The present study describes risk factors, the incidence of complications and mortality in the anaesthetized patient. The aims were further to identify additional patient-, anaesthesia-, technique-, and surgery-related factors associated with cardiopulmonary complications and mortality, to describe the value of preoperative radionuclide cardiography in patients with cardiopulmonary insufficiency, and to evaluate the importance of perioperative manual evaluation of the response to train-of-four nerve stimulation for the occurrence of residual neuromuscular blockade in the recovery room. Complications attributable to anaesthesia-complications caused mainly by the anaesthetic procedure-occurred in 0.6% (1:170) of the patients, and mortality attributable to anaesthesia was found to be 0.04% (1:2500). An analysis of the patient data suggests that the seriously ill patients (ASA-class > or = 3) were more likely to be affected by errors and a substantial negative outcome such as acute myocardial infarction, irreversible cerebral damage or death, than were more healthy patients (ASA 1-2). One-third of the complications attributable to anaesthesia are judged preventable. Cardiopulmonary complications associated with anaesthesia and surgery and requiring intervention occurred in 1:11 of the anesthetized patients. The cardiopulmonary complications were associated with elderly patients (> or = 70 yr), patients with preoperative clinical signs of ischaemic heart disease and recent myocardial infarction, chronic heart failure, and chronic obstructive lung disease, as well as perioperative and emergency procedures involving major abdominal surgery. In patients with severe cardiovascular or pulmonary insufficiency (high-risk patients) preoperative radionuclide cardiography could distinguish between different levels of cardiopulmonary risk in the anaesthetized patient. Patients with a preoperative left ventricular ejection fraction < 50% or > 70% demonstrated a high incidence of cardiopulmonary complications following anaesthesia (70%). It is recommended that left ventricular ejection fraction be measured in patients referred for major surgery who have an increased risk of cardiopulmonary complications as evidenced clinically by heart failure or severe ischaemic heart disease. Hypotension before anaesthetic induction is associated with a high incidence of cardiopulmonary morbidity and mortality. Postoperative pulmonary complications in comparable groups of patients depend primarily on the type of surgery, as major abdominal surgery was related to the highest incidence of pulmonary complications. Regional anaesthesia may be a superior technique to general anaesthesia, especially in elderly patients with chronic obstructive lung disease admitted to major orthopaedic surgery. Furthermore, in avoidance of postoperative complications such as residual neuromuscular blockade, the choice of muscle relaxant was more decisive than was manual evaluation of the response to train-to-four nerve stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)