It is known that the oxygenotherapy is one of ways of treatment of a koronavirusny infection. The most widespread ways of supply of oxygen include oxygen cylinders, concentrators of oxygen and the centralized pipeline oxygen systems. The choice of a method of supply of oxygen will depend on local resources and the supporting infrastructure. At the organization of an oxygenotherapy it must be kept in mind the fact that in the conditions of a pandemic of healthcare institution will be overloaded. In this article we will consider approaches to carrying out an oxygenotherapy in the conditions of COVID-19 pandemic.
The World Health Organization (WHO) provided useful recommendations about various sources of oxygen. Oxygen cylinders provide supply of oxygen under pressure and demand regulators of pressure (reducers) and flowmeters for safe supply of oxygen to the patient. Despite simplicity of their use, the common problem of use of oxygen cylinders consists in leak of oxygen because of improper adapters that can lead to loss up to 70% of oxygen volume in a cylinder. Oxygen cylinders in the conditions of a pandemic will need to be changed often, especially when the big stream of oxygen is required.
Use of oxygen concentrators which receive oxygen from air through azotopogloshchayushchy zeolitic membranes is not a technical problem. Nevertheless, oxygen concentrators need to be provided constantly with power supply, they demand maintenance and regular replacements of filters. Not all models are suitable for use in the tropical countries, the hot and damp environment as maintenance of such devices can be a serious problem. The majority of oxygen concentrators give oxygen with a speed up to 6 l/min that it is enough for carrying out an oxygenotherapy not to the really heavy patients infected with COVID-19, but there is not enough for treatment of heavier hypoxia. Nevertheless, oxygen concentrators with a productivity up to 10 l/minute become more and more available.
The centralized pipeline oxygen systems are used in intensive care units (ORIT). They give oxygen under pressure through the conclusions on a wall or the ceiling console located close to a bed. To such systems oxygen supply usually goes from a big tank for liquid oxygen or big oxygen cylinders. Technical experience and high-quality servicing are necessary for the correct functioning of such centralized oxygen systems. The majority of modern devices of ventilation of the lungs use both oxygen, and compressed air. Oxygen cylinders can be applied to this purpose, but they will demand frequent replacement. Thus, the centralized systems of supply of oxygen and air are the best option for ensuring operation of ventilators. Operation of some devices does not require compressed air as they create own working pressure by means of internal air compressors. Oxygen concentrators can be used for providing with oxygen the devices working from compressors, but the lack of such approach is that exact definition of oxygen concentration on a breath is at a loss.
At patients with moderately severe form of COVID-19 oxygen can be given by means of simple nasal a cannula or front masks with an oxygen stream up to 5–6 l/min. The flow rate can be titrated by means of the pulsoksimetrichesky monitoring showing oxygen content in an arterial blood (SpO2). If at the patient decrease in a saturation less than 88-90% is observed for a long time, then supply of oxygen can be increased by means of an irreversive mask. These masks contain an additional respiratory bag where oxygen arrives. It helps to provide fraction of the inhaled oxygen to 60-80%, but the oxygen stream with the minimum speed of 10-15 l/min will be required. Use of irreversive masks can be an important additional way for increase in supply of oxygen to the patient with a heavy current of COVID-19.
Besides, patients can give oxygen in a ventral decubitus (pron-position) that can improve oxygenation considerably. Positioning on a stomach facilitates ventilation of back departments of lungs, improving the ventilating and perfusion relations, and, therefore, blood saturation by oxygen.
The high-line nasal oxygenotherapy (HFNO) can be also applied to significant increase in oxygen concentration on a breath. HFNO for adult patients can be carried out as by means of fans with the corresponding option, and autonomous systems which require the constant power supply.