Project Summary
While survival rates for critically ill patients during their acute illness continues to improve, the long-term
outcomes for these patients are dismal. When ICU survivors progress to a state of chronic critical illness (=14
days in the ICU), the majority develop significant disability and prolonged recovery times fraught with multiple
complications. Ultimately, about 50% eventually succumb to their illness at one year. Unfortunately, once
patients progress to a state of chronic critical illness, there is nothing more than supportive care. Given that the
healthcare costs required to manage these patients is estimated to be over $20 billion per year, chronic critical
illness is creating a new health care crisis. As an ICU physician and basic science researcher, I have the
unique ability to both manage these patients at the bedside and actively investigate new ways to improve their
care. With all the effort invested in these patients to help them survive their acute illness, it seems like a failure
that we are not able to help them long term.
The greatest risk factor for the progression to chronic critical illness is the profound immunosuppression
that can occur. In the normal response to injury or infection, both the innate and adaptive immune systems
deactivate once the inflammatory insult is cleared. However, with a significant insult, such as trauma or sepsis,
deactivated immune cells are replaced by more immature cells from the bone marrow that have decreased or
suppressive activity and may be unable to effectively eradicate the source. Many have been able to show this
immunosuppressed state in critically ill patients, but no one has been able to reverse this response. This
proposal synergizes both human and animal studies to better understand the diversities on how individuals
respond to a significant injury or infection and attempt to reverse any immunosuppression that may occur. In
the first project, four different murine models of injury or infection are utilized and the immune profile of each
individual mouse is identified. If they display any type of suppression in their innate or adaptive immune
system, or both, specific reversal agents are administered to determine if we can improve their immune
response. In the second project, blood samples from critically ill patients admitted to the Surgical ICU are
analyzed to determine their immune profiles over the first two weeks of admission. Univariate and multivariate
regression analyses will then be performed to determine which immune phenotypes are associated with worse
outcomes, with the primary outcome being chronic critical illness. Successful completion of these studies will
significantly advance the field of immune phenotypes and set the groundwork for developing individualized
immune therapies for a variety of critically ill patients.