Respiratory rate responses to both hypercapnia and acidaemia are modified by age in patients with acidosis.

ABSTRACT

OBJECTIVE: To explore the associations between arterial pO2, pCO2 and pH and how these are modified by age. METHODS: An analysis of 2598 patients admitted with a diagnosis of Covid-19 infection to a large UK teaching hospital. RESULTS: There were inverse associations for arterial pO2, pCO2 and pH with respiratory rate. The effects of pCO2 and pH on respiratory rate were modified by age; older patients had higher respiratory rates at higher pCO2 (p = 0.004) and lower pH (p = 0.007) values. CONCLUSIONS: This suggests that ageing is associated with complex changes in the physiological feedback loops that control respiratory rate. As well as having clinical relevance, this may also impact on the use of respiratory rate in early warning scores across the age range.