolysis era and 116 (60%) thrombolysis era. Thrombolysis era patients were more likely (p < 0.0001) to have time of symptom onset documented, and also had significantly (p = 0.0003) shorter time intervals between referring and receiving hospital arrival. The shorter time intervals were due in part to decreased time lapse between referring hospital arrival and that hospital's request for helicopter transport; thrombolysis era patients were 2.5 times more likely than pre-thrombolysis era patients to have HEMS activation within three hours of community hospital arrival.
  
  
  CONCLUSIONS
  Helicopter EMS transport is playing an increasing role in interfacility transfer of patients with ischemic stroke. Earlier HEMS activation is associated with decreased time lapse between referral and receiving hospital arrival.
authors.affiliation: Boston MedFlight Critical Care Transport Service, Massachusetts, USA. thomas.stephen@mgh.harvard.edu
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Thomas
authors.forename: Christine
authors.initials: C
authors.lastname: Kociszewski
authors.forename: Lee H
authors.initials: LH
authors.lastname: Schwamm
authors.forename: Suzanne K
authors.initials: SK
authors.lastname: Wedel
mesh_terms: D017732:Air Ambulances / Q000458:organization & administration*; D001900:Boston; D006302:Health Services Research; D006782:Hospitals, Special / Q000706:statistics & numerical data*; D006801:Humans; D008485:Medical Audit; D010360:Patient Transfer / Q000379:methods*; D017064:Process Assessment, Health Care; D012189:Retrospective Studies; D020521:Stroke / Q000628:therapy; D015912:Thrombolytic Therapy; D013997:Time Factors; D014187:Transportation of Patients / Q000379:methods*; D014481:United States