The protocol for this retrospective observational study was approved by the Institutional Review Board of the Hallym University Sacred Heart Hospital, and the requirement for informed consent was waived because formal consent is not required for retrospective studies. We reviewed the electronic medical records of the patients with major trauma who were admitted to the ED between March 2013 and November 2017. Patients with an injury severity score of >15, with chest or/and abdominal blunt injury with or without brain or other injuries, with systolic blood pressure (SBP) of <90 mmHg or heart rate of >120 beats/min within 30 minutes upon ED arrival, who underwent WBCT (brain, chest, abdomen, and spine), and who underwent CVC in the ED were included in the study. Patients aged <18 years, who had an arrest before ED arrival, and who were transferred from another hospital were excluded. In particular, because the role of WBCT in patients with penetrating trauma is not yet established, only those with blunt trauma were included in the present study. Fig. 1 presents a flow chart of the patient selection process. All patients were initially managed in accordance with the 10th advanced trauma life support guidelines. After performing early resuscitation, the clinician decided to perform a CT scan in patients whose vital signs were within the acceptable range (percutaneous oxygen saturation, 90%; heart rate, 120 beats/min; and SBP, 70 mmHg).

Data on patients’ baseline characteristics (age and sex) and factors known to influence mortality were collected. The initial vital signs (SBP, diastolic blood pressure, pulse pressure, heart rate, and body temperature), initial laboratory findings (pH, base excess, lactate, and hemoglobin), mechanism of injury, clinical scores (Glasgow coma scale [GCS] score, revised trauma score [RTS], injury severity score [ISS], and focused assessment with sonography in trauma [FAST]), clinical practice (intubation, catecholamine administration, and type of central venous catheter), intervals (from ED arrival to CT, insertion of central catheter, transfusion, and definite bleeding control [embolization or operation]), and clinical outcomes (hospital and intensive care unit [ICU] lengths of stay [LOS], and survival rate at 24 hours and 28 days) were recorded. The RTS assessment was based on three parameters: neurological evaluation by the GCS, hemodynamic evaluation by the SBP, and respiratory rate [8].

The normality of data distribution was evaluated using a Kolmogorov-Smirnov test to select the appropriate parametric and nonparametric statistical methods. Continuous variables were reported as median with interquartile range (25–75 percentile) and categorical variables as numbers (%). Continuous variables were analyzed using a Mann-Whitney test, and categorical variables were analyzed using a Pearson’s chi-square test or Fisher’s exact test. The independent factors affecting the decision to perform CVC before CT were evaluated using multivariate backward stepwise logistic regression after adjustment for confounding factors (defined as factors that were significant in the univariate analysis based on a type I error of 0.05). For all comparisons, the tests were two tailed, and group differences were regarded as significant at p<0.05. SPSS version 18.0.0 statistical software for Windows (SPSS, Inc., Chicago, IL, USA) was used for all analyses.

The pre-CT group comprised 34 patients (48.6%), while the post-CT group comprised 36 patients (51.4%). The baseline characteristics and mechanisms of injury of all the patients are summarized in Table 1. No significant difference was observed between the two groups in terms of sex (22 vs. 28 men, p=0.226), age (49.0 vs. 56.0 years, p=0.175), and mechanism of injury (p=0.702). Table 2 presents the initial vital signs, laboratory parameters, FAST-positivity, and clinical scores of both groups. The pre-CT group had a higher pulse pressure (39.0 vs. 30.0 mmHg, p=0.002), lower pH (7.28 vs. 7.35, p=0.030), higher FAST-positivity rates (70.6% vs. 44.4%, p=0.027), and higher ISS (41.0 vs. 26.0, p<0.001) than the post-CT group no significant difference was observed between the two groups (13.0 vs. 13.3, p=0.274 and 6.9 vs. 7.1, p=0.700) in terms of GCS and RTS. The pre-CT group had a higher rate of intubation (64.7% vs. 22.2%, p<0.001), and most patients were intubated before CT (90.9%, Table 3). With regard to the type of central catheter, larger-size (9 french lumen) catheters were more frequently used in the pre-CT group (94.1% vs. 44.4%, p<0.001) than in the post-CT group. In contrast, the type of treatments did not differ significantly between the groups (p=0.659).

Table 4 shows the time interval data and clinical outcomes of the pre-CT and post-CT groups. The pre-CT group had a longer time interval from ED arrival to CT (46.0 vs. 27.0 minutes, p=0.011) and to definite bleeding control (193.5 vs. 167.5 minutes, p=0.038) than the post-CT group. The time intervals from ED arrival to CVC and transfusion were significantly different between the two groups (26.0 vs. 97.0 minutes, p<0.001 and 79.5 vs. 108.0 minutes, p=0.018). Although not considered significant, the pre-CT group tended to have lower survival rates at 24 hours and 28 days than the post-CT group (76.5% vs. 88.9%, p=0.168 and 64.7% vs. 77.8%, p=0.226). In terms of hospital and ICU LOS, significant difference was observed between the two groups (25.0 vs. 13.0 days, p=0.018 and 19.0 vs. 4.0 days, p=0.053).

Univariate logistic regression analysis revealed that the ISS, intubation, pulse pressure, FAST-positivity, and pH were significantly different between the pre-CT and post-CT groups (all p<0.05). Subsequent multivariate analysis showed that ISS and intubation were independently associated with CVC before CT (odds ratio [OR]: 0.912, 95% confidence interval [CI]: 0.858–0.969, p=0.003 and OR 3.335, 95% CI: 1.039–10.703, p=0.043; Table 5).

Although there is controversy regarding the survival benefit, the time interval from ED arrival to CT scanning is considered an important factor in trauma patients. Furugori et al. [7] emphasized that shortening the time to CT by adjusting the distance to the CT room could be critical in severe trauma patients, allowing the detection of life-threatening problems and earlier critical decision making. They showed that the presence of a CT machine in the trauma room reduced the time to CT by 14 minutes (from 37 minutes to 23 minutes) and 18 minutes (from 40 minutes to 22 minutes) after propensity score matching. The present study also showed the same results. Although there was no significant difference in the survival rates at 24 hours and 28 days between the pre-CT group and the post-CT group (76.5% vs. 88.9%, p=0.168 and 64.7% vs. 77.8%, p=0.226), the timing of performing CVC before and after CT scanning affected the time intervals. CVC performed after CT shortened the time from ED arrival to CT completion by 19 minutes and to bleeding control by 26 minutes compared to CVC performed before CT. In terms of hospital and ICU LOS, the post-CT group were shortened by 12 days and 15 days, respectively, compared with those of the pre-CT group. Results suggested that a shorter LOS was due to the high ISS in the pre-CT group.

Since no studies have reported on factors affecting the decision to perform CVC before CT, we inevitably evaluated the factors known to be associated with mortality (SBP, pulse pressure, pH, base excess, FAST-positivity, ISS, and intubation). In a randomized controlled trial study on blunt trauma patients with hemorrhagic shock, Dutton et al. [9] administered fluids with an SBP target of 70–80 mmHg until surgical control was achieved and showed that despite the presence of a low BP in actively bleeding patients, the mortality rate was unaffected. In addition, Wigginton et al. [10] proposed that controlled hypotension can benefit patients with blunt trauma who are actively bleeding until surgical control. Our center also applied the permissive hypotension strategy, and clinicians were aware of this concept. We suggested that as a result, SBP did not act as a determinant of CVC. Rather, the SBP of the pre-CT group was higher than that of the post-CT group. In clinical practice, FAST-positivity in the initial assessment implies the potential risk of a sudden drop in the blood pressure and may compel the clinician to perform CVC. Interestingly, we found that the pulse pressure, known as a risk factor for mortality in patients with sepsis, trauma, and shock [11–13], was also higher in the pre-CT group. The clinical practice to use pH as an important parameter in treating patients with major trauma was also reflected in the present result. We also evaluated the standard anatomic scores (ISS) and physiologic score (RTS) of the pre-CT and post-CT groups. In general, the RTS can be available early in treatment, but an important limitation of the ISS is the difficulty associated with its early application. Our results demonstrated that while the RTS did not show a statistical difference between the two groups, the ISS was a factor affecting the decision to perform CVC before CT as revealed in the multivariate analysis. A study of whether clinicians actually use the anatomic assessment rather than the physiologic assessment in making an early decision may be an interesting subject topic.

Intubation was also among the factors that affected the clinician’s decision. Several pathophysiological studies showed that intubation with positive pressure ventilation reduces venous return and that the medications used for intubation and the maintenance of sedation decrease vascular tone and myocardial depression [14,15]. Green et al. [16] reported that trauma patients requiring intubation develop post-intubation hypotension at a rate of 36.3%, which increases their mortality (29.8% vs. 15.9%, p=0.001). In addition, they observed that post-intubation hypotension development in trauma patients was associated with a prolonged requirement for treatment with vasopressors. The present study suggested that the intubated patients more frequently experienced post-intubation hypotension before CT scanning. This physiologic situation forces clinicians to perform CVC before CT scanning.

This study has several limitations. First, the study’s small sample size and single-center design were associated with known risks of bias. Second, the retrospective design may be associated with a selection bias, as we only included hemodynamically unstable patients who underwent WBCT and CVC in the ED. This severity reflected a higher mortality than that observed in previous studies.