Grading of injury severity - What should be the prerequisites to separate multiply injured patients from those in critical condition and polytrauma?

The grading of injury severity has become a crucial issue in health care. In developed countries, multiple different scoring systems serve various purposes. Some of them were developed to grade patients on scene, some on admission and some during the hospital course. In addition, many scores are in use to monitor complications, such as ARDS, MODS or MOF. It is important to consider reasons for grading multiply injured patients. In general, three different views can be identified, such as medical, socioeconomic and administrative aspects. In this respect, hospital administrators require a certain assessment in order to calculate resource allocations. Hospitals usually receive additional support from the government, if their trauma load exceeds certain numbers of cases. Some of these trauma patients are frequently uninsured and underrepresented in the given insurance system. National registries separate hospitals according to the level of care and so do hospital administrations. These mostly use grading systems for benchmarking purposes. Finally, physicians measure the quality of medical care used in order to quantify their medical success rate. In the USA most clinicians differentiate between multiply injured, severely injured/polytrauma patients and critically injured patients. However, none of these are precisely defined. Most scientists separate any patient with an injury severity score (ISS) (reference) of more than 16 points as a multiply injured patient. It appears that the following questions are of value from a medical point of view: