The "vertical response time": barriers to ambulance response in an urban area.
BACKGROUND
Ambulance response time is typically reported as the time interval from call dispatch to arrival on-scene. However, the often unmeasured "vertical response time" from arrival on-scene to arrival at the patient's side may be substantial, particularly in urban areas with high-rise buildings or other barriers to access.


OBJECTIVE
To measure the time interval from arrival on-scene to the patient in a large metropolitan area and to identify barriers to emergency medical services arrival.


METHODS
This was a prospective observational study of response times for high-priority call types in the New York City 9-1-1 emergency medical services system. Research assistants riding with paramedics enrolled a convenience sample of calls between 2001 and 2003.


RESULTS
A total of 449 paramedic calls were included, with a median time from call dispatch to arrival on-scene of 5.2 minutes. The median on-scene to patient arrival interval was 2.1 minutes, leading to an actual response interval (dispatch to patient) of 7.6 minutes. The median on-scene to patient interval was 2.8 minutes for residential buildings, 2.7 minutes for office complexes, 1.3 minutes for private homes (less than four stories), and 0.5 minutes for outdoor calls. Overall, for all calls, the on-scene to patient interval accounted for 28% of the actual response interval. When an on-scene escort provided assistance in locating and reaching the patient, the on-scene to patient interval decreased from 2.3 to 1.9 minutes. The total dispatch to patient arrival interval was less than 4 minutes in 8.7%, less than 6 minutes in 28.5%, and less than 8 minutes in 55.7% of calls.


CONCLUSIONS
The time from arrival on-scene to the patient's side is an important component of overall response time in large urban areas, particularly in multistory buildings.
Silverman
Robert A
RA
Department of Emergency Medicine, Long Island Jewish Medical Center, New Hyde Park, NY, USA. aresilv@aol.com
Galea
Sandro
S
Blaney
Shannon
S
Freese
John
J
Prezant
David J
DJ
Park
Richard
R
Pahk
Raymond
R
Caron
Djorge
D
Yoon
Sonia
S
Epstein
Jonathan
J
Richmond
Neal J
NJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000552:Ambulances / Q000706:statistics & numerical data* / Q000600:supply & distribution; D002648:Child; D002675:Child, Preschool; D004631:Emergency Medical Service Communication Systems; D004632:Emergency Medical Services / Q000706:statistics & numerical data* / Q000600:supply & distribution; D005160:Facility Design and Construction; D006297:Health Services Accessibility / Q000706:statistics & numerical data*; D006798:Housing; D006801:Humans; D007223:Infant; D008875:Middle Aged; D009519:New York City; D011446:Prospective Studies; D013997:Time Factors; D013996:Time and Motion Studies; D019037:Urban Health Services / Q000145:classification / Q000706:statistics & numerical data* / Q000600:supply & distribution