Atrial fibrillation and chronic neuropathic pain are adverse events occurring after posterolateral thoracotomy for lung resection. The continuous application of magnesium sulphate may have a prophylactic effect. The investigators record the incidence of atrial fibrillation during a seven day period after thoracotomy as well as the incidence of chronic neuropathic pain during a three months period, comparing one group with a continuous application of magnesium sulphate against one group without magnesium sulphate.