Emergence delirium occurs immediately following emergence from general anesthesia. All age groups are affected, but it occurs most commonly in children and adolescents. The symptoms of emergence delirium are extensive and involve changes of personality, perception disorders, disorientation, and cognitive disorders. The acute delirium imitates the excitation stage of anesthesia with ether.

The hyperactive form is usually clinically apparent, which typically keeps the personnel in the PACU busy. The hypoactive form is seldom recognized, since the patients withdraw to their inner selves. Emergence delirium has a short duration, and the affected patients later participate normally in their environment.

Since acute delirium is only seldom seen after regional anesthesia, many anesthesiologists incorrectly assume that the incidence of perioperative cerebral dysfunction after regional anesthesia is less than after general anesthesia.

Postoperative delirium develops usually after a period of clarity and awareness, typically on the first to third post-op day. The brief reactive psychosis is usually fully reversible with an average duration of a few hours or days, but it can also last for weeks and months. It is characterized by an acute onset with reduction in awareness of the environment and a disturbance in attention.

The incidence of postoperative delirium in older patients after general anesthesia is about 5–15 % [3], after hip surgeries about 35 % [4], and can also occur independent of surgery in internal medicine patients. The risk factors are age of >70 years, hearing loss, visual disturbances, malnutrition, presence of a urinary catheter, fixation devices, electrolyte disorders, volume deficiency, blood transfusions, and severe postoperative pain. Contrary to popular belief, the choice of anesthesia technique has no effect on the incidence [6].

The term postoperative cognitive dysfunction describes deterioration in cognition, which arises following anesthesia and surgery. With emergence and postoperative delirium, there are also changes in behavior; these may not be present in postoperative cognitive dysfunction which makes the diagnosis more difficult. The comparison of the pre- and postoperative status is the deciding factor, which is seldom measured and has a high interindividual variability.

Various studies conclude that 25 % of elderly patients experience a cognitive disorder within the first 10 days after an operation. Furthermore, in 10 % of the older patients, the disorder is present 3 months after the operation and is gone at the 1-year point [9]. The one and only certain risk factor is the age of the patient. Also, the choice of anesthesia techniques has no influence on the incidence. Some data suggest that postoperative delirium is associated with postoperative cognitive dysfunction [10].

The various types of perioperative cerebral dysfunction differentiate from one another according to the time of the appearance (Fig. 18.2).

>> Dr. Hugh was uncomfortable with the topic that Ms. Martinez had raised. As an anesthesiologist, he usually had little to do with it. “I promise to carefully provide a very mild and gentle anesthesia for you. Everything will be OK” was his response.

A spinal anesthesia is technically easy, has a high success rate, and generally has a low rate of complications. Nowadays, reduced levels of local anesthetics are given resulting in minimal cardiovascular changes. The analgesia lasts into the postoperative phase, which many patients find comfortable. Spinal anesthesia might be especially beneficial in the presence of pulmonary or cardiac diseases which increase the risk of general anesthesia.

All regional anesthesia techniques have the disadvantage of requiring patient cooperation. This applies to the period of time required for placement – patients must sit or lie on their side for the placement – as well as for the surgery. The noises of the OR can be very upsetting for some patients. Spinal anesthesia has a limited duration of action and a less than 100 % success rate. In patients with blood clotting disorders/coagulopathies, the indication must be strictly evaluated. From the surgical point of view, a disadvantage of spinal anesthesia is delayed neurological evaluation of the operated leg.

In epidural anesthesia, possible circulatory system changes occur more slowly than with spinal anesthesia. Redosing the catheter is possible at any time, should the surgery become prolonged. In addition, the catheter can be used for postoperative pain therapy, and systemic side effects of other pain medication are avoided.

A small disadvantage is that the placement is technically more challenging than spinal anesthesia. Rare complications such as hematomas or abscesses are more common. Care of the catheter on the ward is time-consuming.

As opposed to the regional anesthesia techniques, general anesthesia requires no cooperation by the patients. There is no time limit on the duration of the surgery, and neurological assessment of the extremity which was operated upon is possible usually right after the surgery.

Listing all possible disadvantages of general anesthesia would fill up this entire book. In older patients, the possible severe circulatory depression with the corresponding therapeutic consequences (including extended cardiovascular monitoring) requires special consideration.

>> Dr. Hugh had made up his mind. “For you, the best thing to do would be spinal anesthesia. Then you may remain awake the whole time, so there is nothing to worry about,” he explained to Ms. Martinez. “Oh, doctor, you most certainly know what is best for me,” was her response. Now the problem was that Ms. Martinez had extreme pain in her hip with the smallest movement. Sitting for the placement of the spinal anesthesia was not an option. But Dr. Hugh had already thought of a solution.