key: cord-0730448-oh7xtk61
authors: Chen, Yan-Hua; Wang, Qing-Jun; Lei, Jian-Ping; Liu, Qi-Zhen; He, Wei; Liu, Song-Yu; Xia, Xu-Hui; Liu, Wei-Pin
title: Design and engineering application of medical oxygen supply system in novel coronavirus pneumonia treatment hospital
date: 2021-09-14
journal: Journal of Building Engineering
DOI: 10.1016/j.jobe.2021.103170
sha: 21a5e692639a3b75b183c2da89d57e0f76c49614
doc_id: 730448
cord_uid: oh7xtk61

Respiratory supporting, as an important medical treatment for new coronavirus pneumonia patients, must be effectively guaranteed by medical oxygen supply. However, the medical oxygen system designed and configured by the existing hospitals according to the current specifications cannot meet the oxygen needs for patients with new coronavirus pneumonia. This paper aimed to study the design of medical oxygen system in new coronavirus pneumonia emergency hospital. By investigating the oxygen treatment plan for the novel coronavirus pneumonia patients in the health emergency hospital, the oxygen treatment characteristics of different patients were studied. The oxygen characteristics of different respiratory support terminals were explored to study the oxygen demands of new coronavirus pneumonia emergency hospitals. Through calculating flow rates of medical gas system air source referring to ‘technical code for medical gases engineering’, the proportion coefficient of severe patients converted into respiratory distress patients was introduced, and the model of calculating flow rates of medical oxygen system air source in emergency hospital was proposed. The cases were verified in a typical health emergency hospital that the developed calculation flow model of medical oxygen source met the demands of hospital oxygen. The outcomes provide a reference for the design and construction of medical oxygen in such health emergency hospitals.

Title:

Design and engineering application of medical oxygen supply system in novel coronavirus pneumonia treatment hospital c Wuhan Kebei Technology Co., Ltd, Wuhan, China.

With the spread of novel coronavirus pneumonia since December 2019, the Chinese government has urgently reconstructed and built temporary emergency infectious disease hospitals in Wuhan and other places, in order to strengthen the treatment of infected patients [1] . As the critical patients need 100% oxygen, the oxygen demand of the patients in critically condition is more than 10 times, resulting in the oxygen consumption of the emergency hospital being reached more than 10 times of the peak daily consumption [2] . In such cases, the problem of insufficient medical oxygen supply is very prominent. The novel coronary pneumonia patients have been classified into light, normal, heavy, and critical Type 4 category. General treatment should promptly give effective oxygen therapy measures, including nasal duct, mask oxygen and nasal high-flow oxygen therapy [3, 4] . In the treatment of severe and critical cases, respiratory support includes:

 Oxygen therapy: the severe patients should receive nasal catheter or face mask for oxygen inhalation, and timely be assessed whether the respiratory distress syndrome and/or hypoxemia are relieved;

 Nasal high-flow oxygen therapy or non-invasive mechanical ventilation: when the patients cannot be relieved from the respiratory distress syndrome and/or hypoxemia after standard oxygen therapy, it can be considered usenasal high-flow oxygen therapy or non-invasive mechanical ventilation. If the condition can be not improved or even worsen within a short time (1-2 hours), organ intubation and invasive mechanical ventilation should be performed in time;

 Invasive mechanical ventilation;  Salvage treatment: for patients with severe acute respiratory distress syndrome (ARDS), prone position ventilation should be used for more than 12 hours per day, and ECMO should be considered as soon as possible.

Novel coronavirus pneumonia patients usually need oxygen therapy, especially in critically ill patients, which require high flow oxygen supply equipment to receive oxygen [5, 6] . The general hospital medical oxygen supply system cannot meet the J o u r n a l P r e -p r o o f demand of temporary large flow. In order to solve the problem of medical oxygen supply, the emergency designated hospital has to expand the medical oxygen supply system temporarily. for example, the Wuhan JinYinTan Hospital has been increased by two sets of liquid oxygen tank (storage capacity 10m 3 ) and vaporizer (vaporization capacity 500Nm 3 /h) oxygen supply facilities, and the Wuhan Red Cross Hospital has also added two sets. Considering the high demands for medical oxygen for the treatment of novel coronary pneumonia, the new Fire God Mountain Hospital and Thunder God Mountain Hospital had both increased the design capacity of the oxygen supply system which was much larger than the national standards of 'Technical code for medical gases engineering' (GB 50751-2012) [7] and 'Code for design of Infectious Disease Hospital' (GB 50849-2014) [8] . Due to the lack of data on the oxygen demands of hospitals for acute respiratory infectious disease, the medical oxygen configuration varies greatly among hospitals.

To answer this question, By investigating the oxygen treatment plan for the novel coronavirus pneumonia patients in the health emergency hospital, the oxygen treatment characteristics of different patients were studied, and the oxygen characteristics of different respiratory support terminal equipment were combined to study the oxygen demand of new coronavirus pneumonia emergency hospital. Based on the formula of calculating flow rate of medical gas system air source in 'technical code for medical gases engineering', the proportion coefficient of severe patients converted into respiratory distress patients was introduced, and the model of calculating flow rate of medical oxygen system air source in emergency hospital was proposed.

this study aims to explore the medical oxygen system of the novel coronary pneumonia hospital, and discuss the medical oxygen supply and system configuration of the hospital. The work is expected provide reference for future design and construction of such hospitals. (2) High-flow nasal cannula oxygen therapy (HFNC), as a new breathing support technology, has been widely used in clinical in recent years. The treatment equipment mainly includes air-oxygen mixer, humidification therapeutic apparatus, high-flow nasal congestion and connecting respiratory pipeline, which can provide patients with a relatively constant oxygen concentration (21%~100%), temperature (31~37℃) and humidity of high-flow (8~80L/min) oxygen, and the oxygen through the nasal congestion treatment with good comfort [9] . For patients with respiratory distress and/or hypoxemia, the range of ventilation flow is 30-60L/min commonly.

Due to the different physical conditions of each patient, the oxygen absorption concentration is different [10] . Generally, the oxygen concentration is around 50% because of the human body cannot continuously inhale high concentration oxygen for a long time [11] . The average flow rate of the oxygen terminal of the high-flow oxygen therapy instrument can be 15~30L/min. Figure 1 operation process of high-flow nasal cannula oxygen therapy [9] (3) Non-invasive ventilator, connected through mouth-nose mask, nasal mask, full-face mask, etc., is mostly used for patients with mild-to-moderate, using continuous positive pressure ventilation CPAP, BIPAP and other breathing modes. The pressure level and ventilation volume are high, generally 40 ~ 60L/min, and the oxygen concentration is set according to the patient's physical conditions [12] . The (4) Invasive ventilator, is mostly used for invasive mechanical ventilation through oral, nasal endotracheal intubation or tracheotomy. There are many ventilation modes commonly used for patients with severe respiratory failure. The oxygen ventilation volume is generally below 30 L/min because of the good airtightness of the pipeline [13] . The oxygen concentration is set according to the patient's physical condition, so the critical value is generally high. Some integrated leak compensation of invasive ventilator can also be used for non-invasive mechanical ventilation, and then the ventilation volume will increase [14] . The invasive ventilator's average flow rate of the oxygen terminal can also be 15~30L/min.

For the above mentioned breathing support methods, the oxygen terminals should consider the average flow, and the terminal interface design needs to meet the peak flow requirements of the device. Some of the ventilator peak flow requirements reach 200L / min [15] .

The novel coronary pneumonia admission hospital in Wuhan are mainly appointed to treat severe, critically ill and ordinary patients, and the makeshift hospitals are mainly for treating light patients. Treating serious patients and critically ill patients in the novel coronary pneumonia hospital require 100% oxygen [16] . Table 1 and   Table 2 . 14.0 

According to engineering practice and case study in this study, some suggestions are summarized here, regarding to selecting the appropriate medical oxygen systems:

1) The selection of oxygen terminals should be able to meet the peak flow requirements of using a ventilator or high-flow oxygen therapy instrument.

2) The design of oxygen pipeline and accessories in the ward should meet the flow requirements of all beds in the ward using ventilator or high-flow oxygen therapy instrument at the same time. 5) The medical liquid oxygen storage tank air supply system is adopted. If using an air-temperature carburetor, the carburetor type is calculated according to the gas source calculation flow model provided in this study. The system flow rate should be considered, as well as the system air leakage rate.

6) When the existing hospital is transformed into a designated hospital, the medical oxygen system should be expanded and transformed referring to the above calculation model to adapt the system to local conditions. Given it is difficult for the existing hospital oxygen system supply pipe network and terminal pipes to be completed in a short time, It is recommended that when the system safety permits, increase the gas supply pressure to ensure the oxygen terminal pressure and flow.

This study analyzes and discusses the characteristics of oxygen terminal gas consumption through exploring the characteristics of novel coronary pneumonia treatment and the demands for medical oxygen in emergency designated hospital. J o u r n a l P r e -p r o o f J o u r n a l P r e -p r o o f The proportion of serious patients converted into respiratory distress patients 

The epidemic of 2019-novel-coronavirus (2019-nCoV) pneumonia and insights for emerging infectious diseases in the future

Novel coronavirus infection prevention and control work in Hubei held seventeenth press conference

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The total number of confirmed patients in Fire God Mountain Hospital is more than 1000