Title: London Hospital Almost Runs out of Oxygen for Covid-19 Patients

Abstract:

Standard delivery of oxygen (O2) to patients with respiratory failure is inadequate, both in pneumonia and in COPD patients.
In COVID-19 mortality rates from pneumonia in UK hospitals rose from 30% to 45%1. This was linked to early use of mechanical ventilation. Similar accounts were reported in USA.2
Currently home O2 is recommended for hypoxic patients at flow rates limited to 3-5L/min for COPD.3 In the USA O2 therapy costs $2.8 billion annually.4 COPD patients appear not to comply with its prescribed use.3 The National Institute Clinical and Care Excellence (NICE) recommends a maximum flow rate of O2 of 15 L/min for patients in acute respiratory failure when arterial O2 saturation (SpO2) falls below 94%.5
These recommended flow rates are below the inspiratory flow rates seen during mild exercise. The Minute Ventilation (MV) rises to 30L/min but requires the peak inspiratory flow rate to rise to 100L/min.6 The same MV occur in pulmonary disease at rest where there is reduction of gas exchange.7 Suggesting that these recommended O2 flow rates for pneumonia or hypoxic COPD patients are too low to match their peak inspiratory flow.
As standard O2 delivery uses open mask to the face/nose, that requires entrainment into the lungs by the inspiratory flow. If the inspiratory flow rate exceeds the flow of O2 then air is entrained so diluting the O2 reaching the lungs.8 The high COVID pneumonia mortality rates and the under use of home O2 can be explained by the use of recommended O2 at flow rates as low as 5L/min to 15L/min could explain.
We recommend instead, automatic matching the flow rate of O2 to the patients inspiratory flow and pulsing automatically selected volumes of O2 to ensure SpO2 remains between 94% - 100%, by using a robotic delivery device.

Biography:

Scientist and Clinician, NHS physician at the Royal Papworth Hospital Cambridge, discoverer of first effective therapies for Pulmonary Arterial Hypertension [PAH] (iv. Prostacyclin and Inhaled NO). Established the UK National Network of PAH centres. Professor, Medicine Sheffield University Medical School and Senior Principal Scientist AstraZeneca plc, Corporate Clinical Director Chiesi Farmaceutici (Italy), Architect of the first triple inhaler for asthma/COPD Trimbow®, Senior Partner TranScrip LLP, R&D Director Allergy Therapeutics plc, Vice President, and President Faculty of Pharmaceutical Medicine Royal Colleges of Medicine UK. CEO and founder of Camcon Robotics Ltd.