1. Does time of the week and month, and seasonal change, influence the number of patients seen in a mature, South African tertiary trauma centre? Karen Milford Pradeep Navsaria Andrew Nicol Sorin Edu Rajiv Gandhi Trauma Center, Groote Schuur Hospital University of Cape Town SAVI 2013

2. ‘It’s the last weekend of the month, so it’s going to be a busy one!’ ‘It’s cold and rainy: maybe they’ll stay at home’

3. Background: Good vs bad weather ‘Good’ weather Increase in total trauma Fewer ‘accidents’ Increased interpersonal violence: Sexual assault Deadly assault Violent crimes Parsons et al: Emerg Med J. Oct 2011 Friede et al: Minnesota Journal of Medicine; Nov 2009 Nitschke et al: Med J Austr; Dec 2007 ‘ Bad’ weather Wet Conditions: Increased total admissions in some studies Increased ‘accidents’ Increased Motor Vehicle Accidents Weston-Simons et al: Injury; Jan 2013 Parsons et al: Emerg Med J. Oct 2011 Cashman et al: Iranian Journal of Medical Science; Feb 2011

4. Background: Weekday vs weekend General increase in all types of trauma on weekend Friede et al: Minnesota Journal of Medicine; Nov 2009 Lemieux et al: Journal of Forensic Science, May 2008 Sivarajasingam et al: Injury; May 2004 No studies comparing month-end to non- month-end

5. Aim How is the patient volume at the Groote Schuur Trauma Unit affected by external factors, namely time of the week, month, and season? Are different types of trauma affected differently by these variables? Staffing issues Preventative interventions

6. Methods Study site: Trauma Center, Groote Schuur Hospital Study design: Retrospective audit Data obtained from trauma log entries: January – June 2011 November 2011 – November 2012

7. Methods 4 Trauma Categories: Motor Vehicle Accidents Interpersonal Violence Accidents Miscellaneous

8. Methods Weekday vs Weekend ‘Week’: Monday 8am to Friday 8pm ‘Weekend’: Friday 8pm to Monday 8am Mid-Month vs Month-End ‘Mid-Month’: Weekend closest to 15 th day of month ‘Month-End’: Weekend closest to last day of month Summer vs Winter ‘Summer’: 1 December – 28 February ‘Winter’: 1 June – 31 August

9. Methods Statistical Analysis – Microsoft Excel – Homo- or heteroscedastic t-test (depending on variances) Statistical significance defined as p = <0.05

10. Results Days assessed534 Number of shifts1068 Number of patients seen16 706

11. Results: Weekday vs weekend

12. Statistically significant increase in patient numbers per shift: MVAs (2.6 vs 3.7 per shift) p = 0.00000000000027 Interpersonal violence (biggest increase – 4.7 vs 10.9 per shift) p = 0.0000000000 Total numbers (13.2 vs 20 per shift) p = 0.0000000000 Decrease: Other accidents (5.4 vs 4.9 per shift) p = 0.027

13. Results: Mid-month vs month-end

14. Slight but statistically significant mid-month weekend vs month-end weekend increase: Interpersonal violence (10.1 vs 12.3 per shift) p= 0.00063 Total numbers (19.3 vs 22.7 per shift) p = 0.00056 Results: Mid-month vs month-end

15. Results: Summer vs winter

16. Slight increase in summer vs winter: Total numbers (16.6 vs 14.4 per shift) p = 0.00064 Most marked in interpersonal violence group (7.7 vs 6 per shift) p = 0.0006

17. Conclusion At the Groote Schuur Trauma Center: Weekends are significantly busier than week days Patient volumes are further increased on summer, month- end weekends In particular, victims of interpersonal violence will present in greater numbers

18. Further analysis Trauma and Soccer Home versus away games? Wins versus losses? Trauma and temperature Trauma and precipitation

19. Discussion Why the big spike in interpersonal violence on the weekends? Can we put specific interventions in place to curb this spike? What does this mean for trauma unit staffing?