DEVELOPMENT CHARACTERISTICS OF MOBILE HOSPITALS

At present, according to the differences of transport media, the mobile hospitals can be categorized into 3 types: terrestrial, floating, and flying. The terrestrial mobile hospital is the most common type, which includes tent hospital, vehicle hospital, shelter hospital, and so forth. The terrestrial mobile hospital is modular. The number of units, spatial organization, and clinical options could be altered as needed. From the point of view of spatial structure, the shelter hospital could respond immediately to disaster calls and immediate departure from the disaster zone when the situation worsens, and it must meet the requirements of flatness for supporting terrain. While the tent hospital has a large available space and low requirements for terrain, its disadvantages are long in deployment and withdrawal time. At present, the configuration forms of terrestrial mobile hospitals in various countries include mainly the shelter combination represented by the United States and France, the tent combination represented by Russia and Italy, and the shelter and tent combination represented by Germany and China. ^{Reference Zheng, Meng and Li3,Reference Tian, Qiao and Wang4}

Shelter hospitals were first developed by developed countries, such as France, Germany, and the United States, which could be divided into non-expansion shelter and expansion shelter from the perspective of structure. ^{Reference Wang5} The non-expansion shelter is basically transformed from a container, while the expansion shelter adopts a folding structure, the area of the structure before unfolding is the same as that of the non-expansion shelter, and the usable area after unfolding will expand. Typically, the types of expansion shelter structure can be divided into folding type, bellows type, and drawing type according to the way of retraction and unfolding. ^{Reference Zheng, Meng and Li3} Although the structure of the shelter varies, in the face of some special rescue-site terrain, the medical shelter is not easy to deploy, so it cannot achieve a rapid and effective medical rescue.

The floating hospital is a self-contained, seagoing medical facility. As early as the end of the 1980s, Germany combined the medical shelter and cargo ship for reconstruction and realized the miniaturization of the hospital ship. ^{Reference Zheng, Tian and Fan6} The hospital ship named Mercy is currently used in the United States for the world’s disaster rescue and humanitarian operations. ⁷ Peace Ark, which is the name of China’s hospital ship, has carried out dozens of humanitarian missions since its commission, treating over 180 000 patients around the world. ⁸ Floating hospitals could only reach destinations near water and required a considerable amount of space to dock the ship and provide access for boats to transport the patients and staff. ^{Reference Bitterman and Zimmer1}

The flying hospital had been adopted by many of the world’s Air Forces, ^{Reference Lam9} non-profit organizations, and governments. The flying hospital could provide surgical hospital services and acute medical care in disaster situations, or humanitarian relief. ^{10,Reference West11} Moreover, aeromedical evacuation provided fast transportation of wounded persons at disaster sites to hospitals. ^{Reference Hou, Lv and Ding12}

PRACTICES OF MOBILE HOSPITALS IN DISASTER RESPONSE

In this section, we collected the data from literature, websites, and scientific reports, to describe and discuss the disaster response of mobile hospitals in recent years.

As seen in Table 1, terrestrial mobile hospitals were most commonly used. In the earthquake in Haiti in 2010, the United States established the first tent hospital in Prince Lane of Haiti, which consists of the first 2 tent units for simple medical rescue, and transferred to the tent hospital with operation and intensive care functions composed of 4 tent units due to demand ^{20,Reference Garzon21} ; in 2013, the strong typhoon Haiyan swept across the central region of the Philippines, damaging infrastructure including hospitals. The medical teams sent by Israel and South Korea, under the command of Philippine authorities, assisted the damaged local hospitals and set up tent hospitals near the local hospitals ^{Reference Lin, Marom and Dagan22,Reference Kim, Ahn and Lee23} ; according to the situation of the rescue site, China’s medical team set up a mobile hospital of inflatable tents in the mountainous area in the 2015 Nepal earthquake ^{Reference Wang, Ding and Lv24,Reference Zheng, Hu and Xin25} (Figure 1). Shelter hospitals played an important role in the rescue during 2 major earthquakes in China: Wenchuan and Yushu earthquakes.

TABLE 1 Disaster Response of Mobile Hospitals in Recent Years

Notes: *Explosion: At 22:51:46 on August 12, 2015, a fire and explosion occurred in the dangerous goods warehouse of Ruihai company located in Tianjin port, Binhai New Area, Tianjin. In this accident, the total explosion energy is about 450 tons of a TNT equivalent.

FIGURE 1 Tent Mobile Hospital Used by Chinese Medical Team in Nepal Earthquake Rescue.

The vehicle hospital is also a main form of a terrestrial mobile hospital. After SARS in 2003, China’s disaster medical rescue system has been greatly developed. With the support of the central and local governments, the National Health Commission of China has established 4 categories (emergency medical rescue team, emergency infectious disease prevention and control team, emergency response team for poisoning, nuclear and radiation emergency health emergency team) and 49 national health emergency rescue teams. These teams are equipped with vehicle hospitals (Figure 2). This year’s outbreak of the novel coronavirus pneumonia named coronavirus disease 2019 (COVID-19) emerged in Wuhan, China. To deal with the surging demands of medical care and cut off the route of transmission to protect susceptible people, multiple national emergency rescue teams rushed to Wuhan through vehicle hospitals, and received and treated COVID-19 patients with mild symptoms. The stadiums were transformed into a temporary ward. A microorganism inspection vehicle and mobile CT vehicle were assembled to detect patients infected with COVID-19. The World Health Organization expert team highly praised this effective measure taken by China to deal with the epidemic.

FIGURE 2 Rescue Material Delivery Vehicle of National Emergency Medical Rescue Team of the Second People's Hospital of Guangdong Province.

The flying hospital is another kind of mobile hospital that can respond quickly to disaster. A flying hospital using a modified Lockheed L-1011 TriStar 50 jet aircraft landed outside of San Salvador, which supported medical assistance for 7000 patients, of which 187 included life-changing surgeries. ^{Reference West11} Furthermore, air transport is the fastest mean of delivering the medical resource to the scene of disaster, or evacuation of wounded persons at disaster sites. In 2010, France proposed air transportation and delivery of medical equipment required by some mobile hospitals in the Haiti earthquake rescue. ^{Reference Benner, Stephan and Renard26} In the 2010 Haiti earthquake rescue, the Canadian medical team delivered mobile hospitals through air transportation. ^{Reference Talbot, Meunier and Trottier27} After a 6.5-magnitude earthquake hit Yunnan Province of China, the Il-76 transport plane of the Ministry of Emergency Situations (as the competent department of civil defense in Russia) took off from Ramenskoye Airport on the outskirts of Moscow, delivering humanitarian aid materials to the disaster area. ²⁸ In 2006, 35 firefighters were trapped during a forest fire in Greater Khingan Range, Heilongjiang province. The China International Search and Rescue team transferred these 35 severe casualties to Peking for treatment by using a modified airliner. ^{Reference Hou, Lv and Ding12}

A hospital ship refers to an unarmed service ship specially used for sea reception, treatment, and evacuation of the wounded and the dead. Continuing Promise 2011 was a 5-month humanitarian assistance/disaster response military aboard the hospital ship Comfort, which deployed to Central and South Americas and the Caribbean between April and September 2011 ^{Reference Hameed, McCaffrey and McCoy29} ; In 2013, during the Philippines super typhoon disaster rescue, as the United Kingdom’s initial response to this disaster, HMS DARING was diverted from her deployment to take part in humanitarian aid, named Operation PATWIN. ^{Reference Butterworth30} From November 24 to December 10, 2013, China’s hospital ship Peace Ark was deployed to the Leyte Gulf in the Philippines to provide humanitarian medical relief in Tacloban after Typhoon Haiyan. ^{Reference Ren, Sun and Wang31}

LESSONS FROM THE FIELD

In the research process of a mobile hospital, innovation breakthroughs in various fields should be able to withstand the test of practice. Only in practice can new problems be found and solved. Among them, the valuable experience gained in the disaster rescue operation has played a crucial role. In a series of disaster rescues, there are still many aspects that need to be improved in the current application of the mobile hospital.

First, there is the problem of limited mobile transportation. After a disaster, it is very important to deliver the mobile hospital to the disaster site reasonably and effectively. At present, most of the terrestrial mobile hospitals rely on road and railway transportation. However, when the road or railway is damaged, the transportation time of the mobile hospital will be delayed, which may result in missing the golden time of rescue. During the Yushu earthquake in China, the locomotive transportation of a shelter hospital rushed to the disaster site overnight, driving 53 hours and 2350 kilometers to reach the disaster area ^{Reference Wang32} ; like the Ya’an earthquake rescue in China, the shelter hospital did not give full play to the role of disaster rescue in the face of problems such as long distance and road damage. ^{Reference Zheng, Tian and Fan6}

Second, special imaging and laboratory examination equipment should be considered, for example, adding a CT scan unit. In a disaster rescue, especially an earthquake, brain injury is the main problem of emergency treatment, and the operation of brain injury needs to use CT for accurate positioning. ^{Reference Li, Wang and Zhang33,Reference Guo, An and Huang34} At the same time of adding necessary medical units, referring to the French practice, a modular unit combination is carried out according to needs, including devices, drugs, and equipment in each unit, forming several groups of combination formation of different functional types. ^{Reference Sun, Tan and Zhang35}

Third, the internal equipment of the mobile hospital should be kept updated, especially the rescue medical equipment. For example, in the Nepal earthquake, it was proposed that due to the imperfection of the equipment, independent operation cannot be performed in the field hospital. ^{Reference Wang, Ding and Lv24} At the same time, there is a growing need to formulate unified standards for mobile hospitals and form an orderly mechanism and system through the standards, so as to achieve standardized and unified management in the disaster site, especially during the international rescue operation.

FUTURE DEVELOPMENT OF THE MOBILE HOSPITAL

Integration and Application of Intelligent Medicine

The applications of machine learning (ML) and big data (BD) have been increasing rapidly in the mobile hospital, including medical imaging (MI), telemedicine, and computer-aided diagnosis (CAD) system. These technologies have become the mainstream of mobile hospitals and will be an important sign of future mobile hospitals.

In MI, the artificial neural network is the backbone of ML and deep learning. ^{Reference Currie, Hawk and Rohren36} An important driver of the emergence of artificial intelligence (AI) in MI has been the enhancement of visual recognition using AI in radiology to produce lower error rates than the human observer. ^{Reference McBee, Awan and Colucci37} Specific capabilities of MI include detection and classification of lesions, automated image segmentation, extraction of radiomic features and study triage, and image reconstruction. ^{Reference Ho, Soon and Caals38-Reference Larson and Boland41}

The combination of a network and the medical field gave birth to telemedicine. The implementation of telemedicine can improve the uneven distribution of regional medical resources; reduce the working pressure of medical staff; shorten the distance between medical staff and patients and medical staff; and improve the timeliness of monitoring, diagnosis, and treatment. In surgical care, ^{Reference Aziz and Ziccardi42} telemedicine technologies ^{Reference Gosman, Fischer and Agha43} have been used to provide pre- and postoperative surgical consultations and monitoring, as well as surgical teleconferencing ^{Reference Numanoglu44} and education across borders. ^{Reference Latifi, Mora and Bekteshi45} The continuous development of telemedicine relies on the continuous innovation of network communication technology; the latest fifth generation wireless systems (5G) is bringing significant changes to mobile communication and other related industries by virtue of its advantages of high data rate and low latency. To fight COVID-19, China Mobile, China Unicom, and China Telecom have recently applied 5G technology in high speed data transmission, telemedicine, and telemonitors in Huoshenshan Hospital in Wuhan.

In 10 years, AI will create preliminary radiology reports about screenings for everything. The Alibaba Group has already developed an AI CT diagnosis technology to assist COVID-19 detection. The AI system could make acceptable diagnostic decisions within 20 seconds, with an accuracy rate of 96%. ⁴⁶ In the future, a computer will show us lesions right before our eyes, ^{Reference Bruckheimer, Rotschild and Dagan47,Reference Kim48} and be able to identify the 12 characteristics of cancer cells so that it will be able to diagnose it more accurately and faster than a pathologist can. ^{Reference Ye49} Recently, IBM teamed up for therapy for diabetic patients by sharing 30 million data of patients with diabetes from clinical databases and 86 million data of patients with prediabetes. Mobile ultrasound, Google Glass, and other mobile devices have already been adopted in medical fields, and data from those wearable devices will be sent to a medical center where clinical review software will be used for the diagnosis and the treatment of patients. ^{Reference Sahyouni, Moshtaghi and Tran50,Reference Kelton, Szulewski and Howes51} Telemedicine using a health spot center or prehospital care will become more prevalent. Figure 3 shows a CAD Architecture, comprising 3 parts: the sensor, CAD, and cloud storage. In the future, all of the new technologies and characteristic will be integrated into Mobile Hospital, telemedicine, computer-aided detection, and surgical robot.

FIGURE 3 Computer-Aided Diagnosis System Architecture. (The solid lines indicate the input data and their direction, and the dashed lines indicate data-out and their direction.)