Before physicians at Massachusetts General Hospital finish their 13-hour shifts in the surgical intensive care unit, they hand off their patients to the crew taking over. The outgoing and incoming doctors carefully exchange important information about each patient to ensure that they are properly cared for through the next shift.

Cheryl Ryan, a clinical nurse specialist who works in the surgical ICU, says the doctors begin conversing about the sickest patients and then make their way down the entire list. “It’s based on the acuity of patients,” she said, “It’s just a standard way they have developed over time.”

But many hospitals don’t follow such a process, increasing the risk of medical errors, according to Dr. Michael Cohen of the University of Michigan.

A new study by Cohen, published this week as a research letter in the Archives of Internal Medicine, found that ICU doctors at one hospital in Ontario, Canada, weren’t discussing cases based on their level of severity but by the patient’s bed number. The doctors spent more time on cases at the top of the list than at the end.

“We call it the ‘portfolio effect.’ It’s the effect that people tend to spend excess time on the early cases on the list. … Because the total time is limited, that means less time [to discuss the cases] at the end,” Cohen said in an interview.

By handing off patients based on their bed number or, Cohen says, last name, those cases needing the most discussion time might be shortchanged. According to the study, previous research suggests that miscommunication during handoffs poses a threat to the safety of patients and may be a factor contributing to preventable medical errors.

Although his study analyzed videos of 23 handoff sessions involving more than 250 patients at a Canadian hospital, the same practice of patient handoffs based on room number or name is “very common” in American hospitals.

“It applies very generally,’ he added, “It’s a very common practice.”

Cohen says there are simple solutions to improve how physicians hand off patients in between shifts.

“Physicians and nurses have to pay attention at the start of the handoff session to which cases require the most discussion time,” he said. “Under the [federal] health care act and the stimulus package, hospitals are being encouraged to adopt electronic health records. [They] can be adopted to support a better picture of which patients need the most discussion.”

Beginning handoff discussions based on case severity should be only part of the solution, Cohen says. Hospitals should put in more effort into programs that would do a better job allocating the limited amount of time doctors and nurses have during handoff sessions.