High Intensity Respiratory Muscle Training as a Pre-habilitation in Lung Surgery

Lung resection surgery is the major curative option for lung cancer. Therefore, it is alarming that up to 37% of suitable patients are considered inoperable because of lung function impairment and those suitable for operation still carry a significant risk of especially postoperative pulmonary complications (PPC) development and increased mortality. Several predictors of postoperative morbidity and mortality have been identified. However, most of the factors are not easily modifiable before surgery. Ventilatory efficiency for carbon dioxide (VE/VCO2 slope) is an exercise parameter that has been shown to predict respiratory complications and mortality of lung resection candidates and to be superior to peak oxygen uptake (peak VO2). Importantly, in contrast to most previously established PPC risk factors, VE/VCO2 slope and peak VO2 may be therapeutically improved by physical and/or respiratory muscle training (e.g. by prehabilitation) and may thereby enable preoperative patient optimization. In thoracic surgery patients, trials looking at improvement of exercise capacity and PPC development give conflicting results, probably because of huge heterogeneity in terms of type, intensity and the length of pre-habilitation program. However, it seems that inclusion of only selected patients that may benefit from pre-habilitation (high risk patients), using VE/VCO2 slope and not peak VO2 to define the high risk patients and using interventions that could effectively improve VE/VCO2 slope (like the inspiratory and expiratory muscle training) is crucial and may be the key to lowering of postoperative pulmonary complications. Therefore, we hypothesize that high intensity respiratory muscle training will improve ventilatory efficiency (VE/VCO2 slope) and will be associated with decreased PPC, decreased mortality and better quality of life in lung resection candidates.