What is the primary indication for using oxygen therapy in asthma patients?

Oxygen therapy in asthma patients is primarily indicated when pulse oximetry readings fall below 90%. This cutoff reflects the threshold at which supplemental oxygen may be required to ensure adequate oxygenation of the tissues and organs, especially during an acute asthma exacerbation. Oxygen saturation levels are crucial indicators of respiratory function, and values below 90% suggest that the patient is not receiving sufficient oxygen due to impaired gas exchange.

While hypercapnia can occur in severe asthma attacks and may necessitate additional interventions, it is not the primary reason for initiating oxygen therapy. Excessive sputum production and vocal cord dysfunction, although relevant in the context of asthma symptoms or complications, do not directly dictate the need for oxygen therapy in the way that low oxygen saturation levels do. Thus, monitoring and addressing hypoxia, as indicated by pulse oximetry, is the primary focus for initiating oxygen therapy in this patient population.