penetrating esophageal injuries ( peesins ) are rare , accounting for < 0.5% of all trauma admissions even in busy urban trauma centers . overall mortality is high ( 44% ) , but the vast majority of these deaths occur within the first 24 h and are likely not attributable to the esophageal injury , but rather to severe associated injuries . since the diagnosis of esophageal injury is not always straightforward , preoperative diagnostic evaluation ( pde ) adjuncts such as endoscopy , computed tomography ( ct ) , and fluoroscopy may be helpful . because of the rarity of this injury , previously published studies trying to address the pros and cons of pde have been limited by small sample size and single center bias . in 2001 , asensio et al . reported in a multicenter american association for the surgery of trauma ( aast ) retrospective study that preoperative evaluation was associated with a significant delay from admission to operative repair ( 13 h vs. 1 h , p < 0.001 ) and with increased complications . the study recommended that the definitive repair should be a priority and not be delayed unnecessarily . in the years since that landmark publication , the immediate availability of adjunct pde modalities has improved in most centers , and thus , the time it takes to obtain these diagnostic tests might have decreased . we also hypothesized that promptly obtaining adjunctive diagnostic studies to aid in the diagnosis of peesin is associated with improved outcomes . the national trauma data bank ( ntdb ) from 2008 to 2010 was queried for patients who suffered esophageal injuries based on international classification of diseases codes 862.22 ( injury of esophagus closed ) or 862.32 ( injury of esophagus open ) . the query was limited to patients who suffered penetrating trauma based on the e - code classification of their mechanism of injury . the ntdb was created by the american college of surgeons committee on trauma in 1997 in order to collect retrospective data about trauma patients . data are submitted from a variety of trauma settings which captures the effects of differing practice patterns on patients with similar injuries . a research dataset is published each year which can facilitate outcomes studies on rare injuries like peesins . patients who expired within 1 day were excluded from the study because their injuries were likely not survivable , and their death was unlikely to be attributable to the esophageal injury . two data elements were critical in our analysis , an operative intervention with a documented time delay and whether or not the patient survived to hospital discharge . if either of these data were missing , the patient was excluded from the study . demographic data included age and gender . the systolic blood pressure ( sbp ) , heart rate ( hr ) , respiratory rate ( rr ) , and glasgow coma scale ( gcs ) upon arrival at the hospital were captured . the modified shock index ( hr / sbp ) and the revised trauma score ( rts , a composite score based on gcs , sbp , and rr ) were calculated for each patient . the patients injury severity score ( iss ) submitted by the trauma center was used in our analysis . esophageal diagnostic procedures were defined as : ct , endoscopy , barium swallow , and other diagnostic procedures on the esophagus . we did not include esophageal diagnostic procedures that occurred more than 1 day after the operative repair , as it may represent routine postoperative care ( e.g. , postrepair swallow study ) or was obtained for unrelated reasons ( e.g. , ct chest to assess for pneumonia ) . the time in hours of the first esophageal diagnostic procedure , the first surgical procedure and the first surgical procedure on the esophagus were queried from the database . the population were divided into two cohorts based on whether or not they underwent an esophageal diagnostic procedure prior to the conclusion of their first surgical procedure . the following outcomes were extracted : length of hospital stay ( los ) and whether the patient survived until discharge . the patients hospital - free days at day 60 were calculated ( 60 - los ) . readmission data are not available in the ntdb and could not be included in our calculation . patients who did not survive to discharge were considered to have zero hospital - free days . statistical analysis was performed using r version 2.15.1 ( r foundation for statistical computing , vienna , austria ) . continuous variables were reported as means and standard deviations or medians and interquartile ranges ( iqrs ) as appropriate . linear regression was used to correlate continuous variables to other continuous and categorical variables ; model coefficients of independent variables are reported with 95% confidence intervals . analysis of variance with tukey 's posthoc test was used to correlate continuous variables to categorical variables , and results are reported as absolute differences with 95% confidence intervals . our query of the ntdb found 523 patients who suffered esophageal injuries as a result of penetrating trauma . of these 523 patients , 165 ( 31.5% ) were excluded because they expired within 1 day , 74 ( 14.1% ) were excluded because no surgical procedure was documented , and 4 ( 0.8% ) were excluded because survival to hospital discharge was not documented . therefore , 280 patients remained for further analysis [ figure 1 ] . these 280 patients were divided into two cohorts based on whether they underwent a pde to assess for esophageal injury prior to the conclusion of their first operation ( pde , n = 75 , 26.8% ) or whether they left the operating room without having undergone such a procedure ( nonpde , n = 205 , 73.2% ) . the characteristics of the two cohorts are displayed in table 1 . when comparing the demographics of the two cohorts , there were no significant differences in baseline demographics , vital signs upon admission or calculated injury scores ( iss and rts ) . flowchart of inclusion and exclusion patient characteristics of the two cohorts the distribution of the first esophageal diagnostic procedures performed in the pde cohort is listed in table 2 . the majority of these patients ( 66.7% ) underwent endoscopy . the median time until the first operation was 1 h shorter in the nonpde ( 2 h , iqr = [ 1 , 5 ] ) as compared to the pde cohort ( 3 h iqr = [ 2 , 6 ] ) ( p = 0.018 ) . distribution of first esophageal diagnostic procedures in the diagnostic cohort ( n = 75 ) table 3 lists the unadjusted outcomes of the two cohorts . before controlling for iss , mortality was significantly greater in the no_diagnostic group than the diagnostic group , 5.4% and 0% , respectively ( p = 0.04 ) . median hospital los of survivors was also significantly longer in the no_diagnostic group than the diagnostic group , 18 days ( iqr = [ 10 , 29 ] ) versus 13 days ( iqr [ 9 , 23 ] ) ( p = 0.030 ) . not surprisingly , median hospital - free days at day 60 , which represents a composite endpoint of these two measures , was significantly less in the no_diagnostic group ( 42 days , iqr = [ 28 , 50 ] ) than the diagnostic group ( 47 days , iqr = [ 38 , 51 ] ) ( p = 0.007 ) . when adjusting for iss using a multiple regression model , pde was no longer a statistically significant predictor for hospital los ( p = 0.10 ) or mortality ( p = 0.99 ) but remained a statistically significantly predictor of hospital - free days at day 60 ( 5 greater hospital - free days in the diagnostic group than the no_diagnostic group , iqr = [ 0.6 , 8.7 ] , p = 0.025 ) . the coefficient of iss was 0.55 ( 0.55 less hospital - free days for each 1 point increase in iss , iqr = [ 0.71 , 0.39 ] , p < 0.00001 ) . our query of the ntdb found 523 patients who suffered esophageal injuries as a result of penetrating trauma . of these 523 patients , 165 ( 31.5% ) were excluded because they expired within 1 day , 74 ( 14.1% ) were excluded because no surgical procedure was documented , and 4 ( 0.8% ) were excluded because survival to hospital discharge was not documented . therefore , 280 patients remained for further analysis [ figure 1 ] . these 280 patients were divided into two cohorts based on whether they underwent a pde to assess for esophageal injury prior to the conclusion of their first operation ( pde , n = 75 , 26.8% ) or whether they left the operating room without having undergone such a procedure ( nonpde , n = 205 , 73.2% ) . the characteristics of the two cohorts are displayed in table 1 . when comparing the demographics of the two cohorts , there were no significant differences in baseline demographics , vital signs upon admission or calculated injury scores ( iss and rts ) . the distribution of the first esophageal diagnostic procedures performed in the pde cohort is listed in table 2 . the majority of these patients ( 66.7% ) underwent endoscopy . the median time until the first operation was 1 h shorter in the nonpde ( 2 h , iqr = [ 1 , 5 ] ) as compared to the pde cohort ( 3 h iqr = [ 2 , 6 ] ) ( p = 0.018 ) . table 3 lists the unadjusted outcomes of the two cohorts . before controlling for iss , mortality was significantly greater in the no_diagnostic group than the diagnostic group , 5.4% and 0% , respectively ( p = 0.04 ) . median hospital los of survivors was also significantly longer in the no_diagnostic group than the diagnostic group , 18 days ( iqr = [ 10 , 29 ] ) versus 13 days ( iqr [ 9 , 23 ] ) ( p = 0.030 ) . not surprisingly , median hospital - free days at day 60 , which represents a composite endpoint of these two measures , was significantly less in the no_diagnostic group ( 42 days , iqr = [ 28 , 50 ] ) than the diagnostic group ( 47 days , iqr = [ 38 , 51 ] ) ( p = 0.007 ) . when adjusting for iss using a multiple regression model , pde was no longer a statistically significant predictor for hospital los ( p = 0.10 ) or mortality ( p = 0.99 ) but remained a statistically significantly predictor of hospital - free days at day 60 ( 5 greater hospital - free days in the diagnostic group than the no_diagnostic group , iqr = [ 0.6 , 8.7 ] , p = 0.025 ) . the coefficient of iss was 0.55 ( 0.55 less hospital - free days for each 1 point increase in iss , iqr = [ 0.71 , 0.39 ] , p < 0.00001 ) . in this analysis of the ntdb , we report that obtaining pde for the diagnostic workup of peesin only slightly delays time to operation and is not associated with worse outcomes when performed in a prioritized and expeditious fashion . while there was no difference in mortality , obtaining a pde was associated with more hospital - free days at day 60 . although the performance of such adjuncts resulted , on average , in a delay of definitive repair by approximately 1 h , the median time to esophageal repair ( 3 h ) was still well below those reported in older studies . for example , asensio et al . reported in 1997 an average of 16.7 h delay from admission to or in the preoperative evaluation group . in the aast multicenter trial from 2001 , asensio et al . reported an average time delay of 13 h from admission to the or in the preoperative evaluation group . our findings likely reflect a real shift in practice , with the recognition that delay of operation is associated with worse outcomes like esophageal - related infectious complications . we initially believed that the nonpde cohort would be more severely injured and would present with worse physiological parameters , thus justifying the decision to forgo adjunctive diagnostic procedures . however , this proved to be untrue as the groups were not significantly different in terms of physiologic derangement and of overall injury severity . it goes without saying that an unstable patient suffering penetrating injury should be taken for immediate operative exploration . however , in the absence of instability , performing an adjunctive procedure such as ct scan or intraoperative endoscopy , if associated with minimal time delay as was the case in our study , has low risk and may contribute to superior outcomes ( increased hospital - free days ) . in the aast multicenter asensio study , roughly half of the patients had undergone preoperative evaluation . this preoperative evaluation consisted of esophagoscopy in 73% , ct the mean iss of 28 and the late death rate of 5.4% in that study were very similar to our findings . while we report similar rates of esophagoscopy ( 66.7% ) and ct scan ( 29.3% ) , we found that contrast fluoroscopy was used much less frequently ( 4% ) . fluoroscopic esophagography is considered the gold - standard in diagnosing esophageal injuries , but recent studies have found ct esophagograms to have acceptable diagnostic accuracy . ct esophagograms can be performed more expeditiously , at a lower expense , and without the direct supervision of a radiologist . an alternative would be to perform upper endoscopy once the patient has been stabilized in the operating room . first , it was not possible to determine the reason why diagnostic procedures ( e.g. , ct neck ) were delayed or omitted in many cases . third , the ntdb does not permit identification and analysis of specific relevant complications , so we exclusively analyzed hospital los , mortality , and hospital - free days . if the time to definitive repair is not excessively delayed , obtaining preoperative evaluation for the diagnostic work - up of peesin is associated with increased hospital - free days in patients with peesin . further studies are needed to better identify the patients who would benefit from prompt pde prior to definitive surgical repair .
background : preoperative diagnostic evaluation ( pde ) of penetrating esophageal injury ( peesin ) can delay treatment and increase morbidity . we sought to study the relationship among pde , delay in definitive treatment , and patient mortality in peesin.materials and methods : the 2008 - 2010 national trauma data banks were queried for peesin . 
 exclusion criteria were death within 1 day of injury , and missing data about survival to discharge or operative intervention . 
 data extracted included demographics , vital signs , injury severity , diagnostic procedures ( endoscopy , computed tomography , and fluoroscopy ) , time to procedures and/or operation , hospital - free days , and mortality.results:of 280 patients , 75 underwent pde and 205 did not . 
 there were no significant differences in baseline demographics , vital signs or injury severity between the two groups . 
 the median time to the first operation was shorter in the nonpde cohort compared to the pde cohort ( 2 vs. 3 h ; p = 0.018 ) . 
 median hospital - free days at day 60 were significantly less in nonpde ( 42 days , interquartile range ( [ iqr ] = [ 28 , 50 ] ) versus pde patients ( 47 days , iqr = [ 38 , 51 ] ) ( p = 0.007 ) . 
 mortality was not statistically different.conclusions:pde in peesin slightly delays the time to operation without worsening mortality , and is a predictor of more hospital - free days .