Unwanted wakefulness during general anesthesia
Klinik für Anästhesiologie, Ludwig-Maximilians-Universität, München.Der Anaesthesist (Impact Factor: 0.76). 07/2004; 53(6):581-92; quiz 593-4.
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.
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ABSTRACT: We report on a 49-year-old female patient suffering from recurrent carcinoma of the rectum, who underwent a palliative Hartmann operation for an anus praeter reconstruction. After a remifentanil bolus of 90 microg and a propofol bolus of 200 mg, anaesthesia was maintained with 0.25 microg/kg/min remifentanil and 4 mg/kg propofol, and after skin incision with 1.0 microg/kg/min remifentanil and 5 mg/kg/h propofol. Throughout the operation, the patient showed a stable blood pressure of 120-130/80 mmHg but 15 min after skin incision the heart rate suddenly rose to 140 beats/min, so remifentanil was increased to 1.8 microg/kg/min and propofol to 8 mg/kg/h. Over a time period of 15 min the heart rate decreased to 90 beats/min. Subsequently vegetative parameters stayed within the normal range (heart rate 90 beats/min, blood pressure 120-130/80 mmHg) so that continuous administration of remifentanil and propofol could be tapered. After completion of skin sutures, administration of remifentanil and propofol was terminated. After extubation the patient reported having heard conversations contributable to the end of the operation and the sentence: "now we're done" was clearly remembered. The patient stated that she had not been able to move any part of her body, that she had perceived the situation as extremely unpleasant and dangerous and that she had felt severe pain. At the postoperative rounds the patient refused any psychological and psychiatric help.Der Anaesthesist 11/2005; 54(10):1000-4. · 0.76 Impact Factor
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ABSTRACT: Intraoperative awareness has been reported to occur in 0.8-5.0% of paediatric patients undergoing anaesthesia and, therefore, seems to be more common than in adults (incidence 0.1-0.2%). In adult patients, the consequences of intraoperative awareness are well known and can be severe, in children, however, they have not yet been adequately studied. The causes for intraoperative awareness can be divided into three broad categories: First, no or only a light anaesthetic is given on purpose, second, an insufficient dose of an anaesthetic is given inadvertently, third, there is equipment malfunction or the anaesthesiologist makes an error. Unfortunately, especially in young children, painful interventions are still performed without adequate analgesia, e.g. awake intubation or fracture manipulation under midazolam sedation alone. The key issue is, however, that pharmacokinetics and pharmacodynamics change enormously from the 500 g preterm baby to the adolescent patient. Adequate dosing is much more difficult in paediatric patients compared to standard adult surgical patients. Solid knowledge of the pharmacokinetic and pharmacodynamic characteristics of commonly used drugs in different paediatric age groups, as well as aiming for perfection in daily care will help to reduce the incidence of awareness. Methods for monitoring the depth of hypnosis, e.g. the bispectral index, will be used increasingly, at least in children above 1 year of age. In addition to clinical parameters, they will hopefully help to further reduce the incidence of intraoperative awareness.Der Anaesthesist 11/2006; 55(10):1041-9. · 0.76 Impact Factor
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ABSTRACT: Providing a secured airway is of paramount importance in cardiopulmonary resuscitation. Although intubating the trachea is yet seen as gold standard, this technique is still reserved to experienced healthcare professionals. Compared to bag-valve facemask ventilation, however, the insertion of a laryngeal mask airway offers the opportunity to ventilate the patient effectively and can also be placed easily by lay responders. Obviously, it might be inserted without detailed background knowledge.The purpose of the study was to investigate the intuitive use of airway devices by first-year medical students as well as the effect of a simple, but well-directed training programme. Retention of skills was re-evaluated six months thereafter. The insertion of a LMA-Classic and a LMA-Fastrach performed by inexperienced medical students was compared in an airway model. The improvement on their performance after a training programme of overall two hours was examined afterwards. Prior to any instruction, mean time to correct placement was 55.5 +/- 29.6 s for the LMA-Classic and 38.1 +/- 24.9 s for the LMA-Fastrach. Following training, time to correct placement decreased significantly with 22.9 +/- 13.5 s for the LMA-Classic and 22.9 +/- 19.0 s for the LMA-Fastrach, respectively (p < 0.05). After six months, the results are comparable prior (55.6 +/- 29.9 vs 43.1 +/- 34.7 s) and after a further training period (23.5 +/- 13.2 vs 26.6 +/- 21.6, p < 0.05). Untrained laypersons are able to use different airway devices in a manikin and may therefore provide a secured airway even without having any detailed background knowledge about the tool. Minimal theoretical instruction and practical skill training can improve their performance significantly. However, refreshment of knowledge seems justified after six months.BMC Emergency Medicine 09/2009; 9(1):18. DOI:10.1186/1471-227X-9-18
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