Computed cardiopulmonography and the idealized lung clearance index, iLCI2.5, in early-stage cystic fibrosis

Sandhu, D; Redmond, JL; Smith, NMJ; Short, C; Saunders, CJ; Couper, JH; Fullerton, CJ; Richmond, G; Talbot, NP; Davies, JC; Ritchie, GAD; Robbins, PA

Journal article

Computed cardiopulmonography and the idealized lung clearance index, iLCI2.5, in early-stage cystic fibrosis

Abstract:: This study explored the use of computed cardiopulmonography (CCP) to assess lung function in early-stage cystic fibrosis (CF). CCP has two components. The first is a particularly accurate technique for measuring gas exchange. The second is a computational cardiopulmonary model where patient-specific parameters can be estimated from the measurements of gas exchange. Twenty-five participants (14 healthy controls, 11 early-stage CF) were studied with CCP. They were also studied with a standard clinical protocol to measure the lung clearance index (LCI_2.5). Ventilation inhomogeneity, as quantified through CCP parameter σlnCl, was significantly greater (P < 0.005) in CF than in controls, and anatomical deadspace relative to predicted functional residual capacity (DS/FRCpred) was significantly more variable (P < 0.002). Participant-specific parameters were used with the CCP model to calculate idealized values for LCI_2.5 (iLCI_2.5) where extrapulmonary influences on the LCI_2.5, such as breathing pattern, had all been standardized. Both LCI_2.5 and iLCI_2.5 distinguished clearly between CF and control participants. LCI_2.5 values were mostly higher than iLCI_2.5 values in a manner dependent on the participant’s respiratory rate (r = 0.46, P < 0.05). The within-participant reproducibility for iLCI_2.5 appeared better than for LCI_2.5, but this did not reach statistical significance (F ratio = 2.2, P = 0.056). Both a sensitivity analysis on iLCI_2.5 and a regression analysis on LCI_2.5 revealed that these depended primarily on an interactive term between CCP parameters of the form σlnCL*(DS/FRC). In conclusion, the LCI_2.5 (or iLCI_2.5) probably reflects an amalgam of different underlying lung changes in early-stage CF that would require a multiparameter approach, such as potentially CCP, to resolve.

Publication status:: Published

Peer review status:: Peer reviewed

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APA Style

Sandhu, D., Redmond, J. L., Smith, N. M. J., Short, C., Saunders, C. J., Couper, J. H., Fullerton, C. J., Richmond, G., Talbot, N. P., Davies, J. C., Ritchie, G. A. D., & Robbins, P. A. (2023). Computed cardiopulmonography and the idealized lung clearance index, iLCI2.5, in early-stage cystic fibrosis. Journal of Applied Physiology, 135(1), 205–221.

MLA Style

Sandhu, D., et al. “Computed Cardiopulmonography and the Idealized Lung Clearance Index, iLCI2.5, in Early-Stage Cystic Fibrosis.” Journal of Applied Physiology, vol. 135, no. 1, American Physiological Society, 2023, pp. 205–21.

Chicago Style

Sandhu, D, JL Redmond, NMJ Smith, C Short, CJ Saunders, JH Couper, CJ Fullerton, et al. 2023. “Computed Cardiopulmonography and the Idealized Lung Clearance Index, iLCI2.5, in Early-Stage Cystic Fibrosis.” Journal of Applied Physiology 135 (1): 205–21.
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