Weekend & Night Outcomes in a Mature State Trauma

System

Brendan G. Carr, MD MS

Department of Emergency MedicineDepartment of Biostatistics and Epidemiology

University of Pennsylvania School of Medicine

Background

• Outcomes for time-sensitive medical conditions are dependent upon the existence of comprehensive systems of care

• Variability in outcomes has been demonstrated for a number of time-sensitive conditions including STEMI, cardiac arrest, and ischemic stroke

The New Jersey STEMI “system”

Background

• Trauma Care in the USVerification processDemonstrated survival benefitExplicit criteria required for:

– Structures (staffing, OR availability)– Processes (QI program, prehospital

notification)

Goals of the Investigation

• We sought to determine whether the probability of death or adverse clinical outcomes was higher among injured patients presenting at night or on the weekend.

Hypothesis

• We hypothesized that outcomes after trauma would be similar for patients presenting during nights or on the weekend.

Methods

• Retrospective cohort analysis• Five years of data (2004-2008)• Pennsylvania Statewide Trauma Registry

32 accredited trauma centersAdmitting diagnosis of injuryAge >18

Methods

• Main Outcomes: In-hospital mortality

• Secondary Outcomes: ICU length of stayHospital length of stayDelay of more than two hours to

laparotomy or craniotomy

Methods

• Exposure:Night presentation

– 11pm – 6:59am

Weekend presentation – 11pm Friday – 6:59am Monday– Saturday 12:01 am – Sunday 11:59pm

Methods - Power

• We calculated the detectable mortality difference given:

Known sample size2-tailed alpha of 0.05Power of 90%Effect size estimate (mortality

differences for night and weekend presentation based on pilot data)

Methods - Analysis

• Unadjusted Pearson’s chi-square, rank sum, T-test,

Logistic regression• Adjusted

Logistic regression Negative binomial regression (LOS)

Methods - Analysis

• Case Mix adjustmentModified Charlson

– 15 instead of 19 comorbid conditions

• Injury Severity adjustmentTRISS (Trauma – Injury Severity Score)

– Anatomic injury scoring system (ISS)– Physiological scoring system (Revised

Trauma Score)

Results - Power

• Night as compared to dayPowered to detect 0.63% mortality

difference• Weekend as compared to weekday

Powered to detect 0.53% mortality difference

Results – Demographics

Results - Demographics

Summary Results (Adjusted)

Night• Mortality

- Age < 55

- Severe injury - Blunt - Penetrating -

• Delay to laparotomy+

• Delay to craniotomy-

• ICU LOS

• Hospital LOS

Weekend• Mortality

Age < 55

Severe injury Blunt - Penetrating -

• Delay to laparotomy-

• Delay to craniotomy-

• ICU LOS-

• Hospital LOS

Limitations

• Retrospective data• Single state analysis• Negative findings raise power concerns • Inadequate injury severity adjustment• Inadequate case mix adjustment• Exclusion of transfer patients

Conclusions

• Patients presenting at night are no more likely to die than patients presenting during the day

• Patients presenting on the weekend are less likely to die than patients presenting on weekdays

Implications

• Explicit staffing and resource requirements for unplanned critical illness protect against the “weekend effect”

• The impact of similar systems based interventions should be tested for other time-sensitive conditions

Acknowledgments

• Co-authorsPat Reilly, MDC. William Schwab, MDCharles C. Branas, PhD Juliet Geiger, RN MSNDouglas J. Wiebe, PhD

• AHRQ K08HS017960• Pennsylvania Trauma System Foundation

Questions?