Max Harry Weil, a physician who helped found the specialty of critical care medicine and elucidate strategies for treating the sickest hospitalized patients, died July 29 at his home in Rancho Mirage, Calif. He was 84 and had prostate cancer.

Weil spent most of his professional career at the University of Southern California, in Los Angeles, where he was on the faculty from 1958 to 1981. He later moved his research organization, the Institute of Critical Care Medicine, to Palm Springs, Calif., and more recently to Rancho Mirage.

Weil’s work in the hospital and laboratory contributed to a long list of insights that led to the dramatic improvement in survival of people with severe infections, congestive heart failure and trauma.

Among the now-standard features of hospital medicine he helped create are the intensive care unit; the rolling “crash cart” that brings resuscitation equipment to a person’s bedside; the “stat lab,” which provides lab results in minutes; the measurement of lactic acid in the blood as a way of determining whether organs are getting enough oxygen; and the computerized monitoring of critically ill patients.

Perhaps his most important insight was the need for a unit that had only those critically ill patients and people with the expertise to care for them — a team that went well beyond physicians to include specially trained nurses, pharmacologists, respiratory therapists, and nutritionists.

In the late 1950s and ’60s, Weil was part of a small group of physicians who realized that patients with dangerously low blood pressure — a condition known in medicine as “shock” — had high mortality rates. Among the reasons they didn’t survive is that shock has many causes, and physicians are often unsure what to do.

Shock kills because there isn’t enough blood flowing to organs to deliver oxygen and carry away carbon dioxide and waste products. It can be caused by overwhelming bacterial infection, bleeding, hormonal calamities or severe heart damage. It is treated with infusions of intravenous fluids, drugs that constrict blood vessels or make the heart pump harder, as well as treatments aimed at the underlying problem.

Weil’s investigation of shock in patients and lab animals, as well as associated physiological events, helped lead to new and better treatments. In 1958, he opened a “shock ward” with four beds in 1958. It became the precursor of the ICU, where teamwork is the order of the day.

Max Harry Weil was born in Baden, Switzerland, on Feb. 9, 1927. In 1936, the family emigrated from Stuttgart, Germany, to the United States, settling in New York City.

Weil attended the Bronx High School of Science and graduated from the University of Michigan in 1948.

He received his medical degree from the State University of New York’s Downstate campus in Brooklyn in 1952 and trained in internal medicine in Cincinnati and Minneapolis. He received a doctorate in physiology from the Mayo Clinic in Rochester, Minn., in 1957.

Weil was a founding member of the Society of Critical Care Medicine and served as its first president, from 1970 to 1972. The latest of his more than 500 research papers was published online in April and appears this month in the journal Resuscitation. He held 19 patents, including ones for a mechanical ventilator and devices to measure physiological variables at the bedside.

He married the former Marianne Posner in 1955. They lived apart for many years, and Weil became the companion of Margery Stone, who died in 2008.

Besides Weil’s wife, of Los Angeles, survivors include two daughters from his marriage, Susan Weil Adesman of Rose Valley, Pa., an obstetrician-gynecologist, and Carol Weil of Bethesda, Md., a medical ethicist at the National Cancer Institute; and four granddaughters.

In an interview, Susan Weil said her father took his desire to help the ill and injured with him everywhere.

“I can’t tell you the number of vacations that got interrupted because he would see an accident on the road and he would pull over,” she said. “Sometimes he’d get involved in the care of somebody. Sometimes he’d follow the ambulance. We learned to always carry a book with us because we never knew when we’d be in a hospital waiting room for five hours.”