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 MilfordPradeep Navsaria

Andrew NicolSorin Edu

Rajiv Gandhi

Trauma Center, Groote Schuur HospitalUniversity of Cape Town

SAVI 2013

‘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’

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 2011Friede 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 AccidentsWeston-Simons et al: Injury; Jan 2013

Parsons et al: Emerg Med J. Oct 2011Cashman et al: Iranian Journal of Medical Science; Feb 2011

Background:Weekday vs weekend

General increase in all types of trauma on weekend

Friede et al: Minnesota Journal of Medicine; Nov 2009Lemieux et al: Journal of Forensic Science, May 2008

Sivarajasingam et al: Injury; May 2004

No studies comparing month-end to non-month-end

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

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

Methods

4 Trauma Categories:

• Motor Vehicle Accidents• Interpersonal Violence• Accidents• Miscellaneous

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 15th 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

Methods

• Statistical Analysis– Microsoft Excel– Homo- or heteroscedastic t-test (depending on

variances)

• Statistical significance defined as p = <0.05

Results

Days assessed 534

Number of shifts 1068

Number of patients seen 16 706

Results: Weekday vs weekend

0

5

10

15

20

25

Motor Vehicle Accidents

Interpersonal

Accidents

Total

Results: Weekday vs weekend

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

Results:Mid-month vs month-end

Mid-Month WeekendMonth-End Weekend

0.00

5.00

10.00

15.00

20.00

25.00

Motor Vehicle Accidents

Interpersonal Violence

Accidents

Total

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

Results:Summer vs winter

SummerWinter

0.002.004.006.008.00

10.0012.0014.0016.0018.00

Motor Vehicle Accidents

Interpersonal Violence

Accidents

Total

Results:Summer vs winter

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

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

Further analysis

• Trauma and Soccer

• Home versus away games?• Wins versus losses?

• Trauma and temperature

• Trauma and precipitation

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?