Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2001
Clinical TrialHemostatic changes in pediatric neurosurgical patients as evaluated by thrombelastograph.
Thromboembolic events are a known complication in neurosurgical patients. There is evidence to suggest that a hypercoagulable state may develop perioperatively. Thrombelastograph (TEG) coagulation analysis is a reliable method of evaluating hypercoagulability. We evaluated coagulation by using TEG data in pediatric neurosurgical patients undergoing craniotomy to determine whether a hypercoagulable state develops intraoperatively or postoperatively. Thirty children undergoing craniotomy for removal of a tumor or seizure focus were studied. Blood was analyzed with TEG) data by using native and celite techniques, at three time points for each patient: preoperatively after induction of anesthesia; intraoperatively during closure of the dura; and on the first postoperative day. Compared with preoperative indices, closing and postoperative celite TEG values were indicative of hypercoagulability with shortened coagulation time values (P < 0.001), prolonged alpha angle divergence values (P < 0.001), and above-normal TEG coagulation indices (P < or = 0.002). Reaction time values were shortened, and maximal amplitude of clot strength values were prolonged but did not reach statistical significance. Hypercoagulation develops early after resection of brain tissue in pediatric neurosurgical patients as assessed by using TEG data. Further studies are needed to determine the clinical significance of this hypercoagulable state. ⋯ Hypercoagulability in postoperative neurosurgical patients has been demonstrated in the adult population, but few studies have dealt with the pediatric population. We found that children undergoing craniotomy for focal resection, lobectomy, and hemispherectomy are hypercoagulable as detected by thrombelastograph coagulation analysis. Further studies are needed to determine whether this is clinically significant.
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Anesthesia and analgesia · Oct 2001
Clinical TrialThe influence of the laryngeal mask airway on the shape of the submandibular gland.
Although transient sialadenopathy of the submandibular gland associated with insertion of the laryngeal mask airway (LMA) has been described, the influence of the LMA on the submandibular gland is unknown. We measured the width and length of the submandibular glands by using ultrasonography in patients in whom the LMA was used. An increased intracuff pressure of the LMA, up to 150 cm H2O, was used in a prospective study of adult patients scheduled for elective surgery. The width of the gland increased with an increasing intracuff pressure from 50 to 100 cm H2O (P < 0.01) and 100 to 150 cm H2O (P < 0.01) but did not change from 0 to 50 cm H2O. There was no change in the length of the gland. We conclude that the submandibular gland was deformed by the insertion of the LMA. ⋯ The findings in our study show that the submandibular triangle can be easily compressed by the insertion of the laryngeal mask airway (LMA). When inserting the LMA, it is important to consider that the LMA cuff may alter these tissues, which are situated between the lingual root and the submandibular triangle.
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Anesthesia and analgesia · Oct 2001
Case ReportsThe inability to detect expired carbon dioxide after endotracheal intubation as a result of one-way valve obstruction of the endotracheal tube.
Failure to tracheally intubate and ventilate the lungs is a major cause of anesthesia morbidity. Expired carbon dioxide monitoring has become a standard for assessing correct endotracheal tube placement. We present a case of failure to detect expired carbon dioxide after successful intubation resulting from a one-way valve obstruction of the endotracheal tube.
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Anesthesia and analgesia · Oct 2001
Oxidative stress status during exposure to propofol, sevoflurane and desflurane.
We evaluated the circulating and lung oxidative status during general anesthesia established with propofol, sevoflurane, or desflurane in mechanically ventilated swine. Blood samples and bronchoalveolar lavage fluid (BAL) specimens were respectively performed via an internal jugular vein catheter and a nonbronchoscopic BAL for baseline oxidative activity measurements: malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPX). A 4-h general anesthesia was then performed in the three groups of 10 swine: the Propofol group received 8 mg x kg(-1) x h(-1) of IV propofol as the sole anesthetic; the Desflurane group received 1.0 minimum alveolar concentration of desflurane; and the Sevoflurane group received 1.0 minimum alveolar concentration of sevoflurane. We observed significantly larger levels of MDA in plasma and BAL during desflurane exposure than with the other anesthetics. We also observed smaller concentrations of circulating GPX and alveolar GPX. We found a significant decrease for MDA measurements in the plasma and the pulmonary lavage during propofol anesthesia. We also found larger values of GPX measurements in the serum and the pulmonary lavage. No significant changes were observed when animals were exposed to sevoflurane. No significant changes were found for circulating concentrations of SOD during exposure to all anesthetics. In this mechanically ventilated swine model, desflurane seemed to induce a local and systemic oxidative stress, whereas propofol and sevoflurane were more likely to have antioxidant properties. ⋯ Superoxide is an unavoidable byproduct of oxygen metabolism that occurs in various inflammatory reactions. Inhalation of volatile anesthetics under mechanical ventilation induces an inflammatory response. We evaluated the bronchoalveolar and systemic oxidative stress in swine during exposure to propofol and newer volatile anesthetics. Desflurane induces more lipid peroxidation than do the other anesthetics.
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Anesthesia and analgesia · Oct 2001
The synergistic interaction between midazolam and clonidine in spinally-mediated analgesia in two different pain models of rats.
Both midazolam, a benzodiazepine gamma-aminobutyric acid type A receptor agonist, and clonidine, an alpha2-adrenergic receptor agonist, induce spinally-mediated analgesia. We investigated the analgesic interaction of spinally-administered midazolam and clonidine in their effects on acute and inflammatory nociception. Rats implanted with lumbar intrathecal catheters were injected intrathecally with saline (control), midazolam (1 to 100 microg), or clonidine (0.1 to 3 microg) to test for their responses to thermal stimulation to the tail (tail-flick test) and subcutaneous formalin injection into the hind paw (formalin test). The effects of the combination of midazolam and clonidine on both stimuli were tested by isobolographic analysis by using the 50% effective doses. The general behavior and motor function were examined as side effects. When combined, the 50% effective doses of midazolam (clonidine) decreased from 1.57 microg (0.26 microg) to 0.29 g (0.05 microg) in the tail-flick test and from 1.34 microg (0.12 microg) and 1.21 microg (0.13 microg) to 0.05 microg (0.005 microg) and 0.13 microg (0.015 microg) in Phase 1 and 2 of the formalin test, respectively. Side effects did not increase by using the combination. These results suggest a favorable combination of intrathecal midazolam and clonidine in the management of acute and inflammatory pain after proper neurotoxicologic studies. ⋯ Spinally-administered midazolam, a benzodiazepine, and clonidine, an alpha2-adrenergic receptor agonist, have significant synergistic effects on thermally-induced acute and formalin-induced inflammatory pain.