Fig. 18.1
The ECG shows a left axis deviation and a regular sinus rhythm. The only abnormality is the Sokolow–Lyon index (S in V2 + R in V5) of >35 mm, indicating left ventricular hypertrophy
The answer is in the legend of Fig. 18.1.
>> “Doctor, I am really very afraid that I won’t be the same again when I wake up. My neighbor went through something like this last year. She couldn’t ever be alone again after the anesthesia, and had to move into a nursing home.”
18.1.2 What Forms of Perioperative Cerebral Dysfunction Do You Know?
Perioperative cerebral dysfunction occurs in all age groups but is more often seen in older patients. Clinically, there are three types of dysfunction [9]: emergence delirium, postoperative delirium (brief reactive psychosis), and postoperative cognitive dysfunction.
18.1.2.1 Emergence Delirium
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.
18.1.2.2 Postoperative Delirium (Transient Reactive Psychosis)
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].
18.1.2.3 Postoperative Cognitive Dysfunction
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).
Fig. 18.2
Occurrence of perioperative cerebral dysfunction. The acute delirium is usually observed in the PACU or already in the operating room (OR). After a symptom- free interval, brief reactive psychosis may appear. There may be no sharp differentiation as the line is crossed to postoperative cognitive dysfunction (Adapted from Silverstein et al. [9] with permission)
>> 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.
18.1.3 Which Types of Anesthesia Are Possible for This Operation, and What Are the Pros and Cons?
The operation could be done with spinal/epidural anesthesia or under general anesthesia.
18.1.3.1 Spinal Anesthesia
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.
18.1.3.2 Epidural Anesthesia
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.
18.1.3.3 General Anesthesia
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.
18.1.4 What Possibilities Does Dr. Hugh Have?
The goal of premedication is discussed in Case 14 (see Sects. 14.1.1 and 14.1.2). An analgesic component is indicated when there is pain during positioning – e.g., with nonstabilized fractures such as this one – or when the patients’ condition causes enough pain to increase the sympathetic response. Apart from the systemic analgesics, Dr. Hugh also has the possibility to do peripheral regional anesthesia. A femoral block should be considered, either as a single shot or in combination with catheter placement. The catheter could later be used for postoperative pain therapy.
>> Dr. Hugh had had significant experience with the femoral block. Placement was simple, and the patients could then be positioned without pain and even sat up. “Before you are taken into the OR, I will take care of the pain,” he said to Ms. Martinez. “I will place a small catheter in your inguinal region…” With the help of a nurse from the ER, he was able to quickly place the femoral catheter with the help of the click method. He injected 30 ml of ropivacaine 0.375 %, and Ms. Martinez’s pain subsided immediately.
Dr. Hugh was in the process of documenting the unremarkable placement when Ms. Martinez called out “Joseph! Why should I take the bus?” Dr. Hugh was quite puzzled for a moment, but when he turned to the patient, she was completely normal again. Signs and symptoms of local anesthesia intoxication were not present. To be safe, he hooked Ms. Martinez up to the ECG monitor. It showed a regular sinus rhythm with a heart rate of 100 beats/min. The nurse measured blood pressure for him and it was still high, 190/100 mmHg. “That will drop when I begin the spinal and give a little sedative,” thought Dr. Hugh as he pushed Ms. Martinez into the OR.
Dr. Hugh was satisfied with his performance. Ms. Martinez had very little pain during transfer to the OR bed. The short phase of disorientation did not reappear. In the OR, CRNA Pamela was waiting. She had already prepared everything for the spinal, since Dr. Hugh had given her a “heads-up ” via the phone. The monitor showed an unchanged blood pressure. Ms. Martinez was sat up with the help of an OR technician, and after touching bone twice, Dr. Hugh successfully reached the subarachnoid space. Clear cerebrospinal fluid dropped from the spinal cannula, and he injected 1.8 ml bupivacaine 0.5 % hyperbaric and 10 μg fentanyl.
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