WASHINGTON – The medical understanding of shock and trauma resuscitation has evolved over many decades. But cutting-edge research is revolutionizing the understanding of the mechanisms of trauma and will eventually have a profound impact on treatment models, according to Dr. Ronald V. Maier.
Dr. Maier, an ACS Fellow and the Jane and Donald D. Trunkey Professor and vice-chair of the department of surgery at the University of Washington, Seattle, delivered the Scudder Oration on Trauma during the American College of Surgeons Clinical Congress. He discussed the development of treatment models for trauma resuscitation in the 20th century, beginning with Cannon’s toxins theory of shock (Cannon WB. Traumatic Shock. New York: D. Appleton & Co; 1923), and continuing into the 1930s with Blalock’s pioneering work in developing the homeostasis theory of trauma treatment (Arch. Surg.1934;29:837-57) .
Many advancements in the theory of trauma came out of experiences on the battlefields of World War I, World War II, the Korean War, and the Vietnam War, he said.
The progression of ideas about treatment also evolved, beginning with a minimalist approach developed during World War I to the more interventionist models involving blood transfusion developed during the Korean War era, leading to a focus on crystalloid resuscitation and oxygen deficit that became prominent during the Vietnam War.
Dr. Maier traced the progression of interventionist strategies, each supplanted by new models based on improved understanding of the mechanism of trauma and a growing realization that many of the earlier approaches amounted to overtreatment with limited improvement in survival rates.
The recent paradigm is summed up as hypotensive resuscitation, meaning damage control and supporting blood pressure without reaching normotension, taking account of the natural coagulation process that occurs in the body in response to trauma.
"The goal is to recognize that if we try to chase interventions until they’ve completely corrected the system they impact, we will end up overtreating and having all the harmful effects of the treatment," Dr. Maier said.
Dr. Maier discussed the emerging "genomic storm" model of the mechanisms of trauma that zeros in on patterns of genetic expression. "In the overall genomic response of injured patients, there is a major change in the genomic activity. After a major injury, [the expression of] 80% of the genes change significantly." Damage to the immune system is evident, especially as reflected in down regulation of T-cell pathways and responses.
Dr. Maier’s research efforts have yielded new insight into the nature of that genomic shift. "What we were able to show is that in the patients who develop major complications vs. those who do not develop complications after severe injury, there is a limited number of genes that have a marked difference in reactivity." Sixty-four genes have been identified as having a bearing on the risk of complications.
The path to recovery involves a return of those patterns to a pre-trauma state. And the pursuit of a treatment model from this new understanding of the trauma mechanism means finding a way of predicting which patients will achieve that pre-trauma pattern and which will need intervention to prevent complicated outcomes.
The next step in this line of research will involve close scrutiny of individual responses to interventions, with a focus on timing and amounts. The details of the human body’s natural response to trauma are largely unknown, so this research will be expensive and time consuming, but according to Dr. Maier, necessary if progress is to be made in treatment models.
Dr. Maier described the emerging paradigm of trauma resuscitation in terms of chaos theory. Chaos theory in the context of trauma means that for the highly complex biological system that is the human body, small early perturbations can create significant changes in outcome. An example would be a small blood transfusion early in the treatment process of a trauma patient could have a profoundly positive impact on outcomes.
Dr. Maier argued that future treatment models will involve giving patients the correct treatment at the correct time and in the correct amounts based on the particular characteristics of the patient and the injury as determined by an understanding of their genetic response pattern and timing. "We have just been funded to develop a bedside test where, with a half cc of blood, we can test the 64 genes, and hopefully, by trending the responses ... we can predict patients who are going to have numerous, severe complications vs. those patients who will not," he said.
Despite the advances that have been made, Dr. Maier acknowledged the remaining challenges in transforming trauma resuscitation. "The holy grail is to be able to identify what patient needs what therapy. That is what we are still aspiring to find, and we have not achieved it yet."