地震後のトリアージ: 医療対応優先順位

Why Triage Is Essential After Earthquakes

Earthquakes can injure thousands of people simultaneously, creating medical emergencies that instantly overwhelm normal healthcare systems. In these situations, even well-resourced emergency medical systems face a fundamental problem: the number of patients requiring immediate care exceeds the number of providers and treatment facilities available. Triage — a systematic process for rapidly sorting patients by injury severity and treatment priority — is the operational response to this imbalance. Understanding triage helps both medical professionals and community members contribute effectively to earthquake medical response.

The word triage comes from the French word for sorting. The underlying principle is ethically challenging but medically necessary: limited resources should go first to those whose survival depends on immediate treatment, rather than being distributed equally among all injured people regardless of need or prognosis. This means that some patients who could survive with immediate care will die if that care is delayed, while others who are lightly injured must wait, and others who are critically injured beyond treatment potential are made comfortable but not actively treated. These are among the most difficult decisions in medicine.

The START System and Its Variants

The Simple Triage and Rapid Treatment (START) system is the most widely used mass casualty triage protocol in the United States and many other countries. Designed to be operated by first responders and even trained laypeople, START allows a single rescuer to assess each patient in approximately 30 seconds and assign them to one of four categories.

Green (Minor) designates patients who can walk — the "walking wounded" who have injuries but can move independently and can be directed to a collection area for later treatment. This single criterion sorts a substantial fraction of patients rapidly. Yellow (Delayed) designates patients who need medical care but can wait — their injuries are serious but not immediately life-threatening. Red (Immediate) designates patients with life-threatening injuries that can be treated with available resources and who will benefit from immediate care. Black (Expectant) designates patients who are either already dead or whose injuries are so severe that survival is unlikely even with immediate treatment.

地域防災対応チーム（CERT）初期消火・捜索救助・トリアージなど、地震発生直後の初期対応に必要な基本的な災害対応技術を地域住民に訓練するボランティアプログラム。 members are trained in START triage as part of their basic curriculum. 捜索救助（SAR）地震後、倒壊した構造物に閉じ込められた生存者を発見・救出するための組織的な活動。発生から最初の72時間が、生存者を発見できる重要な時間帯とされる。 teams integrate triage assessment as part of their casualty extraction protocols.

Specific Injury Patterns After Earthquakes

Earthquake injuries differ systematically from the injury patterns that emergency medical systems are optimized to handle. The most common severe injuries in major earthquakes include crush injuries from falling debris, blast-like injuries from structural collapse, traumatic brain injuries, penetrating injuries from glass and metal fragments, burns from post-earthquake fires, and crush syndrome — the systemic condition that develops when muscles compressed under debris are released.

Crush syndrome (technically rhabdomyolysis combined with traumatic rhabdomyolysis) deserves special attention because it is difficult to recognize in field conditions and can be fatal hours after a patient appears stable. When large muscle masses are compressed for extended periods, the muscle cells die and release myoglobin, potassium, and other substances. When the pressure is released — either naturally or during rescue — these substances flood the bloodstream. The kidney can be fatally damaged by myoglobin precipitation. Field medical teams routinely initiate intravenous fluid therapy before and during extrication of patients who have been trapped for more than an hour.

Respiratory Injuries and Dust

Concrete dust generated by building collapse contains silica particles that cause acute and long-term respiratory damage. Survivors and rescuers in dusty environments benefit from respiratory protection, and patients with heavy dust exposure may develop respiratory distress hours after rescue. Medical teams managing earthquake casualties should monitor for delayed respiratory symptoms.

Field Medical Stations and Hospital Surge

In the immediate aftermath of a major earthquake, functioning hospitals must implement mass casualty protocols while simultaneously assessing their own structural integrity. Hospitals in the earthquake zone may be damaged, and the first task of hospital administrators is determining whether their building is safe to operate in — a task requiring structural engineering assessment that may not be possible immediately.

Field medical stations established away from damaged buildings serve as collection and treatment points for walking wounded and moderately injured patients, reserving hospital beds for the most severely injured. These stations are typically established by emergency medical services agencies, military medical units, and disaster medical assistance teams (DMATs) that are deployed regionally or nationally.

The role of 地域防災対応チーム（CERT）初期消火・捜索救助・トリアージなど、地震発生直後の初期対応に必要な基本的な災害対応技術を地域住民に訓練するボランティアプログラム。 teams at field medical stations is to assist with initial triage documentation, patient movement, and logistics — not to provide advanced medical care beyond their training. The triage tags used in mass casualty events document each patient's initial triage category, vital signs assessment, and treatment received, providing a paper trail when digital systems are overwhelmed.

Pediatric and Geriatric Considerations

Children and elderly people require modified triage approaches. Children have different physiological norms — heart rate, respiratory rate, and blood pressure all differ by age — so adult triage criteria do not apply directly. JumpSTART, a pediatric modification of START, adjusts the assessment thresholds for pediatric patients. The physiological reserve of elderly patients is often reduced, meaning they can deteriorate more rapidly from seemingly moderate injuries. Both groups are also more vulnerable to environmental stressors like heat, cold, and dehydration that compound injury severity in field conditions.

Mental Health Triage

Psychological casualties — people experiencing acute stress reactions, panic attacks, or psychological trauma — can present in large numbers after a major earthquake and affect the functioning of triage and treatment operations. Mental health first aid triage identifies people who are at immediate risk of harming themselves or others, those who are unable to function or comply with instructions due to psychological crisis, and those who have acute grief reactions requiring compassionate support but not medical intervention.

Psychological first aid — a set of humane, supportive techniques that any trained person can provide — has become standard in disaster medical response. Trained volunteers work alongside medical personnel to provide psychological first aid to survivors waiting for medical assessment, reducing panic, providing accurate information, and identifying those who need escalated mental health support.

After the Mass Casualty Event: Medical System Recovery

A major earthquake injures the healthcare system itself, not just individual patients. Hospital buildings may be damaged or destroyed. Medical staff may be injured or unable to reach their workplace. Medical supplies chains are disrupted. Morgue facilities are overwhelmed. Recovery of medical system capacity is a critical component of overall earthquake recovery — not just treating the injured from the earthquake, but restoring the ability to manage routine medical emergencies (heart attacks, births, road accidents) that continue occurring throughout the disaster period.

Pre-earthquake hospital resilience — earthquake-resistant construction, backup power systems, stored medical supplies, and pre-positioned medical disaster response equipment — is the most effective investment in earthquake medical preparedness. The 耐震基準建物の最低限の耐震安全性を確保するための、設計・建設に関する法的要件の体系。大地震で新たな脆弱性が明らかになるたびに更新される。 requirements for hospitals are typically more stringent than for other buildings in well-designed seismic codes precisely because hospitals must remain functional when they are most needed.