Respiratory muscle strength after lung volume reduction surgery

Loss of elastic recoil in emphysema causes hyperinflation of the lung tissue, stretching the respiratory muscles. Maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) decline in severe emphysema. We hypothesized that treating hyperinflation with lung volume reduction surgery (LVRS) or via bronchoscopic lung volume reduction (BLVR) with valves could lead to improved MIP or MEP. Consecutive emphysema patients referred for treatment with LVRS or BLVR from October 2020 to June 2023 were included. We applied a mixed linear model with the different treatments as independent variables to compare MIP/MEP prior to treatment, with values at 3-month follow-up. A total of 61 patients had preoperative MIP/MEP done prior to LVRS (42) or BLVR (19) treatment. Thirty-nine also had MIP/MEP measurements at 3 months follow-up, 31 after LVRS and 8 after BLVR, respectively. There was no significant increase in MIP from baseline to follow-up in the LVRS (p = 0.37) and BLVR (p = 0.32) groups. Nor was there any difference between the BLVR and LVRS group at baseline (p = 0.12) or at follow-up (p = 0.19). Similarly, MEP values were unchanged in the BLVR and LVRS groups from preoperative level to 3-month follow-up for BLVR (p = 0.59) and for LVRS (p = 0.11).