Mary Jean White, RN Vivian C Wolf- Wilets, R N

Memory loss following halothane anesthesia Amnesia induced by anesthesia should be taken into consideration in planning the time and style of nursing intervention. Knowledge of the physiological basis for memory loss or lack of retention will help nurses understand the patient’s needs so that they may alter the care plan correspondingly. If possible amnesia is not taken into account, tasks, medications, and restrictions that have been explained to the patient may not be remembered. Because of this, there may be health implications for the patient and legal responsibility for the staff. Our research indicates that the best time to give patients instructions is some time prior to surgery. Little is known about the degree, nature, and extent of amnesia following inhalation anesthesia. Amnesia, or loss ~~

~-

~

~~

Mary Jean White, RN, MN, is a nurse clinician with Neurological Associates of Washington, Inc, in Bellevue, Wash. A diploma graduate of St Frances X Cabrini School of Nursing, Seat-

tle, she received her bachelor’s in nursing from Seattle University and her master’s in nursing from the University of Washington in Seattle. Vivian C Wolf-Wilets, R N , PhD, is associate professor, Department of Physiological Nursing, University of Washington School of Nursing, Seattle.She received her diploma from the Presbyterian St Luke’s School of Nursing in Chicago, her bachelor’s in nursing from North Central College in Naperville, 111, and her master’s and doctorate in education from the University of Chicago.

of memory, describes the inability of the patient to register, consolidate, or recall ongoing events, in this case following the operative and anesthesia experience. Amnesia may be either retrograde or anterograde. In retrograde amnesia, memory is blocked or destroyed for input occurring prior to an event. In anterograde amnesia, memory is blocked or destroyed for input occurring after an event. For example, a n individual could be unable to remember the input immediately prior to anesthesia (retrograde amnesia) or could be unable t o remember input immediately following the anesthesia (anterograde amnesia). Amnesia can complicate the postoperative period in some patients, whereas for others, amnesia for some postoperative events may be therapeutic. Following operations with general anesthesia, many patients are unable to carry out cognitive functions (ie, registration, retention, and retrieval) and “exhibit symptoms of vagueness about time, place and person.”’ Elderly postoperative patients may be confused or disoriented owing to homeostatic imbalances. Even after uncomplicated procedures that do not involve homeostatic imbalances, patients may have no subsequent recall of ongoing events for a period even longer than eight hours.2 Nurses involved in preoperative teaching and the protection of the patient during the operative and immediately postoperative phase of the surgi-

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cal experience should be aware that hours and sometimes days pass before cognitive function returns to the level normal for that patient. This occurs despite the fact that the patient may appear to be fully awake and r e s p ~ n s i v e . ~ Patients in their recuperative period will often ask the staff questions such as “What day is it?” “What happened yesterday (the operative day)?” “Who visited me?” “Did I say anything that I should not have said?’ Anesthetic. For our study of amnesia resulting from anesthesia, we chose to limit the anesthetic to one particular agent because different anesthetic agents vary in the potency of their effect on memory. Halothane was chosen because it is widely used and it has been shown to have prolonged amnesic effect~.~ Halothane is a nonflammable, clear, nonirritating inhalation anesthetic. In the first ten minutes after administration, halothane is found in the circulatory system; it is then present in the muscle group for approximately 2 % hours; and, finally, fat continues to take up halothane after all other tissues have ceased doing SO.^ Most halothane research has been done with animals. These studies have shown that when halothane is administered after a learning experience, it impairs the retention of that experience.6 In dogs, halothane anesthesia lowers both the mean arterial blood pressure and the plasma levels of both epinephrine and norepinephrine.’ Decreased catecholamine levels with halothane may be responsible for modulating neural systems t h a t affect memory storage and block the consolidation of short-term memory into long-term memory (see below).R Preoperative drugs. Preoperative drugs commonly identified to cause amnesia a r e scopolamine9 a n d diazepam.I0 Atropine can also cause amnesic effects when given a t higher 1054

dose levels than the amount needed to produce amnesia with scopolamine, but it is not effective in producing amnesia when administered in clinically acceptable doses.’ T h e anesthesiologists cooperating in this study chose other premedications t h a n scopolamine or diazepam for the patients participating in this research so that these variables could be controlled. Memory processes. There are three stages in the memory process: registration, retention, and retrieval. Registration is t h e transaction between organism and environmental stimulus that produces lasting aftereffects. Retention involves the storage of acquired information in the form of traces of remembered stimuli. Retrieval is the process of responding; this reveals the effects of stored information acquired a t one point in time and evoked at a later time.12 The memory process consists of s h o r t - t e r m memory a n d long-term memory. Short-term memory is a phase like a reverbatory circuit that may be ablated by coma, electroconvulsive shock, or anesthesia.13 It lasts from a few seconds to as long as 30 minutes.14 Long-term memory is “the consolidation of information with long-term storage” and is the basis of memories of the remote past. This phase is also identified with molecular changes in neurons and may involve protein synthesis.15 Long-term memory may be consolidated for as little as 30 minutes to as long as a n entire lifetime. Once memory is fixed or consolidated, it is difficult to disrupt or dislodge.16 It is not clear if there is a sequential progression from short-term to long-term memory or if they are two distinct but parallel m e c h a n i ~ r n s Recent .~~ memory is evidently stored in t h e hippocampus, whereas consolidated, long-term memory is thought to be stored in the greater part of the cortex.ls In addition, there may be subdivi-

A0R.V J o o m u l . Decemher 1977, V o l 2 6 , No 6

isual information may be stored separately from auditory and verbal information.

V

sions of short-term and long-term memory for separate sense modalities. For example, visual information may be held and stored separately from auditory and verbal informati~n.’~ For this reason it is important to test the verbal, visual, and auditory subdivisions of memory separately. The difference between recognition and recall in memory function is important in testing and research. Recall is thought to involve the search and retrieval of information i n storage, whereas recognition is the matching of information in storage with information in the environment.20 Some research shows that recognition memory is superior to recall, especially with increasing age.21 There a r e many theories on t h e physiology of memory. The “neuronal consolidation” hypothesis postulates t h a t t h e reverberation of firing in neural chains leads to a permanent modification of one neuron exciting the other, causing a permanent growth change or “engram” that remains in the nervous system until a certain input elicits a corresponding output.22 In the “mnemon concept,” short-term memory is the formation of a weak engram or memory trace containing few mnemons or units of memory, whereas long-term memory is composed of many m n e r n o n ~ According .~~ to this theory, there is a “threshold” or certain number of mnemons required for recall. If the recall threshold is increased by the ef-

fect of a n anesthetic agent such as halothane, the patient would be unable to retrieve information by recall. An alternative explanation is that during anesthesia insufficient mnemons are laid down to attain threshold. Since long-term memory is resistant to electroconvulsive shock and concussion, another theory is that memory is stored as an actual chemical change in neurons. Unger isolated peptides that were loosely bound to ribonucleic acid (RNA) in trained animals and produced a memory for the tasks in untrained animals after intercisternal injections of these pep tide^.^^ Other researchers, however, have had difficulty reproducing these results. RNA and protein synthesis are apparently important in long-term memory storage. According to Uphouse, et al, the brain, upon receiving a stimulus, “decides” to store the information in long-term memory. This necessitates increased RNA and protein synthesis. The increase in RNA synthesis occurs within 30 minutes of the time of input. There is a resulting increase in the number of cytoplasmic polyribosomes, which code for some species of proteins. Some of these proteins then alter the transmission characteristics of t h e ce11.25 Purpose and methods of study. In this study, we investigated the mechanisms of short-term and long-term memory in patients undergoing uncomplicated surgical procedures where there was lit-

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tle or no change in body homeostasis and where halothane had been determined the anesthetic of choice. Halothane anesthesia included the intravenous injection of a muscle relaxant and a fast-acting barbiturate, followed by t h e administration of halothane combined with nitrous oxide and oxygen. We were particularly interested in the following: 0 Is amnesia a consistent finding in patients undergoing uncomplicated surgical procedures with halothane as the primary inhalation anesthetic? 0 How long does anesthesia interrupt short-term memory? 0 If amnesia is present, what is the type and duration of that amnesia? 0 Is there a difference in the subject’s ability to retain verbal, visual, and auditory information? 0 Is there a relationship between amnesia and body weight, preoperative medications, age, or the length of anesthesia? 0 Do the type, dosage, and frequency of postoperative analgesics influence the length of amnesia? Does the person’s subjective recall of memory coincide with the staff nurse’s or investigator’s perception of the patient’s return of memory? We recruited volunteers for this study from persons scheduled t o have halothane anesthesia for elective surgery at a university medical center in Seattle. No effort was made to select a specific patient on the basis of age or sex. Nine patients participated, and each was assigned a number so that his identity remained confidential. There were five males and four females with a mean age of 31.44 years and a n age range of 23 to 45 years. Of this number, six subjects completed all components of the study. Anyone with visual difficulties, hear-

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ing disabilities, obesity, epilepsy, allergy to narcotics, psychiatric disorders, or a history of prolonged use of alcohol or psychotropic drugs was excluded from the study. This information was secured from the patient chart and the initial interview. The Wechsler Memory Scale Form I was administered to all participants preoperatively to screen out gross learning problems and to provide baseline data for correlation with the results of Form 11, which was administered postoperatively. Essentially, t h i s t e s t measures t h e efficiency of general memory function and yields a score called a memory quotient (MQ). I t measures information and orientation (general time and place orientation), mental control (a measure of speed and accuracy in relation to a series of numbers and letters), logical memory (auditory-verbal recall of written information), digit span (immediate auditory-verbal recall of numbers), visual reproduction (requires one to draw from memory simple, nonstandard geometric forms), and associate learning (auditory-verbal recall of pairs of related words).26 Each patient was tested during the final interview with Wechsler Memory Scale Form 11. Form I1 matches similar items in Form I, and there is an estimated reliability coefficient of about .83 for clinical populations. We used this particular test because each of t h e Wechsler Memory Scale tests is standardized, and the scores may be used to compare preoperative and postoperative memory function. Both forms take a short time to administer, measure several aspects of memory, and norming data are available. In addition to the Wechsler tests, we had several tasks for the patients to perform. Each subject was interviewed six times, during which recall and recognition were tested (Table 1).After the ini-

AORN Journal, December 1977, Val 26,No 6

Table 1

Protocol for data collection I. Initial preoperative

II. Immediately before

interview

anesthesia induction

explanation

teach task B (no hot coffee for six hours after surgery)

consent form Wechsler Memory Scale Form I

Ill. One hour after surgery

test task B (no hot coffee for six hours after surgery) teach task C (what analgesics are available to the patient)

task A taught (goat picture) IV. Four hours after surgery

V. Eight hours after surgery

test task C (what analgesics are available to the patient)

test task D (should not drive for 18 hours following surgery)

teach task D (should not drive for 18 hours following surgery)

teach task E (play brass chime to assess auditory m em ory )

VI. Termination interview

test tasks A, B, C, D, and E

subjective statement from patient recalling sequence of events since his operation Wechsler Memory Scale Form II

tial preoperative interview (I), the patients were contacted immediately before anesthesia induction (interview 11); one (interview III), four (interview IV), and eight (interview V) hours postoperatively; and in a final termination interview (VI) 24 hours after surgery. Task A was designed to test visual memory. The subject was shown a picture of an easily identifiable animal (goat) and was subsequently asked to recall the picture 24 hours later at the sixth interview. We planned that if a subject did not have free recall of the goat picture, it would be placed with three other animal pictures (rabbit, calf, and dog) to test recognition. The pictures were in black and white to avoid any color biases. Tasks B, C, and D tested verbal memory. These three tasks were taught at predetermined intervals to assess the subject’s ability t o retain input in short-term memory storage and to consolidate information into long-term memory storage.

Task B was given after the administration of the preoperative medication. The subject was instructed by the anesthesiologist not to drink hot coffee for six hours after surgery. Recall of this instruction was tested one hour postoperatively (interview 111)and again in the final interview (VI). Task C was given one hour after the patient arrived in the recovery room. The investigator told the patient the names of the medications t h a t were available for sleep and discomfort, as indicated by the physician’s postoperative order. The subject was asked to repeat this information so that the investigator could determine if the instructions were understood. Recall of this instruction was tested four hours after surgery (interview IV) and again during the final interview. Task D was given four hours (interview IV) after the completion of the surgical procedure. The subject was instructed not to drive a car for 18 hours after his operation. Recall of this re-

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striction was tested in the fifth interview four hours later and in the final interview. These tasks were chosen because of their simplicity and possible meaningfulness to the subject because they pertained to his surgical procedure. Task E was designed to test auditory memory. Eight hours after surgery (interview V), the investigator played a brass chime out of sight of the subject, who was then asked to describe the sound. The purpose of this task was to assess the auditory component of memory. At the termination interview, the subject was tested on the recall of the sound, as well as recognition of the sound when two other bells were also rung out of the patient’s sight. A record was kept on all subjects regarding their assigned number, age, weight, height, operative procedure. amount of induction agent, preoperative medications, anesthetic agents used, duration of anesthetic and surgery, and use of intraoperative and postoperative medications. The history of the subject’s previous surgeries a n d anesthetic agents as well as the person’s recall of these events were collected for this record. The nursing staff was informed of this investigation and asked to participate. They were instructed to evaluate the time when the patient appeared to be fully awake and resume normal cognitive function. The questionnaire was designed to assess the nurse’s perception of the subject’s awareness during the 16 hours between the fifth and sixth interviews. This information was desired so the nurse’s conception of the patient’s memory function could be compared with the patient’s own perception. Results. Unfortunately, not all of the subjects could complete the study. Eight of the original nine subjects completed the tests of tasks A through E. Three

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patients, however, were not able to be tested on Form I1 of the Wechsler Memory Scale: two were discharged before it could be administered and the third patient’s tongue was too swollen from dental surgery for him to speak. Table 2 presents the incidence of recall a t specific testing times. For task A, all patients tested (8) freely recalled the picture of the goat. This is probably because the goat picture had time to be consolidated into long-term memory before anesthesia was administered. In contrast, task B (no hot coffee for six hours), taught immediately before the administration of anesthesia, was freely recalled by one subject one hour after surgery and by two subjects out of eight tested 24 hours after surgery. The mnemon theory discussed above would imply that anesthesia may increase the threshold for recall. This theory would explain why some patients were unable to recall information given them when they were first tested immediately after surgery when some residual halothane might be rnaintaining a high threshold. This would be consistent with the finding that patients were later able to recall the task when the effects of halothane may have been eliminated. I t is also possible t h a t short-term memory is ablated by anesthesia and that retrograde amnesia occurs for events immediately prior to the administration of a n e ~ t h e s i a . ~ ’ Four hours after surgery (interview IV), the patients were tested on their ability to name the pain medication they were asked to remember one hour after their operations (task C). Seven of the nine patients tested had no recall of the information. Six of these seven patients were unable to recall it even during the final interview (the seventh had been discharged). Knowledge of the pain medication avaliable to them is pertinent to the maintenance of the patient’s comfort.

AORN Journal. Decernher 1977, V o l 2 6 . N o 6

Table 2

Frequency and occurrence of amnesia Tasks

Incidence of recall in postoperative interviews 1 hr 4 hr 8 hr 24 hr

Time taught

A

12 to 16 hr preoperatively

6

immediately preoperatively

C

1 h r postoperatively

D

4 hr

E

8 hr postoperatively

8 of 8 1 of9

2 of 8 2 of 9

3of9

postoperatively

During the fifth interview, eight hours after surgery, six of the nine persons tested did not remember being told a t four hours after surgery not to drive for 18 hours following surgery (task D). In the final interview, one of these six freely recalled the information and another patient recalled it with prompting (another was not tested). In an outpatient facility, it is possible that these six patients would be discharged a t this approximate time. What might the legal implications be if patients who could not remember the instruction that they were not to drive the 18 hours following their surgery were discharged, drove their cars, and an accident occurred? What argument can be offered against the statement “I didn’t know I wasn’t supposed to drive”? How many other patients leave the hospital not knowing information vital t o t h e i r health and safety? Twenty-four hours postanesthesia, auditory memory was tested. Four of the eight tested had free recall of the chime played eight hours after surgery, one had recall with prompting, and the remaining three had no recall. Two of the three subjects with no recall could not distinguish the sound of the chime played f o r them eight hours a f t e r surgery from the sound of a cowbell and

2 of 8

4of8 4 of 8

a n old brass bell. It was interesting that both of these subjects had described the sound of the brass chime as a cowbell when they initially heard it. Subsequently, these patients chose the clanging cowbell as the correct sound when they heard it played with the other bells 16 hours later. This evidence suggests that faulty auditory coding mechanisms were in operation when they first heard t h e chime played. Perhaps to these patients, the sound was distorted in such a way that the chime did sound like a clanging cowbell instead of a chiming brass bell. This distortion was reinforced by their verbalization that what they had heard was a cowbell. If the investigator had corrected the error the first time, the incorrect coding would probably not have been revealed. Reality orientation becomes an important concept in view of this kind of finding and the question is raised, “How often are surgical patients oriented to their surroundings?” Our finding emphasizes the need for continuing ongoing reality orientation of the surgical patient. Although amnesia was not a universal finding because one patient recalled all events, it was predominant. The goat picture, which was presented in the preoperative visit, was remembered by

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all patients, and the highest incidence of amnesia occurred during the period immediately after surgery. Even a t 24 hours postoperatively, only one-half of the patients were able to recall freely important instructions. In regard to the differences in ability to retain verbal, visual, or auditory information, we found that the only task all patients successfully recalled was the visual task (task A). However, in our study this was not adequately tested because a visual task was given only once and that was 12 to 16 hours before surgery. We did note that in every visit to the patients, the investigator was immediately recognized. Some of them addressed the researcher by name and all of them mentioned the picture of the goat they had been shown the night before their surgery, although this task was not tested for our records until the last interview. The face of the investigator and the picture of the goat seem to have been imprinted in the patients’ long-term storage. Another interesting observation was that even though the subjects could not remember the instructions they had been given for the verbal tests, they consistently recalled that the investigator had been there to visit them. Some could remember that the investigator told them a t what time she would next see them or how many hours would elapse until the next visit. Often, events pertaining to the visit were recalled-for example, what the patient in the next bed in the recovery room looked like. One patient was able to describe in detail t h e investigator’s eyeshadow color, neckscarf, and earrings and could remember repeating the task out loud, yet he could not remember the task. These details could not have been associated with seeing t h e investigator preoperatively nor would the attire worn by the inves-

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tigator on the following day provide any clues. The results of the auditory and verbal tests indicate that all of these tests were correctly identified by only one patient and that some patients were unable to recall any of the tasks. Therefore, these tasks seem to discriminate between various patients’ abilities to recall fromdifferent sensory modalities. To determine if there is a relationship between amnesia and body weight, preoperative medication, or length of anesthetic, we analyzed some of the relevant data. The mean weight of the subjects in this study was 66.9 kg. The range was from 60.0 to 81.8 kg, including 61.8,64.5,62.0,81.0,66.0, and 65.0 kg. Comparison of this variable to the tasks recalled showed no direct relationship. An analysis to determine if preoperative medicines could be related to a pattern of recall was made, but no relation could be determined. Postoperative amnesia has been shown elsewhere to be related primarily to the general anesthetic (thiopental sodium, halothane, nitrous oxide) rather than to the preoperative medications (atropine, meperidine, pentobarbital sodium).28In this study, the most potent amnesic preoperative drugs had been eliminated by design. Patients under the mean age of 31.44 were able to recall nine more items than those above the mean age, but these findings are inconclusive. No other relationship to age was seen. The mean duration of anesthetic time of the nine patients in this study was 3 hours and 31 minutes, with a range of 1 hour and 5 minutes to 5 hours and 15 minutes. From our evaluation, there did not appear to be a relationship between these variables. We also recorded the type, dosage, and frequency of postoperative analgesics to determine if these had a

AORN Journal. December 1977, V o l 2 6 , No 6

here did not appear to be a defined point of total recall.

T

bearing on the length of amnesia. Five patients (who could not recall the tasks they had been given) had received analgesic medications one t o three hours before interviews IV, V, and VI. A sixth patient had received codeine within one to three hours of these three interviews and yet was able to recall the information. Only one patient was consistently unable to recall the tasks after medication was given one to three hours before the interviews, yet recalled task A. Although amnesia might be explained as a result of postoperative medications in some patients, it cannot account for the three patients who had one or no medication during the testing periods and yet had no recall of the tasks. No conclusive results regarding the patient’s subjective recall could be obtained from the observations of the staff nurses. More than half of the questionnaires were not filled out by the staff nurses because their other duties precluded participation. One subject appeared to the nurses to be somewhat confused about the time of day and evening; yet he stated that he first woke up in his room “sometime during the afternoon.” Another subject reported being aware of her surroundings in the late afternoon and yet at 8:30 pm when she asked the nurse what time it was, she was surprised that it was still the same evening and not the next morning. To us, there did not appear to be a

defined point of total recall in the patients studied. For the most part, their comments were vague, with no exact time or activity involved in remembering. Only one patient was able to recall any specific detail of the events that followed surgery. She was able to recall the name of the patient in the next bed in the recovery room although she had never seen him before that time and was able t o relate communications she overheard between the staff. The Wechsler Memory Scale preoperative Form I and postoperative Form I1 scores were then analyzed. The mean memory quotient (MQ)for Form I for nine patients was 103, ranging from 81 to 135. Form I1 MQ mean for six subjects was 100, with a range of 81 t,o 114. Three of the patients increased their MQ postoperatively by two or three points. Two subjects decreased their MQ scores, one by nine and one by six points. The patient that could recall eight items out of eight had a postoperative score nine points lower than his preoperative score; however, his postoperative score was still higher than any of the other subjects taking Form 11. The Wechsler Memory Scale is more successful in evaluating short-term memory than it is the consolidation of short-term memory into long-term memory. This is because the subject is asked to recall information immediately and not to retrieve information

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after a period of time when consolidation has occurred. Short-term memory may function normally postoperatively, as indicated by three patients who increased their scores. However, this finding should not lead health care workers to believe that patients will be able to retrieve newly given information from long-term memory a t a later time. The practice gained from taking the first test may also account for the increased score. Conclusions. This was a descriptive study based on short-term and longterm memory theory and designed to test and assess the postoperative amnesic effect of halothane anesthesia in persons undergoing uncomplicated surgical procedures. Halothane anesthesia included the use of a short-acting barbiturate and a muscle relaxant followed by the administration of the inhalation anesthetic halothane combined with nitrous oxide and oxygen. Each subject was tested on his recall eight times; three tasks were tested twice. The results of this study suggest that there are variations in patients’ abilities to register, retain, and recall information following their exposure to halo t hane anesthesia. Age, weight , preoperative medication, and postoperative analgesia did not appear to be related to the return of memory, but the sample size makes these results only tentative. A visual examination of the Wechsler Memory Scale scores for six cases appeared to be random. Our study has shown that the patient’s ability to repeat instructions immediately does not mean that these instructions will be remembered. The results of this study do not provide complete guidelines for the practitioner in assessing the patient’s complete return of cognitive function. However, they do emphasize the importance of retesting any information t a u g h t postoperatively.

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Reality orientation whenever and wherever appropriate should be applied, especially in the first 24 postoperative hours. The deficits noted in this study occurred following uncomplicated surgical procedures on young patients (age 23 to 45 years). This emphasizes all the more the orientation needs of the patient undergoing more complicated surgery. Another implication that bears careful consideration and positive action is the legal aspect of these findings. Outpatient surgery is a relatively new concept. Many procedures are performed under halothane anesthesia and apparently require only a few hours stay in the hospital before the patient is discharged. A few of these might be dental procedures, incision and drainage of abscesses, dilation and curettage of the u t e r u s , a n d legal abortions where halothane inhalation anesthesia is employed. If a patient cannot retain information regarding his care a t one, four, and eight hours postoperatively, as revealed by this study, what steps are necessary t o ensure that the patient can adequately care for himself when he is discharged? It may not be as important to remember not to drink hot coffee for six hours after surgery, but remembering the name and directions of a prescribed medication or the instruction not to drive could be imperative in some circumstances. If a patient is given specific instructions that he does not remember and a complication occurs, can the hospital, physicians, and nurses be held legally accountable? An unexpected finding of this study was the nature and duration of the recall of the task given to the patients the evening before their surgery. Not only were the patients able to recall a t all times that the subject of the first test was a goat, but they also could give vivid descriptions of its spots, the collar around its neck, and the size of its horns.

AORN Journal, December 1977. Vo126, N o 6

R

emembering the instruction not to drive could be imperative.

Some of the problems and limitations of this research were the availability of uncomplicated surgical procedures, the duties of the staff nurses that precluded their participation, the difficulty in finding a psychologist to administer the Wechsler Memory Scale tests, and the time involved in gathering the data. Approximately ten hours of the investigator's time were spent studying each patient, although the actual testing time was limited to 50 minutes. The psychology intern was able to administer the Wechsler Memory Scale Forms I and I1 in 30 minutes total time. The number of interviews and their range in time need to be extended in a further study to determine when all patients have a complete return of memory functions. The study emphasizes the necessity of preoperative teaching before the day of surgery. Anything the physicians or nurses feel would speed the process of recuperation should be taught to the patient early so that he or she has the opportunity for rehearsal and time for coding the information. This information can then be remembered and used by the patient immediately after surgery and later. 0 Notes 1. Barbara J Gruendemann, et al, The Surgical Patient: Behavioral Concepts for the Operating Room Nurse (St Louis: C V Mosby Company, 1973). 2. W Larnbrechts,J Parkhouse, "Postoperative

amnesia," British Journal of Anaesthesiology 33 (1961) 397-404. 3. /bid. 4. V C Wolf, "Some implications of short-term, long-term memory theory," Nursing Forum 10 (1971) 150-165. 5. Fluothane (Halothane): For Precision lnhalation Anesthesia (New York: Ayerst Laboratories, 1973). 6. C Angel, M S Bounds, A Perry, "A comparison of the effects of halothane on the blood-brain barrier and memory consolidation," Diseases of the Nervous System 33 (1971) 87-93; A Cherkin, E Lee-Teng, "Interruption of memory consolidation by halothane," Federation Proceedings 24 (1965) 328; W C Penrod, R Boice, "Effects of halothane anesthesia on the retention of passive avoidance tasks in rats," Psychoneurological Science 23 (1971) 205207. 7. L B Perry, R A Van Dyke, R A Theye, "Sympathoadrenal and hemodynamic effects of isoflurane, halothane, and cyclopropane," AnesthesiOlOgy 40 (1974) 465-470. 8. James L McGaugh, Paul E Gold, "The effects of drugs and electrical stimulation of the brain on memory storage processes," Advances in Behavioral Biology, vol 10: Neuro-Humoral Coding of Brain Function, R D Meyers, R R Drucker-Colin, eds. (New York: Plenum Press, 1974) 189-206. 9. M E Jarvik, E R Gritz, N G Schneider, "Drugs and memory disorders in human aging," Behavioral Biology 7 (1972) 643-668; S K Pandit, J W Dundee, "Preoperative amnesia," Anaesthesia 25 (1970) 493-499; S K Pandit, J W Dundee, S R Keilty, "Amnesia studies with intravenous medication," Anaesthesia 26 (1971) 421-428; T J Crow, I G GroveWhite, "An analysis of the learning deficit following hyoscine administration to man," British Journal of Pharmacology 49 (1973) 322-327. 10. "Anguish unremembered?" Lancet 1 (1974) 968-979; A W Duncan, A M Barr, "Diazepam premedication and awareness during general anaesthesia for bronchoscopy and laryngoscopy," British Journal of Anaesthesiology 45 (1973) 1150-1152;

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Pandit. Dundee, Keilty, "Amnesia studies with intravenous medication": L Eisenberg, H A Taub, A Burana, "Memory under diazepam-morphine neuroleptanesthesia in male surgical patients," Anesthesia and Analgesia: Current Researches 53 (1974) 488-495. 11. Crow, Grove-White, "An analysis of the learning deficit." 12. R G Rahwan, "The biochemical and pharmacologicalbasis of learning and memory." Agents and Actions 2 (1971) 87-102. 13. J E Cooper, F E Bloom, R H Roth. The Biochemical Basis of Neuropharmacology, 2nd ed (New York: Oxford University Press, 1974). 14. Jack Botwinick, Aging and Behavior (New York: Springer Publishing Company, 1973). 15. Cooper, Bloom, Roth, The Biochemical Basis of Neuropharmacology. 16. W F Ganong, Review of Medical Physiology (Los Altos, Calif: Lange Medical Publishing Company, 1973). 17. L L Uphouse et al, "Role of RNA and protein in memory storage: A review," Behavioral Genetics 4 ( 1 974) 29-81. 18. Rahwan. "The biochemical and pharmacological basis of learning and memory." 19. R C Atkinson, R M Shiffrin. "Human memory: A proposed system and its control processes," The Psychology of Learning and Motivation: Advances in Research and Theory, vol 2. K W Spence, J T Spence, eds. (New York: Academic Press, 1968). 20. Botwinick, Aging and Behavior. 21. D Schonfield, "Memory changes with age," Nature 28 (1965) 918. 22. J C Eccles. "The physiology of imagination," Altered States of Awareness: Readings from Scientific American (San Francisco: W H Freeman and Company, 1972) 31-40. 23. A Cherkin. "Toward a quantitative view of the engram," Proceedingsof NationalAcademy of Sciences 55 (1966) 88-91. 24. G Unger, "Commentary: Peptides and memory," Biochemical Pharmacology 23 (1974) 15531558. 25. Uphouse et al, "Role of RNA and protein in memory storage." 26. V C Wolf, "Pilot study of pre- and postoperative memory-nursing care," unpublished grant proposal submitted to University of Washington (Seattle: 1974). 27. Cooper, Gloom, Roth, The Biochemical Basis of Neuropharmacology. 28. R P Gruber, D R Reed, "Postoperative anterograde amnesia," British Journal of Anaesthesiology 40 (1968) 845.

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Few bypass patients regain work capacity Coronary artery bypass surgery relieves the severe chest pains of heart disease in thousands of individuals each year, but the procedure contributes little to getting these individuals back to work, according to a report in the Journal of the American Medical Association. Glenda K Barnes, RN, and colleagues at the Medical Center of the University of Birmingham (Ala) analyzed the work capacity of 350 patients who had coronary artery bypass grafting procedures to determine change in work status as a result of the operation. "Overall, there was no improvement in return to work or hours worked after surgery," says Barnes. An estimated 65,000 coronary bypass procedures are being performed annually in the United States at an approximate cost of $1 0,000 each, Barnes points out. Justification for these complex and costly procedures is based primarily on relief of pain and improvementof the "quality of life," rather than the increased survival demonstrated in a few subgroups, she says. At least 70% to 80% of such patients get partial or complete relief of their angina in the early years after their operations. Such data would suggest that the majority of these patientscan be expectedto return to work and more productive lives after surgery, but this doesn't happen. "In the group of 350 patients studied before and one year after coronary bypass grafting, there was no noticeable increase of work activities postoperatively.Forty-four percentof the patients decreased their hours worked per week, 24% remained the same, and 32% increased hours worked. Thus, there was no net improvement in status." Physical or mental demands of the job may have precluded some of the persons from working, Barnes says. Fear of such stress causing further heart problems may be a deterrent. Others may not return to work because of lack of incentive, especially money. Some may draw more from disability payments than they could earn on the job.

AORN Journal, December 1977, V o l 2 6 , No 6