Elektromyographische Bestimmung der Ermüdbarkeit von Atem- und Beinmuskeln vor und nach aortokoronarer Bypass-Operation

Abstract

To study the effect of postoperative confinement to bed on respiratory muscle fatigue, 31 male subjects (age, 34–66 years) undergoing coronary artery revascularization were examined. Fatigue of both respiratory muscles (musculi intercostales externi) and leg muscles (musculus gastrocnemius) was determined by electromyography prior to and 7 and 12 days after operation. Additionally, oscillatory resistance to breathing and phase angle were measured. Pre- and postoperative routine lung function tests were performed. A comparison between preoperative and postoperative measurements reveals that respiratory as well as leg muscle fatigue occurred at higher loads during the preoperative and the second postoperative than during the first postoperative determination. After surgery vital capacity, total lung capacity, 1-second capacity, and, to a lower extent, thoracic gas volume were diminished, while specific airway conductance, oscillatory resistance to breathing, phase angle, residual volume, and relative 1-second capacity remained unchanged. The constancy of the latter parameters indicates that neither airway obstruction nor a significant restriction of the lung and/or thorax occurred due to surgery. Therefore, the increase of respiratory muscle fatigue after surgery may more probably be attributed to a lack of training of respiratory muscles which may contribute to limitation of ventilation in bedridden patients

Prophylactic Inspiratory Muscle Training in Patients Undergoing Coronary Artery Bypass Graft

“…The postoperative ventilation problems could be due to either zones of atelectasis (found in Ͼ 30% of patients after the surgery) [5], pleural changes such as effusion or thickening (found in Ͼ 40% of the patients) [11], abnormal rib cage motion secondary to the trauma of surgery [12], and respiratory muscle weakness, as was found in most of the patients following CABG [4]. Respiratory muscles may be injured directly or indirectly during CABG.…”

“…In fact, many studies showed that there is decreased postoperative alveolar ventilation, gas exchange [5], and lung function [6,7]. Few studies have investigated the respiratory muscle performance after CABG, but they have shown a decrease in the respiratory muscle strength and unior bilateral phrenic nerve paralysis [4]. It is reasonable to assume that the respiratory muscle weakness is associated with direct or indirect injury to the respiratory muscles during surgery, which may lead to respiratory muscle dysfunction and respiratory failure.…”

“…Operations with thoracotomy, such as a coronary artery bypass graft (CABG), carry with them a high risk for pulmonary complications [2]. Postoperative pulmonary complications could be due to: (1) lung-related injuries such as pulmonary embolism or adult respiratory syndrome (ARDS); (2) pleural problems [3], such as effusion or thickening; or (3) pump-related problems, such as ventilatory muscle weakness or hemidiaphragmatic paralysis secondary to phrenic nerve injury [4]. In fact, many studies showed that there is decreased postoperative alveolar ventilation, gas exchange [5], and lung function [6,7].…”