**4. Other terms used in literature**

Another term similar to "adverse event" that ranks second in terms of incidence is the term "sentinel event." The Joint Commission on Accreditation of Healthcare Organizations (JCAHO) (2003) defined it as an unexpected event that involves death, serious physical or psychological damage, or risk of those. Serious physical or psychological damage refers to the loss of a body part or a function, whereas the risk of such damages refers to any variation of the procedure, the revision of which would entail the risk of serious medical error occurrence or would pose a threat of an adverse event. The term "sentinel," is interpreted as a guard or a watchman and is used for events that require immediate investigation and handling [32]. Such events are as follows:

**i.** any event that led to amputation of a human body part or loss of function, not related to the underlying disease; and

**ii.** events such as suicide, rape, delivery of a newborn to the wrong family, violent abduction of a patient, surgery on the wrong body part of a patient, etc.

The terms "close call" or "near miss" are almost identical and refer to certain actions or situations, which could have caused an "adverse event" but were timely detected and prevented or randomly prevented [33].

A term that is often used when referring to "adverse drug events" is that of "side effects," which regard the known effects of a drug and are different than those for which the drugs were originally designed [34].

"Iatrogenic injury" or "illness" is another term, which refers to undesirable effects that result, partly or entirely, from the medical process or medication treatment and do not constitute a direct or an indirect complication of the patient's initial state or the disease. This term is similar (or identical) to the side effects. The difference between "iatrogenic injuries" and "side effects" is that the first are not known and therefore they are totally unexpected. Furthermore, they are not caused due to technical failures, and therefore they do not constitute a criminal offense. This term is not also different from an "adverse event" [35].

The term "incident" occurs frequently in cases relating to patient safety, and it is used as a general term until the moment the event has been classified [36]. It characterizes an event that has already led or could lead to an artless injury and patient complain, and loss or damage [37]. The National Research Council (NRC) defined "incident" as an event that could be considered an accident, if it had taken place under slightly different circumstances. A critical event regards an event that leads to serious damage or even death [38].

The concept of "error" is often confused with the concept of "injury". WHO defines "injury" as tissue damage caused due to a factor or under certain circumstances? "Errors" become noticeable when they cause a certain "adverse event" or "injury" to the patient and influence health outcomes in a negative way [34]. Leape [10] argues that most "errors" do not lead to "injury".

The term "harm," which is typical of the body's structural or functional impairment and the resulting negative effects, is also frequently used in the study [34].

The term "hazard" has the meaning of risk factor and refers to anything that causes damage. A "hazard" is also defined as a factor, a situation, or an action, which may lead to or increase risk. In his article titled "The hazards of hospitalization" published in 1964, Schimmel refers to the terms "hazard," "adverse reaction," "adverse episodes," "incidence," and "risk" and categorizes reactions into those caused by diagnostic or therapeutic interventions that occurred in the hospital and those resulting from physicians' or nurses' errors of negligence [27].
