The Thin End

Reports today that the UK government have decided not to go ahead with the plan to get ventilators manufactured by Formula 1 teams like Renault and Red Bull. Ventilation of the lungs isn't like filling a balloon with air. The use of PEEP, positive end-expiratory pressure, isn't how the lungs function usually.  Inflation of our lungs occurs by developing a negative pressure in the thorax by contracting the diaphragm and raising the muscles between our ribs. This both keeps the air sacs (alveoli) open and inflates them, producing airflow. It is the negative pressure compared to the air surrounding us that pulls air into the lungs.  The air moves down the pressure gradient.  Applying a pressure inside the air sacs can cause damage t o the delicate lining leading to pulmonary oedema and worsening hypoxemia that can prolong mechanical ventilation, this can then lead to multi-system organ dysfunction, and increased mortality.  Not all COVID-19 patien...