The prevention of adverse events and medical injuries due to malpractice or suboptimal delivery of health care services is one of the major concerns of citizens and Health Care Organizations. One way to understand adverse events is to analyze the compensation requests for medical injuries that are claimed to hospital or health care services. In this paper we describe the results obtained by applying a probabilistic model, called the actuarial model, to analyze 317 cases of injuries with compensation requests collected from 1999 to the first semester of 2007 by the Azienda Ospedaliera (A.O.) of Lodi, in the Northern part of Italy. The approach, adapted from operational and financial risk management, proved to be useful to understand the risk structure in terms of frequency, severity, expected and unexpected loss related to adverse events.