K. Basiouny1, N. Gamsky1, B. Sarani1, P. Dangerfield1, R. L. Amdur1, M. Rose2, J. Dunne1 2George Washington University School Of Medicine And Health Sciences,Department Of Anesthesia,Washington, DC, USA 1George Washington University School Of Medicine And Health Sciences,Division Of Trauma, Department Of Surgery,Washington, DC, USA
Introduction
Multiple rib fractures are associated with significant morbidity and mortality. Attempting to find a way to mitigate theses complications, we began placing paravertebral blocks (PVB) in such patients. The goal of this study is to assess the efficacy of PVB in patients with multiple rib fractures compared to the national trauma data bank (NTDB). We hypothesize that PVB significantly improve survivability.
Methods
The 2008 NTDB was to develop expected death rates based on patient characteristics and compared against a consecutive cohort of patients in a single level I trauma center from 2011 to 2014. Patients 18 years or older with ≥ 3 rib fractures or a sternal fracture and hospital length of stay > 3 days were included. Variables abstracted include: demographics; rib fracture variables (number of ribs fractured, sternum fracture, flail-chest); injury type (blunt, penetrating, burn); Glasgow coma score (GCS), and injury severity score (ISS). A logistic regression model using gender, age, GCS, ISS, and number of ribs fractured was developed from the NTDB and then used in our sample to predict death. The PVB x risk interaction was added to this model to determine if the association between risk and outcome varies significantly based on whether or not PVB was present. Probability of death was grouped into 6 risk strata: 10th, 25th, 50th, 75th, and 90th percentile and examined with chi-square grouped by the presence or absence of PVB.
Results [BS1]
The NTDB cohort consists of 35058 patients. The lowest 10% had a death rate of 0.3%, while the highest 10% had a death rate of 32.6. The association between the risk category and death was strong (phi=.40, p<.0001). There were 318 GW patients with 3 or more rib fractures with 81 that received PVB, all trauma patients cared for from 2011 to 2014. We collected age, ISS, GCS, gender, and total fracture numbers. There appeared to be difference between the GW cohort and the NTDB. Patients with the highest two risk stratified death rates who received a PVB had a much lower than the expected death rate. In the model using Risk score and PVB as predictors, the prediction model for death was very accurate (c=.95) with sensitivity and specificity of .89 & .90 respectively. The OR for Risk was 7.86 [3.80-16.26], p<.0001. This indicates that for every 1-step increase in the risk score (from 1 to 6), the odds of death increases almost 8 times. The OR for PVB was 0.14 [0.02-1.22], p=.075. The length of stay in the hospital was significantly higher in the highest risk stratified group who received PVBs with an R2 of .41.
Conclusion
Patients in the highest risk stratified groups with ≥ 3 rib or sternal fractures have improved survival with use of paravertebral blocks.
