The FDA does regulate medical software as a device. One category of medical software is "software accessories," which is actively regulated by the FDA. Software accessories are attached to (or used with) other medical devices such as a patient physiologic monitor. For example, systems for digital analysis and graphical representation of electroencephalographic (EEG) data connected to EEG acquisition systems are FDA regulated. In contrast, it has been unclear how, or to what extent (if at all), stand-alone software should be regulated by the FDA.20 With respect to neurophysiologic decision support systems, in general, all-in-one monitoring solutions connect directly with patient monitoring devices and, therefore, fall into the regulated FDA category of software accessory. In contrast, ICU-wide solutions often start by collecting data from patient monitors and storing it in a database. In a second separate step, data analysis and visualization software query data from the database, thereby being classified as stand-alone software that has not been regulated. There is the potential for causing harm when using CDSS,21 and issues regarding liability and negligence with CDSS use are not currently clear.20 Two independent organizations have been focusing on these issues,22,23 and in 2011 the FDA announced Class I requirements (ie, requiring general controls) for 'Medical Device Data Systems' and Class I, II, or III requirements for 'Mobile Medical Applications' depending on what the application does. An application that allows a user to input patient-specific information and - using formulae or processing algorithms - output a patient-specific result, diagnosis, or treatment recommendation to be used in clinical practice constitutes a regulated software application. Discuss these new regulations with vendors and if you plan to create applications to help analyze patient data call the FDA and find out if there are regulatory requirements that must be met.