and rapid treatment s.t.a.r.t. (simple triage and rapid treatment) is a simple triage system that can be performed by lightly trained lay and emergency personnel in emergencies. it was developed at hoag hospital in newport beach, california for use by emergency services in 1983. triage separates the injured into four groups: the expectant who are beyond help the injured who can be helped by immediate transportation the injured whose transport can be delayed those with minor injuries who need help less urgently triage also sets priorities for evacuation and transport as follows: deceased are left where they fell. these include those who aren't breathing and repositioning their airway efforts were unsuccessful. immediate or priority 1 (red) evacuation by medevac if available or ambulance as they need advanced medical care at once or within one hour. these people are in critical condition and would die without immediate assistance. delayed or priority 2 (yellow) can have their medical evacuation delayed until all immediate people have been transported. these people are in stable condition but require medical assistance. minor or priority 3 (green) are not evacuated until all immediate and delayed persons have been evacuated. these will not need advanced medical care for at least several hours. continue to re-triage in case their condition worsens. these people are able to walk and may only need bandages and antiseptic. jumpstart triage main article: jumpstart triage the jumpstart pediatric triage mci triage tool is a variation of the s.t.a.r.t. model. both systems are used to sort patients into categories at mass casualty incidents (mcis). however, jumpstart was designed specifically for triaging children in disaster settings. though jumpstart was developed for use in children from infancy to age 8, where age is not immediately obvious, it is used in any patient who appears to be a child (patients who appear to be young adults are triaged using start). australia and new zealand in hospital settings, australia and new zealand rely on the australasian triage scale (abbreviated ats and formally known as the national triage scale). the scale has been in use since 1994. the scale consists of 5 levels, with 1 being the most critical (resuscitation), and 5 being the least critical (nonurgent). australasian triage scale level description should be seen by provider within 1 resuscitation 0 minutes 2 emergency 10 minutes 3 urgent 30 minutes 4 semi-urgent 60 minutes 5 nonurgent 120 minutes in field settings, various standardized triage systems are used, and there is no area wide standard. canada in 1995, the caep triage and acuity scale was launched in canada relying on a simplified version of the australian national triage scale. this scale used three categories, emergent, urgent, and non-urgent. this scale was deprecated in 1999 with the introduction of the canadian triage and acuity scale (ctas), which is used across the country to sort incoming patients. the system categorizes patients by both injury and physiological findings, and ranks them by severity from 1–5 (1 being highest). the model is not currently used for mass casualty triage, and instead the start protocol and mettag triage tags is used. canadian triage and acuity scale (ctas) level description should be seen by provider within 1 resuscitation 0 minutes 2 emergency 15 minutes 3 urgent 30 minutes 4 less urgent 60 minutes 5 non urgent 120 minutes france in france, the prehospital triage in case of a disaster uses a multi-tier scale: décédé (deceased), or urgence dépassée (beyond urgency) extrême urgence (extreme urgency): requiring care within a half hour. urgence absolue (absolute urgency): requiring care within an hour. urgence relative (relative urgency): requiring care, but not immediately. blessé léger (slightly injured) impliqué (involved, but not directly injured) this triage is performed by a physician called médecin trieur (sorting medic). germany the german triage system uses four color codes: german triage system category meaning action examples category ti acute, life threatening condition immediate, highest priority treatment arterial lesions, internal haemorrhage, major amputations category t2 severe injury requiring urgent treatment rapid transport and treatment minor amputations, flesh wounds, fractures and dislocations category t3 minor injury or no injury physician examination, clearance and discharge as soon as possible minor lacerations, sprains, abrasions deceased already dead, or expectant no/low priority. identification, guarding and evacuation as possible death, injuries not compatible with life hong kong in hong kong, triage in accident & emergency departments is performed by experienced registered nurses, patients are divided into five triage categories: critical, emergency, urgent, semi-urgent and non-urgent. in mass casualty incidents, the start triage system is used. japan in japan, the triage system is mainly used by health professionals. the categories of triage, in corresponding color codes, are: category i: used for viable victims with potentially life-threatening conditions. category ii: used for victims with non-life-threatening injuries, but who urgently require treatment. category iii: used for victims with minor injuries that do not require ambulance transport. category 0: used for victims who are dead, or whose injuries make survival unlikely. singapore all public hospitals in singapore use the patient acuity category scale (pacs) to triage patient in emergency departement. pacs is a symptom-based differential diagnosis approach that triages patients according to their presenting complaints and objective assessments such as vital signs and glasgow coma scale, allowing acute patients to be identified quickly for treatment. pacs classifies patients into four main categories: p1, p2, p3, and p4. patient acuity category scale category (priority level) category name description example p1 critically ill and requires resuscitation state of cardiovascular collapse or in imminent danger of collapse and require immediate medical attention. multiple major trauma, head injury with loss of consciousness, shortness of breath, unconsciousness from any cause p2 major emergency unable to walk and are in some form of distress, appear stable on initial examination, and are not in imminent danger of collapse, requires very early attention chest pain, major limb fractures, major joint dislocations, spinal cord injury, trunk injury with stable vital signs p3 minor emergency able to walk, have mild to moderate symptoms and require early treatment all sprains, mild constant abdominal pain, fever with cough for several days, insect stings or animal bites (not in severe distress), superficial injuries with or without mild bleeding, minor head injury (alert, no vomiting), foreign object in ear, nose, or throat, urinary tract infections, headaches. p4 nonemergency old injury or condition that has been present for a long time. chronic lower back pain, high cholesterol, acne. in mass casualty incidents, the start triage system is used. spain in spain, there are 2 models which are the most common found in hospitals around the country: the sistema estructurado de triaje (set), which is an adaptation of the model andorrà de triatge (mat). the system uses 650 reasons for medical appointment in 32 symptomatic categories, that together with some patient information and basic exploratory data, classifies the emergency within 5 levels of urgency. the "manchester", based on the system with the same name in the uk, use 51 reasons for consultation. through some yes/no questions, addressed in a diagram, it classifies the emergency in 5 severities. in mass casualty incidents, the modelo extrahospitalario de triaje avanzado (meta)/advanced triage out of hospital model system is used. meta is a seven stage system, classifying patients as: red 1st, red 2nd, red 3rd, yellow 1st, yellow 2nd, green, and deceased. the system aligns with the abcde framework. advanced triage out-of-hospital model/modelo extrahospitalario de triaje avanzado (meta) category meaning red 1st compromised airway red 2nd not breathing, or abnormally breathing red 3rd asystole, arrhythmia, or hemorrhage yellow 1st injury requiring urgent care yellow 2nd injury requiring delayed care green mildly or non-injured deceased dead united kingdom in april 2023, the nhs and ambulance services adopted the major incident triage tool, a new triage tool that is used in mass causality incidents. this tool is a result of large multi-disciplinary review led by the nhs but its implementation became more urgent after the manchester arena inquiry made it a monitored recommendation for the nhs and national ambulance resilience unit to adopt. united states a multitude of triage systems exist in the united states, and there is no national standard. among local, regional, state, and interstate systems, the start triage method is most commonly used. united states armed forces the u.s. armed forced utilize a four stage system, a battlefield situation, care providers rank casualties for precedence, treat those who they can safely, and transport casualties who need it to a higher level of care, either a forward surgical team or combat support hospital. the triage categories (with corresponding color codes), in order of priority, are: u.s. armed forces triage categories category description conditions immediate life threatening injury airway or breathing issues, hemmorhage delayed potentially life threatening injury shock, fractures and dislocations, abdominal, spinal, thoracic, or head injuries, uncomplicated major burns minimal not life threatening injuries cuts, bruises, abrasions, small bone fractures, minor burns, strains/sprains, frostbite expectant non-survivable injuries cardiac arrest, massive head or brain trauma, second or third degree burns over 70% or more of body limitations of current practices notions of mass casualty triage as an efficient rationing process of determining priority based upon injury severity are not supported by research, evaluation and testing of current triage practices, which lack scientific and methodological bases. start and start-like (start) triage that use color-coded categories to prioritize provide poor assessments of injury severity and then leave it to providers to subjectively order and allocate resources within flawed categories. some of these limitations include: lacking the clear goal of maximizing the number of lives saved, as well as the focus, design and objective methodology to accomplish that goal (a protocol of taking the worst immediate – lowest chances for survival – first can be statistically invalid and dangerous) using trauma measures that are problematic (e.g., capillary refill) and grouping into broad color-coded categories that are not in accordance with injury severities, medical evidence and needs. categories do not differentiate among injury severities and survival probabilities, and are invalid based on categorical definitions and evacuation priorities ordering (prioritization) and allocating resources subjectively within immediate and delayed categories, which are neither reproducible nor scalable, with little chance of being optimal not considering/addressing size of incident, resources, and injury severities and prioritization within its categories – e.g., protocol does not change whether 3, 30 or 3,000 casualties require its use, and regardless of available resources to be rationed not considering differences in injury severities and survival probabilities between types of trauma (blunt versus penetrating, etc.) and ages resulting in inconsistent tagging and prioritizing/ordering of casualties and substantial overtriage research indicates there are wide ranges and overlaps of survival probabilities of the immediate and delayed categories, and other start limitations. the same physiologic measures can have markedly different survival probabilities for blunt and penetrating injuries. for example, a start delayed (second priority) can have a survival probability of 63% for blunt trauma and a survival probability of 32% for penetrating trauma with the same physiological measures – both with expected rapid deterioration, while a start immediate (first priority) can have survival probabilities that extend to above 95% with expected slow deterioration. age categories exacerbate this. for example, a geriatric patient with a penetrating injury in the delayed category can have an 8% survival probability, and a pediatric patient in the immediate category can have a 98% survival probability. issues with the other start categories have also been noted. in this context, color-coded tagging accuracy metrics are not scientifically meaningful. poor assessments, invalid categories, no objective methodology and tools for prioritizing casualties and allocating resources, and a protocol of worst first triage provide some challenges for emergency and disaster preparedness and response. these are clear obstacles for efficient triage and resource rationing, for maximizing savings of lives, for best practices and national incident management system (nims) compatibilities, and for effective response planning and training. inefficient triage also provides challenges in containing health care costs and waste. field triage is based upon the notion of up to 50% overtriage as being acceptable. there have been no cost-benefit analyses of the costs and mitigation of triage inefficiencies embedded in the healthcare system. such analyses are often required for healthcare grants funded by taxpayers, and represent normal engineering and management science practice. these inefficiencies relate to the following cost areas: tremendous investment in time and