SEARCH · PubMed Health

Results for “Intraoperative Awareness”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources

PubMed2000

Patient satisfaction after anaesthesia and surgery: results of a prospective survey of 10,811 patients.

Patient satisfaction after anaesthesia is an important outcome of hospital care. We analysed our anaesthetic database to identify potentially modifiable factors associated with dissatisfaction. At the time of analysis, our database contained information on 10,811 in-patients interviewed on the first day after operation. The major subjective outcome measure was patient satisfaction. We also measured other predetermined outcomes, such as nausea, vomiting, pain and complications. The overall level of satisfaction was high (96.8%); 246 (2.3%) patients were 'somewhat dissatisfied' and 97 (0.9%) were 'dissatisfied' with their anaesthetic care. After adjustment for patient and surgical factors, there was a strong relation between patient dissatisfaction and: (i) intraoperative awareness (odds ratio (OR) 54.9, 95% confidence intervals (CI) 15.7-191); (ii) moderate or severe postoperative pain (OR 3.94, 95% CI 3.16-4.91); (iii) severe nausea and vomiting (OR 4.09, 95% CI 3.18-5.25); and (iv) any other postoperative complications (OR 2.04, 95% CI 1.61-2.56). Several factors associated with dissatisfaction may be preventable or better treated.

Adult↗

PubMed1996

Comparison of the effects of enflurane/N2O on the 40-Hz auditory steady-state response versus the auditory middle-latency response.

The auditory middle-latency response (AMLR) is a sequence of negative-positive waves occurring 12-50 ms after the onset of an auditory stimulus presented at rates of 10/s or less. When the rate of stimulus presentation is increased to approximately 40/s, overlapping of the AM-LRs results in a sustained, nearly sinusoidal wave, called the "40-Hz auditory steady-state response" (40-Hz ASSR). The AMLR and 40-Hz ASSR have been used to study the effects of general anesthetics on the brain. The primary aim of this investigation was to determine whether the effects of a general anesthetic, namely enflurane, on the 40-Hz ASSR can be predicted from its effects on the AMLR. A secondary aim was to examine the relationship between the level of consciousness and the 40-Hz ASSR during emergence from anesthesia. Twelve ASA class I-II women undergoing reduction mammoplasty were tested. Anesthesia was induced with fentanyl (3 micrograms/kg) and thiopental (3-5 mg/kg) intravenously and was maintained with enflurane (0.5%, 0.8%, or 1.1% end-tidal; four patients per concentration; random assignment) in N2O (66% end-tidal), along with fentanyl (1 microgram/kg as needed). The 40-Hz ASSR and AMLR were recorded before induction and during anesthesia and surgery. The 40-Hz ASSR was also recorded during emergence. The amplitude of the 40-Hz ASSR was reduced profoundly during anesthesia and surgery (P < 0.001). The attenuation was not dose-dependent, and was much more pronounced than predicted by the effects of enflurane on the AMLR. The 40-Hz ASSR during anesthesia was surprisingly large (0.09 and 0.11 microV) in two patients, both of the 1.1% enflurane group. The regaining of the ability to follow verbal commands was associated with a significant (P < 0.001) increase in the amplitude of the 40-Hz ASSR. We conclude that, although auditory neurons remain capable of responding at a slow stimulus rate during enflurane-N2O anesthesia, their ability to be driven at a faster stimulus rate is markedly curtailed. The 40-Hz ASSR may be useful for detecting unintentional intraoperative awareness because the return of consciousness is associated with a clear increase in amplitude.

Adjuvants, Anesthesia↗

PubMed2000

The visual analog scale allows effective measurement of preoperative anxiety and detection of patients' anesthetic concerns.

UNLABELLED: The advent of managed care, reduction of costs, and advances in medical technology place increasing demands on anesthesiologists. Preoperative anxiety may go unnoticed in an environment that stresses increased productivity. The present study compares different methods for measuring preoperative anxiety, identifies certain patient characteristics that predispose to high anxiety, and describes the quantity and quality of anxiety that patients experience preoperatively. Seven hundred thirty-four patients participated in the study. We assessed aspects of anxiety by means of visual analog scales (VAS) and the State Anxiety Score of the Spielberger State-Trait Anxiety Inventory (STAI). The mean STAI anxiety score was 39 +/- 1 (n = 486) and the mean VAS for fear of anesthesia was 29 +/- 1 (n = 539). Patients feared surgery significantly more than anesthesia (P < 0.001). The VAS measuring fear of anesthesia correlated well with the STAI score (r = 0.55; P < 0.01). Young patients, female patients, and patients with no previous anesthetic experience or a previous negative anesthetic experience had higher anxiety scores. Patients worried most about the waiting period preceding surgery and were least concerned about possible awareness intraoperatively. Factor analysis of various anxiety items showed three distinct dimensions of fear: 1) the fear of the unknown 2) the fear of feeling ill, and 3) the fear for one's life. Among these dimensions, fear of the unknown correlated highest with the anxiety measuring techniques STAI and VAS. The simple VAS proved to be a useful and valid measure of preoperative anxiety. IMPLICATIONS: The study of qualitative aspects of anxiety reveals three distinct dimensions of preoperative fear: fear of the unknown, fear of feeling ill, and fear for one's life. Groups of patients with a higher degree of preoperative anxiety and their specific anesthetic concerns can be identified using the visual analog scale.

Adult↗

PubMed2002

Bispectral index in patients with target-controlled or manually-controlled infusion of propofol.

UNLABELLED: In this prospective, randomized study we compared bispectral index (BIS), hemodynamics, time to extubation, and the costs of target-controlled infusion (TCI) and manually-controlled infusion (MCI) of propofol. Forty patients undergoing first-time implantation of a cardioverter-defibrillator were included. Anesthesia was performed with remifentanil (0.2-0.3 micro g. kg(-1). min(-1)) and propofol. Propofol was used as TCI (plasma target concentration, 2.5-3.5 micro g/mL; n = 20) or MCI (3.0-4.0 mg. kg(-1). h(-1); n = 20). BIS, heart rate, and arterial blood pressure were measured at six data points: T1, before anesthesia; T2, after intubation; T3, after skin incision; T4, after first defibrillation; T5, after third defibrillation; and T6, after extubation. There were no significant hemodynamic differences between the two groups. BIS was significantly lower at T3 and T4 in the TCI group than in the MCI group. The mean dose of propofol was larger in TCI patients (5.8 +/- 1.4 mg. kg(-1). h(-1)) than in the MCI patients (3.7 +/- 0.6 mg. kg(-1). h(-1)) (P < 0.05), whereas doses of remifentanil did not differ. Time to extubation did not differ between the two groups (TCI, 13.7 +/- 5.3 min; MCI, 12.3 +/- 3.5 min). One patient in the MCI group had signs of intraoperative awareness without explicit memory after first defibrillation (BIS before shock, 49; after shock, 83). Costs were significantly less in the MCI group (34.83 US dollars) than in the TCI group (39.73 US dollars). BIS failed to predict the adequacy of anesthesia for the next painful stimulus. IMPLICATIONS: In this prospective, randomized study, bispectral index (BIS), hemodynamics, time to extubation, and costs of target-controlled infusion (TCI) and manually-controlled infusion of propofol were compared. TCI increased the amount of propofol used. BIS failed to predict the adequacy of anesthesia for the next painful stimulus.

Aged↗

PubMed1979

Comparison of anesthesia with diazepam and ketamine vs. morphine in patients undergoing heart-valve replacement.

Because of its analgesic and amnesic effects, ketamine has potential advantages as a primary agent for patients undergoing open-heart surgery. However, the undesirable positive inotropic and chronotropic effects associated with ketamine have deterred its use. Diazepam pretreatment appears to block these unwanted effects. Sixteen randomly selected patients were given a combination of diazepam, 0.4 mg/kg, followed by ketamine, 2 mg/kg, and nitrous oxide, 50%. The authors compared the circulatory responses to induction, intubation, and operation with those obtained in a matched group of patients who received morphine, 3 mg/kg, and nitrous oxide, 50%. All patients underwent mitral- or aortic-valve replacement. Circulatory responses were not significantly different between the two groups. In both groups, heart rate, mean arterial blood pressure, and rate-pressure product increased significantly with intubation of the trachea, incision of the skin, and sternotomy. The incidences of hypertension, hypotension, and arrhythmias, and the need for inotropic drugs were not significantly different between the two groups. No intraoperative awareness occurred in either group. It is concluded that diazepam-ketamine anesthesia is a satisfactory alternative to morphine anesthesia for patient undergoing heart-valve replacement.

Adult↗

PubMed2001

Monitoring depth of anesthesia.

Devices which monitor some aspect of anesthetic drug effects have evolved in the past few years into imperfect, but very useful, clinical tools. With appropriate respect for their limitations these monitors can be used to reduce anesthetic drug utilization and turnover time. The intriguing hypothesis that such monitors will reduce the risk of intraoperative awareness is currently under test.

Journal Article↗

PubMed2002

Multiple sclerosis and anesthetic implications.

PURPOSE OF REVIEW: Multiple sclerosis remains prevalent among young women in the United States of America. It is a disease of the central nervous system that possesses many anesthetic implications. Anesthesia providers need to understand this disorder and its multiple anesthetic ramifications. RECENT FINDINGS: Recent work has provided more insight into the etiology of multiple sclerosis, its pathogenesis, diagnosis and natural history. A number of new medications have also been added to the therapeutic armamentarium. Optimal anesthetic care entails a thorough preoperative evaluation, medication history and neurologic examination, intraoperative awareness of conditions that may precipitate attacks and lead to potentially life-threatening complications, as well as postoperative attention to respiratory and other risks. Recommendations for management are based on information from small retrospective studies and anecdotal reports. SUMMARY: In summary, our aim is to provide an updated view of multiple sclerosis from the perspective of perioperative care, emphasizing interactions between the disease, surgery and anesthesia.

Journal Article↗

PubMed2004

Bispectral index monitoring in pediatric anesthesia.

PURPOSE OF REVIEW: Anesthetic management guided by bispectral index monitoring has been demonstrated to facilitate earlier recovery in adults. Recent preliminary data also suggest that titration of drugs to achieve a specific bispectral index value may reduce the incidence of intraoperative awareness in high-risk adults. It is unclear, however, if this technology will benefit children as it is based on an algorithm developed from adults. This article reviews the literature on the use of the bispectral index monitor in children. RECENT FINDINGS: In recent studies, bispectral index scores were shown to correlate well with sedation scores during conscious and deep sedation in pediatric patients, and also with end-tidal concentrations of inhalation agents in children, although bispectral index values may differ with equipotent doses of different agents. Other studies have shown that titrating anesthetic agents to a specific bispectral index value during general anesthesia in the pediatric age group is associated with the use of lower amounts of anesthetic agents and faster recovery from anesthesia in children over 2 years old. However, the utility of bispectral index monitoring in infants, particularly those less than 6 months old, is questionable, as there is little correlation between bispectral index values and other measures of the depth of anesthesia in this subset of patients. SUMMARY: Bispectral index monitoring may be used to guide anesthetic administration in older children, but its use as a tool for guiding sedation in the younger pediatric patient needs further investigation. It may be necessary to develop a different bispectral index algorithm for children in the younger age groups.

Journal Article↗

PubMed2003

Remifentanil: an update.

PURPOSE OF REVIEW: Remifentanil has now reached maturity, as reflected by the increasing number of clinical papers relating to its use. Its position among anaesthetic drugs is now better understood, and this review will attempt to place it in the context of current clinical practice. RECENT FINDINGS AND SUMMARY: Propofol reduces the initial distribution of remifentanil, leading to higher concentrations during induction. Propofol and remifentanil administered together at sedative doses display a major synergistic interaction on the respiratory drive. Remifentanil accelerates the penetration of sevoflurane to its site of effect. The risk of intraoperative awareness seems to be low when remifentanil is associated to very low concentrations of hypnotic drugs, but this field warrants further investigation. Acute tolerance to opioids and its prevention remain controversial. SUMMARY: Remifentanil is the opioid of choice for tracheal intubation without muscle relaxants. It provides an alternative to regional anaesthesia in labour pain control. Target-controlled infusion may further improve the administration of remifentanil.

Journal Article↗

PubMed1989

Isoflurane or halothane for cesarean section: comparative maternal and neonatal effects.

The maternal and neonatal effects of isoflurane and halothane combined with 50% N2O - 50% O2 were compared in 60 healthy parturients undergoing primary or repeat cesarean section. All patients had rapid sequence induction of anesthesia with sodium thiamylal 4 mg/kg followed by succinylcholine for tracheal intubation. Patients were randomly assigned to one of three groups of 20 each (inspired 0.5% isoflurane, 1% isoflurane or 0.5% halothane), combined with 50% N2O and O2. After delivery, 67% N2O in O2 was used, supplemented by butorphanol. Maternal blood loss did not differ significantly among the three groups and none of the patients developed intraoperative awareness. At the time of delivery, maternal plasma epinephrine levels were significantly above preinduction levels in the 0.5% isoflurane group but unchanged in the other two groups. Neonatal status as ascertained by Apgar scores, cord acid base status and the Neurologic and Adaptive Capacity Scores (NACS) was equally good in the three groups of patients. Serum inorganic fluoride concentrations in the mother after anesthesia were not significantly above preanesthetic levels in any of the groups and there was no biochemical evidence of renal toxicity. In all neonates fluoride ion concentrations in the first voided urine sample were less than 7 mumol/l, a value well below that associated with nephrotoxicity. It is concluded that isoflurane is a safe supplement to N2O - O2 mixture for cesarean section and is a safer alternative to halothane in situations when patients receiving beta-adrenergic therapy require cesarean section since halothane might potentiate arrhythmias caused by beta adrenergic agonists.

Adult↗

PubMed1995

Intravenous propofol vs thiamylal-isoflurane for caesarean section, comparative maternal and neonatal effects.

Several studies on propofol (Diprivan) for induction of anaesthesia during caesarean section have demonstrated its safety, however, it safety during maintenance of anaesthesia is not yet fully evaluated. The present study was undertaken to compare the maternal and neonatal effects of propofol or isoflurane in 74 term parturients undergoing primary or repeat caesarean section. Patients were randomly assigned to two groups, propofol group (n = 37) received propofol 1.5-2.5 mg.kg-1 for induction followed by a continuous infusion of propofol of 0.05-0.2 mg.kg-1.min-1. The isoflurane group (n = 37) received thiamylal 3-4mg.kg-1 for induction followed by isoflurane 0.25-0.75% for maintenance. All patients had rapid sequence induction using succinylcholine and endotracheal intubation, 50% N2O and O2 were used in all patients until delivery. After delivery N2O concentration was increased to 67% and intravenous butorphanol (Stadol) was given as needed. Patients in the propofol group had less hypertension after intubation (P < 0.05) and this was also of shorter duration compared to patients in the isoflurane group (5 min vs 10 min respectively). Maternal blood loss as well as intraoperative awareness and recovery time did not differ significantly between the two groups. Neonatal status as ascertained by Apgar scores, cord acid base status and the neurological and adaptive capacity scores (NACS) was equally good in both groups. It is concluded that propofol used for induction and maintenance of anaesthesia is a safe alternative to thiamylal/isoflurane for patients undergoing caesarean section and is associated with less hypertensive response during laryngoscopy and intubation.

Acid-Base Equilibrium↗

PubMed1996

Midlatency auditory evoked potentials during anaesthesia with increasing endexpiratory concentrations of desflurane.

BACKGROUND: Under general anaesthesia with the volatile anaesthetics halothane, enflurane and isoflurane, midlatency auditory evoked potentials (MLAEP) are suppressed dose-dependently. Therefore, MLAEP have been used to measure depth of anaesthesia and to indicate intraoperative awareness. Desflurane is a new volatile anaesthetic and its effect on MLAEP have not been studied previously. METHODS: We have studied MLAEP during general anaesthesia with increasing endexpiratory concentrations of desflurane in 12 patients scheduled for elective gynaecological surgery. Auditory evoked potentials were recorded in the awake state and during anaesthesia with endexpiratory steady state concentrations of 1.5, 3.0, 4.5 and 6.0 vol % of desflurane on vertex (positive) and mastoids on both sides (negative). Latencies of the peaks V, Na, Pa, Nb, Pl (ms) and amplitudes Na/Pa, Pa/Nb and Nb/Pl (micro V) were measured. RESULTS: In the awake state, MLAEP had high peak-to-peak amplitudes and a periodic waveform. During general anaesthesia with increasing endexpiratory concentration of desflurane, the latency of the brainstem response V increased only slightly. In contrast, MLAEP showed a marked dose-dependent and statistically significant increase in latencies of Na, Pa, Nb and Pl and decrease in amplitudes of Na/Pa, Pa/Nb and Nb/Pl. Under 6.0 vol % of desflurane MLAEP were severely attenuated or even abolished. CONCLUSION: Based on these observations, endexpiratory concentrations of > or = 4.5 vol % desflurane should suppress awareness phenomena such as auditory perceptions during anaesthesia.

Adult↗

PubMed2005

Combined general-epidural anesthesia decreases the desflurane requirement for equivalent A-line ARX index in colorectal surgery.

BACKGROUND: The present study used the A-line ARX index, derived from auditory evoked potential measurements, to examine the effect of epidural lidocaine on the end-tidal concentration of desflurane during general anesthesia. METHODS: Thirty ASA I-II patients scheduled for elective colorectal surgery were included and randomized, in a double-blinded fashion, to receive general anesthesia, and 15 ml of either 2% lidocaine (group GE, n=15) or normal saline (group GS, n=15) was administered epidurally with a maintenance infusion rate of 6 ml h-1. After a 10-min high-flow oxygen wash-in period, desflurane was titrated to a target A-line ARX index (AAI) of 20+/-5. RESULTS: Epidural lidocaine reduced the end-tidal concentration of desflurane required to maintain an adequate clinical effect by 42% compared to general anesthesia alone (2.6% vs. 4.5%, respectively; P<0.001). The initial mean value of AAI was 87.8 (range 78-99) in group GE and 88.13 (79-99) in group GS before general anesthesia induction, the AAI values were approximately 19.7 (15-25) in group GE and 20.2 (16-25) in group GS during anesthesia maintenance, and returned to 84.53 (77-98) in group GE and 86.87 (79-98) in group GS when the patients regained consciousness in the recovery room. No statistical difference in the AAI values was observed either before, during, or after emergence of anesthesia. No patient reported intraoperative awareness. CONCLUSIONS: Lower-than-expected concentrations of volatile anesthetics are sufficient to maintain appropriate a clinical anesthesia effect during combined general-epidural anesthesia under auditory-evoked potential monitoring.

Aged↗

PubMed2005

Emergence from propofol anesthesia in a nonagenarian at a Bispectral Index of 52.

In this case report, we describe a nonagenarian patient who could respond completely to verbal commands at a Bispectral Index (BIS) value of 52 after epidural lidocaine and IV propofol anesthesia. Measured blood lidocaine and propofol concentrations were 0.69 microg/mL and 0.74 microg/mL, respectively. Intraoperative awareness even in the recommended BIS range of 40-60 remains possible.

Aged↗

PubMed1995

Neurological and psychiatric adverse effects of anaesthetics: epidemiology and treatment.

The practice of anaesthesia has changed considerably over the past 20 to 30 years owing largely to technological advances in patient monitoring and an expanded and improved pharmacological repertoire. While patient safety in anaesthesia has greatly improved, the risk of neurological and psychiatric adverse effects of anaesthetics remains and is the focus of continued investigation. For example, a great deal of attention has recently been directed at intraoperative awareness. This adverse event can be caused by delivering an inappropriate amount or type of anaesthetic. Another risk of anaesthesia involves drug-induced unpleasant subjective states in patients. Those drugs most frequently associated with these states include ketamine, droperidol and scopolamine. This risk can often be attenuated by careful adjustment of drug dose and the use of adjunctive agents such as benzodiazepines which may produce amnesia of the unpleasant subjective state. While it is well established that modern anaesthetic drugs cause acute impairment of cognition and psychomotor functioning, there is little evidence that these drugs have long term impairing effects. Finally, a particular kind of surgery, cardiac surgery requiring cardiopulmonary bypass, can be associated with adverse neurological and psychiatric sequelae which, while not directly related to anaesthesia, are of intense interest to anaesthesiologists.

Anesthetics↗

PubMedDate not supplied

[Postoperative cognitive deficits].

Cognitive dysfunctions are relatively common in postoperative and critically ill patients. This complication not only compromises recovery after surgery, but, if persistent, it minimizes and compromises surgery itself. Risk factors of postoperative cognitive disorders can be divided into age and comorbidity dependent, and those related to anesthesia and surgery. Cardiovascular, orthopedic and urologic surgery carries high risk of postoperative cognitive dysfunction. It can also occur in other types of surgical treatment, especially in elderly. Among risk factors of cognitive disorders, associated with comorbidity, underlying psychiatric and neurological disorders, substance abuse and conditions with elevation of intracranial pressure are in the first place in postoperative patients. Preoperative and perioperative predisposing conditions for cognitive dysfunction and their incidence were described in our paper. These are: geriatric patients, patients with substance abuse, preexisting psychiatric or cognitive disorders, neurologic disease with high intracranial pressure, cerebrovascular insufficiency, epilepsia, preeclampsia, acute intermittent porphyria, operation type, brain hypoxia, changes in blood glucose level, electrolyte imbalance, anesthetic agents, adjuvant medication and intraoperative awareness. For each of these factors, evaluation, prevention and treatment strategies were suggested, with special regard on anesthetic technique.

Cognition Disorders↗

PubMed1987

Intraspinal narcotic anesthesia in open heart surgery.

Intraspinal narcotic anesthesia was performed in 180 open heart surgery patients. 0.1 mg/Kg of morphine or 1.5 mg/Kg of meperidine was administered as the primary anesthetic in the subarachnoid space using the barbotage technique. Of the 180 patients scheduled for open heart surgery, morphine was administered to 95 patients, meperidine to 55 and a mixture of morphine and meperidine to 30 patients. From a clinical point of view, there were no significant cardiovascular problems, however, respiratory depression seemed to be most serious after morphine administration. Mild complications such as pruritus (11.1%), voiding difficulty (10.6%), intraoperative awareness (4.4%) and spinal headache were observed, however these were mild, not major clinical problems and were acceptable. Postoperative analgesic effect and respiratory controllability were excellent.

Anesthesia, Spinal↗

PubMed1999

[Recollections of ventilated patients after a stay in the intensive care unit].

UNLABELLED: A review of the literature reveals only scarce data and observations concerning the recollections of patients treated in a intensive care unit, although intraoperative awareness under general anaesthesia has been extensively reported. In the present study we investigated the recollections of patients who had undergone artificial ventilation in intensive care units. METHODS: Fifty patients who had undergone mechanical ventilation in intensive care units at the University Hospital of Vienna were retrospectively interviewed in regard of their experience during the treatment. A score was used to quantify discomfort. RESULTS: All patients remembered having been treated at the intensive care unit. The most unpleasant experience was tracheal suctioning which was remembered by 60%. The next most unpleasant experience was extubation; 52% remembered this intervention. Eighty-four per cent of patients remembered the medical staff, 90% of them had confidence in them, 86% remembered the nursing staff and 91% had confidence in them. CONCLUSION: In spite of unpleasant memories of intensive care treatment, of which tracheal suctioning was perceived as most unpleasant, the majority of patients expressed a positive evaluation of their treatment at the intensive care unit.

Adult↗