The Daily Dose • Monday, April 24, 2023

The Past, Present, and Future of Innovation in Critical Care

Jane S. Moon, MD

How did a poliomyelitis epidemic inspire the creation of the first intensive care unit (ICU)? What does the history of innovation in critical care medicine tell us about the discipline’s future? These questions and more were explored at the International Science Symposium, “Impact of Innovation and Technology in Critical Care: Past and Future,” on Saturday, April 15 at the IARS 2023 Annual Meeting.

The session was moderated by Beverley Orser, MD, PhD, Chair-Elect of the IARS Board of Trustees and Chair of the Department of Anesthesiology and Pain Medicine at the University of Toronto.

Hannah Wunsch, MD, MSc, Professor in the Department of Anesthesiology and Pain Medicine and the Interdepartmental Division of Critical Care Medicine at the University of Toronto, discussed the role of a polio epidemic in Denmark in driving the birth of the modern ICU in her presentation, “From Polio to COVID-19: Lessons from the Past.” Dr. Wunsch had researched this topic in depth for her upcoming book, The Autumn Ghost: How the Battle Against a Polio Epidemic Revolutionized Modern Medical Care, to be released in May 2023.

Dr. Wunsch traced the beginning of critical care medicine to the autumn of 1952, during the peak of the polio epidemic in Copenhagen, Denmark. Blegdam Hospital, the city’s only hospital for infectious diseases, received around 50 new admissions each day, and 10 to 20 of them had respiratory failure. Nearly all polio patients with respiratory involvement died.

This was the era before mechanical ventilators, blood gas analyzers, and a larger armamentarium of antibiotics. There was only one “iron lung” at Blegdam, and its negative-pressure mechanism often pulled respiratory secretions deeper down into the lungs.

Dr. Wunsch then told an intriguing tale of an anesthesiologist named Bjørn Ibsen, who had previously saved the life of a tetanic child with sedation, curare, and manual bag ventilation. Dr. Ibsen was invited for a consultation at Blegdam Hospital on August 25, 1952.

In spite of his inexperience with polio, Ibsen quickly determined that the elevated “total bicarbonate level” of the patients he saw — in actuality, a combination of carbon dioxide and bicarbonate in the blood — indicated not a primary alkalosis (as traditionally believed), but rather a severe respiratory acidosis.

Although initially skeptical, Chief Physician Dr. Henry Lassen allowed Ibsen to trial positive-pressure ventilation on one patient: Vivi Ebert, a 12-year-old girl who was admitted on August 26, 1952, with likely fatal bulbar polio. The very next day, Vivi underwent a tracheostomy and then was hand ventilated with a Waters to-and-fro circuit — a technique that had only been used by anesthesiologists in the operating room. Pentothal was also given to calm her spasms and agitation, greatly facilitating ventilation. She survived.

Having witnessed a miracle, Lassen mandated the application of Ibsen’s technique to all polio patients with respiratory paralysis at Blegdam. In the absence of mechanical ventilators, over 1,200 medical students were recruited to provide continuous ventilation by hand for 6 hours at a time. Mortality from bulbar polio decreased from almost 90% to around 11% by the end of the epidemic.

Dr. Wunsch then spoke on how the adoption of Ibsen’s ideas not only revolutionized the treatment of polio, it also transformed the fields of respiratory physiology and vaccine development. Furthermore, physicians began to apply knowledge and techniques initially used in the operating room to the management of critically ill patients in a new area of the hospital called the ICU. Ibsen would establish the world’s first modern ICU at Copenhagen’s public hospital in 1953. It was a dedicated area with 24-hour staffing, specialized nursing, basic mechanical ventilation, blood gas analysis, and frequent monitoring of vital signs.

After reflecting on Ibsen’s legacy and the power of critical care medicine to save lives, Dr. Wunsch set the stage for the next speaker’s presentation by discussing the long-term sequelae of specific viral illnesses, with a focus on postpolio syndrome, which 20-80% of polio patients go on to develop. Postpolio syndrome is characterized by weakness, fatigue, pain, and functional loss of the limbs. The most common explanation for such symptoms is eventual metabolic fatigue of motor units unaffected by the virus.

Selma Calmes, MD, Retired Clinical Professor of the UCLA Department of Anesthesiology and Perioperative Medicine and Retired Chief of Anesthesiology of Olive View-UCLA, then shared her personal memories of having polio as a child and then developing postpolio syndrome as an adult in a prerecorded video interview conducted by Dr. Wunsch.

In 1948, when Dr. Calmes was 8 years old, a polio epidemic began to ravage her town of Long Beach, California. “I couldn’t get up out of bed,” she said, recalling her presenting symptom. Her family physician visited her at home, performed a physical exam that included the nuchal rigidity test, and then directed her to go to the Los Angeles County Hospital, where new polio patients had to be quarantined for 2 weeks.

Dr. Calmes had bleak memories of her hospitalization, first at the County Hospital, then at a local facility near her house in Long Beach. She recalled initially undergoing a spinal tap by two male interns in a “very dark” room with poor lighting. After the procedure, she was sent to a floor that was “just packed with polio cases.”

“I was a very feisty kid, and I decided I was going to run away from the hospital,” she said. The nurses were extremely distraught when she “fell in a heap on the floor” instead.

Although Dr. Calmes did not have respiratory failure due to polio, both her legs were paralyzed, and she could not walk for a long period of time. For around 2 years after her initial diagnosis, Dr. Calmes had to use crutches, and it took even longer for her to be able to run.

Dr. Calmes credited her interest in medicine to being hospitalized as a child, although she felt discouraged about how difficult and expensive her education would be. She credited her college organic chemistry teacher for encouraging her and helping her complete the admissions process for Baylor College of Medicine in Houston. Only 6% of physicians in the United States at the time were women. Dr. Calmes’ mother “took out a second mortgage on her house” to help pay for her daughter’s medical school tuition.

Dr. Wunsch also asked about how the practice of anesthesiology had evolved over her career.  Dr. Calmes shared that at the main University of Pennsylvania hospital where she completed her residency training, there was “a very rigid schedule of [intravenous] pentothal and nitrous [oxide] and ether by mask.” She learned to use halothane, which provided a faster and smoother induction, only after being trained to use ether.

Dr. Calmes also described a general lack of monitoring equipment for a significant portion of her career. EKGs, pulse oximeters, arterial blood gas analyzers remained scarce resources for a long time.

She then shared her disappointment with developing debilitating symptoms of postpolio syndrome after becoming a department chair. “I had ignored polio for such a long time,” she said. She began to have worsening muscle weakness, especially of her arms, which were not as affected when she had polio as a child. The arm debility also caused neck problems, and her overall stamina declined significantly.

As words of parting advice to the younger physician generation, Dr. Calmes encouraged everyone to “recognize the effect of disease on our patients.” She emphasized the value of the postoperative visit in communicating a commitment to patients and families as whole people. “It’s so easy to get lost in the things we have to do, but we’re here to take care of the patients and give them the best experience possible,” she said.

James Blum, MD, FCCM, Chief Medical Information Officer and Associate Professor of Anesthesiology and Computer Science at the University of Iowa, gave the final presentation of the session on “How Cutting-Edge Technologies are Modifying Clinical Practice.” He picked up where Dr. Wunsch had left off by discussing major advances in critical care technology from the birth of the ICU in the 1950s to the present day. He also projected the future of technology’s impact on critical care medicine.

Dr. Blum described technological progress as a dance between incremental evolution and radical revolution — a process that requires periods of steady growth punctuated by ones of disruption, disintegration, and starting anew. He also discussed the Gartner Hype Cycle as a helpful representation of the life cycle of an emerging technology: (1) the “technology trigger” of initial interest and publicity, (2) the “peak of inflated expectations,” (3) the “trough of disillusionment” as early implementations fail to deliver, (4) the “slope of enlightenment” as successful examples emerge, and (5) the “plateau of productivity” as mainstream adoption begins.

Dr. Blum first described the “Gadget Era” in critical care technology as roughly spanning the mid- to late 20th Century. During this period, all kinds of new technologies were introduced. The Engström positive-pressure ventilator (Engström 1954), which revolutionized the care of polio patients with respiratory paralysis, was the “first piece of technology that defined critical care.” Other inventions that occurred around this time period included peritoneal hemodialysis, echocardiography, and the Seldinger technique.

The 1960s saw the growth of right heart catheterization, central venous pressure (CVP) measurement, the proliferation of more advanced ventilators, and the development of concepts like atelectasis, positive end-expiratory pressure (PEEP), and ventilator-induced lung injury. The 1970s witnessed the advent of arteriovenous hemofiltration, the Swan-Ganz catheter, extracorporeal membrane oxygenation (ECMO), transesophageal echocardiography (TEE), and pulse oximetry.

The late 1970s and early 1980s marked the beginning of the “Hybrid Era,” during which continuing gadget improvement was paired with a growing appreciation for technology as a tool to improve processes for optimizing patient outcomes. Dr. Blum pointed to a paper by Grundy et al. on telemedicine in critical care (Grundy 1977) as far ahead of its time in describing the use of mobile camera units and remote monitoring stations to provide a new system of healthcare delivery as early as the 1970s.

By the early 2000s, intensivists fully understood the importance of process in improving outcomes. One landmark NEJM paper, for example, discussed a successful system-wide intervention to decrease catheter-related bloodstream infections (Pronovost 2006), while another described the efficacy of early goal-directed therapy in treating severe sepsis and septic shock (Rivers 2001).

In recent decades, machine learning models for the prediction of life-threatening conditions like sepsis and organ failure have abounded. However, most have been ineffective in providing meaningful improvements to patient care.

Looking to the future of critical care technologies, Dr. Blum projected that the next decade would be focused on “process improvement.” The ongoing development of Centers for Medicare and Medicaid Services (CMS) process and outcome measures will likely incentivize healthcare systems to complete checklists to prevent unwanted complications or treat specific conditions. To achieve sustained success, technology-driven processes must reduce the cost of care and improve population outcomes while minimizing complications and interventions. Effective artificial intelligence models should be able to triage patients at higher risk of clinical deterioration earlier in their clinical course.

Dr. Blum predicted that in the decade after the next, closed-loop automation for the delivery and titration of pharmacologic agents like sedatives (Squara 2020) and vasopressors (Desebbe 2022) will revolutionize the care of critically ill patients.

All in all, Dr. Blum characterized the upcoming decades as a new era of “personalized medicine.” With rapid advances in pharmacogenetics, for example, clinical decision support models can now predict an individual’s physiological response to specific medications (e.g., the degree of antiplatelet response to clopidrogrel (Liu 2021).

While standard critical care prediction models incorporate data like demographic variables, vital signs, and lab values from the electronic health record (EHR), the most powerful prediction models today incorporate “-omic data,” or genetic data (e.g., genomics, transcriptomics, proteomics, metabolomics). For example, a sophisticated prediction model based on imaging genomics can accurately predict lung cancer recurrence (Jia 2023) and thus has tremendous potential to save lives.

Dr. Blum projected that by 2030, we should have enough “-omic data” to start delivering highly personalized care. Armed with state-of-the-art prediction models, clinicians should see reduced rates of clinical deterioration and increased efficacy and precision in the treatment of critical illness.

The International Science Symposium provided a sweeping overview of the past, present, and future of critical care medicine, as well as a moving account of a pioneering physician who survived the devastating illness that started it all.