[Edwina Lee (OP)]

I understand that oxygen masks provides increased oxygen concentration.
A ventilator supplies oxgen through a cut in the throat.
But I remember reading about an early patient in China receiving oxgen through his blood ( an oxygenator?) and still died.

I decide to start this thread because our PM Boris Johnson has been transfered to an ICU (Intensive Care Unit) because of worsening condition with quick transfer to a ventilator should the need arise.

It puzzles me why use a ventilator, when covid-19 cause glassy knots to form in the fine air passages thus preventing the transfer of air into the avioli .So no amount of air from the outside is going to get there until the knots are removed.

So the sensible solution is to oxygenate the blood straight away!  Surely!

[chris]

It puzzles me why use a ventilator, when covid-19 cause glassy knots to form in the fine air passages thus preventing the transfer of air into the alveoli .So no amount of air from the outside is going to get there until the knots are removed.

Thank you for this interesting question.

The answer is that Covid19 causes inflammation in the lung tissue; this causes congestion and collapse of the distal airways and air sacs (alveoli) where gas exchange takes place. As a result, less lung surface area is available for gas exchange and the distance over which the oxygen has to move to get into the blood is increased. Both factors combine to reduce the rate at which oxygen can move into the blood for delivery to our other organs.

The initial intervention under these circumstances is to give supplemental oxygen. The rationale for this is that, if you increase the concentration of oxygen in the inhaled air, this will compensate for the reduced surface area and greater diffusion distance, helping to normalise blood oxygen levels.

If this simple, non-invasive measure fails, then the next step is to use a positive pressure mask. This fits tightly over the nose and mouth and the raised pressure helps to push more oxygen into the bloodstream as well as hold open some of the collapsed airways to improve lung surface area and gas exchange.

If this fails, the next step is to put the patient to sleep, insert a tube into the windpipe (trachea) and use a machine to take over the work of breathing. This is what's referred to as being on a ventilator. This enables the ITU staff to control the pressure in the airways, the concentrations of oxygen the patient breathes, and the rate of breathing. Together these measures can enable the ITU team to support the patient's blood oxygen level, which is critical if they are to survive.

[Edwina Lee (OP)]

Ventilator design requirements:- wow, so complicated!

[XDRAGON]

I appreciate there must be many factors considered before placing someone on a ventilator, but does anyone know how low a person's oxygen saturation levels in terms of SpO2 % need to get, first before supplemental oxygen is recommended, then at what levels ventilation is considered?

[Edwina Lee (OP)]

Ha, got my answer       UK does indeed use oxygenators, but in 5 hospitals only. 

https://www.facebook.com/sergio.reserva/videos/10159764671007571/