The Covid-19 pandemic has drawn attention to the struggle to find effective treatments and cures. When most people speak of the science of medicine, they are referring to a process of deduction, whereby investigators propose and test hypotheses to reach a factual conclusion. Perhaps the best known and understood example of the deductive method in medicine is the randomized controlled trial that scientists use to test new drugs, as in the case of remdesivir, the drug that the FDA has just approved for emergency use in severely ill hospitalized Covid-19 patients.

Randomized clinical trials are what people mean when they say that a drug has been “tested,” and such trials remain the scientific gold standard. In many cases, though, bedside observation or laboratory serendipity has led us to effective treatments and cures. In the case of medicine, inductive reasoning starts with observation and eventually moves to new recommendations or guidelines for standards of care.

The discovery of the smallpox vaccine is a good example of a medical discovery made through inductive reasoning. Declared eradicated worldwide in 1980, smallpox was a viral disease with a 30 percent mortality rate. The U.S. stopped vaccinating children in 1972; those of us born before that time have a small scar on our shoulders from this vaccination. The inventor of the smallpox vaccine, British physician Edward Jenner, observed at the end of the eighteenth century that individuals who milked cows and were exposed to cows suffering from cowpox were immune to human smallpox infection. He correctly reasoned from this observation that a vaccine (from the Latin vacca, for “cow”) made from smallpox lesions could be protective.

Modern antibiotics were discovered when someone left a bacterial culture near an open window in a London laboratory, and mold spores landed in the petri dish, inhibiting the growth of the bacteria. Alexander Fleming noticed this phenomenon, cultured the mold, and thus discovered penicillin. This wonder drug was developed using a combination of inductive and deductive processes, both of which fell under the name of “science.”

Inductive reasoning and bedside observations have led to several advancements in our treatment of moderate to severely ill Covid-19 patients, who have provided physicians with the unfortunate opportunity to make and confirm observations about the progression of the disease and ways to ameliorate it. Physicians then share these observations with their peers through discussions, scientific presentations, or published case reports. It is in this way that the care of severely ill Covid-19 patients has improved, absent any lab-tested therapies.

One such inductive therapeutic discovery has to do with how physicians treat dangerously low blood-oxygen levels. Many symptomatic Covid patients suffer from a dry cough, difficulty breathing, fever, and fatigue, and their chest x-rays come back abnormal. Some have low blood oxygen and need extra support. In extreme cases, patients are put on a mechanical ventilator, which requires admission to an intensive-care unit and the insertion of a breathing tube into the windpipe and lungs. While mechanical ventilation can be helpful, it has its own complications for patients and taxes the resources of the hospital. New information has emerged that may change the standard of care. Emergency-room physicians in Chicago observed that if they administered pure oxygen to these patients through the nose and laid them on their belly, they could forgo mechanical ventilation and its complications.

Another observation that has led to new treatment guidelines is related to the increased risk for blood clots in patients with moderate to severe Covid-19 infection. Some Covid-19 patients develop blood clots in their legs, brains, and lungs, and suffer significant complications, including strokes. Many physicians are now recommending that all moderate to severe hospitalized patients receive blood thinners.

Many other observations have been made about treatment of Covid-19 patients. Fortunately, dedicated and well-trained physicians, nurses, and other medical professionals have been able to use inductive reasoning to propose and deliver supportive therapies that should reduce the complications of infection and prevent death. The progress of medical science has always depended on the use of both inductive and deductive processes to achieve its goals of prolonging human life.

Photo by Misha Friedman/Getty Images


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