[The high risk cardiac patient in anesthesia]

Abstract

As a result of more offensive therapeutic measures and the given abilities of modern medicine and the increasing number of geriatric patients who are characterized by multimorbidity, more perioperative complications, in particular those of cardiac origin, can be expected. As in any other medical discipline, the safety of anaesthesiological care of the patient very much depends on the individual professional qualification and competence of the physician. For the field of anaesthesiology it can be concluded that it is necessary to tackle the specific problems of this risk group in order to reduce the rate of complications to a minimum. In line with a number of studies showing equal manifestation of cardiac risk factors during the pre-, intra- and postoperative periods, we should concentrate on the consistent use of all preventive and therapeutic measures available during these three periods. Besides evaluation of the cardiac risk factors and planning of the intra- and postoperative management, premedication is of particular importance in the preoperative period. To avoid sympathicoadrenergic contraregulations, benzodiazepines are particularly recommended because of their anxiolytic and sedative effects. The selection of a special anaesthetic method suitable for the patient with high cardiac risk should be influenced not only by anaesthesiological aspects but also by the complex effects of anaesthetic drugs on the determinants of the myocardial oxygen balance. In this connection, an increased sympathicoadrenergic tonus is of particular importance, i.e. extreme changes in blood pressure or heart rate--compared to preanaesthetic values--and an increase in diastolic wall tension should be avoided. An anaesthetic regime comprising gentle general anaesthesia combined with epidural block and small doses of opioids or local anaesthetics meets these requirements, as does a combination of opioids with low doses of volatile anaesthetics or intravenous hypnotics. The quality of perioperative management is also strongly determined by careful haemodynamic monitoring and early correction of circulatory disturbances. Since cardiac patients remain at risk up to three days after surgery, a level of haemodynamic monitoring appropriate to the level of cardiac risk must be maintained. Three main symptoms--increasing oxygen uptake (as a product of pain or shivering), hypoventilation and hypoxaemia--should be avoided in the postoperative period. Therefore, respiratory insufficiency should be diagnosed without fail by respiratory monitoring. If required, artificial ventilation must be continued, with particular attention being given to circulatory effects during artificial ventilation and weaning from the ventilator.