TUESDAY, Aug. 28, 2012 (HealthDay News) -- Misdiagnosis causes or contributes to as many as 40,500 patient deaths in intensive care units in U.S. hospitals each year, which is about the same number of deaths caused each year by breast cancer.
That's the finding of a team of researchers who reviewed 31 studies that provided details about more than 5,800 autopsies conducted to detect diagnostic errors in adult intensive care unit (ICU) patients.
The investigators found that 28 percent of those ICU patients -- more than one in four -- had at least one missed diagnosis at death. In 8 percent of the patients, the diagnostic error was serious enough that it may have caused or directly contributed to the patients' deaths and, if known, would have led to changes in their treatment.
Infections and vascular conditions, such as heart attack and stroke, accounted for more than three-quarters of the fatal diagnostic errors, according to the researchers at the Johns Hopkins Armstrong Institute for Patient Safety and Quality.
The conditions most commonly missed by medical staff included heart attack; pulmonary embolism, typically a blood clot in the lungs; pneumonia; and aspergillosis, a fungal infection that most commonly affects people with a weakened immune system. Together, these four conditions accounted for about one-third of all illnesses that doctors failed to detect in ICU patients.
The study was released online in advance of print publication in the journal BMJ Quality & Safety.
Despite the fact that diagnostic errors in the ICU claim so many lives a year, they are an underappreciated cause of preventable patient harm, the study authors noted in a Johns Hopkins news release.
"Our study shows that misdiagnosis is alarmingly common in the acute care setting," lead author Dr. Bradford Winters, an associate professor of anesthesiology and critical care medicine and neurology and surgery in the Johns Hopkins University School of Medicine, said in the news release.
"To date, there's been very little research to determine root causes or effective interventions," Winters said. He pointed out that less-deadly patient safety risks have received greater attention.
He and his colleagues also found that adult ICU patients are up to two times more likely to be the victim of a potentially fatal diagnostic mistake than adult hospital patients overall.
"It may be counterintuitive to think that the patients who are the most closely monitored and frequently tested are more commonly misdiagnosed, but the ICU is a very complex environment," Winters said.
In the ICU, doctors have to cope with a huge amount of information in a distracting setting in which the sickest patients in the hospital compete for attention, and most of the patients can't communicate with their medical team, he explained.
"We need to develop better cognitive tools that can take into account the 7,000 or more pieces of information that critical care physicians are bombarded with each day to ensure we're not ruling out potential diagnoses," Winters said.
Even if misdiagnoses in the ICU do not lead to patient death, they can lead to unnecessary surgery, a longer hospital stay and reduced quality of life for patients.
The study findings highlight the need for more research to identify the causes of misdiagnosis in the ICU and to develop ways to help doctors more accurately assess patients, the researchers concluded.
The Society of Critical Care Medicine has more about critical care.