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ASC 2015 Searchable Abstracts

9.01 Improving Predictive Value of Trauma Scoring Through Integration of ASA-PS with ISS

D. Stewart1, C. Janowak1, H. Jung1, A. Liepert1, A. O’Rourke1, S. Agarwal1 1University OfWisconsin,Surgery,Madison, WI, USA

Introduction: Many methods exist for predicting mortality among adult trauma patients; however, most systemsignore patient co-morbidity, a significant predictor of outcome, in their calculations. The American Society ofAnesthesiologists Physical Status (ASA-PS), a well-validated and easy-to-use scale, is an assessment of pre-operative status that has been shown to accurately predict post-operative mortality. Using the ASA-PS as a marker ofcumulative patient comorbidity severity we sought to test whether we would be able to improve the predictive powerof the Injury Severity Score (ISS), the most commonly utilized trauma grading system, with respect to mortality, majorcomplication, and discharge disposition.

Methods: A retrospective review of a prospectively collected and internally validated database at an academic LevelI trauma center was performed for consecutive adult admissions between 2009-2013. Abbreviated Injury Scale (AIS)was measured by region (head/neck, face, thorax, abdomen, extremities, general) and severity of injury (1 to 5). ISSwas measured by summing the squares of the three most injured regions [(AIS1)2 + (AIS2)2 + (AIS3)2]. ASA-PSscores were assigned based on patient comorbidities and then integrated with the traditional ISS in a variety ofpermutations, including adjustments of ASA-PS for patient age >70 and using individual AIS components of ISS. Weassessed these various models for predictive ability with a primary outcome of mortality and secondary outcomes ofmajor complications as per National Trauma Data Bank (NTDB) definitions as well as discharge disposition usingreceiver operating characteristic (ROC) analysis. These were compared with the ISS.

Results: All of the ISS/ASA-PS hybrid formulas outperformed ISS alone in predictive power for mortality, majorcomplication, and discharge disposition. The best overall permutation, (AIS1)2+(AIS2)2+(Age-Modified ASA-PS)2,yielded an ROC of 0.888 for mortality as compared to ISS with an ROC=0.853 (p<0.001). Similar differences wereseen for discharge disposition (Hybrid ROC=0.743; ISS ROC=0.639, p<0.001) and major complication (HybridROC=0.761; ISS ROC=0.719, p<0.001).

Conclusion: Incorporating ASA-PS into calculations of trauma scoring is both simple and more predictive of mortality,major complication, and discharge disposition than the traditional ISS metric. Replacing ISS with this new method,which takes patient age and comorbid condition into account through adaptation of the ASA-PS improvesprognostication of outcomes and enables care providers to prioritize resources for injured patients.

Presentation Time: Tuesday, 7:30am - 9:30am

68.18 ASA-PS is Associated With Mortality Rate Among Adult Trauma Patients

D. Stewart1, C. Janowak1, A. Liepert1, A. O’Rourke1, H. Jung1, S. Agarwal1 1University OfWisconsin,Surgery,Madison, WI, USA

Introduction: American Society of Anesthesiologists-Physical Status (ASA-PS) classification assesses pre-anesthesia surgical risk. Numerous studies correlate higher ASA-PS classification with increased perioperativemortality. As the number of comorbidities in a traumatically injured patient is correlated to mortality rate, we evaluatedif ASA-PS was an indicator of mortality risk for adult trauma patients.

Methods: Our prospectively collected and internally validated database at an academic Level I trauma center wasretrospectively reviewed for adult patients for 2009-2013. ASA-PS scores were assigned based on patientcomorbidities. Three different methods were used to reflect a lack of concordance on the consideration of patient agein establishing ASA-PS. In all three methods, NTDB-defined comorbidities were assigned an ASA-PS value andsummed for each risk level. Patients with no comorbidities were considered PS1, while PS2 consisted of those with asingle PS2 condition. Multiple PS2 conditions were considered multi-system disease, elevating a patient’s risk toPS3. Presence of 3+ PS3 conditions led to a PS4 classification. We then evaluated mortality rates as a primaryoutcome for each ASA-PS class using receiver operating characteristic (ROC) and Pearson Chi-Square analysis. Discharge disposition and major complications were assessed as secondary outcomes.

Results: Model 1 (ASA), considered patient age >70 as a PS2 comorbidity, yielded an ROC of 0.619 for predictingmortality. Model 2, not including age as a factor in ASA-PS (ASA–w/o Age), produced an ROC of 0.615. Model 3,Age-Modified ASA (AM-ASA), produced an ROC of 0.648 (p<0.001). Cross-tabulation revealed mortality rates of

2.4%, 2.4%, 4%, and 13.2%, for PS1, PS2, PS3, and PS4, respectively. ASA–w/o Age (2.4%, 2.7%, 3.9%, and13.2%) showed a similar trend, as did AM-ASA (2.4%, 1.9%, 2.9%, 10.2%), albeit with a dip in mortality rate for PS2. All three ASA models had two-sided p<0.001 under Pearson Chi-Square analysis of mortality rates. For dischargedisposition (ASA ROC=0.668; ASA–w/o Age ROC=0.650; AM-ASA ROC=0.693) and major complications (ASAROC=0.648; ASA–w/o Age ROC=0.653; AM-ASA ROC=0.641) all three models showed moderate predictive power.

Conclusion: ASA-PS classification models show an association between higher risk status and increasing mortalityrate. ASA-PS is moderately predictive of mortality, discharge disposition, and major complications per ROC analysis. AM-ASA performed significantly better for mortality and discharge disposition, indicating that age can serve as anadjustment to the codified system to improve accuracy in the trauma population.

Presentation Time: Thursday, 1:30pm - 3:30pm

39.07 The Surgical Apgar Score in Major Esophageal Surgery

C. F. Janowak2, L. Taylor2, J. Blasberg1, J. Maloney1, R. Macke1 1University Of Wisconsin,Division OfCardiothoracic Surgery,Madison, WI, USA 2University Of Wisconsin,Department Of Surgery,Madison, WI, USA

Introduction: Most postoperative assessments and triage decisions are based on subjective evaluation of apatient’s risk factors and overall condition. The Surgical Apgar Score (SAS) is a validated prognostic tool used topredict postoperative morbidity and mortality in a wide variety of surgical patients. The esophagectomy population isa unique subset of surgical patients who are high risk for post-operative complication and disposition resources. Anobjective prognostic metric is an appealing and efficient way to allocate limited care resources to the sickest of

postoperative patients. Although other more complex risk calculators have been developed, the SAS is a simple,bedside usable, model that has been validated in a variety of surgical populations. We evaluated the reliability of theSAS in a major esophageal surgery population.

Methods: A retrospective review of a prospectively collected and internally validated database of cardiothoracicoperations was performed for consecutive esophagectomies from 2009 to 2013. Basic demographics, comorbidities,post-operative complications, and intraoperative variables were collected for all patients. The primary outcomesstudied were mortality and NSQIP-defined in-hospital major complication; secondary outcomes were prolonged lengthof hospital stay (LOS) greater than 10 days and post-operative disposition. We used descriptive statistics, receiveroperating characteristics (ROC) and Pearson Chi-Square analysis to analyze primary and secondary outcomeprediction efficacy of SAS. Preoperative comorbid conditions were also analyzed for association with post-operativeoutcomes prognostication using odds ratio (OR) analysis.

Results: A total of 172 consecutive esophageal resections over four years were reviewed. Overall mortality was 5deaths (2.9%) with 4 occurring within 30 days of surgery, 1 after discharge within 30 days, and 1 after 90 days ofhospitalization. Overall SAS 9-10, n=16; SAS 7-8, n=113; SAS 5-6, n= 42; and SAS ≤ 4, n=1. Of these, 34.3% had amajor complication, 27.3% had a prolonged LOS, and 12.2% were discharged to a care facility other than home. Nosignificant correlation was demonstrated between complication, LOS, or discharge disposition and the SAS withrespective ROC of 0.44, 0.43, and 0.44. Of the preoperative comorbid conditions analyzed, only neoadjuvantchemoradiation significantly increased the risk of any outcome, with an OR of 3.59 (95% CI 1.38-9.37, p < 0.01) riskof discharge to care other than home.

Conclusion: The perioperative performance measure of the SAS does not appear to have a good ability to predictmajor post-operative adverse outcomes in a major esophageal surgery population.

Presentation Time: Wednesday, 7:30am - 9:30am