Tsunami

Acknowledgments

The author thanks Kingkarn Waiyanak for the literature search and retrieval, Glenn K. Shingledecker for his help in editing the manuscript, and the staff personnel at Krabi Hospital, Krabi, and Wachira Phuket Hospital, Phuket, Thailand, for providing valuable pictures.

Description of event

A tsunami is one of the most devastating disasters worldwide. It has huge human, physical, economic, and social impacts. This event usually follows a high-magnitude earthquake of greater than 7.0 on the Richter scale, accompanied by landslides and volcanic eruptions. There are two types of tsunami waves: near-field and far-field. The near-field tsunami is caused by a nearby earthquake that significantly shakes the population. Its wave usually arrives at the shore within 5 to 20 minutes. The far-field tsunami is caused by a faraway earthquake without any significant shaking effects noticed on the shore. This wave usually arrives within 40 to 60 minutes. A powerful harbor wave can exceed 490 miles per hour depending on the water depth, and its height can reach 38 m, resulting in massive destruction.

During the years 1700 to 2000, tsunamis killed more than 420,000 people with thousands more injured or missing. The earthquake near Sumatra Island in Indonesia in 2004, with a magnitude of 9.3 on the Richter scale, was one of the most devastating tsunamis in history ( Fig. 98-1 ). More than 200,000 people died or went missing, more than 400,000 people became homeless, and more than 1.2 million people were displaced. This enormous disaster required response from a diverse group of humanitarian organizations and military troops and made some scientists believe that tsunami science and engineering were crucial to saving coastal societies, industries, and environment. The complexity of the large earthquake and the tsunami that caused serious damage to the nuclear power plant in Japan on March 11, 2011, made the disaster relief operation more difficult, shocking the people of Japan and the world. It is important to understand the course of this natural catastrophic event. Even though we cannot prevent the disaster from happening, we can prevent its adverse consequences.

Pre-incident actions

Tsunami Mitigation and Planning

A tsunami disaster cannot be prevented, but planning and preparedness can mitigate its effects. Well thought-out risk and emergency management, planning, and preparedness can enable the community at risk to be ready to respond to a disaster in an effective manner. The strategies include a detailed hazard vulnerability analysis (HVA), evaluation of risks in the area (risk assessment), learning from previous experience and available data, and coordination with all of the community’s stakeholders. The significance of socioeconomic factors in making people vulnerable to a disaster should be recognized and included in action plans. The magnitudes of future tsunamis should be predicted during the planning and preparedness process, which is a combination of three components: defense structure, tsunami-resistant town development, and evacuation based on advanced warning.

Earthquake-resistant and shock-absorbing buildings, with their own electric power supply in tsunami-prone areas, is one strategy to prevent building collapse and mitigate the number of casualties. Concrete seawalls with tsunami-absorbing areas and the relocation of population centers to higher ground areas are other strategies to reduce the effects of a tsunami. Accurate warning systems combined with individual, family, and community preparedness will help a population evacuate to designated routes and shelters more effectively.

Community surge capacity information is necessary for planning and preparedness. A method to gather accurate information on damage, logistics of the evacuation, and supplies should be implemented. Two-dimensional (2D) and 3D technology can be used for run-up simulation to estimate the destruction and make a damage assessment (e.g., destruction of structures and the impact of drifting lumber, cars, or boats). Then tsunami hazard maps can be created to provide information for planning, response, and public education. Community and individual awareness and preparedness are very important in tsunami mitigation, and community readiness is a cornerstone for an effective response. An investment in community disaster education and training needs to be made, along with planning for exercises and drills. It has been proven that preparedness and periodic drills have helped people evacuate more smoothly and safely.

Communication is one of the most important components for a more effective response when a tsunami strikes. The chaotic environment in a tsunami disaster makes communication more complex with greater possibilities for failure. Redundancy in communication backup systems (e.g., amateur radio communication, satellite communication systems, and walkie-talkies) is necessary in a plan for disaster response.

In a large-scale disaster with a multiple number of agencies responding, good strategic planning to coordinate all of the responders can facilitate a more effective response. When expanding the preparedness to regional, national, and international levels, a well-organized effort depends on effective command and control. The incident command system (ICS) is the cornerstone for disaster-response readiness. The command and coordination protocols should be prepared before a tsunami strikes, or set up immediately in the aftermath using prior liaisons with external organizations to mobilize their resources for the stricken community.

Financing is one of the challenging issues in a disaster. Public health planning has to ensure that victims can seek medical care without health insurance cards and with co-pays waived.

Community hospitals should prepare and create graded mass casualty or disaster plans to operate the hospitals at full capacity for at least 48 to 72 hours without any external resource requirements. Regular training and mass casualty exercises and drills will help hospitals be ready to respond to any disaster.

Post-incident actions

In the immediate aftermath of a tsunami, the local government should be the first to respond and set up an emergency operation center, apply the ICS, secure the affected area, establish the search and rescue procedure, commit resources to assess the damage, evacuate residents to designated shelters, provide first aid and relief to victims, and establish the standard internal and external community communication systems. The incident commander needs to mobilize all of the available necessary resources to the affected area. In a complex tsunami with damage to the infrastructure, the initial rescue and response will be less effective because of destruction of transportation systems and the lack of gasoline and supplies. Local health care facilities should be prepared with flexible surge capacity plans to respond to a disaster for at least 48 to 72 hours before external agencies or a disaster medical assistance team (DMAT) can reach the affected area. In the early stages of a disaster, local health care facilities need to prepare for a maximum influx of patients within the first 24 to 48 hours. Enabling health care facilities to treat and support victims while also providing for basic needs (shelter, food, clean drinking water, and sanitation) is crucial for injured and uninjured survivors.

The emergency phase is usually followed by the reconstruction and rehabilitation phase. The large-scale influx of aid workers often comes later, and this foreign aid will have an impact on all levels of society during the recovery process. Disasters by nature are intermittent, happen unexpectedly, and require massive recovery efforts, especially in the developing world, which does not have the same capacity and ability to recover from disasters as more developed countries. Recovery activities include restoring the infrastructure, reestablishing communication systems, and rebuilding socioeconomic systems with the main purpose of returning the affected community to its pre-incident state.

Immediately after the response to a tsunami or any other disaster, an after action review (AAR) should be performed to identify good practices and windows of opportunity for improvement. Combining this review with a community risk assessment for pre-incident action will create a more effective response in future tsunami disasters.

Currently, only a small number of research papers with good methodology are available. Conducting basic and advanced research in a tsunami disaster will provide valuable knowledge and information for the future.

Medical treatment of casualties

Providing medical relief and understanding the medical needs for an affected area in a timely manner is not easy. The roles of governmental health agency in a disaster include securing medical and nursing care, providing public health services with maximal safety protocols, ensuring the safety of food and water supplies, and conducting surveillance of endemic diseases. All health institutions in disaster-prone areas should be equipped with emergency care facilities able to provide care when needed ( Fig. 98-2 ). The triage system normally establishes patient priorities by the severity and number of victims versus response assets available in the event of a large influx of patients in the immediate aftermath of a tsunami. On scene or in-hospital initial treatment and stabilization procedures are required. Patient transportation to other hospitals may be necessary for some victims. In the first few days after a tsunami, the immediate health care requirement is treating life-threatening and emergency conditions (e.g., aspiration, blunt and penetrating trauma, and wounds), while in the following weeks, medical assistance usually requires taking care of acute exacerbations of chronic diseases with minor injuries, endemic disease prevention, and psychological support. The deployment of DMATs from the external community or central government is necessary to provide emergency medical assistance at the local hospitals and support for transporting patients in an affected area.

Wound Management

The powerful waves cause many people to be injured. Victims usually suffer from aspiration, drowning and near drowning, blunt and penetrating trauma, and musculoskeletal injuries that include both fractures and dislocations. Most wounds are severely contaminated with foreign bodies, mud, dirt, sand, debris, seawater, seaweed, feces, and saliva. Contaminated wounds are prone to infection by the Clostridium tetani organism. The incidence of tetanus infection significantly increases in: wounds more than 1 cm long, wounds that are left without management at least 6 hours, wounds of the avulsion type, cases involving massive devitalized tissue, and wounds that are grossly contaminated.

The disaster response team from Songklanagarind Hospital working at the Krabi Provincial Hospital (one of the most affected areas from the 2004 tsunami in Thailand) found that at least 67% of the contaminated wounds were infected as early as within 24 hours; the most common procedure done was aggressive wound debridement. The infection rate remained high even though some victims initially received antibiotics. Mixed organisms were the most common pathogens causing wound infection, with a high rate of antibiotic resistance. The most effective antibiotics for these organisms were third- or fourth-generation cephalosporins, aminoglycoside, and quinolone ( Table 98-1 ). Many victims developed wound infections associated with complications and needed aggressive wound management (i.e., surgical wound debridement, limb amputation, and intensive care).

Table 98-1

Summary of Wound Infection Information for Tsunami Disasters

Authors (year)	Population	Infection rate	Organism	Antibiotic- susceptible
Hiransuthikul	777 patients	66.3%	Polymicrobial Aeromonas	Aminoglycoside Quinolone
Kespechara et al.	391 patients	89%	Klebsiella pneumoniae, Proteus species, Escherichia coli, Aeromonas	Aminoglycoside Quinolone 3rd, 4th generation cephalosporin
Johnson	777 patients	66%	Aeromonas	Aminoglycoside Quinolone 3rd, 4th generation cephalosporin
Katnimit	59 patients	100%	N/A	N/A
Llewellyn	17 patients	100%	Acinetobacter E. coli	Ceftazidime, carbapenem
Edsander-Nord	75 patients	Most (esp. primary closure)	Unusual organism, Mycobacteria, Acinetobacter, Aeromonas, fungus	N/A
Prasartritha	2311 patients	70%	Polymicrobial Aeromonas Vibrio Klebsiella	Gentamicin, ciprofloxacin
Doung-Ngern	523 patients (1013 wounds)	66.5%	45% polymicrobial	Aminoglycoside Quinolone
Janda	305 patients	N/A	Aeromonas	Aminoglycoside Quinolone