In the present study, we demonstrated two major findings: 1) trauma treatment in hybrid ERs does not increase the mortality of patients with severe trauma compared with previous conventional treatment in non-hybrid ERs; and 2) trauma resuscitation in a hybrid ER reduces the amount of blood transfusion required in the resuscitation.
The hybrid ER system is a new treatment concept, and the clinical effects of hybrid ERs in trauma treatment have not been clearly defined. In particular, the safety of using hybrid ERs for trauma treatment has not been reported. Therefore, this study was necessary to clarify the safety of hybrid ERs for trauma management. Previous reports showed that the time to CT initiation, time to definitive therapy (including thoracotomy or laparotomy), and time to TAE in trauma workflows in hybrid ERs were significantly reduced compared with those in non-hybrid ERs (12, 22). Reduction in time to CT scan and intervention is one of the greatest advantages of hybrid ER. However, the safety of the new trauma workflow for performing a CT scan during the primary survey has not been evaluated. In this study, we demonstrated that a hybrid ER is as safe as conventional treatment. This result suggests that it may be reasonable to actively use the hybrid ER system in patients with severe trauma.
In our trauma protocol for hybrid ERs, a CT scan is performed instead of FAST and radiography of the chest and pelvis. It has been emphasized in trauma surveys that this three-point examination is simple and can be performed without transferring the patient. At this point, CT imaging in hybrid ER is similar to FAST and radiography of the chest and pelvis, as in conventional imaging surveys. Additionally, the whole-body CT scan can reveal findings unknown in the primary survey, including intracranial bleeding, mediastinal hematoma, and retroperitoneal hematoma around the aorta or kidney. This provides advantages over conventional methods; if this information is available during the primary survey, it can guide the appropriate management strategy. Moreover, patients can immediately undergo resuscitative surgery, including hemostasis, without transfer. In fact, our results revealed that the time from arrival to CT scan and resuscitative interventions was significantly reduced with hybrid ER use. This may benefit patients requiring the shortest possible time from hemostasis to surgery or IVR. Moreover, if a CT scan in the hybrid ER reveals an intracranial hematoma with concurrent massive abdominal bleeding, simultaneous craniotomy and resuscitative laparotomy can be performed in the emergency department without patient transfer. The hybrid ER has another advantage in that two or more surgeries can simultaneously be performed in the emergency department.
However, a whole-body CT scan in the primary survey may increase radiation exposure. In fact, the radiation exposure dose of whole-body CT scans is higher than that of regular X-rays. Therefore, we must make an effort to reduce the radiation exposure when using the hybrid ER. Only patients with high-intensity injuries or critical illness are transferred to the hybrid ER in our trauma center, and other patients are treated in the regular emergency room. Whole-body CT scans in the hybrid ER should only be performed in patients for whom it is essential. We also usually used X-ray machines in hybrid ERs for patients with rib fractures to reduce radiation exposure. Many of these patients in the hybrid ER group needed CT examination after the secondary survey; therefore, they underwent CT even if they were treated in a regular emergency room (non-hybrid ER). The radiation exposure in a hybrid ER is similar to that of a regular CT scan. Consequently, it was estimated that there would be no difference in the total radiation exposure in the emergency department between the two groups, although there was no data to support this finding. The hybrid ER can be a useful system, as described above, when used effectively in patients with life-threatening conditions.
We had initially believed that hybrid ER, where the C-arm was easily available, appeared to be suitable for REBOA (resuscitative endovascular balloon occlusion of the aorta). However, this was proved wrong when we actually used a hybrid ER. Laparotomy or pelvic packing can be performed quickly without patient transfer in a hybrid ER to control bleeding in patients who need REBOA because a hybrid ER also includes an operating room. If possible, definitive hemostasis should be performed earlier than temporary hemostasis by REBOA. Patients requiring resuscitative thoracotomy are likely to develop cardiac arrest, and REBOA is no longer indicated. In this study, none of the patients needed REBOA in the hybrid ER. We believe that intraoperative bleeding control can be achieved in the hybrid ER during the induction of REBOA.
Various specialties are required to make effective use of hybrid ERs. Without an interventionalist, the hybrid ER cannot fully demonstrate its capabilities. In our trauma center, trauma surgeons resuscitate the patient and perform open surgeries in the hybrid ER. Interventionalists are available every day in our trauma center, so there is minimal waiting time for IVR. Some trauma surgeons have even mastered emergency IVR techniques in our trauma center. If the interventionalist is not available, the trauma surgeon may perform IVR. In addition, the role of a radiologist is also extremely pivotal in hybrid ER. At our trauma center, the radiologist arrives at the emergency department before the patient arrives to prepare for the hybrid ER, and thus is a part of the team. Teamwork is also extremely important for the effective use of hybrid ER.
A previous report showed that trauma workflow using the hybrid ER system decreased the mortality of patients with severe trauma (12). This was the first clinical effect of the hybrid ER system. However, our results showed that there was no difference in the survival of hybrid ER patients compared with those of patients in the non-hybrid ER. We also assessed the survival benefit (survival and unexpected survival rate) at <50, 50-64, 65-79, and 80 ≤ years of age between the two groups. Unfortunately, there were no significant differences in survival and unexpected survival rates between the non-hybrid ER and hybrid ER groups in the four age groups. Thus, it may be difficult to improve survival using hybrid ER, as the survival rate in the conventional group (non-hybrid ER) was high. Another report indicated that more severely injured patients can survive in a hybrid ER (23). This report showed that the TRISS Ps of survival patients treated in the hybrid ER were lower than that of those in non-hybrid ER. This suggests that hybrid ERs may contribute to survival in more severe trauma patients with a high ISS (e.g., ISS ≥ 36).
We also focused on the amount of blood transfused because massive transfusion plays an important role in resuscitation during trauma treatment. Massive transfusion is a concept that forms the basis of DCR, as evidence for the efficacy of DCR has been reported extensively in the literature (15, 16). To determine the effect of blood transfusion in the hybrid ER, we compared the amount of blood transfused between the two groups. Our results revealed that the hybrid ER significantly reduced the amount of blood transfused to patients. This is the first report of the effectiveness of blood transfusion in hybrid ER. A hybrid ER can provide accurate injury information and reduce the time until hemostasis. This result suggests that faster hemostasis using a hybrid ER may have reduced blood transfusion in trauma resuscitation. The hybrid ER may thus make a medical contribution by reducing blood transfusions.
There are however, some important limitations to our results. First, this was a retrospective study conducted at a single institution. Since there may be several biases in such a study, these results should be verified in a prospective, multicenter study. Second, this study cannot identify whether a suitable criteria for admission to a hybrid ER is trauma resuscitation. Although severe trauma patients with ISS ≥ 16 were analyzed in our study, suitable clinical criteria for a hybrid ER should be assessed in the future. Third, it is said that a significant barrier to the installation of a hybrid ER is cost. We did not assess the costs and benefits of using a hybrid ER in trauma treatment. We usually use a hybrid ER as a CT scan room in an emergency room. Even if surgery is not performed on all patients, it may be possible to pay for a hybrid ER by performing CT examination a certain number of times in a day. In Japan, a dual-room-type hybrid ER has recently been released in consideration of cost merit (24). The cost-effectiveness of the hybrid ER should be estimated accordingly. Finally, the radiation exposure dose for whole-body CT scans in both groups was not assessed in this study. Radiation exposure should be reduced for medical examination; therefore, an accurate dose of radiation in both the groups should be assessed in the future.