Influence of pain on postoperative ventilatory disturbances. Management and expected benefits.

Abdominal surgery induces postoperative ventilatory dysfunction related to a combination of reflex diaphragmatic inhibition, respiratory muscle injury and pain. The role of pain is difficult to isolate from other components. Thoracic epidural analgesia using local anesthetics is able to partially reverse the diaphragmatic dysfunction. However, this effect seems not directly related to analgesia. Regardless of the mechanisms, epidural analgesia has been shown to improve the postoperative ventilation and to prevent the occurrence of pulmonary complications. Pain relief, either by parenteral administration of opiate, and/or parietal blockade has been shown to improve the diaphragm motion and the overall respiratory status. All analgesic strategies may facilitate the implementation of postoperative physiotherapy which has a significant interest in preventing postoperative pulmonary complications.