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  • Print publication year: 2004
  • Online publication date: August 2009

19 - Cortical electrical activity monitoring

from Section 6 - Monitoring



One of the most difficult tasks of modern anesthesia is to assess how much anesthetic drugs administration influences on central nervous system (CNS) function.

Clinical signs, such as blood pressure and heart rate are not always reliable parameters, since they vary according to many other factors (cardiovascular patient's condition before and during anesthesia, influence of non-anesthetic drugs on hemodynamic function, etc.). In addition, not all anesthetic drugs produce the same kind of hemodynamic changes when administered for obtaining analgesia or pharmacological hypnosis.

When the anesthesiologist solely relies on clinical signs for guiding anesthetic drugs administration, the analysis of the cortical electrical activity showed a large variation among individuals, mainly when a certain group of patients were considered, like pregnant women undergoing Cesarian section and general anesthesia was provided.

Particular clinical conditions which would demand special precautions in order to avoid unwanted episodes of superficial anesthesia are showed below (Table 19.1).

Morbid obesity is on the list of the high risk patients for whom the use of clinical hemodynamic parameters might be not enough to guide anesthetic drugs dosing.

Cortical electrical activity monitoring in the morbidly obese: its importance

Epidemiologic factors

The prevalence of obesity is permanently increasing. Modern society offers easy approach for food consumption, especially fast food, which is rich in calories, lipids and carbohydrates.