Cardiopulmonary response to exercise after lung transplantation

Introduction: Cardiorespiratory fitness (VO 2peak ) remains low after lung transplantation (LTx) despite improvement in lung function. The extent and reasons for this are unclear. Aim: To evaluate the cardiopulmonary response during a maximal cardiopulmonary exercise test (CPET) in LTx recipients, and to detect exercise limiting factors. Method: Bilateral-LTx recipients (n=47, age 20-67 years, 23 men) underwent a treadmill CPET. Exercise limiting factors were classified as a breathing reserve (BR) 2 -saturation 2 -output relationship (VE/VCO 2 ) ≥34. Inefficient ventilation was not seen as a limiting factor unless the patient desaturated. Results: Median (range) time since LTx was 29 (6-59) months. The table shows the physiological response during CPET. Five patients had a VO 2peak within normal range (VO 2peak u003e80% predicted). Six patients had a small BR, which indicates ventilatory limitations, and 3 had exercise-induced hypoxemia. Thirty-five demonstrated a low VO 2peak having none of the limitations above. Seventeen had inefficient ventilation, but did not desaturate. Conclusion: LTx recipients demonstrated low cardiorespiratory fitness. One-fifth had cardiorespiratory limitations, whereas a majority was deconditioned without such limitations. This may suggest a substantial need for exercise training after LTx.