Patterns of oxygen saturation in prolonged recovery from COVID-19 pneumonia

During the second wave of the COVID-19 pandemic in South Africa, a recurrent pattern of prolonged recovery after acute COVID-19 pneumonia, characterised by low oxygen saturation levels forgt;2 weeks, was observed in an intermediate-care facility in Cape Town. A case study together with a series of 12 patients is presented to illustrate this phenomenon, and two types of 'sats gap' are described, which were used by physiotherapists and doctors to monitor daily progress. We attempt to explain this prolonged recovery in terms of the possible pathophysiology, and suggest a number of learning points to guide further research.