When managing the treatment of severe blunt trauma admissions rapid assessments of patient injuries are essential. This must be balanced with the need for high quality information that will inform subsequent surgical procedures. The development of high performance diagnostic imaging techniques, such as whole-body computerized tomography (CT), has aided progress in the critical care of severe blunt trauma patients. However the value of whole-body CT in pre-operative surveys of patients requiring emergency bleeding control is still unclear, with some guidelines explicitly recommending whole-body CT after surgery. Daiki Wada of Osaka General Medical Center, Japan and colleagues investigate the impact of whole-body CT on mortality in a retrospective study of severe blunt trauma patients, published in a study in Critical Care. Wada explains their findings and the potential for future use of pre-operative CT scanning in trauma.
How did you become interested in research into emergency and critical care?
Following my surgical medical training, I chose to join the Critical Care and Trauma Center of the Osaka Prefectural Hospital Organization. Approximately 24,000 trauma deaths occur in Japan annually, making trauma the fifth leading cause of death, and among young adults, trauma is the leading cause of death. I became interested in trauma care, because I hope to decrease the number of trauma deaths, working closely with Assistant Professor Yasushi Nakamori of the Department of Emergency and Critical Care Medicine at Kansai Medical University. We have often experienced that pre-operative computer tomography (CT) has contributed to the development of effective intervention strategies for emergency bleeding control in cases of severe blunt trauma. We therefore became interested in investigating these benefits of pre-operative CT on mortality in severe blunt trauma patients requiring emergency bleeding control.
Can you elaborate on the controversy surrounding the use of pre-operative diagnostic CT in patients with severe blunt trauma?
Although x-ray and FAST (Focused Assessment with Sonography for Trauma) are readily accessible and widely used during primary evaluations, their sensitivity in recognizing a number of injuries is limited. CT has become the gold standard for definitive diagnostic imaging in severely injured patients. However, CT scanning has often required patient transfers, which is time-consuming and laborious. Trauma care guidelines suggest that CT scans, when indicated, are carried out as part of a secondary evaluation so as to not delay the resuscitation process. However, several approaches to installing CT scanners close to or inside emergency rooms have been presented and recent technical improvements have included increased scanning speeds.
What new insights does your study bring to light?
Although several studies have reported that CT in early trauma care improves outcomes, little was known about the impact of CT on mortality when pre-operative CT is performed for blunt trauma patients requiring emergency bleeding control, especially for patients at high risk of death and for hemodynamically unstable patients. We find that in these cases CT performed before emergency bleeding control is associated with significantly improved survival.
ATLS (Advanced Trauma Life Support) guidelines recommend CT scanning after emergency surgery in hemodynamically unstable patients, which goes against your findings. What mechanisms do you think underlie the improved survival you found in this group of patients?
Our study revealed that pre-operative CT might be associated with improved survival in patients at high risk of death (with a low score for probability of survival according to the Trauma Related Injury Severity Score) and in hemodynamically unstable patients. In patients with a high risk of death and more than one site of bleeding, survival rate in the CT group was significantly higher than that in the non-CT group. I think this is because CT helps in prioritizing the type of emergency bleeding control required in the first instance and is helpful in promptly tailoring subsequent treatment.
What are the challenges of conducting prospective interventional studies in emergency medicine?
In our study, the decision criterion for performance of CT and the imbalance in sample size may be the major biases. Because it is difficult to perform CT in hemodynamically unstable patients, the number of patients recruited in the CT group may often be lower than that recruited for the non-CT group. In interventional studies in emergency medicine, it is possible that these selection biases cannot be controlled entirely.
Are you planning any prospective studies on the use of diagnostic CT in blunt trauma patients?
We are planning a multicentre study to clarify in which populations with severe trauma, will CT have the most significant effect on patient outcome.
Technical advances have reduced CT scanning times. Do you think pre-operative CT scanning will ever replace x-ray imaging in the management of trauma in the emergency room?
In the trauma care environment of our study, the time needed for the CT scan including patient transfer time was about 20 minutes. Thus, I think that such CT scanning could not necessarily replace x-ray imaging in trauma care. In 2011, we implemented a new trauma workflow concept with a sliding CT scanner system with interventional radiology features (IVR-CT) in our emergency room. All life-saving procedures including damage control surgery and transcatheter arterial embolization (TAE) can be performed without relocating the patient. In the IVR-CT system, time to CT initiation was ten minutes, and times to the start of emergency bleeding control procedures were 45 minutes for surgery and 54 minutes for TAE – obviously shorter than those of our previous reports. We think that our IVR-CT system allowing faster diagnosis and definitive interventions will replace x-ray imaging in future trauma care.