Thursday 16th April 2020
COVID Figures for 15th April
UK Hospital Deaths 761 / Total 12,868
James Cook Hospital – Total deaths – 122
James Cook cases in Critical Care – 22 / 11 ventilated
I am working a night shift tonight so am trying to catch up with home life today. Things are getting increasingly disorganised with both of us spending more time at the hospital.
I thought I would briefly explain the concept of ‘prone ventilation’ which is a treatment being offered to many of our coronavirus patients.
Most of the time, when a patient is ventilated in ICU, they are lying on their back (the supine position). Prone ventilation occurs when a ventilated patient is lain on their front (the prone position). It is a strategy used to improve oxygen levels in patients who are very difficult to ventilate. The ventilator settings may remain the same, it’s just the patient’s positon that is changed.
Why would this help?
Prone ventilation alters the mechanics of the chest and improves the amount of lung that takes part in ventilation in order to increase the amount of oxygen entering the blood. It does this in a number of ways.
When placed prone, the larger parts of the lung are now on top rather than on the bottom so can take part more evenly in ventilation. This prevents parts of the lung closing off and the remainder becoming over-distended. The heart also sits better against the sternum rather than squashing the left lung and the diaphragm moves better to allow bigger breaths. There are improvements in blood flow through the lung and any secretions or sputum will drain out of the lung better. Prone ventilation can also allow the abdomen to move out of the way and not squash the lungs. As one of my older colleagues first explained it to me – we were designed to walk on all fours with our lungs in this position. We breathe better that way. Over-simplistic, yes, but you get the idea.
The logisitics of turning over an unconscious patient who is ventilated are not to be underestimated. It takes many members of staff and is potentially dangerous, especially if the patient is overweight. Once again, our Anaesthetic colleagues have come to the rescue. They have offered their services as a ‘proning team’ to help deal with the large numbers of patients that will need ‘flipping’ twice a day for the next few months. The team are now very slick at quickly and safely turning patients back and forth as needed.
We often see prone ventilation improving oxygen levels in patients with severe coronavirus pneumonitis. There is some evidence to suggest that as well as just making the numbers better, prone ventilation may improve the chances of survival in patients with the worst types of respiratory failure.
It remains a very simple and useful tool in our coronavirus shed.
Prone ventilation
(Image from Medscape)