We present a retrospective analysis of severely injured patients suffering from thoracic trauma of different magnitude. As in other studies [
8,
10,
17‐
20], our population consists mainly of middle-age males with a mean ISS ≥ 16 suffering from blunt trauma. We deliberately excluded patients suffering from severe head trauma AIS
Head ≥ 4 to prevent confounding, since severe head trauma alone can be an indication for intubation [
18]. This allowed us to distinguish between additional reasons for intubation in severely injured patients due to chest injuries.
It has been suggested that patients sustaining trauma to the chest and suffering from three or more rib fractures be transferred to a trauma center, as well as seriously injured patients for whom transportation to a high-volume Level 1 trauma center is recommended [
9,
21,
22]. In line with the aforementioned recommendation, our patients were treated mainly at Level 1 and Level 2 trauma centers participating in the TR-DGU.
Injuries
As one would expect in a population of severely injured patients, we detected an array of injuries to other body regions. Our moderate percentage (18%–20%) of head trauma in patients with an AISThorax ≥ 4 is because we excluded patients with severe head trauma (AISHead ≥ 4) from our statistical assessment, since higher impact and kinematics causing major thoracic injuries will often result in significant head injuries also.
Higher percentages in concomitant abdominal and extremity injuries in severely injured patients with milder thoracic trauma are, in our opinion, attributable to the fact that to maintain an ISS ≥ 16 in the absence of significant thoracic injuries, these must have been compensated by more severe injuries to the extremities and/or the abdomen. Interestingly, about a quarter of patients with severe to critical chest injuries (AISThorax ≥ 3) suffered from abdominal injuries that were at least serious (AISAbdomen ≥ 3) in each group.
The highest rate of patients with cerebral dysfunction we report (29%), expressed as GCS ≤ 8, occurred in severely injured patients with AISThorax ≥ 5, compared to 14%–17% in AISThorax ≤ 4. This is consistent with the highest rate of systolic BP < 90 mmHg in AISThorax ≥ 5 patients, since cerebral dysfunction is an early sign of hypovolemia, in addition to the hypoxia encountered in severe thoracic trauma.
A recent study demonstrated that thoracic injuries in critical trauma patients were independently associated with a delayed diagnosis of injury. The overlooked injuries affected the chest and every other body region to varying degrees. The authors note that clinicians are easily distracted or preoccupied by more obvious or threatening conditions [
23]. It is therefore not surprising that chest injuries are overlooked, even in thoracic trauma patients, as we identified higher rates of multiple injuries to the chest with higher AIS
Thorax. Most of the patients in our investigation underwent WB-MSCT for comprehensive diagnostic workup, as recommended [
24]. This is no doubt why we detected a plethora of injuries (up to 2.43 ± 1.18 injuries) in thoracic trauma by computed tomography, which is known to be more sensitive than plain radiographs [
25].
Prehospital and early clinical management
The prehospital management of severely injured patients varies with the extent of chest trauma. We noted a major increase in prehospital intubation rates in patients with AIS
Thorax = 4 to ≥ 5 (44% vs. 58%), consistent with previous intubation and ventilation rates reported to be between 50 and 70% depending on the severity of the initial blunt thoracic trauma [
4,
26,
27].
Continuously-rising rates of chest tube insertion were documented for our patient cohorts in conjunction with increasing AIS
Thorax. Overall, 8% (1%–22%) required preclinical chest tube placement, rising to overall 27% (2%–62%) chest tube placements during the early hospital resuscitation phase. Higher frequencies of prehospital thoracic decompression with increasing AIS
Thorax are in line with other reports [
28]. Additionally, our rates of chest tube placements are within published rates of 44%–53% in patients presenting to the hospital with severe chest trauma [
27,
29], and a rate of about 25% in patients presenting with major trauma [
29,
30]. On the other hand, the rate of overall chest tube insertions in severely injured patients was recently reported to be dropping [
30]. Reasons for the increase in chest tube placements we documented may be more severe pneumo- and hemothoraces with higher AIS
Thorax scores and, within the AIS
Thorax = 5 group, mandatory chest decompression because of tension pneumothorax.
When considering our patient groups’ circulatory condition, it is important to note that up to AISThorax = 3, the reported rates of systolic BP below 90 mmHg followed by catecholamine administration did not differ. The first increase in the incidence of hypotension (systolic BP < 90 mmHg) and catecholamine use appears with AISThorax = 4, and even more substantially in AISThorax ≥ 5, where a third reportedly had been in shock. This might be due to the fact that, for example, relevant hemothorax involving a blood loss exceeding 1000 ml is coded as AISThorax = 4, while tension pneumothorax is AISThorax = 5. Injuries to the chest coded as AISThorax < 4 seem to have an additional impact on circulation in severely injured patients.
Not contradictory is the rate of prehospital CPR in our population of severely injured patients, where about 1%–3% with an AIS
Thorax ≤ 4 underwent CPR. Past studies reporting on patients from the TR-DGU describe about 3% of severely injured patients undergoing CPR attempts outside the hospital [
31]. There is a discrepancy in our AIS
Thorax ≥ 5 patients, 11% of whom underwent CPR due to greater chest trauma severity and reached the hospital showing signs of life. Furthermore, the highest rate of prehospital chest tube placement occurred in patients with AIS
Thorax ≥ 5, 22% of whom received this therapy. Presumably, tension pneumothoraces – one possibility for an AIS
Thorax = 5 score – resulted in cardiopulmonary arrest and, when properly treated via chest decompression, the appropriate management to facilitate sufficient CPR occurred as well. This might be why prehospital chest tube insertion has been observed to be a strong predictor for survival in the resuscitation of patients in traumatic cardio-respiratory arrest [
32], and correlates with findings that 13% of traumatic cardiac arrests were ascribed to tension pneumothoraces [
33]. Taken together, this highlights the fact that the most common management error in traumatic cardiac arrest is failing to decompress the tension pneumothorax [
32,
34]. With the results of our study we can emphasize that severe thoracic trauma is a significant cause for CPR in the severely injured patient.
The application of packed red blood cells and massive transfusion was most frequent (35% and 12%, respectively) in patients with AIS
Thorax ≥ 5, which is consistent with the highest rate of systolic BP < 90 mmHg during the early clinical resuscitation phase. Overall, we report rates of 26% of patients requiring transfusions and 7% undergoing massive transfusion, resembling other reported rates of 24% and 5.6% in multiple-injury patients [
20]. Consistent with this, we found 17% of severely injured patients with an AIS
Thorax ≥ 5 in such dire straits that they required emergency surgery. Additionally, we were able to show that massive transfusion and emergency surgery is significantly associated with severe thoracic trauma (AIS
Thorax ≥ 4) in severely injured patients.
Outcome
Consistent with others, we report an increasing mortality with thoracic trauma severity. Albeit, our reported mortality is lower than previously published, which may in part be due to our deliberate exclusion of patients with severe head injury [
3,
19]. Our reported median times of overall hospital stay are about comparable to the shorter of the previously-reported mean stays of 20 days – 38 days [
19]. Interestingly, we found the longest inpatient periods with AIS
Thorax ≥ 5. This is in contrast to previous results [
19], yet we included only surviving patients in our analysis. Patients with higher AIS
Thorax might experience an earlier death compared to others, thus statistically shortening the inpatient period, if not controlled for by exclusion.
Limitations
This study has several limitations. One is its retrospective nature. Not all data were recorded on some procedures and characteristics, but those cases were still comprehensive. All hospitals participating in the TR-DGU submit to regular audits and sample tests are performed to ensure data quality. However, the documentation’s validity is not controlled by external monitoring as in prospective trials [
35].
Additionally, patients from different European hospitals are included in this study. Although mainly Level 1 and 2 trauma centers contribute to this database, we cannot comment on locally implemented protocols or specialized training (e.g., ATLS®) for trauma care. But the vast majority of our patients received care in German hospitals where training in ATLS® courses and protocols has been established since 2003 [
36]. During the years of our study this standardized training spread to participating hospitals, and presumably over time our patient cohort received similar early clinical treatment according to their injury severity. Nevertheless, contributing hospitals to the database change over time and so does the mixture of participating trauma center levels.
In our study, we excluded patients with severe head injury (AISHead ≥ 4) to minimize confounding and, as a result, our findings cannot be readily transferred to severely injured patients sustaining additional major head trauma.