Preventable mistakes are common in medicine. For example, at 1 hospital, a patient received patient-controlled analgesia (PCA),
a combination of local anesthetic and narcotic. The medication was intended to be infused into the epidural space. Instead, a nurse inadvertently connected the tubing to an intravenous catheter, delivering potentially lethal anesthetic into the patient's bloodstream. What followed were the nurse's anguish and guilt and, almost as inevitably, the hospital's root cause analysis (RCA). In the last decade, this process has become the main way medicine investigates mistakes and tries to prevent future mistakes. But like many innovations in medicine, RCA has never been evaluated for effectiveness.