Discordance, Pendelluft, and Electrical Impedance Tomography.

Pendelluft, the internal redistribution of gas within the lung, was first described as a phenomenon related to high breathing frequencies and regional differences in time constants. The availability of electrical impedance tomography has transformed our understanding of this form of intrapulmonary discordance, revealing that effort-related pendelluft occurs commonly in mechanically ventilated patients and may contribute to patient self-inflicted lung injury. Emerging evidence suggests associations between pendelluft and adverse clinical outcomes, though meaningful gaps in our understanding remain. This review examines the pathophysiology of effort-related pendelluft, methods for its detection using EIT, factors influencing its occurrence, and associations with clinical outcomes.