Nielsen discuss in his Alertbox from april 11, 2005 medical usability. "A field study identified twenty-two ways that automated hospital systems can result in the wrong medication being dispensed to patients. Most of these flaws are classic usability problems that have been understood for decades."
The results are interessting even if the study has some methodical weaknesses.
"Medical Usability: How to Kill Patients Through Bad Design"@useit.com
"Role of Computerized Physician Order Entry Systems in Facilitating Medication Errors" (This is the study Nielsen is talking about.)