Background
Pelvic injuries occur frequently, amounting to almost 9% of all blunt trauma patients [
1]. Blunt pelvic injuries from high-energy mechanisms such as a fall from a height or road traffic collision are often associated with pelvic fractures and injuries to the rectum and genitourinary tract [
1‐
4]. The seriousness of blunt pelvic fractures lies in the possible occurrence of retroperitoneal hematomas and hemorrhagic shock [
5,
6]. Most pelvic hemorrhage occurs from venous and fracture sites (85%) [
7,
8]. However, in the hemodynamically unstable patient with severe pelvic injury, arterial bleeding is frequent [
4,
8]. The overall mortality rates of patients with pelvic ring fractures range from 8% to 13.5% [
1,
9‐
11]. Pelvic bone fractures with hemodynamic instability are associated with a higher incidence of pelvic vascular injury and hemorrhage, and the mortality rates are reported to be 30%-57% [
10,
12,
13].
The recent evolution of rapid pelvic stabilization by external fixation or pelvic binding, and of hemostasis by angiographic embolization, resuscitative endovascular balloon occlusion, or preperitoneal pelvic packing has significantly decreased the mortality rates in devastating pelvic injuries [
14‐
20]. However, early detection of bleeding is not easy in blunt pelvic fractures. Furthermore, in blunt pelvic trauma with hemodynamic instability, it is difficult to achieve adequate hemostasis due to rapid exsanguination.
Therefore, early recognition of bleeding is important because it may increase the success rate of non-surgical treatment, such as angioembolization, and even if surgery is indicated, early surgery has better prognosis. If hemorrhage and coagulopathy progress significantly, no treatment can be expected to produce good clinical outcomes [
18,
19,
21]. Thus, the purpose of this study was to investigate early factors predicting the need for hemorrhage control intervention in patients with blunt pelvic trauma.
Discussion
Blunt pelvic injuries from high-energy mechanisms are often associated with pelvic fractures and injuries to the rectum and genitourinary tract [
1‐
4]. The seriousness of blunt pelvic fractures lies in the possible occurrence of retroperitoneal hematomas and hemorrhagic shock [
5,
6]. Unstable pelvic fractures are associated with massive hemorrhage [
22], which is the leading cause of death in patients with major pelvic fractures [
23,
24]. In the present study, patients with pelvic bleeding had significantly higher in-hospital mortality rates than those without pelvic bleeding. Moreover, among patients with pelvic bone fractures, trauma-related severity scores such as the GCS, ISS, RTS, and TRISS were significantly higher in the hemorrhage control intervention group than in the non-hemorrhage control intervention group. Therefore, trauma patients in need of emergent intervention or surgery for ongoing hemorrhage have increased chances of survival if the elapsed time between traumatic injury and bleeding control intervention is minimized [
5,
10,
16,
25].
The recent evolution of rapid pelvic stabilization by external fixation or pelvic binding and of hemostasis by angiographic embolization, resuscitative endovascular balloon occlusion, or preperitoneal pelvic packing has significantly decreased the mortality rates of devastating pelvic injuries. However, early detection of bleeding is not easy in blunt pelvic fractures [
14‐
20]. Furthermore, despite ongoing bleeding in a severely injured patient arriving at a hospital, the vital signs of the patient may not show typical changes in the immediate and early periods after injury [
26,
27]. In blunt pelvic trauma with hemodynamic instability, it is difficult to achieve adequate hemostasis due to rapid exsanguination. Therefore, early and quick prediction of the need for hemorrhage control interventions for pelvic injuries is important.
In the present study, type B and C fractures according to the OTA/AO classification were revealed as independent factors predicting the need for hemorrhage control intervention in patients with blunt pelvic trauma. Type B and C fractures show pelvic bone fracture patterns including posterior pelvic ring instability. Type B fracture is a result of rotational forces that cause partial disruption of the posterior sacroiliac complex [
28,
29]. Complete disruption of the posterior complex occurs in type C fractures, which are both rotationally and vertically unstable [
28,
29]. In this study, the need for early hemorrhage control interventions was 4 and 7 times higher for type B and C fractures than for type A fractures, respectively.
Although patients with high-grade pelvic ring injuries may not have significant bleeding, the bleeding risk generally increases with the degree of instability of the posterior pelvic ring [
30,
31]. Manson et al. [
24] reported that transfusion requirements and mortality were significantly higher in the posterior ring instability pattern than in the pelvic bone fracture pattern
without involvement of the
posterior structures, and this suggests that stretching and tearing of soft tissues, like artery and vein, around the posterior pelvic ring showed greater hemorrhagic instability in lateral compression III, anterior-posterior compression III, and vertical shear. Costantini et al. [
32] similarly concluded that there is a higher need for hemorrhage control intervention in the posterior pelvic ring instability patterns, such as anterior-posterior compression III or open pelvic fracture. In the current guidelines, markers of pelvic hemorrhage also include anterior-posterior and vertical shear deformations on standard roentgenograms [
33‐
35].
In the present study, patterns of pelvic fracture were evaluated with pelvic radiography. To date, CT has replaced radiography in classifying pelvic fractures [
35]. Contrast-enhanced CT also helps diagnose pelvic hematoma and active extravasation of contrast [
7]. Multidetector CT has short acquisition times and allows for rapid identification and assessment of pelvic hemorrhage [
36]. However, CT cannot be performed for all patients and is dependent on the situation, such as hemodynamic instability or absence of resources in each institution [
36]. Although evaluation of the sacrum and sacroiliac joints is sometimes limited on a portable anteroposterior pelvic radiograph, pelvic radiography is one of the tools that can easily and quickly reveal the pelvic bone fracture pattern, and it is generally performed as an initial examination in the trauma bay [
37,
38]. Furthermore, pelvic radiography in hemodynamically unstable patients helps in identifying life-threatening pelvic ring injuries [
39].
The patterns of pelvic fracture were classified as types A, B, and C using the OTA/AO classification. The OTA/AO classification was based on fracture stability, especially the stability of the posterior lesion [
28,
40‐
42]. Unstable pelvic fractures are more frequently associated with hemorrhage [
4,
8]. The OTA/TA classification is easier to use in classifying patterns of pelvic fracture through pelvic radiography than the Young-Burgess classification, which is based on mechanism of injury [
38,
42]. Furthermore, the Young-Burgess classification scheme for pelvic ring injury basically cannot be used to guide transfusion requirements and the need for angiography and embolization in individual cases [
30].
In the multivariable regression analysis, the body temperature was significantly low in the hemorrhage control intervention group. In other words, hypothermia was a predictor of the need for hemorrhage control intervention. Hypothermia is common in trauma victims and is associated with an increased risk of severe bleeding and increased mortality [
43,
44]. In the study of Gentilello et al. [
45], the group of trauma patients with a mean body temperature of 34.5°C showed a mortality of 100% when they failed to be rewarmed to 36°C. Therefore, warming and euthermia in a trauma patient with pelvic bone fracture are crucial.
The current guidelines recommend either serum lactate or base deficit measurements as sensitive tests to estimate and monitor the extent of bleeding and shock [
46‐
49]. Additionally, serial measurement of these parameters can be used to monitor the response to therapy [
48]. The amount of lactate produced by anaerobic glycolysis is an indirect marker of oxygen debt, tissue hypoperfusion, and severity of hemorrhagic shock [
47,
50]. Similarly, base deficit values derived from arterial blood gas analysis provide an indirect estimation of global tissue acidosis due to impaired perfusion [
50,
51]. Moreover, the lactate and base deficit have been mentioned in many studies as predictive values related to bleeding in pelvic bone fractures in trauma patients [
52‐
55]. In this study, serum lactate was identified as an independent predictor of the need for hemorrhage control intervention. In other previous studies, both initial serum lactate and lactate clearance after 6 hours were identified as independent risk factors for mortality in trauma patients [
56]. In addition, an increased serum lactate level is associated with massive hemorrhage in pelvic ring fractures [
57], and the serum lactate level measured in the pre-hospital period was found to be associated with the clinical outcome in trauma patients [
58].
We additionally conducted a multivariable logistic regression analysis including “anticoagulant use” as potential predictor. It is indisputable that anticoagulants may worsen bleeding in a trauma patient. However, despite the clinical significance of anticoagulants, the results have not changed whether anticoagulant use is included or not in the multivariable logistic regression analysis. Therefore, our results should be carefully interpreted and used strictly in a wider context of the patient’s clinical condition, clinical setting, and individual included factors.
There are several limitations to the present study. First, it is a retrospective study. Second, it may be difficult to generalize the results of this study, as it is a single-center study. Third, the statistical power is insufficient because of the small number of subjects. Therefore, multicenter studies are needed to overcome these limitations.