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PP30 Comparing on-scene times and conveyance rates in medical, traumatic and psychiatric presentations to the ambulance service
  1. Richard Corrall1,
  2. Dougie Marks2
  1. 1West Midlands Ambulance Service University NHS Foundation Trust, UK
  2. 2University of Glasgow, UK


Background Whilst psychiatric presentations represent 10-12% of ambulance service demand, research into such presentations is disproportionately sparce. This study builds on literature which explores psychiatric dispositions by comparing conveyance rate and on-scene times with other common ambulance service presentations.

Methods This study was a single centre retrospective observational study investigating on scene time and conveyance rate variances between medical, traumatic and psychiatric presentations to the ambulance service. Call timings and disposition were recorded from computer aided dispatch data and clinical impressions from associated electronic patient records were used to categorise cases. 720 records were sampled between January and December 2019, consisting of 20 randomised cases per month per case type.

Results Analysis of variance identified a statistically significant effect of case type on on-scene time (F(2,717) = 7.14), p = 0.001, η2 = 0.02) and conveyance rate (F(2,717) = 8.59, p < 0.001, η2 = 0.02). Across all dispositions patients medical cases required 8.18 fewer minutes (p < 0.001, 95% CI[3.65,12.7]) on-scene than psychiatric cases and 6.67 fewer minutes (p = 0.004, 95% CI[2.14,11.19]) than trauma cases. Psychiatric on-scene times were 9.9 (p = <0.001, 95% CI [3.53, 16.29]) and 10 (p = 0.001, 95% CI [4.37, 15.70]) minutes longer than medical and trauma cases where patients were not conveyed to hospital. Conveyance rates were 15% (p = 0.001, 95% CI[-0.23, -0.06]) lower and 17% (p < 0.001, 95% CI[-0.26, -0.08]) lower in psychiatric and trauma cases respectively than medical cases.

Conclusion Psychiatric on-scene times were longer than medical presentations irrespective of conveyance and longer than both medical and traumatic presentations where patients were not conveyed. Conveyance rates in psychiatric presentations were lower than medical cases. Further research is required to understand factors which may contribute to this variation and how this may impact on service and care delivery.

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