key: cord-0712624-tcdh7axf
authors: Chen, Yizhe; Yang, Yue; Peng, Wenpeng; Wang, Hui
title: Influence and Analysis of Ambulance on the Containment of COVID-19 in China
date: 2021-02-05
journal: Saf Sci
DOI: 10.1016/j.ssci.2021.105160
sha: 74e76bbeb6901e1c15ffe651e28fc75437354e9f
doc_id: 712624
cord_uid: tcdh7axf

New coronavirus (COVID-19) is a newly emerging and highly infectious form of typical pneumonia with a high rate of transmission. The COVID-19 pneumonia has spread to 147 countries and areas as of Mar.16th 2020, which has tremendous impact on the global public health. It is well known that, in China, the pandemic has been contained effectively with a series of emergency measures. It is necessary to share the existing experience of China in the fight against the pandemic to the world. Especially, during the process of prevention and containment of the pandemic, ambulances play an important role in transporting infectious patients. In this paper, focusing on the safety and quantity of negative pressure ambulances, the influence of ambulance on newly confirmed cases is given. Analysis of negative pressure ambulance on the containment of COVID-19 is shown. The potential development of ambulance is discussed. While the pandemic still continues spreading across the world, we hope to share our experience in the implementation of these strategies by China to save more life.

The ward type ambulance refers to an ambulance that has first-aid resuscitation equipment and necessary medicines. It can rescue critically injured people on the scene or during transportation.

The transfer type ambulance can be used to transfer relatively stable patients to the hospital. During the transfer, only some simple medical treatments such as infusion, oxygen inhalation, hemostasis, and bandaging are allowed. According to various conditions of patients, different ambulances with different functions are generated. Especially, the negative pressure ambulance urgently needed in this epidemic is a type of transfer vehicle.

Negative pressure ambulances used to transport infected patients are regarded as the key point in the containment of COVID-19. Negative pressure ambulance is a vehicle used for first aid and transfer of patients with highly infectious disease. It first appeared during the SARS epidemic in 2003 [6] . The working principle of the negative pressure ambulance is to add a negative pressure cabin or negative pressure equipment in the ambulance, causing a pressure difference of 10Pa to 30Pa between the exhaust and supply equipment in the ambulance. The influence of the negative pressure ambulance on COVID- 19 has not yet been reported, and this information needs to be shared to assist countries with severe epidemics in formulating control strategies.

In this paper, focusing on the safety and quantity of negative pressure ambulances, the influence of ambulance on newly confirmed cases is given. Analysis of negative pressure ambulance on the containment of COVID-19 is shown. The potential development of ambulance is discussed.

While the pandemic still continues spreading across the world, we hope to share our experience in the implementation of these strategies by China to save more life.

After the outbreak, the output of ambulances in China increased rapidly. As can be seen from Fig. 1 , the total output of ambulances in China in 2019 was 8,949 [7] . During the epidemic, the output of ambulances in the first quarter of 2020 reached 9,396, exceeding the total amount of 2019.

In particular, comparing the proportion of the number of ambulances in Hubei Province to China, it can be found that the ratio of ambulances in Hubei Province in the first quarter of 2019 was 4%, and this was increased to 14.3% in 2020. It shows that during the epidemic, the increase in the number of ambulances in Hubei Province is one of the important measures to control the spread of the epidemic. Ordinary ambulances are inadequate in transporting new crown patients. New coronavirus spreads mainly through direct transmission and contact. On Feb. 5th, 2020, the National Health and Health Commission issued the Diagnosis and treatment of pneumonia caused by novel coronavirus infection (trial version 5) [8] , aerosol and gastrointestinal transmissions were also listed as possible routes of transmission to be identified. Therefore, COVID-19 can not only be transferred to subsequent patients and to EMS workers by direct contact with the surfaces or by indirect transmission via hands, but also there is a risk of leakage of virus with air as the medium. According to WHO, when a person coughs, sneezes, laughs, or talks, large (>5 μm diameter) and small (≤5 μm diameter) droplets or aerosols are generated. Due to gravity, larger droplets fall to the ground quickly. Therefore, droplet transmission requires close physical proximity between an infected individual and a susceptible individual. On the other hand, small droplets or small particle residues of evaporated droplets have a low settling velocity, so they may remain in the air for a longer time and travel further before they can enter the respiratory tract or contaminate surface [9] . Kutter et al. [10] suggested that aerosols especially in highly virulent pathogens could travel more than 6 feet. Therefore, in the treatment and transfer of infected patients, ordinary ambulances are incapable.

Some special protective ambulances are needed to prevent the epidemic from spreading further, as well as protect the EMS workers and also other people nearby.

At the beginning of the pandemic, negative pressure ambulance resources were insufficient because too many patients needed to be transferred and treated. Then, the Ministry of Industry (short for 'Ministry of Industry and Information Technology of the People's Republic of China') took steps, and requested some domestic auto companies to work overtime, as shown in Fig. 2 . Up to Feb. 5th, it took 10 days to produce 244 negative pressure ambulances. As of Feb. 15th, 360 negative pressure ambulances were transported to Hubei. On Mar. 3rd, there were 690 negative pressure ambulances in Hubei Province, and 239 in Wuhan. As of Mar. 5th, major manufacturers have transported nearly 2,000 negative pressure ambulances to all parts of the country, while a total of 700 negative pressure ambulances had been transported to Hubei. On Mar. 12th, a total of 800 negative pressure ambulances were transported to Hubei. Thanks to manufacture's efficient production, more infectious patients could be transferred quickly, thus more life were saved. From these figures, it can be seen intuitively that from February to March, there have been more and more negative pressure ambulances in Hubei Province, while the number of new cases dropped rapidly. On Feb. 5th, there were 224 negative pressure ambulances, and 2957 newly confirmed cases. Interestingly, on Mar. 12th, there were 800 negative pressure ambulances, and only 8 newly confirmed cases. In order to make this point clearer, the variation of newly confirmed cases with negative pressure ambulance is shown in Fig. 3 . There was an obvious monotonic decreasing law between the two data. The variation curve fitted well with the actual data. The ratio of negative pressure ambulances to newly confirmed cases in Hubei increased from 0.08 to 100, which ensured that infectious patients could be safely transported and treated in time. The pandemic has been effectively contained in China.

However, the pandemic still continued spreading across the world, worsening the situation in many countries. The number of confirmed cases in some countries is not directly proportional to the supply of negative pressure ambulances, and patients cannot be resettled in time. In South Korea, the number of confirmed cases across the whole country increased largely from Jan. 20th to Feb.

23th. But transportation of all patients is no longer possible. As of Feb.26th, there is only one negative pressure ambulance in Gwangju [11] . With 7 cases of COVID 19 infected in Gwangju, 6 were tranported by ordinary ambulances and only 1 was transported by negative pressure ambulances. Even though the government took many steps, as of Mar. 5th, many patients in Daegu and Gyeongsangbuk-do still cannot be transported to hospitals [12] . In Iran, many drugs and medical equipment rely on imports. Due to U.S. sanctions on Iran, many advanced medical devices are banned and medical resources are in short supply. In Italy, as of Mar.9th, the scope of the blockade in response to the epidemic has been extended to the whole country. On Mar. 8th, doctor Daniele Macchini from Bergamo Intensive Care Unit [13] stated that, as the number of confirmed cases continued to rise, medical equipment and beds could not cope with the increasing patients. On Mar.

9th, the Niguarda Hospital in Milan [14] stated that, in the face of the shortage of resources, the Niguarda Hospital began to classify patients to ensure targeted treatment for critically ill patients. 

Through the analysis in the previous section, after increasing the number of negative pressure ambulances, the number of confirmed cases decreased significantly. In many epidemics, negative pressure ambulance has made great contributions to the safe and effective transfer of patients due to its special functions. With the outbreak of COVID-19, on Jan. 29th, in accordance with the relevant requirements of the Technical specifications for disinfection of medical institutions ( WST367-2012 ) [15] and the characteristics of the epidemic, the National Health and Health Commission has formulated the Work plan on the transfer of cases of pneumonia due to new coronavirus infection [16] . It clarified the transfer workflow of specific patients, and gave the requirements for ambulance cleaning and disinfection. The disposal of medical waste shall be carried out in accordance with the Hospital infection management measures and Technical standard for disinfection and related regulations. Focusing on the influence of negative ambulance, the mechanism of adding negative pressure ambulances to control the epidemic mainly includes the following aspects.

During the using of the negative pressure ambulance, the air can only flow from the outside to the inside of the ambulance. The disinfection and filtering device are used to sterilize the air entering the ambulance before discharging (which can kill 99.97% of bacteria). Therefore, a fixed air flow field area is formed in the negative pressure compartment. The air can flow from the clean area (medical staff area) to the infectious source area (patient area). The dead space and vortex of the air flow can be minimized. Schematic diagram of negative pressure ambulance is shown in Fig. 4 . To achieve the goal of protective isolation, the negative pressure ambulance is mainly equipped with three devices: negative pressure generator, ventilation equipment and isolation stretcher. The negative pressure generator is responsible for generating a pressure difference between the inside and outside of the ambulance, and creating a negative pressure environment for the interior of the ambulance. The ventilation equipment is responsible for delivering fresh air to the interior of the vehicle. It has a purification function to ensure that the air entering and outside the vehicle is clean.

The isolation stretcher is responsible for transporting and placing patients. It is shaped like a capsule.

It has an air filter inside to ensure that air contaminated by the viruses or microbes cannot flow out.

It can be seen that, compared with traditional ambulances, negative pressure ambulances are easier to control the virus under this function to protect the safety of other personnel.

During the procedures for the disinfection of negative pressure ambulance, disinfectants such as ether, 75% ethanol, chlorine-containing disinfectants, peracetic acid, and chloroform can be highly effective at killing coronavirus. After each transportation the ambulance needs to be disinfected. The procedures includes: Spraying the compartment with 5% peroxyacetic acid disinfectant, closing the compartment for two hours for fumigation, opening the window for 30 minutes, wiping the compartment with a concentration of 1000mg / L disinfectant, and wiping the instruments with 75% alcohol or disinfection water, and using ultraviolet germicidal irradiation for half an hour in the final step. These procedures are tedious and time-consuming. On some negative pressure ambulances, automatic biological disinfection or sterilization equipment is installed, which can shorten the time from 90 minutes to 30 minutes compared with traditional disinfection methods.

Some negative pressure ambulances are equipped with a linear ozone sensor, which can monitor the ozone concentration in the ambulance in real time. When the ozone concentration in the ambulance drops to a safe range, the detector will send a notice to the management staff as soon as possible.

This saves the time for the driver and medical staff to wait for the purified negative pressure ambulance compartment. In terms of wearing protective equipment for hospital medical staff, the national emergency issued the Technical guidelines for the protection of medical personnel during a new coronavirus-infected pneumonia outbreak [17] . Taking the standards of the Shanghai Public Health Clinical Center as an example. Table 1 shows the protection requirements of the medical staff responsible for the operation and disinfection of the ambulance. systems have several potential advantages for terminal disinfection. They are relatively simple and easy to use, and do not leave chemical residues or risk exposing patients and workers to toxic chemicals. However, UVGI systems has limitations [18] .Researchers in the United States have studied the efficacy of the ultraviolet radiation sterilization device installed in different positions in the ambulance, and concluded that appropriate installation position could increase the ultraviolet reflectivity, thereby shortening the disinfection time and improving the disinfection efficiency [19] .

Also, reasonable staffing of the ambulance medical team and the provision of adequate disinfection equipment in the hospital, can help improve the safety and reliability of the ambulance [20] , improve the treatment rate of infectious patients, and ensure the safety of medical staff.

In Wuhan, Hubei, in order to treat the critical ill patients in time, on Jan. 23th, the Wuhan on Jan. 28th, the steel structure was built in the double-layer ward area; on Jan. 29th, the board room construction was fully rolled out, and the electromechanical equipment was installed; on Jan. 30th, the impermeable membrane laying work was fully completed; on Jan. 31st, 90% containers assembly were completed; on Feb. 1st, medical supporting equipment was fully installed; on Feb.

2nd, the hospital was completed. The progress of the construction of Huoshenshan and Leishenshan hospitals is shown in Fig. 5 . In order to fight against Covid-19, a number of Chinese automotive and air equipment manufacturers resumed production in advance (under the premise of safety) and worked overtime to make products while guaranteeing product quality. A large number of advanced negative pressure ambulances were provided in a short time, as shown in Table 3 . On Feb. 4th, 2020, Geely Group started the research of "all-round healthy car" with virus prevention function [24] . On Feb. 24th, 2020, Geely ICON went on the market, becoming the first mass-produced car equipped with the CN95 air filter in the auto industry. ICON has functions of isolating harmful substances in the external air and purifying the air in the car. Focusing on making a breakthrough in the functions and technologies of virus prevention, the "all-round healthy car" will use materials with higher environmental protection, lower emission. Also it needs abilities of inhibiting bacteria and surface sterilization. Anti-virus vehicles launched by Geely for ordinary consumers can realize the goal of civilianization of anti-virus, and make people travel more safely.

Before the outbreak of COVID-19, the annual production and sales of negative pressure ambulances in China was only about 50. And as of Mar. 5th, the daily output of negative pressure ambulances in China had exceeded 100. The daily output of negative pressure systems has been increased from less than 20 to more than 120. To date, many manufacturers had delivered nearly 2,000 negative pressure ambulances to the whole country, of which a total of 800 negative pressure ambulances had been delivered to Hubei [25] .

The development of the 5G, big data and smart technologies will promote the innovation of pre-hospital treatment methods. During the epidemic, the traffic was inconvenient, because all the public transportation and private cars were all restricted. Also there was a risk of infection when going out. So far, a wide range of distinct operational procedures and measures have been implemented with respect to the inconvenient traffic, such as community service vehicle, remote consultation technology. The continued challenges of social distancing, containment, isolation, and surge capacity in already stressed hospitals, and emergency departments also have led to a swell in remote consultation. Through remote consultation technology, high-level hospitals could provide guidance to some country-and town-ship level health centers, also this could help avoid crossinfection. Moreover, remote consultation technology could help reduce some patients' financial burden on treatment because of traffic fees and higher fees of high-level hospitals. In addition, it could balance the level of hospitals' response to epidemics.

On Feb. 12th, the first 5G + 4K transfer ambulance of the New Coronavirus Pneumonia Patient

Transfer Command was put into use in Nanjing, Jiangsu [26] . The combination of intelligent technology and the big data can bring a major breakthrough in ambulance rescue. In Japan, the researchers developed a smart ambulance approach alarm system, which could open the position information of ambulances within a necessary minimum range. This information helps an ambulance operation to choose a traveling route avoiding a heavy traffic jam.

Thus the combination of smart phones, car navigation equipment and car navigation application can make ambulance be operated more efficiently in the future [29] . Iranian scholars studied that, for some patients who need real-time monitoring or in unstable conditions, wearable electronic devices can continuously monitor the situation of patients. Nowadays, the rapid development of intelligent systems and advanced devices provides the possibility for the use of wearable systems in the future.

Designing smart tools such as wearable smart blankets plays an important role in monitoring, recording, and transferring vital signs especially in ambulance [30] . With the development of vehicle networks and driver-less technology, ambulance is expected to provide patients with more secure and private remote consultations [31] . Self-driving ambulances can increase the rate of consultations [32] . Active collaboration of intelligent technology and emergency personnel can improve the efficiency of pre-hospital treatment for patients [33] .

Moreover, the ambulance dispatch data can intuitively reflect the spread speed of acute infectious diseases (such as influenza) in a certain region. It is suggested as a means of real-time, syndromic surveillance for early detection for infectious diseases. Due to ambulance's wide reach into the community, the onset and outbreak of infectious diseases can be figured out, thus guidance for the prevention and control of seasonal influenza can be provided. Researchers from Australia [34] and the Netherlands [35] had studied the ambulance dispatch data of the city of Melbourne and the Netherlands respectively, and revealed that ambulance dispatch data really could analysis the situation of pandemic.

In summary, the development of the 5G, big data and smart technologies will promote the innovation of pre-hospital treatment methods. Combination of advanced technology and medical equipment will enable future ambulances to provide patients with more efficient, safe and intelligent services. This can help to improve the efficiency of the treatment for patients, thus reduce the burden on hospitals, and make a new medical breakthrough. Still, there are no definite answers when will the COVID-19 pandemic end and whether COVID-19 will re-emerge. The threat posed by this most recent emerging disease has however prepared improved ambulance not only to be used in potential future cases of COVID-19 but also other emerging threats to public health.

New coronavirus (COVID-19) is a newly emerging and highly infectious form of typical pneumonia with a high rate of transmission. The pandemic has been contained effectively with a series of emergency measures in China. Ambulances play an important role in transporting infectious patients.

Focusing on the safety and quantity of negative pressure ambulances, the existing experience of China in the fight against the pandemic is shared from the following aspects.

1) The number of ambulances of China was greatly increased, especially for the negative pressure ambulance. The production of ambulance in the first quarter of 2020 has exceeded the whole number of 2019. In addition, the ratio of ambulance in Hubei Province to the whole country has been increased a lot comparing the data in 2019 and 2020.

2) Negative pressure ambulances had positive influence on the contain of COVID-19. The newly confirmed cases were decreased dramatically from 800 to 8 with the negative pressure ambulance from 200 to 800 in Hubei Province. There was an obvious monotonic decreasing law between the two data. The variation curve fitted well with the actual data.

3) The reason of negative pressure ambulance on the containment of COVID-19 is analyzed. The effective negative pressure and strict disinfection requirements ensured the control and elimination of the virus. Meanwhile, the fast supply of hospital beds and negative pressure ambulance supporting by all the country can quickly handle confirmed patients and avoid further spread of the virus.

4) The development of the 5G, big data and smart technologies will promote the innovation of pre-hospital treatment methods. Combination of advanced technology and medical equipment will enable future ambulances to provide patients with more efficient, safe and intelligent services.

While the pandemic still continues spreading across the world, we hope to share our experience in the implementation of these strategies by China to save more life.

WHO names new coronavirus "COVID-19" _Geneva

Editorial: China's Anti-epidemic Experience Is Worth Learning For Every Country-Xinhua Daily Telegraph

WHO agrees on China's strategic and tactical approach to the outbreak_GMW

New Coronavirus Predictions and Global Trends

COVID-19 diagnosis and management: a comprehensive review

Analysis of the ambulance market in the first quarter of 2020

Diagnosis and treatment of pneumonia caused by novel coronavirus infection (trial version 5) _Chinese Government

Possible aerosol transmission of COVID-19 and special precautions in dentistry

Transmission routes of respiratory viruses among humans

7MHz -Negative Pressure Ambulance for COVID19 transportation

South Korea transfers patients to Gwangju, medical protection supplies are nearly exhausted_Sina

Con le nostre azioni influenziamo la vita e la morte di molte persone

Covid-19, tanti giovani in terapia intensiva_ l'audio shock dal Niguarda -Il Mio Giornale

Technical specifications for disinfection of medical institutions

Work plan on the transfer of cases of pneumonia due to novel coronavirus infection_Chinese Government

Technical guidelines for the protection of medical personnel during a new coronavirus-infected pneumonia outbreak_Xinhuanet

Ambulance disinfection using Ultraviolet Germicidal Irradiation (UVGI): Effects of fixture location and surface reflectivity

How was the "mobile N95" made? Visiting Jiangling Group, the largest ambulance manufacturer in China_Xinhua

Geely invests 370 million in research and development of anti-virus vehicles_NetEase Auto

Ministry of Industry and Information Technology: a total of nearly 700 negative pressure ambulances have been delivered to Hubei, which is equivalent to 14 years of production and sales in China under normal circumstances

Jiangsu's first 5G + 4K new coronavirus pneumonia patient transfer vehicle runs in Nanjing_People

Mobile 5G Helps Fight the "Last Kilometer" of Epidemic Prevention-The First 5G + 4K New Coronavirus Patient Transporter Launched in Nanjing_Jiangsu Media

Huawei Cloud WeLink provides remote medical services to 6,000 hospitals across the country_Chinanetfile

Cluster Computing(Cluster Comput

Sustainability(Sustainability)

Emerg Infect Dis(Emerging infectious diseases)

The authors would like to acknowledge the financial support from the National Natural Science