Major Questions in Perioperative Medicine Examined

By Douglas A. Colquhoun, MB ChB, from the IARS, AUA and SOCCA 2019 Annual Meetings*

In the AUA Scientific Advisory Board Oral Session III on Friday examined four cutting-edge questions in perioperative medicine. The session featured Dr. Jae-Woo Lee from University of California, San Francisco, Kevin Nguyen from University of Central Florida, Dr. Dusan Haidizar from Massachusetts General Hospital and Dr. Behrouz Ashrafi from University of Miami presenting their work.

Dr. Jae-Woo Lee, a Professor of Anesthesiology at University of California, San Francisco, presented his work entitled, “Therapeutic effects of hyaluronic acid in E coli bacterial pneumonia in ex vivo perfused human lungs.” Using human lungs not suitable for transplantation, Dr. Lee’s team, prepared these lungs using an ex-vivo perfusion system and inoculated them with extracellular vesicles derived from E Coli. This led to the development of an intense inflammatory response, which could be ameliorated by the delayed addition of hyaluronic acid. Dr. Lee suggested that this may be related to the therapeutic effect by blocking effect hyaluronic acid of the binding of extracellular vesicles via a CD44 receptor.

Kevin Nguyen, a fourth-year medical student at UCF working at the laboratories of Dr. Mansoureh Eghbali and Dr. Soban Umar at University of California Los Angeles on a FAER Medical Student Anesthesia Research Fellowship presented his work entitled, “Ventilator induced lung injury in a rat model of pulmonary fibrosis is influenced by disease severity and tidal volume.” Using a bleomycin model to induce moderate and severe pulmonary fibrosis in rats, the group then subjected these lungs to mechanical ventilation with low and high tidal volume regimens. Summarizing experiments judged based on alveolar wall thickness and modified ventilator induced lung injury (VILI) score. The pulmonary fibrosis appeared to be more susceptible for VILI, however it was unclear if the severity of this process modulated this effect. The experiments suggested low tidal volume may offer some protection in the pulmonary fibrosis group.

The third presentation during the session was by Dusan Hanidziar, MD, PhD, from Massachusetts General Hospital. The presentation, entitled, “A Systems Approach to Characterize Lung Immune Response to Hyperoxia,” described the use of a mouse model of hyperoxic lung injury with well-defined histologic changes but less well-defined immune responses. Using a mass cytometry analysis of the immune cells obtained from these lungs, computational analysis revealed a marked decrease in a subpopulation of B-cells and increase of NKT cells and alveolar macrophages in the presence of hyperoxic lung injury. Further analysis of the macrophages revealed that autotaxin, a surface enzyme, may be associated with the development of this mechanism. Dr. Hanidziar went on to posit that available pharmacologic agents, which inhibits this enzyme may offer a potential treatment opportunities.

In a presentation entitled, “Total Intravenous Anesthesia with a Novel Formulation of Isoflurane perfluorocarbon based nano-emulsion,” Behrouz Ashrafi, MD, from University of Miami, described work in the development of a perfluorocarbon based emulsion nano-particles. These particles have long-term stability and a sufficiently small enough particle size, which Dr. Ashrafi believed could be useful for anesthetic delivery. Using a 6% solution of isoflurane in this delivery mechanism, the team were able to use this as a sole anesthetic for induction and maintenance of a 1-hour general anesthetic in four beagles each undergoing three separate general anesthetics. End tidal isoflurane was able to be used as a surrogate for depth of anesthesia with expected dose response effects on blood pressure. Follow up measurement did not reveal any changes in renal and liver function. Dr. Ashrafi was presented the Junior Faculty Research Award for this work.

Drs. Lee, Hanidziar, Ashrafi and Mr. Nguyen’s e-Posters are available for viewing at https://tinyurl.com/AM19eposters.

*Coverage from the AUA Scientific Advisory Board Oral Session III during the AUA 2019 Annual Meeting