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[Intraoperative awareness].

The first cases of general anesthesia were already cases with awareness. Until today, case reports of patients with awareness are published. These published cases are likely to be the top of the iceberg, as most patients with postoperative recall do not inform their anesthesiologist. Incidence of awareness with recall is between 0.1 and 0.2 %. In a large multicenter-study, incidence of recall was 0.1 % without, and 0.18 % with the use of muscle relaxants. The risk is increased with decreased doses of anesthetics, e.g. in patients with hemodynamic instability (trauma cases), patients undergoing cesarean section or cardiac surgery. Intraoperative awareness does not necessarily cause explicit (conscious) memory. Even in the absence of explicit memory, implicit (unconscious) memory can still have consequences for the patient. In the worst case, it can cause post-traumatic stress disorder. There is doubt whether patients may profit from positive suggestions given during intraoperative awareness. Recommendations to administer benzodiazepines to prevent explicit memory must be reconsidered. Complete neuromuscular block should be avoided whenever possible. If a patient is thought to be aware, he should be contacted, his situation should be explained and affirming comments should be given until consciousness is lost again. Postoperative visit should include questions about awareness and recall. The anesthetist should not disbelieve reported recall. Explanation of what had happened and referral to an experienced psychologist must be offered. Thus, the incidence of severe sequelae should decrease.

Anesthesia, General↗

The insertion/deletion polymorphism in the angiotensin-converting enzyme gene and hypoglycemia awareness in patients with type 1 diabetes.

Impaired hypoglycemia awareness affects approximately 25% of all patients with type 1 diabetes (T1DM). Duration of diabetes and tight glycemic control represent main risk factors of impaired hypoglycemia awareness. However, even among patients with good glycemic control and longstanding T1DM, awareness of hypoglycemia may be intact. Genetic factors might explain some of this remaining variability. Recently, the insertion/deletion ( I/ D) polymorphism in angiotensin converting enzyme gene ( ACE) was shown to be associated with significantly higher risk of hypoglycemic events in subjects with T1DM. Here, we studied the effects of genetic polymorphisms in the ACE on impaired hypoglycemia awareness in 231 Caucasian T1DM patients. Hypoglycemia awareness status was determined using standardized questionnaires (Clarke et al. and Edinburgh Hypoglycemia Scale). ACE I/ D genotype was determined by PCR amplification of the respective fragments from intron 16 of the ACE and size fractionation (I allele frequency=0.49; P=0.74 for Hardy-Weinberg equilibrium). In the logistic regression analysis, significant risk factors of impaired hypoglycemia awareness were duration of diabetes, C-peptide and HbA (1c) (all P<0.01). However, no significant effect of the I/ D polymorphism on impaired hypoglycemia awareness was observed with and without adjustment for age, diabetes duration, C-peptide and HbA (1c). Even though the study provides a relatively large dataset, it is possible that small differences may have been missed.

Adult↗

Self-awareness after acquired and traumatic brain injury.

Self-awareness deficits are common after acquired and (traumatic) brain injury (ABI), particularly in social behaviour, yet the underlying cognitive and neuroanatomical structures supporting social self-awareness are not fully understood. This paper reviews the current literature on prevalence, type and severity of self-awareness deficits in ABI. Neuropsychological and neuroanatomical models are reviewed and theoretical frameworks are examined. We summarise results of a case-control comparison of 20 ABI patients with and 20 ABI patients without behavioural disturbance. Our research found that lack of social self-awareness predicts behavioural disturbance in acquired and traumatic brain injury independent of cognitive and executive function. Theory of mind ability was related to self-awareness and a possible role for metacognition and affective processes in self-awareness is discussed to account for social self-awareness deficits.

Adult↗

Follow-up study investigating the benefits of phonological awareness intervention for children with spoken language impairment.

The efficacy of phonological awareness intervention for children at risk for reading disorder has received increasing attention in the literature. This paper reports the follow-up data for participants in the Gillon (2000a) intervention study. The performance of twenty, 5-7-year-old New Zealand children with spoken language impairment, who received phonological awareness intervention, was compared with the progress made by 20 children from a control group and 20 children with typical language development approximately 11 months post-intervention. The children with spoken language impairment all had expressive phonological difficulties and demonstrated delay in early reading development. Treatment effects on strengthening phoneme-grapheme connections in spelling development were also investigated. The results suggested that structured phonological awareness intervention led to sustained growth in phoneme awareness and word-recognition performance. At the follow-up assessment, the majority of the children who received intervention were reading at, or above, the level expected for their age on a measure of word recognition. The phonological awareness intervention also significantly strengthened phoneme-grapheme connections in spelling as evidenced by improved non-word spelling ability. In contrast, the control group of children with spoken language impairment who did not receive phonological awareness intervention showed remarkably little improvement in phoneme awareness over time and the majority remained poor readers. The results highlight the important role speech-language therapists can play in enhancing the early reading and spelling development of children with spoken language impairment.

Awareness↗

Lack of awareness of need to clean CFC-free metered-dose inhalers.

BACKGROUND: Chlorofluorocarbon (CFC)-free metered-dose inhalers (MDIs) were introduced into Australia in 1999. Device care instructions were modified (e.g., CFC-free salbutamol inhalers to be washed weekly), but this information was not communicated directly to health care professionals. OBJECTIVE: This pilot study aimed to assess the level of awareness of device care protocols for CFC-free MDIs by patients and their pharmacists. SETTING AND DESIGN: Purchasers of CFC-free MDIs were recruited from four community pharmacies. They were interviewed regarding information sources, knowledge of propellant change, and awareness of and adherence to device care protocols. The dispensing pharmacists were interviewed for knowledge of CFC-free device care. The primary outcome variable was awareness of the relevant device care protocol. RESULTS: Thirty-nine patients were interviewed. Most patients (77%) were aware of the change to CFC-free propellant. Only nine patients (23%) were aware of the need to wash the device holder, and four patients (10% of total) complied with the specified protocol. One of the ten dispensing pharmacists could describe correct device care protocols for the CFC-free MDIs. CONCLUSIONS: Although most patients are aware that MDIs are now CFC-free, there is a low level of awareness of the device care required for these inhalers, and a very low rate of compliance with recommended practice. Although the clinical impact of failing to wash the device holder is unclear, this added instruction may have substantial implications for patient satisfaction and medication delivery. Pharmaceutical manufacturers need to highlight to health care professionals any clinically important changes in device care instructions, so that appropriate information may be passed on to patients.

Australia↗

Control of the transition from sensory detection to sensory awareness in man by the duration of a thalamic stimulus. The cerebral 'time-on' factor.

A 'time-on' theory to explain the cerebral distinction between conscious and unconscious mental functions proposes that a substantial minimum duration ('time-on') of appropriate neuronal activations up to about 0.5 s is required to elicit conscious sensory experience, but that durations distinctly below that minimum can mediate sensory detection without awareness. A direct experimental test of this proposal is reported here. Stimuli (72 pulses/s) above and below such minimum train durations (0-750 ms) were delivered to the ventrobasal thalamus via electrodes chronically implanted for the therapeutic control of intractable pain. Detection was measured by the subject's forced choice as to stimulus delivery in one of two intervals, regardless of any presence or absence of sensory awareness. Subjects also indicated their awareness level of any stimulus-induced sensation in each and every trial. The results show (1) that detection (correct greater than 50%) occurred even with stimulus durations too brief to elicit awareness, and (2) that to move from mere detection to even an uncertain and often questionable sensory awareness required a significantly larger additional duration of pulses. Thus simply increasing duration ('time-on') of the same repetitive inputs to cerebral cortex can convert an unconscious cognitive mental function (detection without awareness) to a conscious one (detection with awareness).

Awareness↗

Awareness and recall during general anesthesia. Facts and feelings.

BACKGROUND: Experiences of awareness and recall during general anesthesia can be most distressing for patients. To obtain relevant information, the authors systematically interviewed patients in whom awareness during surgery had occurred, and questioned them about their experiences. METHODS: Twenty-six patients, referred by colleagues, described the facts and feelings they had experienced during the period of awareness, and whether these had had any consequences. Available anesthetic records were independently judged by three experienced anesthesiologists for relevant parameters. RESULTS: Auditory perception and the sensation of paralysis were most frequently mentioned, followed by the sensation of pain. Patients' feelings were mostly related to anxiety, panic, powerlessness, and helplessness. Eighteen patients (70%) experienced unpleasant aftereffects, including sleep disturbances, dreams and nightmares, and flashbacks and anxiety during the day. Only nine patients (35%) had informed their anesthesiologists about what had taken place. Twelve anesthetic records were assessed. In three, the occurrence of awareness had been indicated, while, in a fourth, it was noted that an amnesic drug had been given at a moment of increased blood pressure. Experienced anesthesiologists were unable to reliably distinguish awareness cases from matched controls when judging the records. CONCLUSIONS: Details recalled from the period of awareness correspond with data from the literature. The anesthesiologist's role in discussing, and dealing with, traumatic experiences related to anesthesia may be of great importance. The hand-written anesthetic record is of limited value in retrospectively explaining why awareness and recall have occurred.

Adult↗

BIS monitoring to prevent awareness during general anesthesia.

BACKGROUND: Unexpected awareness is a rare but well-described complication of general anesthesia that has received increased scientific and media attention in the past few years. Transformed electroencephalogram monitors, such as the Bispectral Index monitor, have been advocated as tools to prevent unexpected recall. METHODS: The authors conducted a power analysis to estimate how many patients would be needed in an appropriately powered study to demonstrate the Bispectral Index monitor reduces awareness, as well as a cost analysis to assess the cost of using the monitor for this purpose alone. RESULTS: If unexpected recall is rare (1 in 20,000), it will require a large study to demonstrate that the monitor reduces awareness (200,000-800,000 patients), and the cost of using it for this purpose alone would be high ($400,000 per case prevented). If awareness is common (1 in 100), then the number of patients needed in a study to demonstrate that the monitor works becomes tractable (1,000-4,000 patients), and the cost of using the monitor for this purpose alone becomes lower ($2,000 per case prevented). Because there are reported cases of awareness despite Bispectral Index monitoring, the authors are certain that the effectiveness of the monitor is less than 100%. As the performance of the monitor decreases from 100%, the size of the study needed to demonstrate that it works increases, as does the cost of using it to prevent awareness. CONCLUSION: The contention that Bispectral Index monitoring reduces the risk of awareness is unproven, and the cost of using it for this indication is currently unknown.

Anesthesia, General↗

Late psychological symptoms after awareness among consecutively included surgical patients.

BACKGROUND: Awareness during general anesthesia can cause late psychological symptoms. Selection bias may have affected the results in previous retrospective studies. The authors used prospective consecutive collection to recruit patients with previous awareness. METHODS: In a cohort of 2,681 consecutive patients scheduled to undergo general anesthesia, 98 considered themselves to have been aware during previous surgery. Six patients died before inclusion, and another 13 were excluded (4 cases of stroke or dementia, 7 declined to participate, and 2 could not be located). Seventy-nine patients were interviewed by telephone, and medical records were checked in uncertain cases. The interview followed a structured protocol, including seven late symptoms (anxiety, chronic fear, nightmares, flashbacks, indifference, loneliness, and lack of confidence in future life). Three persons independently assessed the interviews for classification, to determine whether awareness had occurred. RESULTS: Four cases were performed using regional anesthesia, and another 29 were not considered as awareness by the assessors. Therefore, the final analyses included 46 patients. Twenty (43%) had experienced pain, and 30 (65%) described acute emotional reactions during the awareness episode. Fifteen (33%) patients had experienced late psychological symptoms afterward. In 6 of those cases, the symptoms lasted for more than 2 months, and 1 patient had a diagnosis of post-traumatic stress disorder. Acute emotional reactions were significantly related to late psychological symptoms (P<0.05). CONCLUSION: The method for recruiting awareness cases in studies on late psychological symptoms may affect the result. The authors found fewer and milder problems, despite a similar degree of initial problems as in previous studies.

Adolescent↗

Bispectral Index (BIS) may not predict awareness reaction to intubation in surgical patients.

Bispectral Index (BIS) has been marketed as a measure of the hypnotic component of anesthesia and is recommended as a guide for the administration of hypnotic drugs during anesthesia. BIS values between 40 and 60 are recommended for surgery under general anesthesia. This study investigates whether a BIS baseline between 50 and 60 prevents awareness reaction to endotracheal intubation. After approval by the university's Ethics Committee, 20 consenting patients were enrolled in the study. Midazolam (0.1 mg/kg PO) was given 30 minutes before induction. Anesthesia was induced with alfentanil (10 mcg/kg, followed by 2 mcg/kg(-1) x min(-1)) and propofol infusion was adjusted to a BIS target level between 50 and 60. Propofol infusion rate was maintained constant for 5 minutes with constant BIS. Prior to intubation, patients were tested in one-minute intervals for awareness using Tunstall's isolated forearm technique. Three minutes after endotracheal intubation, the study period ended and surgery was performed. After intubation, 8 of 20 patients showed an awareness reaction, squeezing the investigator's hand in response to a command. No patient had recall. Comparison of patients with and without awareness reaction revealed no differences in BIS before or after intubation. This study shows that a BIS value between 50 and 60 prior to intubation is inadequate to prevent an awareness reaction to endotracheal intubation during propofol/alfentanil anesthesia. Because BIS cannot differentiate between patients with and without awareness reaction, its value as a monitor for awareness and a measurement of the hypnotic component of anesthesia must be questioned.

Adult↗

Intraoperative awareness in children: myth or reality?

PURPOSE OF REVIEW: This review will outline old and recent data about the prevalence, causes and potential consequences of intraoperative awareness in children and give details on its detection. RECENT FINDINGS: Recent studies have confirmed the higher incidence of intraoperative awareness in children than in adults while using modern anaesthetic techniques. To detect this complication in children, the Brice interview, commonly used in adults, has to be adapted to children's cognitive capacities, with an extended follow-up. Neither the old nor the recent studies clearly identify predictive risk factors. Children describe the same perceptions as adults during their awareness period (mainly auditory and tactile sensations), but with fewer negative thoughts. Moreover, they do not seem to be affected by this experience, as they do not have long-term psychological sequelae. The prevention of intraoperative awareness in children is the same as in adults, the major factor being awareness of this complication. SUMMARY: Intraoperative awareness is a reality in school-aged children. A larger multicentre study and large-scale follow-up is required in order to confirm the higher incidence of awareness and identify the risk factors and long-term psychological sequelae of this complication in the paediatric population.

Adolescent↗

Awareness affects the response of human subjects exposed to a single whiplash-like perturbation.

STUDY DESIGN: Human subjects were exposed experimentally to a single whiplash-like perturbation. OBJECTIVE: To determine how awareness of the presence and timing of a whiplash-like perturbation affects the onset and amplitude of the neck muscle response and the peak magnitude of head and neck kinematics. SUMMARY OF BACKGROUND DATA: Although most whiplash injuries are sustained in rear-end collisions, which occur without warning, most studies of whiplash injury have used subjects aware of the imminent perturbation. METHODS: Seated subjects (35 women and 31 men) underwent a single forward horizontal perturbation (peak acceleration, 1.5 g). Surface electromyography measured the sternocleidomastoid and cervical paraspinal muscle activity. Three awareness conditions were tested: a countdown for subjects alerted to their perturbation, a perturbation without an alert for subjects who expected it within 60 seconds, and an unexpected perturbation for surprised subjects who were deceived. RESULTS: The muscle and kinematic responses of aware (alerted and unalerted) subjects were not significantly different. Sternocleidomastoid activation occurred 7 ms later in surprised subjects than in aware subjects (P < 0.0002). Cervical paraspinal amplitudes were 260% larger and angular head accelerations in flexion were 180% larger in surprised male subjects than in alerted male subjects. Surprised female subjects exhibited a 25% larger head retraction and a 30% lower forward acceleration of the mastoid process than aware female subjects. CONCLUSIONS: The larger retractions observed in surprised females likely produce larger tissue strains and may increase injury potential. Aware human subjects may not replicate the muscle response, kinematic response, or whiplash injury potential of unprepared occupants in real collisions.

Acceleration↗

Parallel acquisition of awareness and trace eyeblink classical conditioning.

Trace eyeblink conditioning (with a trace interval >/=500 msec) depends on the integrity of the hippocampus and requires that participants develop awareness of the stimulus contingencies (i.e., awareness that the conditioned stimulus [CS] predicts the unconditioned stimulus [US]). Previous investigations of the relationship between trace eyeblink conditioning and awareness of the stimulus contingencies have manipulated awareness or have assessed awareness at fixed intervals during and after the conditioning session. In this study, we tracked the development of knowledge about the stimulus contingencies trial by trial by asking participants to try to predict either the onset of the US or the onset of their eyeblinks during differential trace eyeblink conditioning. Asking participants to predict their eyeblinks inhibited both the acquisition of awareness and eyeblink conditioning. In contrast, asking participants to predict the onset of the US promoted awareness and facilitated conditioning. Acquisition of knowledge about the stimulus contingencies and acquisition of differential trace eyeblink conditioning developed approximately in parallel (i.e., concurrently).

Aged↗

Symptomatic awareness of hypoglycaemia: does it change on transfer from animal to human insulin?

A retrospective survey of symptomatic awareness of hypoglycaemia was performed in 189 randomly selected patients with insulin-treated diabetes who had been transferred from highly purified animal insulins to human insulin in the preceding 24 months. Of the 189 patients 44 (23%) complained of chronic hypoglycaemic unawareness, unrelated to ambient blood glucose control, before change of insulin species. Only 12 of the remaining 145 patients reported a reduction in awareness of hypoglycaemia following transfer to human insulin (6% of the whole group), while 6 (3%) reported an increase in awareness following the transfer. The 12 patients reporting reduced awareness had a mean duration of diabetes of 24 +/ 10 years compared to a duration of 15 +/- 10 years in the patients with normal awareness. The mean glycosylated haemoglobin concentrations were similar in all of the groups of patients. Six patients had developed total loss of awareness of the onset of hypoglycaemia, with all but one patient having suffered multiple episodes of severe hypoglycaemia. This reduced hypoglycaemic awareness on human insulin therapy was not associated with any significant improvement in blood glucose control.

Adult↗

Understanding employee awareness of health care quality information: how can employers benefit?

OBJECTIVE: To analyze the factors associated with employee awareness of employer-disseminated quality information on providers. DATA SOURCES: Primary data were collected in 2002 on a stratified, random sample of 1,365 employees in 16 firms that are members of the Buyers Health Care Action Group (BHCAG) located in the Minneapolis-St. Paul region. An employer survey was also conducted to assess how employers communicated the quality information to employees. STUDY DESIGN: In 2001, BHCAG sponsored two programs for reporting provider quality. We specify employee awareness of the quality information to depend on factors that influence the benefits and costs of search. Factors influencing the benefits include age, sex, provider satisfaction, health status, job tenure, and Twin Cities tenure. Factors influencing search costs include employee income, education, and employer communication strategies. We estimate the model using bivariate probit analysis. DATA COLLECTION: Employee data were collected by phone survey. PRINCIPAL FINDINGS: Overall, the level of quality information awareness is low. However, employer communication strategies such as distributing booklets to all employees or making them available on request have a large effect on the probability of quality information awareness. Employee education and utilization of providers' services are also positively related to awareness. CONCLUSIONS: This study is one of the first to investigate employee awareness of provider quality information. Given the direct implications for medical outcomes, one might anticipate higher rates of awareness regarding provider quality, relative to plan quality. However, we do not find empirical evidence to support this assertion.

Awareness↗

An appraisal of the level of awareness and utilization of the Pap smear as a cervical cancer screening test among female health workers in a tertiary health institution.

Papanicolaou (Pap) smear test is considered the best approach to reduce cervical cancer incidence worldwide. We surveyed 195 female health workers with structured questionnaires to identify factors that could influence the awareness and utilization of the Pap smear as a cervical cancer screening test. More than 65% of the respondents were aware of the disease, cervical cancer, and approximately 64% were aware of the Pap smear test. Seven three (39.7%) of the respondents had their sexual debut (coitarche) before the age of 20 years, while 109 (59.9%) have had multiple sexual partners. The modal number of sexual partners was 3, range 0-8. Pap smear awareness level significantly varied among the categories of the female health workers (P < 0.001). A minority of 14.1% have had a Pap test. There was a significant variation in utilization of Pap test across the various categories of the health workers (Pearson Chi-square 14.67, P < 0.05), and a significant correlation between Pap smear awareness and utilization (P < 0.001). The majority, 89%, believed that they were not at risk of developing cervical cancer. The self-reported utilization of Pap test among health workers was low. While there was a positive correlation between Pap test awareness and utilization, screening uptake was very poor due to a combination of inappropriate beliefs, misapprehension, and deficient knowledge. There is an urgent need for an aggressive awareness campaign and the provision of a screening program nationally.

Adult↗

Intact verbal description of letters with diminished awareness of their forms.

Visual processing and its conscious awareness can be dissociated. To examine the extent of dissociation between ability to read characters or words and to be consciously aware of their forms, reading ability and conscious awareness for characters were examined using a tachistoscope in an alexic patient. A right handed woman with 14 years of education presented with incomplete right hemianopia, alexia with kanji (ideogram) agraphia, anomia, and amnesia. Brain MRI disclosed cerebral infarction limited to the left lower bank of the calcarine fissure, lingual and parahippocampal gyri, and an old infarction in the right medial frontal lobe. Tachistoscopic examination disclosed that she could read characters aloud in the right lower hemifield when she was not clearly aware of their forms and only noted their presence vaguely. Although her performance in reading kanji was better in the left than the right field, she could read kana (phonogram) characters and Arabic numerals equally well in both fields. By contrast, she claimed that she saw only a flash of light in 61% of trials and noticed vague forms of stimuli in 36% of trials. She never recognised a form of a letter in the right lower field precisely. She performed judgment tasks better in the left than right lower hemifield where she had to judge whether two kana characters were the same or different. Although dissociation between performance of visual recognition tasks and conscious awareness of the visual experience was found in patients with blindsight or residual vision, reading (verbal identification) of characters without clear awareness of their forms has not been reported in clinical cases. Diminished awareness of forms in our patient may reflect incomplete input to the extrastriate cortex.

Awareness↗

The incidence of awareness during anesthesia: a multicenter United States study.

Awareness with recall after general anesthesia is an infrequent, but well described, phenomenon that may result in posttraumatic stress disorder. There are no recent data on the incidence of this complication in the United States. We, therefore, undertook a prospective study to determine the incidence of awareness with recall during general anesthesia in the United States. This is a prospective, nonrandomized descriptive cohort study that was conducted at seven academic medical centers in the United States. Patients scheduled for surgery under general anesthesia were interviewed in the postoperative recovery room and at least a week after anesthesia and surgery by using a structured interview. Data from 19,575 patients are presented. A total of 25 awareness cases were identified (0.13% incidence). These occurred at a rate of 1-2 cases per 1000 patients at each site. Awareness was associated with increased ASA physical status (odds ratio, 2.41; 95% confidence interval, 1.04-5.60 for ASA status III-V compared with ASA status I-II). Age and sex did not influence the incidence of awareness. There were 46 additional cases (0.24%) of possible awareness and 1183 cases (6.04%) of possible intraoperative dreaming. The incidence of awareness during general anesthesia with recall in the United States is comparable to that described in other countries. Assuming that approximately 20 million anesthetics are administered in the United States annually, we can expect approximately 26,000 cases to occur each year.

Adult↗