PubMed Health⌕ Search

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 127 records · Page 7Linked to original sources
PubMed2000

[Two cases of extreme hemodilution caused by massive hemorrhage immediately after start of operation].

We describe two cases of extreme hemodilution due to large amounts of fluid infusion for unexpected massive hemorrhage. In both cases, unexpected hemorrhage with difficult hemostasis occurred within 60 min after the start of the operation. For lack of transfused blood, large amounts of fluid infusion using crystalloid and colloid solutions including 5% albumin, plasma expander and lactated Ringer's solution were administered to maintain circulatory blood volume. The hemoglobin concentration and hematocrit had been below 2.0 g.dl-1 and 10% for approximately one hour, respectively. The extreme hemodilution improved by the urgent blood transfusion. In one case, intraoperative autotransfusion with Cell-Saver was performed. In spite of intraoperative extreme hemodilution, their postoperative courses were uneventful. Intraoperative awareness was present in both cases.

Adult↗
PubMed2000

Anesthesia for left ventricular assist device placement.

Appropriate anesthesia for LVAD placement needs to incorporate an understanding of the surgical procedure and LVAD physiology, the altered physiology and pharmacology of the cardiac failure patient, and a knowledge of the interaction of anesthesia with the potent cardiac drugs used in end-stage heart failure therapy. The anesthesiologist is faced with a critically ill decompensated patient, often with altered renal and hepatic function, but must ensure adequate anesthesia to avoid intraoperative awareness. Intelligent use of TEE can assist the surgeon to pinpoint potential pitfalls of LVAD placement and can have a significant effect on improving outcome in these challenging patients.

Anesthesia↗
PubMed2002

[Application of bispectral index (BIS) monitoring to anesthetic management of posterior spinal fusion in a patient with Duchenne muscular dystrophy].

A 12-year-old boy with Duchenne muscular dystrophy underwent posterior spinal fusion for progressive scoliosis. Preoperative evaluation was focused on respiratory function as well as cardiac function, which revealed markedly reduced respiratory reserve (FVC 0.77 l, %FVC 25.9%, FEV1.0 0.48 l, %FEV1.0 62%) and well-preserved biventricular function. A possible association between malignant hyperthermia and Duchenne muscular dystrophy has been documented. Thus anesthesia was administered without triggering agents. Propofol and fentanyl were used for induction and maintenance of anesthesia, and the patient was ventilated with O2-nitrous oxide mixture. The anesthesia machine, prepared by using a disposable circuit and fresh CO2-absorbent and disconnecting the vaporizers, was flushed with O2 at a rate of 10 l.min-1 for 20 minutes before use. A small dose of vecuronium was administered while monitoring the train-of-four ratio. The bispectral index (BIS) was utilized to optimize the depth of anesthesia so that the wake-up test could be performed promptly on surgeon's request while avoiding the intraoperative awareness. The BIS was helpful in continuously assessing the wakening process. BIS increased from 40's to 80's in 15 minutes after discontinuation of propofol and nitrous oxide during the test. The patient was kept under close observation postoperatively without any sign of malignant hyperthermia.

Anesthesia, General↗
PubMed2003

A survey of combined epidural-propofol anesthesia with noninvasive positive pressure ventilation as a minimally invasive anesthetic protocol.

BACKGROUND: Combined epidural-propofol anesthesia with use of noninvasive positive pressure ventilation (NPPV) via the nose has been used routinely in our operating theaters. The purpose of this report was to present a survey of this anesthesia. MATERIAL/METHODS: 265 adult patients undergoing lower extremity or lower abdominal gynecological surgery during 1999 were examined. After epidural anesthesia, patients were given propofol infusion. NPPV was applied with an inspiratory/expiratory positive airway pressure of 14/8 cm H2O, a respiratory rate of 10 breaths/min, and oxygen delivery into the nasal mask resulting in a concentration of 40% or an inspiratory oxygen fraction of 0.35. Epidural anesthesia was continuously applied after surgery for postoperative pain relief. Various data related to the surgery or anesthesia were evaluated both on the day of surgery and on postoperative day 1. RESULTS: Of 265 patients, 3 patients could not receive our anesthetic protocol. Of the residual 262 patients, no patients showed serious clinical problems during anesthesia, excluding for hypotension, which was observed in 31-56% patients and was treated with ephedrine injection. Patients informed us of good analgesia (98%), feelings (78%) and dreams (47%). On postoperative day 1, postoperative analgesia and mood conditions were satisfactory. There were no patients complaining of intraoperative awareness. CONCLUSIONS: The principle of our anesthesia consists of epidural anesthesia, sole propofol infusion and noninvasive airway management, so as to provide an anesthetic technique with minimal invasiveness. Although airway maintenance by NPPV is not always suitable, our anesthesia is practicable for certain kinds of operations.

Adult↗
PubMed1992

Total intravenous anesthesia with a continuous propofol-alfentanil infusion.

A total intravenous anesthetic using propofol and alfentanil was evaluated to determine if it would provide a shorter recovery-room stay than a more traditional balanced anesthetic using isoflurane and alfentanil. Forty-three ASA I or II patients between 17 and 50 years of age undergoing major abdominal or orthopedic procedures were studied. The propofol group received alfentanil 50 mg/kg followed by propofol 1 mg/kg for anesthesia induction. Continuous propofol infusion was initiated at induction using 170 mg/kg/min for 10 minutes, followed by 130 mg/kg/min for 10 minutes, then maintained at 100 mg/kg/min until 10 minutes before the end of surgery. Ventilation was supported with an air-oxygen mixture. The group receiving balanced anesthesia received alfentanil 1 mg/kg, and anesthesia was induced with sodium thiopental 4 mg/kg. A 1% isoflurane inhalation with air-oxygen was initiated immediately upon induction. Both groups received a continuous infusion of alfentanil titrated to maintain heart rate within 10% of preinduction levels. Recovery from anesthesia was measured using a subjective pain assessment, a verbal fluency test, and a short-term memory test. No differences were detected in the rate of recovery at 30 minutes or 60 minutes postextubation. Hemodynamic stability during induction and intubation was slightly better in the propofol group than in the isoflurane group. One episode each of intraoperative awareness and delayed eye opening occurred in the propofol group. Total intravenous anesthesia using propofol and alfentanil is just as effective as a balanced inhalation anesthetic and provides equally rapid recovery. However, practitioners are cautioned to include an amnestic adjuvant when using propofol as the sole anesthetic agent.

Adolescent↗
PubMed2004

[Paediatric anaesthesia: inhaled or intravenous technique?].

Total intravenous anaesthesia has recently gained more interest in paediatric anaesthesia. However, the global experience with children is limited, therefore, the knowledge acquired in adult practice is often applied uncritically to the paediatric patient. Induction of anaesthesia by mask is a widely used and generally accepted technique; it has gained even more popularity since the introduction of sevoflurane into clinical practice. This drug has markedly improved the safety because of the reduced cardiovascular side-effects. The availability of venous access is a prerequisite for intravenous induction. Pain on injection, bradycardia, and difficulties in dosing the individual patient are the main drawbacks. Inhaled anaesthetics allow to monitor breath by breath the individual pharmacokinetics. On the other hand, maintenance of anaesthesia by an intravenous infusion of propofol is mainly based on assumptions, even when the drug is administered by computer-controlled pumps. Large aberrations from the predicted values can occur in the individual patient. Intraoperative awareness is possible, however, its incidence is generally underestimated. Paravenous infusion and pump dysfunction are typical complications of an intravenous technique. A reduced incidence of postoperative vomiting and agitation are recognised advantages of an intravenous technique. Propofol-infusion-syndrome results from prolonged administration in children and in adults. It can even occur after the use of the substance for a few hours. The duration of a safe period for administration is completely unknown, especially for neonates and infants. In summary, both techniques can be used in children; both have advantages and drawbacks. Because the experience with small children is very limited, we have to re-evaluate our practice with a critical eye day by day.

Anesthesia, Inhalation↗
PubMed1990

[Mid-latency auditory evoked potentials during induction of intravenous anesthesia using midazolam, diazepam and flunitrazepam].

Since intraoperative awareness is not infrequently observed under balanced anaesthetic regimens employing benzodiazepines for suppression of consciousness, we studied the effect of intravenous induction of general anaesthesia using the benzodiazepines midazolam, diazepam and flunitrazepam on mid-latency auditory evoked potentials and auditory evoked neuronal 30-40 Hz oscillation. Following informed consent in 30 patients scheduled for minor gynaecological procedures, anaesthesia was induced with midazolam (0.2-0.3 mg/kg b.w. i.v., group I n = 10), diazepam (0.3-0,4 mg/kg b.w., i.v., group II n = 10) or flunitrazepam (0.03-0.04 mg/kg b.w., i.v., group III n = 10). Auditory evoked potentials were recorded before, during and after induction of general anaesthesia on vertex (positive) and mastoides on both sides (negative). Auditory clicks were presented binaurally at 70 dBnHL with a frequency of 9.3 Hz. Using the electrodiagnostic system Pathfinder I (Nicolet), 1000 successive stimuli were averaged over a 100 ms poststimulus period and analysed off-line. Latencies of the peak V, Na, Pa were measured. By means of Fast-Fourier transformation-analysis corresponding power spectra were calculated to analyse energy portions of the AEP frequency components. In the awake state AEP showed an oscillatory component between 20 and 100 ms poststimulus latency. Corresponding power spectra indicated a predominant 30-40 Hz frequency. After induction of general anaesthesia using midazolam, diazepam and flunitrazepam, there was no increase in latencies of the peaks V, Na, Pa, but only a small decrease in amplitudes Na/Pa without statistical significance. The auditory evoked mid-latency neuronal oscillation persisted under induction of general anaesthesia with midazolam, diazepam, flunitrazepam.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

[Does anesthesia always involve analgesia?].

The primary aim of anesthesia is the prevention of pain perception (analgesia), intraoperative awareness (hypnosis), and postoperative recall (amnesia) (anesthetic trade). Analgesia would be a component of the anesthetic state. Pain is the conscious perception of a noxious stimulus and analgesia is the abolished perception of pain in an otherwise conscious patient. During general anesthesia pain can not be experienced, since the patient is unconscious. However, there is no certainty that during anesthesia a blockade of the nociceptive system is reliably provided in all circumstances. The impact of insufficient blockade of nociceptive pathways during anesthesia on mental status and implicit memory are largely unknown. Therefore, the anesthetic trade should consist of hypnosis, amnesia and antinociception.

Analgesia↗
PubMed1998

[The switching time of propofol syringes for the propofol specific pump is dependent on the familiarity of pumps].

The switching time of syringes during propofol anesthesia was investigated among various anesthesiologists. One hundred and thirty times of exchanges were observed in the early 82 propofol anesthesia cases using a propofol specific syringe pump STC-525 X (Terumo, Japan) since the introduction of propofol in our hospital. The anesthesiologists were divided into three groups: group A; the board certified anesthesiologists with more than one month experience of propofol anesthesia, group B; the board certificed anesthesiologists with less than one month experience, group C: the trainee. There were no cases of intraoperative recall case. The median times of switching syringes were 14 seconds, 26 seconds, 56 seconds in the group A, group B, group C, respectively. Group A is significantly quicker than the other groups. This indicates that switching time is dependent on the experience with propofol and syringe pumps. We conclude that not only trainees but also expert anesthesiologists should be accustomed to switching syringes in order to avoid intraoperative awareness.

Anesthesiology↗
PubMed1985

[The significance of tramadol as an intraoperative analgesic. A randomized double-blind study in comparison with placebo].

Tramadol-N2O anaesthesia as recommended by Stoffregen was studied in 40 patients (ASA I-II) undergoing elective orthopaedic or lower abdominal surgery. Fentanyl and droperidol (Thalamonal)/atropine were given as i.m. premedication, induction was performed using methohexitone, succinylcholine and pancuronium, ventilation was controlled by means of a Takaoka respirator (N2O/O2 79:21, 4 breaths/min). Intraoperative analgesia was provided by a biphasic tramadol infusion. However, half the patients were given placebo infusion (0.9% NaCl) instead of tramadol in a randomized and double-blind manner in order to evaluate tramadol efficacy as one component of balanced anaesthesia. Whenever anaesthetic depth appeared to be insufficient enflurane (0,5-1.5 vol.%) was administered for short periods. Blood pressure, pulse rate as well as cumulative enflurane dose were documented; postoperative analgesic requirement and awareness of intraoperative events (tape recorder music offered via earphones) were further used to assess tramadol effects. Anaesthesia proved to be quite comparable in both groups; patients felt satisfied without exception. Relative cumulative enflurane times (vol.% . min, related to duration of anesthesia) did not differ significantly (tramadol 5.9%, placebo 4.9%). When enflurane had not been necessary (tramadol n = 13, placebo n = 10), mean percentage rises of blood pressure or pulse rate, related to preoperative values, were found to be slightly higher in the tramadol group. Postoperative analgesic requirement was reduced significantly after tramadol. Striking differences between the two groups, on the other hand, were shown with respect to intraoperative awareness: while patients receiving placebo proved to be amnaesic, 65% of tramadol patients were aware of intraoperative music.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2004

[Unwanted wakefulness during general anesthesia].

Intraoperative wakefulness ("awareness") is still a relevant problem. Different stages of wakefulness exist: conscious awareness with explicit recall of pain in 0.03% and with nonpainful explicit recall in 0.1-0.2% of all anesthesias; amnesic awareness or implicit recall may occur with unknown, even higher incidences. Sufficient analgesia minimizes possible painful perceptions. Opioids, benzodiazepines, and N(2)O alone or combined lead to the highest incidences of nonpainful intraoperative wakefulness. Volatile anesthetics, etomidate, barbiturates, and propofol in sufficient doses effectively block any sensory processing and therefore abolish intraoperative wakefulness. Intraoperative awareness with recall may lead to sustained impairment of the patients, in severe cases even to a post-traumatic stress disorder (PTSD). The observation of clinical signs does not reliably detect intraoperative wakefulness in all cases; monitoring of end-tidal gas concentrations, EEG, or evoked potentials may help in prevention. Active information is recommended only for patients at higher risk. Complaints about recall of intraoperative events should be taken seriously; in cases of sustained symptoms psychological help may be necessary.

Anesthesia, General↗
PubMed2001

[Depth of anesthesia, awareness and EEG].

Inapparent adverse intraoperative wakefulness is still a relevant problem in modern anaesthetic routine. It can be associated with serious negative effects on the postoperative recovery of the patients. Several different procedures have been developed to monitor and therefore avoid intraoperative situations of wakefulness during general anaesthesia. The most promising methods are the PRST-score, calculated from changes in the blood pressure, heart rate, sweating and tear production, the so-called isolated forearm technique, spontaneous EEG and its derived parameters such as spectral edge frequencies or BIS and finally mid-latency auditory evoked potentials. The observation of clinical autonomic signs, even including the calculation of the PRST-score does not seem to be valid enough to indicate or predict intraoperative wakefulness. The isolated forearm technique can be regarded as the most reliable tool to detect intraoperative wakefulness, but it can only be applied for a very limited period of time. The processed EEG with the median frequency, spectral edge frequency or bispectral index are important scientific tools to quantify central anaesthetic effects especially to develop pharmacodynamic-pharmacokinetic models of anaesthetic action. But they seem to be less suitable to indicate situations of intraoperative wakefulness or awareness. The mid-latency auditory evoked potentials are depressed dose-dependently by a series of anaesthetic agents, which correlate with the occurrence of situations of intraoperative wakefulness and awareness. There is a hierarchical correlation between certain values of the MLAEP and intraoperative wakefulness defined by purposeful movements, amnesic awareness with only implicit recall and conscious awareness with explicit recall. For some of the most commonly used anaesthetics reasonable threshold values of the MLAEP for the different states of consciousness have already been determined. Future studies in broad patient populations with all of the different routinely used anesthetics and procedures will have to finally identify the importance of the recording of mid-latency auditory evoked potentials as a routine method to assess the depth of anaesthesia.

Anesthesia↗
PubMed1999

[The effects of propofol anesthesia with or without the use of nitrous oxide on the intraoperative involuntary movement, the postoperative awareness and vomiting].

The authors investigated the effect of anesthesia with nitrous oxide and propofol on intraoperative involuntary movement, muscle relaxant usage, postoperative nausea and vomiting, the total amount of propofol used, and recovery time from anesthesia. Eighty-eight patients for gynecological surgery were randomly divided into group PE: propofol/epidural (n = 44), and group PEG: propofol/epidural/nitrous oxide (n = 44). The frequency of postoperative nausea and vomiting were assessed at 24-h postoperatively by blinded observers. There were significant decreases of the mean amounts of propofol and muscle relaxant used between group PEG and group PE. The authors found no correlation between the use of nitrous oxide and intraoperative involuntary movement, subsequent development of postoperative quality of awareness, recovery time, nausea and vomiting. We recommend PEG method for gynecological surgery rather than PE from an economical viewpoint because it is associated with the reduction of mean propofol and muscle relaxant used.

Adult↗
PubMed1995

Intraoperative complications during total hip arthroplasty.

Total hip replacement is one of the most common adult reconstructive procedures performed today. Even though training in total hip replacement has become fairly common in many orthopedic residency programs, complications can still occur during surgery. Preoperative planning and close attention to detail may prevent intraoperative problems. Awareness of the potential downfalls allows the surgeon to properly prepare for surgery, avoid intraoperative complications, and manage unavoidable problems when they do arise.

Acetabulum↗
PubMed2002

Application of artificial neural networks as an indicator of awareness with recall during general anaesthesia.

OBJECTIVE: Awareness with recall is a rare but serious complication of general anaesthesia with an incidence ranging from 0.1%-0.7%. In the absence of a reliable depth-of-anaesthesia monitor, attempts have been made to predict awareness from intraoperative haemodynamic monitoring data, with little success. Artificial neural networks can sometimes detect relationships between input and output variables even when conventional methods fail. Therefore, we subjected standard intraoperative monitoring data to both artificial neural models and conventional statistical methods in an attempt to predict awareness with recall. METHODS: Anaesthesia records from 33 patients with awareness and 510 patients without awareness were collected. Summary data (mean, maximum, and minimum) of end-tidal carbon dioxide concentration, arterial blood oxygen saturation, systolic and diastolic blood pressure, and heart rate were calculated for each patient. These data were subjected to an analysis by artificial neural networks and by Poisson regression. RESULTS: The two best neural models both had sensitivity and specificity of 23% and 98%, respectively. The models have high specificity, and in view of the low incidence of awareness, a high negative predictive value. The prediction probabilities P(k) (SE) for the best neural models were 0.66 (0.08) and 0.60 (0.10), respectively. In the Poisson regression, there were significant differences in systolic and diastolic blood pressures and heart rate between patients with and without awareness. CONCLUSIONS: A prediction indicating awareness by the network is very suggestive of true awareness and recall. Blood pressure and heart rate are significantly higher on average in patients with awareness than in patients without. In an individual patient, however, none of our artificial neural models can detect awareness sufficiently reliably.

Adult↗