Preoperative assessment and preparation of patients with diseases affecting the central nervous system.

PURPOSE OF REVIEW: This review will examine the most important issues of preoperative evaluation and preparation in relation to patients with deseases affecting the central nervous system. Those patients may undergo various forms of surgery unrelated to the central nervous system disease. We discuss the effect of physiologic and pharmacological factors on cerebral autoregulation and control of intracranial pressure alongside its clinical relevance with the help of new evidence. RECENT FINDINGS: Regardless of the reason for surgery, coexisting diseases of brain often have important implications when selecting anesthetic drugs, procedures and monitoring techniques. Suppression of cerebral metabolic rate is not the sole mechanism for the neuroprotective effect of anaesthetic agents. There are certain general principles, but also some specific circumstances, when we are talking about optimal anesthetic procedure for a patient with coexisting brain disease. Intravenous anesthesia, such as combination of propofol and remifentanil, provides best preservation of autoregulation. Among inhaled agents isoflurane and sevoflurane appear to preserve autoregulation at all doses, whereas with other agents autoregulation is impaired in a dose-related manner. During maintenance of anesthesia the patient is ventilated by intermittent positive pressure ventilation, at intermediate hyperventilation (PaCO2 25-30 mmHg). SUMMARY: Intraoperative cerebral autoregulation monitoring is an important consideration for the patients with coexisting neurological disease. Transcranial Doppler based static autoregulation measurements appears to be the most robust bedside method for this purpose.

Preoperative preparation for patients with nutritional disorders.

Eating disorders are very common today. An increasing number of patients that undergo anesthesia and surgery have some nutritional disorder. These disorders are very versatile starting from obesity to anorexia. Significant changes in all organ systems are present. These pathophysiological changes are increased with the duration of the disease. There are many changes in the functioning of the cardiovascular system in all these diseases and there are significant. Respiratory and ventilatory functions are changed too. There are also many endocrine disorders. As a final result, there are many serious biochemical and coagulation disorders. These patients are often under some drug treatment. Patients could be under psychiatric therapy (psychiatric drugs) and/or could take drugs for relieving symptoms related to the pathophysiological changes in different organ systems. Preoperative preparation of patients must be detailed. All changes must be improved to optimal condition. In addition, it is necessary to think about the possible influence of used drugs on the anesthesia.