Peak pressures or plateau pressures in asthma

Excerpt

Sir: We thank Drs. Agarwal and Nath for their interest in our recent publication [1]. We agree that the difference between peak inspiratory pressure (PIP) and plateau pressure (Pplat) is widened in patients with reactive airway disease such as asthma. We also concur with their observation that Pplat better reflects the degree of alveolar hyperinflation. However, we disagree with their statement that PIP has no clinical relevance in children with severe asthma. On the contrary, it is PIP (or the difference between PIP and Pplat) that is elevated in asthma and is correlated with the degree of bronchospasm and increased airway resistance. We feel that PIP is a better surrogate than Pplat of the degree of airway obstruction (due to airway inflammation and bronchospasm, the underlying pathophysiology of acute asthma) and better reflects both disease severity and the response to bronchodilators and anti-inflammatory agents. Isoflurane was used in our patients to reduce the severely increased airway resistance, and we feel that PIP reflects this resistive component better than Pplat. …