<prompt> Nitrogen washout curve is used inVital capacityInspiratory reserve volumeFunctional residual capacityResidual volume  <response>: C. i.e. Functional residual capacity 62- 63 Anesthesia - Janes - Duke 3rdFunctional residual capacity RV ERV Measuring FRC is the cornerstone for determining the remainder of the lung volumesThree different technique1. Helium equilibration dilution2. Nitrogen wash out3. Body plethysmography Plethysmography is most accurate for determining FRC in patients with COPD and applies Boyles law 