Ambulance call-outs and response times in Birmingham and the impact of extreme weather and climate change.

Although there has been some research on the impact of extreme weather on the number of ambulance call-out incidents, especially heat waves, there has been very little research on the impact of cold weather on ambulance call-outs and response times. In the UK, there is a target response rate of 75% of life threatening incidents (Category A) that must be responded to within 8 min. This paper compares daily air temperature data with ambulance call-out data for Birmingham over a 5-year period (2007-2011). A significant relationship between extreme weather and increased ambulance call-out and response times can clearly be shown. Both hot and cold weather have a negative impact on response times. During the heat wave of August 2003, the number of ambulance call-outs increased by up to a third. In December 2010 (the coldest December for more than 100 years), the response rate fell below 50% for 3 days in a row (18 December-20 December 2010) with a mean response time of 15 min. For every reduction of air temperature by 1°C there was a reduction of 1.3% in performance. Improved weather forecasting and the take up of adaptation measures, such as the use of winter tyres, are suggested for consideration as management tools to improve ambulance response resilience during extreme weather. Also it is suggested that ambulance response times could be used as part of the syndromic surveillance system at the Health Protection Agency.