Association between ambulance dispatch priority and patient condition.
OBJECTIVE
To compare chief complaints of the Medical Priority Dispatch System in terms of the match between dispatch priority and patient condition.


METHODS
This was a retrospective whole-of-population study of emergency ambulance dispatch in Perth, Western Australia, 1 January 2014 to 30 June 2015. Dispatch priority was categorised as either Priority 1 (high priority), or Priority 2 or 3. Patient condition was categorised as time-critical for patient(s) transported as Priority 1 to hospital or who died (and resuscitation was attempted by paramedics); else, patient condition was categorised as less time-critical. The χ2statistic was used to compare chief complaints by false omission rate (percentage of Priority 2 or 3 dispatches that were time-critical) and positive predictive value (percentage of Priority 1 dispatches that were time-critical). We also reported sensitivity and specificity.


RESULTS
There were 211 473 cases of dispatch. Of 99 988 cases with Priority 2 or 3 dispatch, 467 (0.5%) were time-critical. Convulsions/seizures and breathing problems were highlighted as having more false negatives (time-critical despite Priority 2 or 3 dispatch) than expected from the overall false omission rate. Of 111 485 cases with Priority 1 dispatch, 6520 (5.8%) were time-critical. Our analysis highlighted chest pain, heart problems/automatic implanted cardiac defibrillator, unknown problem/collapse, and headache as having fewer true positives (time-critical and Priority 1 dispatch) than expected from the overall positive predictive value.


CONCLUSIONS
Scope for reducing under-triage and over-triage of ambulance dispatch varies between chief complaints of the Medical Priority Dispatch System. The highlighted chief complaints should be considered for future research into improving ambulance dispatch system performance.
Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.
Stephen J
SJ
Ball
Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.
Teresa A
TA
Williams
Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.|Research and Evaluation, Ambulance Victoria, Melbourne, Victoria, Australia.|Discipline of Emergency Medicine, The University of Western Australia, Perth, Western Australia, Australia.
Karen
http://orcid.org/0000-0002-9057-0685
K
Smith
Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
Peter
P
Cameron
Discipline of Emergency Medicine, The University of Western Australia, Perth, Western Australia, Australia.|Emergency Medicine, Royal Perth Hospital, Perth, Western Australia, Australia.|Centre for Clinical Research in Emergency Medicine, Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia.
Daniel
http://orcid.org/0000-0001-9414-6905
D
Fatovich
School of Education, Curtin University, Perth, Western Australia, Australia.
Kay L
KL
O'Halloran
School of Public Health, Curtin University, Perth, Western Australia, Australia.
Delia
D
Hendrie
St John Ambulance (WA), Perth, Western Australia, Australia.
Austin
A
Whiteside
Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.
Madoka
M
Inoue
St John Ambulance (WA), Perth, Western Australia, Australia.
Deon
D
Brink
St John Ambulance (WA), Perth, Western Australia, Australia.
Iain
I
Langridge
School of Public Health, Curtin University, Perth, Western Australia, Australia.
Gavin
G
Pereira
Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.
Hideo
H
Tohira
St John Ambulance (WA), Perth, Western Australia, Australia.
Sean
S
Chinnery
Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
Janet E
JE
Bray
St John Ambulance (WA), Perth, Western Australia, Australia.|Emergency Medicine, St John of God Hospital Murdoch, Perth, Western Australia, Australia.
Paul
P
Bailey
Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.|Discipline of Emergency Medicine, The University of Western Australia, Perth, Western Australia, Australia.
Judith
J
Finn
D000552:Ambulances; D006801:Humans; D062072:Patient Acuity; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014218:Triage / Q000592:standards* / Q000706:statistics & numerical data; D014904:Western Australia
ambulance; critically ill; paramedic; patient acuity; triage