In the early days of the pandemic, clinicians were puzzled by the dangerously low levels of oxygen measured in those COVID-19 patients who have apparently normal lung mechanics. In response to this finding, a myriad of speculations have emerged, ostensibly implicating a problem with red blood cells (RBCs), the blood-borne carriers of oxygen. Indeed, inadequate oxygen transport by RBCs would manifest as hypoxia even with normal lung function, but critically, these patients would not necessarily benefit from supplemental oxygen on a ventilator. Thus, information about the state of RBCs is very important for ICU doctors who must decide on the best intervention to improve blood gases in critically-ill patients. The hypothesised link between coronavirus infection and RBCs has received renewed attention following proposals that SARS-CoV-2 impairs haemoglobin metabolism and epidemiological ‘hints’ that haemoglobin disorders influence disease outcome. Strikingly, these speculations were not based on any functional appraisal of RBC function.
A new DPAG study from the Swietach Group, conducted in collaboration with Oxford’s Peter Medawar Building for Pathogen Research, showed that oxygen transport by RBCs freshly obtained from coronavirus-infected patients were no different to cells from healthy donors. The method used for this research was recently developed in DPAG, and has the ability to quantify oxygen carrying capacity, as well as the kinetics of loading and unloading from individual cells.
Associate Professor Pawel Swietach said: “I’m very excited about this negative result. It provides important information about how the virus acts on the body, and is helpful in formulating guidelines for treatment, especially as we face the threat of a second wave in Europe. DPAG has a long-standing tradition of working closely with ICU doctors because of our common research interests, and because our department plays a leading role in training future doctors in physiology. I’m grateful to the University’s COVID-19 research response fund for supporting this work, and particularly to our safety office for ensuring that the work is performed safely and at the highest level of scientific rigour.”
The full paper, first authored by KC Park, "Single‐cell oxygen saturation imaging shows that gas exchange by red blood cells is not impaired in COVID‐19 patients" is available to read on the British Journal of Haematology website.
More information on the technique used to obtain these results, single-cell oxygen saturation imaging, can be found in DPAG news article "New technique could shed light on how blood transports oxygen in disorders such as COVID-19."