Disaster medicine

Introduction

• Disaster = Serious disruption of the functioning of a community or society causing widespread human, material, economic or environmental losses which exceed the ability of the affected community or society to cope using its own resources
• Disaster risk management
  • The range of activities designed to establish and maintain control over disaster and emergency situations and to provide a framework for helping at-risk populations avoid or recover from the impact of a disaster
  • Addresses healthcare, hazard identification, vulnerability analysis, risk assessment, risk evaluation and risk treatments
• Disaster medicine
  • Study and application of clinical care, public health, mental health and disaster management to the prevention, preparedness, response and recovery from the health problems arising from disasters

• Complex disaster
  • Disaster complicated by civil unrest, government instability, macro-economic collapse, population migration or elusive political solution
• Natural disasters
  • Hydrological – Floods, wet mass movements
  • Meteorological – Storms, climatological, extreme temperatuers, fires, droughts
  • Geophysical – Earthquakes, tsunami, volcano, dry mass movements
  • Biological – Insect/pest, epidemics
• Technological
  • Industrial: Chemical spills, building collapse, explosions, fires, gas leaks, poisoning, radiation
  • Transport: Air, rail, road, water
  • War/Terrorism/Complex emergencies

Epidemiology

• Complex disasters carry the most number of deaths
• Number of disasters per year has risen from 50/year to 700/year over the last 50 years
• 200 million people directly affected per year
• Asia has 41% of disasters each year
• Heatwaves highest cause of death in Australia
• Terrorist attacks contribute a very small number of deaths
• Floods, storms then cyclones have greatest economic impact in Australia

Disaster management

• State and territory government carry primary responsibility for coordinating disaster management activities
• Local government play an active role in risk assessments, land-use planning, public education, local emergency planning and providing local resources in emergency relief and recovery
• Federal government support State and territory governments in coordinating a national strategic policy, assist with disaster information and knowledge management, cost-sharing and operational support if response exceeds state or territories resources
• Comprehensive approach
  • Prevention
  • Preparedness
  • Response
  • Recovery

• Disaster equivalent of primary prevention includes measures to prevent or mitigate the effects of disasters and reduce community exposure to hazards
  • E.g. Immunisation, improving baseline health, improved nutrition, population health measures to prevent outbreaks, education
• The prepared community
  • Community self-help can provide the most immediate, decisive and effective relief as external resources may not always be available

Disaster response planning

• Identify main hazards
• Clarify capabilities, roles and responsibilities of organisations
• Strengthen emergency networks
• Emergency communications and public warning systems
• All-hazards approach
  • Risk assessment
  • Incident management
  • On-scene and overall disaster command
  • Relief operations
  • Risk communication and media management
  • Reconstruction
  • Community recovery

• Specific hazard approach
  • Subplans for specific hazards e.g. terrorist/radiation/biological/epidemic
• Regular disaster exercises
  • Desktop simulations through to realistic field scenarios
• Regular review and update

Incident management

• Scene assessment and stabilisation
  • First responders communicate to Ambulance Communications
  • Nature and magnitude of disaster, ongoing hazards, estimated number of victims, need for further assistance and most appropriate routes of access
  • Site security and safety are paramount
• Hazard-specific issues (terrorist, radiation, chemical or biological)
  • Recognise potential terrorist events, avoid affected area, isolate affected area and notify
  • The four don’ts: Don’t become a victim, don’t rush in, don’t TEST (taste, eat, smell, touch anything), don’t assume anything
• Site arrangements
  • Forward command post near site communicating with regional or state emergency operations centre
• Communications
  • Designated phone lines, single radio frequencies, megaphones and regular contact between agencies avoiding jargon

Medical management

• Personnel
  • Inexperienced personnel without training for the field environment may well hinder the medical response
  • Should work in familiar environment e.g. ambulance at scene, doctors in ED
• Pre-hospital mass casualty management
  • 50-80% of victims arrive at nearest medical facilities within 90 minutes
  • The vast majority of victims self-evacuate without benefit of pre-hospital triage, transport or decontamination
  • Casualty flow plans are crucial
  • Casualty collection area should be established at a site close enough to disaster scene to allow easy access but far enough to ensure protection from ongoing hazards
    • Assembled and triaged here before transport to Patient Treatment Post, where triaged again  and basic medical care provided
  • Ambulance Loading Point and Ambulance Holding Point also clearly marked
  • Landing Zone for helicopter to avoid noise pollution, hazard exposure and down-wash from rotor blades
  • Temporary morgue

Triage

• Directing limited resources to those who are most likely to benefit
• Single most important medical activity at the disaster site
• Dynamic, ongoing process that occurs at disaster site, Casualty Collection Area, Patient Treatment Post and at hospital
• Conditions often alter so repeated examinations are required
• Learned skill and should be conducted by most experienced medical or ambulance officer at scene

• Immediate care
  • Critically unwell with simple life-saving procedures e.g. manual clearing of airway
• Delayed care
  • Significant injuries but likely to survive if treatment postponed several hours
• Minimal care
  • Generally ambulatory until other patients appropriately treated
• Expectant or unsalvageable
  • Acutely life-threatening injuries that require advanced resuscitation or non-survival injuries
• Advanced life support measures are rarely indicated in disaster scenarios and these patients are palliated once immediate care patients are treated

Stabilisation

• Following triage, rapid stabilisation of ABC provided to those with greatest potential for survival
• Secure airway, administer oxygen, external pressure to control external haemorrhage and insertion of IVC
• Analgesia may assist with extrication of entrapped individuals
• Special on-scene treatments are sometimes required for those with crush, blast, burn or hypothermia injuries
• Amputation of a mangled limb may be lifesaving for an entrapped patient

Decontamination

• CBRN (Chemical, biological, radiological and nuclear) agents
• Staff and site preparation with hot/warm/cold zones
• Casualty, staff and crowd protection
• Decontamination procedures
  • Remove clothes and washing of skin ASAP with soap and water and hypochlorite 0.5-2% (household bleach)
  • Ideally in warm zone and prior to transportation
  • Biological agents are less dermally active
• Clinical treatment of contaminated patients and transport to definite care
• Recovery of environment

Transportation

• Must not transport disaster scene to local hospitals
• Need bed availability communication
• Walking wounded may overwhelm local hospitals

Health facility management

• Internal and external disaster management plans must be in place
• Clear non-critical patients
• Discharge stable ward pateints
• Well stocked supplies
• Rapid replenishment of supplies must be possible
• Recall system for medical and nursing staff
• Extra security staff for management of families, friends, onlookers and media
• Re-triage at presentation to ED by a senior medical officer
  • Acutely life-threatening injuries – Immediately resuscitated
  • Less severe injuries – Regularly reviewed while awaiting definitive care
  • Expectant, unsalvageable patients are palliated and condition explained to relatives
  • Documentation limited to acute issue and treatment
  • Respect cultural and religious requirements for dead bodies

Urban search and rescue

• Science of locating, reaching, treating and safely extricating those entrapped following structural collapse
• Scene safety is of critical importance

Mental health

• Psychological support is crucial to disaster-affected communities
• Crisis counselling may play an important role in overall medical care
• Rescue personnel themselves may require support

Population health

• Key role in guidance on evacuation following exposures, mass decontamination and mass distribution of iodine

Triage

• The ongoing process of sorting patients based on urgency (as distinct from severity and complexity)
• Correlates to resource use and patient outcome in short-term
• Underlying principles of equity (or justice) and efficiency
• ATS uses question:
  • This patient should wait for medical assessment and treatment no longer than…”
  • ATS 1: Immediate
  • ATS 2: 10 minutes
  • ATS 3: 30 minutes
  • ATS 4: 60 minutes
  • ATS 5: 120 minutes

• Use beyond waiting time
  • Individual triage categorisation can reflect only the probability of certain outcomes
  • Large groups of triaged patients exhibit predictable patterns
  • Strong linear relationships between triage category and:
    • Rate of admission, transfer or death (80-100% ATS 1 vs. 0-20% ATS 5)
  • Good inter-rater reliability
  • Admission rates by triage category have been shown to be constant over time in individual institutions
  • Case-mix
    • ED outcome accounts for largest variance in cost (admission/transfer/death vs. discharge), then triage category and then age
  • Mean cost of care for Cat 1 is 10x a Cat 5
  • Strong predictor of ED outcome and utilisation of critical-care resources
  • Poor predictor of outcome at hospital discharge
    • Many patients with serious illness that care later death are triaged lower as no urgency in being seen in ED earlier

• Streaming lower acuity patients to ’fast-track’ decreases equity (i.e. less urgent patients seen quicker than more urgent ones) but get overall benefit in efficiency
• Streaming should be an ongoing strategy reflecting urgency of patients and resources available i.e. no streaming if critically unwell patients overwhelming resources
• Structure and function of triage site
  • Single point
  • Appropriate facilities for brief assessent and first aid
  • Balance of accessibility, confidentiality and security
  • Contemporary data on state of ED and expected patients

Pre-hospital triage

• Rapid response, immediate response, routine response or no transport
• Patient benefit in major trauma and STEMI, paediatric, obstetric transport to particular hospitals

Humanitarian crises

• Refugee (UNHCR)
  • Person, who owing to a well-founded fear of being persecutred for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his nationality and is unable or, owing to such fear, unwilling to avail himself of the protection of that country; or who, not having a nationality and being outside the country of his former habitual residence as a result of such events, is unable or, owing to such fear, is unwilling to return to it
• Internally displaced persons (IDP)
  • People displaced from their home but have not crossed an international border
  • State authorities may be the cause of this but may lack will and/or capacity to assist
• 93% of refugees are hosted within the region in which they have fled
• 46% under 18 years old
• Beneficiaries must be actively involved in planning and delivery of aid
• Sphere handbook provides universal minimum standards for humanitarian response

• Emergency phase
  • Initial assessment: Population structure, basic needs, medical needs involving local leaders
  • Measles immunisation: Case fatality rate of up to 33% in setting of malnutrition
    • All children 6 months to 15 years
    • Combined with administration of vitamin A (reduces disease mortality and morbidity un children under 5 by improving immune response
  • Water and sanitation: 5L/person/day and up to 15L/person/day when possible
    • Minimum number of latrines, washing facilities and location of these services as per Sphere guidelines
  • Food and nutrition
    • At-risk young and elderly groups particularly
    • 2100kcal/person/day initial food ration
    • Must undertake surveys for micronutrient deficiencies
    • Mid-upper arm circumference of children 6 months to 5 years is a quick way to assess overall nutritional status of the population
  • Shelter and site planning: Careful planning to consider security, access, water, drainage
  • General healthcare: Medical needs and endemic disease assessments
  • Control of infectious disease: Diarrhoea, malaria, respiratory infections and measles
    • Good, basic living conditions are care
    • Surveillance for outbreaks and early establishment of oral rehydration centres
  • Public health surveillance
    • Crude mortality rate (deaths/10 000/day)
    • Double the baseline CMR indicates emergency threshold
    • If baseline not known, >1/10 000/day for adults and >2/10 000/day for children is cutoff
  • Human resources and training

• Post-emergency phase
  • Basic needs met and CMR back to basline
  • Consolidation, preparation for possible new emergencies and future sustainability
  • Continued water quality monitoring, public health surveillance and nutritional assessments
  • Curative healthcare services
  • Reproductive healthcare including STI
  • Child health activities including expanded immunisation programmes
  • TB programmes
  • Addressing psychosocial and mental health issues

• Permanent solutions
  • Repatriation preferred
  • Integration into host population (becoming less common)
  • Resettlement in another (usually Western) country

To report an incident

• METHANE
  • Major incident standby/declared
  • Exact location
  • Type of incident
  • Hazards present
  • Access for rescue vehicles
  • Numbers of cases (and severity/type)
  • Emergency services present or required

Disaster response order – CSCATTT

• Chain of command between and within services
• Safety
• Communications
• Assessment
• Triage
• Treatment
• Transport

Sieve and Sort

• Sieve
  • Initial triage to identify order of transfer to treatment areas from scene
  • Divided into:
    • Delayed (walking)
    • Dead (not breathing despite airway opening)
    • Immediate (RR <10 or >30 or cap refill >2 seconds
    • Urgent (RR 10-30 and cap refill <2 seconds
• Sort
  • More detailed physiological criteria to determine order of transport to hospital
  • Based on revised trauma score parameters (GCS, SBP, RR)
    • Score 12 = Priority 3
    • Score 11 = Priority 2
    • Score <=10 = Priority 1

Surge capacity

• 4S’s
  • Staff
  • Stuff
  • Structure (physical and management)
  • Space

On arrival to scene

• First two ambulance officers become transport collection officer and casualty collection officer
• Responsible for organising the casualty clearing system for removing all patients from scene
• Casualty collection officer carries out initial triage sieve, delivering minimal first aid
• Senior medical officer on sight has responsibility for management of medical resources at the site and liases with command centre
  • Note: Does not treat or triage patients themselves
• Disaster teams come in to treat patients unable to be extricated or transported (basic not intubation or CPR)

1-2-3 of safety

• Self
• Scene
• Casualties

Last Updated on November 23, 2021 by Andrew Crofton