Patients with underlying lung disease, especially lung disease that predispose a patient to hypoxaemia (or oxygenation failure), will tolerate COVID-19 less well than the general population.
The most significant are those patients who have Interstitial Lung Disease (ILD), a disease that causes diffusion defects at the alveolar capillary membrane, and typically develop Type I Respiratory Failure (or oxygenation failure). These patients are at particularly high risk of COVID-19, which will worsen their oxygenation failure.
Other patients with underlying lung disease include patient with Chronic Obstructive Lung Disease (COPD). These patients are more likely to develop Type II respiratory failure (or hypercapnic respiratory failure), which means they are hypoxaemia AND hypercapnic. Patients with underlying COPD should have blood gases taken to check for hypercapnic respiratory failure, and treated with bilevel ventilation according to the All-Wales Acute NIV guideline (attached below). In patients who do not have hypercapnic respiratory failure, they can be managed as normal with oxygen and CPAP.
Finally, patients with Asthma who develop COVID-19 should be treated as normal with high flow oxygen and CPAP. However, if they develop symptoms of wheeze and bronchoconstriction, steroids and nebulised bronchodilators will have to be administered as well.