Shining the spotlight on blood
Severinghaus lecturer Bruce D. Spiess, MD, FAHA, displayed his remarkable research on blood and how it applies to anesthesiology.
Blood is a vital, complex organ – and don’t tell Bruce D. Spiess, MD, FAHA, otherwise. Dr. Spiess, who is Professor Emeritus in the Department of Anesthesiology at the University of Florida in Gainesville, delivered the John W. Severinghaus Lecture on Monday morning.
His presentation featured revolutionary research performed by him, multiple colleagues like Dr. Robert Winslow and Dr. Thomas Hornbein, and Dr. Severinghaus himself. Dr. Spiess even referred back to the 16th century to recognize the progressive, foundational work of Leonardo da Vinci, who dissected a human cadaver, from its aorta to capillaries, to illustrate and describe blood vessel anatomy.
Dr. Spiess admitted he was reluctant to become a researcher early on but said, “It’s become one of the most wonderful, joyful experiences I’ve traversed in life.” He also shared how much of an honor it was to be associated with Dr. Severinghaus, whom he highly regarded.
Much of Dr. Spiess’ research has focused on perfluorocarbon (PFC) oxygen therapeutics. A Japanese researcher who wrote on the topic incited this quest, he said, particularly this statement: “Everyone here should realize that PFCs make not only oxygen fully soluble in blood but nitrogen and all other respiratory gases.”
He was also inspired by his dad, Elliott, an evolutionary geneticist, who said, “One cannot understand biology (medicine) without evolutionary context.” So that’s what Dr. Spiess did – he looked at how hemoglobin evolved to carry oxygen and how closely similar it is to the function of chlorophyll in plants.
Highlights of his career, Dr. Spiess said, include working with the U.S. Navy on treating decompression sickness with hyperbaric oxygen therapy. He also collaborated with the U.S. Army to train special operations combat medics, like green berets, on using critical oxygen delivery on the battlefield to treat trauma-induced coagulopathy.
Dr. Spiess also revealed he had created a new word that better addresses the biocomplexity of blood: sanguothelium. “Sanguis” is Latin for blood, and the sanguothelium, he emphasized, is a vital organ. It is anthropomorphic in that it doesn’t have one single, significant function. In fact, it is an organ that all other human organs depend on, and it supports whole blood health. He said it’s extra important to anesthesiologists, who administer more than 50% of the blood in the U.S. – which quantifies to 11-14 million RBC units/year.
Knowing all this, Dr. Spiess said the medical and scientific communities cannot continue to simplify blood to one specific thing: hemoglobin. Rather, they need to “embrace the biocomplexity of blood,” which he said contains more than 2,800 proteins.
Other applications for PFC oxygen delivery (diffusion) when there is low to no flow of plasma, he said, are cardiac arrest, stroke, traumatic brain injury, spinal cord trauma and surgery, and solid-tumor cancer immunotherapy. Within cardiac surgery, he said research shows that PFC added to cardiopulmonary bypass prime reduces cerebral air emboli by 98%.
Dr. Spiess challenged anesthesiologists to continue in his research footsteps, especially as it relates to blood transfusions. Ordering a blood transfusion based on hemoglobin levels is not physiologic, he said, because there is no proven threshold.
“Tissue oxygen supply is not hemoglobin-dependent until extremely low levels.” Levels, he said, haven’t been met in randomized controlled trials evaluating restrictive versus limited transfusions.
Everything anesthesiologists do is based on macrocirculation, said Dr. Spiess. But anesthesiologists need to focus on microcirculation and develop a tool to measure it. “This,” he said, “is the business-end of where things happen.”
Dr. Spiess’ enthusiasm and dedication were on full display throughout his presentation and will surely be remembered far beyond the annual meeting.
