Many people don’t know that the polio epidemic during the 1950s led to the critical innovation of the intensive care units that have become a keystone in thoracic medicine and sparked the development of other vital developments in health care, such as ventilators, blood gas analysis, systematic understanding of respiratory physiology, major vaccines, the rise of rehabilitation medicine and disability rights, and the recognition that viral infection can have long-term sequelae.

“Polio was a key moment in the development of ventilation,” said Hannah Wunsch, MD, MSc, professor of anesthesiology, vice chair for research, and director of outcomes research at Weill Cornell Medicine. “The iron lung, developed in 1928 for polio, was the first time that there was an intervention that supported breathing for an extended period.”

Lessons learned from the polio epidemic that gripped Copenhagen, Denmark, during the summer and autumn of 1952 led to the first hospital ward with routine round-the-clock staffing, blood gas analysis, invasive ventilation, specialized nursing, and other organ support and resuscitation with frequent, scheduled monitoring of vital signs. In December 1953, Dr. Bjørn Ibsen opened the first ward at Copenhagen’s Municipal Hospital, which became the model for ICUs worldwide.

Dr. Wunsch described the legacy of polio in medicine and the relatively unknown connections between the disease and the emergence of modern medical paradigms in her book, The Autumn Ghost: How the Battle Against a Polio Epidemic Revolutionized Modern Medical Care, and during her Keynote Series presentation on Monday, May 20.

The need for intensive care was clear as Copenhagen saw a spike in polio cases in 1952. Admissions to Bledgam Hospital, the city’s infectious disease hospital, spiked from virtually zero to more than 300 cases per day. Mortality rates hovered around 90 percent and clinicians had little to offer in terms of treatment or hope. Denmark had just one iron lung and sox cuirass respirators.

While ventilation devices were used for anesthesia at the time, there was little coordination between surgeons and other specialists and no synthesis of technologies from these different branches of medicine, Dr. Wunsch said.

Dr. Ibsen visited Massachusetts General in 1949 to learn the latest anesthesia techniques. He came home amazed by the free expression of ideas and opinions among young physicians in the U.S.

When he had an opportunity to visit a polio ward at Bledgam, he saw patients exhibiting hypertension, clammy skin, confusion, twitching, and tachycardia. Local physicians saw polio patients on the verge of death; Dr. Ibsen saw patients with CO₂ retention. He proposed positive pressure ventilation to ease the CO₂ load.

“Positive pressure was never used outside the OR,” Dr. Wunsch said. “Using positive pressure to reduce CO₂ is obvious now, but it wasn’t obvious in 1952.”

Dr. Ibsen performed a tracheotomy on a 12-year-old girl with polio as a last-ditch attempt to save her life. The experiment worked.

“There was only one problem,” Dr. Wunsch continued. “There were no positive pressure ventilators in Denmark. So, they called in 1,200 medical students with anesthetic bags to ventilate patients by hand 24/7.”

The hospital didn’t have pH monitors either. However, pH monitoring was a crucial step in brewing beer and Carlsberg Brewery happened to be just down the street. The brewery donated a pH meter. Between adequate ventilation and blood gas monitoring, mortality rates dropped from a high of 87 percent to 11 percent.

Dr. Ibsen moved to Copenhagen Municipal Hospital in 1953 and pushed to combine what he had learned about providing intensive care into a single ward.

“He made the leap that the care they provided for polio patients could be extended to all patients,” Dr. Wunsch said. “Creating the ICU is a strong argument that alternative perspectives matter, diversity matters. You never know who will have that different perspective, that one piece of information, that unique attitude, that will move the needle. It wasn’t until 1958 that the U.S. got its first ICUs.”