Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2003
Case ReportsInadvertent positive end-expiratory pressure caused by a malfunctioning ventilator relief valve.
During anesthesia, a nurse draped several gas hoses over the ventilator relief valve on the back of the anesthesia machine, causing a malfunction. Unintended positive end-expiratory pressure was administered to the patient. Causes of this mishap, anesthesia machine design, and nonanesthesiologist familiarity with anesthesia machine components and their function, are discussed.
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Anesthesia and analgesia · Aug 2003
Propofol-induced anesthesia in mice is mediated by gamma-aminobutyric acid-A and excitatory amino acid receptors.
To elucidate the role of gamma-aminobutyric acid (GABA)(A) receptor complex and excitatory amino acid receptors (N-methyl-D-aspartate [NMDA] and non-NMDA receptors) in propofol-induced anesthesia, we examined behaviorally the effects of GABAergic and glutamatergic drugs on propofol anesthesia in mice. All drugs were administered intraperitoneally. General anesthetic potencies were evaluated using a righting reflex assay. The GABA(A) receptor agonist muscimol potentiated propofol (140 mg/kg; 50% effective dose for loss of righting reflex) induced anesthesia. Similarly, the benzodiazepine receptor agonist diazepam and the NMDA receptor antagonist MK-801 augmented propofol anesthesia, but the non-NMDA receptor antagonist CNQX did not. In contrast, the GABA(A) receptor antagonist bicuculline antagonized propofol (200 mg/kg; 95% effective dose for loss of righting reflex) induced anesthesia. However, neither the benzodiazepine receptor antagonist flumazenil, the GABA synthesis inhibitor L-allylglycine, nor the NMDA receptor agonist NMDA reversed propofol anesthesia. Conversely, the non-NMDA receptor agonist kainate enhanced propofol anesthesia. These results suggest that propofol-induced anesthesia is mediated, at least in part, by both GABA(A) and excitatory amino acid receptors. ⋯ We examined behaviorally the effects of GABAergic and glutamatergic drugs on propofol-induced anesthesia in mice. The results suggest that propofol anesthesia is mediated, at least in part, by both GABA(A) and excitatory amino acid receptors.
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Anesthesia and analgesia · Aug 2003
Neurotrophic factors can partially reverse morphological changes induced by mepivacaine and bupivacaine in developing sensory neurons.
Both bupivacaine and mepivacaine induce morphological changes in growing neurons. We designed this study to investigate the role of some neurotrophic factors (NTFs) in supporting developing neurons exposed to the deleterious effects of these drugs. Dorsal root ganglia were isolated from chick embryos and exposed to either bupivacaine or mepivacaine. After 60 min of exposure, the culture media were replaced with fresh culture media free from local anesthetics. NTFs-brain-derived NTF, glial-derived NTF, or neurotrophin-3-were added to the replacement media, and the cells were examined up to 48 h after the washout. The growth cone collapse assay was applied by a quantitative method of assessment. When the replacement media were not supported by any NTF, the growth cone collapse values were significantly larger than the control values at 20 h after the washout of mepivacaine and 48 h after the washout of either bupivacaine or mepivacaine (P < 0.05). However, when any of the NTFs were used, the collapsing activity was significantly attenuated, and growth cone collapse values showed no statistically significant differences in comparison with the control values at these time points (P > 0.05). We conclude that several NTFs support the recovery of neurons after exposure to local anesthetics. The supporting effects of NTFs on the reversibility of mepivacaine-induced collapse tended to be more obvious than those seen after the bupivacaine washout. ⋯ Three neurotrophic factors (NTFs) can partially support the reversibility of mepivacaine- and bupivacaine-induced growth cone collapse in growing primary cultured sensory neurons. The effect of NTFs is more apparent after mepivacaine than after bupivacaine washout.
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Anesthesia and analgesia · Aug 2003
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of the costs and efficacy of ondansetron and dolasetron in the prophylaxis of postoperative vomiting in pediatric patients undergoing ambulatory surgery.
Postoperative vomiting (POV) after ambulatory surgery remains a major problem. We designed this study to determine the smallest dose of dolasetron equivalent to the Food and Drug Administration approved dose of ondansetron 100 micro g/kg IV, for the prophylaxis of POV in children undergoing surgery. In this double-blinded controlled study, 204 healthy ASA I-II children aged 2-12 yr, undergoing superficial ambulatory (day-case) surgery, were randomized to receive either ondansetron 100 micro g/kg IV, or dolasetron 45, 175, 350, or 700 micro g/kg IV during a standardized perioperative regimen. The primary end-point was the incidence of complete response, defined as the absence of POV symptoms. Costs were calculated from the perspective of the hospital using a previously described model. The incidence of early (0-6 h) and 24-h emesis was more frequent in the dolasetron 45 micro g/kg group compared with the dolasetron 350 and 700 micro g/kg groups and with the ondansetron group. Repeated POV occurred more often when dolasetron was used in a dose <350 micro g/kg. There were no significant differences in emesis rates between the dolasetron 175, 350, and 700 micro g/kg groups or between these groups and the ondansetron 100 micro g/kg group. The smallest dose of dolasetron with acceptable equivalent efficacy and patient satisfaction scores to ondansetron 100 micro g/kg was 350 micro g/kg. Institutional costs for managing POV were less with dolasetron 350 micro g/kg than with ondansetron. ⋯ This randomized double-blinded dose-ranging study concluded that dolasetron, 350 micro g/kg IV, was the smallest dose that provided acceptable equivalent efficacy and patient satisfaction scores to ondansetron, 100 micro g/kg IV, for the prophylaxis of postoperative vomiting in children undergoing outpatient surgery. However, with this dose, the costs to the institution for managing postoperative vomiting were less.