He and others often rely on their instincts and experience. When Ms. Sayon’s second blood test for Ebola came back, the results were negative, but the doctors were wary of releasing her. She was bent over in a chair, shaking. Her eyes and cheeks were sunken. Keeping her in the ward for suspected cases risked infecting her with the virus, but the physicians reasoned she already had significant exposure from her family, and virus detection can sometimes lag symptoms by up to three days. (They also suspected there might have been a mix-up because of labeling problems that day with blood samples that the new center quickly worked to fix.)

“Solomon would be on his knees after a week here,” Dr. Hatch said. “Every day there’s a new dilemma we haven’t considered.”

Making Do

The risk-benefit calculus shapes almost everything. Before going into the treatment wards, one physician recently proposed setting clear priorities and one-hour limits. Drawing blood is vital, so Colin Bucks, an emergency doctor from Stanford, improvised tube holders to make the process safer. Doctors and nurses operate blindly at times, so they are seeking more diagnostic tools. Some staff members cheered Wednesday when Dr. Patricia Henwood, an emergency medicine specialist at the University of Pennsylvania volunteering here, announced that she hoped to get a portable ultrasound machine through a nonprofit she helped found. If one had been here already, doctors might have quickly ruled out a blood clot as the cause of Ms. Sayon’s swollen arm and been more certain that treating her with antibiotics for a possible life-threatening infection was the correct course.

The center dispenses drugs to alleviate Ebola symptoms, including anti-nausea medicine, a Tylenol-like painkiller that reduces fever and Haldol, an antipsychotic medication for patients writhing in delirium. It also has a team of mental health professionals who provide counsel and comfort. (The center’s first movie night, with “The Lion King” projected on a sheet outdoors, drew even some of the sickest patients last week.)

A nurse gave a generic version of the sedative Valium to Ms. Sayon when she was feverish and appeared depressed. But with some supply shortages, staff members try to be prudent. “You have to be conscious of not just throwing everything at everyone,” Dr. Henwood said. If the center ran out of the sedative, and it was needed for a patient suffering a prolonged seizure, “You wouldn’t have medicine for them.”