Anesthesia and analgesia
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Anesthesia and analgesia · May 2004
Trends in the practice of parental presence during induction of anesthesia and the use of preoperative sedative premedication in the United States, 1995-2002: results of a follow-up national survey.
Both parental presence during induction of anesthesia and sedative premedication are currently used to treat preoperative anxiety in children. A survey study conducted in 1995 demonstrated that most children are taken into the operating room without the benefit of either of these two interventions. In 2002 we conducted a follow-up survey study. Five thousand questionnaires were mailed to randomly selected physician members of the American Society of Anesthesiologists. Mailings were followed by a nonresponse bias assessment. Twenty-seven percent (n = 1362) returned the questionnaire after 3 mailings. We found that a significantly larger proportion of young children undergoing surgery in the United States were reported to receive sedative premedication in 2002 as compared with 1995 (50% vs 30%, P = 0.001). We also found that in 2002 there was significantly less geographical variability in the use of sedative premedication as compared with the 1995 survey (F = 8.31, P = 0.006). Similarly, we found that in 2002 parents of children undergoing surgery in the United States were allowed to be present more often during induction of anesthesia as compared with 1995 (chi(2) = 26.3, P = 0.0001). Finally, similar to our findings in the 1995 survey, midazolam was uniformly selected most often to premedicate patients before surgery. ⋯ Over the past 7 yr there have been significant increases in the number of anesthesiologists who use preoperative sedative premedication and parental presence for children undergoing surgery.
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Anesthesia and analgesia · May 2004
A model for evaluating droperidol's effect on the median QTc interval.
Controversy surrounds the use of the antiemetic droperidol, because of the Food and Drug Administration-imposed "black box" warning alleging that even small doses of the drug can lead to serious (even fatal) arrhythmias when it is used for antiemetic prophylaxis during the perioperative period. We used mathematical modeling of electrocardiographic QT interval data published in a peer-reviewed manuscript to evaluate the relationship between the dose of droperidol (0.1-0.25 mg/kg i.v.) and QT(c) prolongation. In comparing the calculated QT(c) values based on the logarithm model (27-63 ms), the linear model (27-67 ms) and the square-root model (36-57 ms) to the actual measured QT(c) values (37-59 ms), the square-root model provided the best simulation of the experimental findings. Other models that we evaluated included the polynomial model and various exponent models (e.g., quartic-root model, cubic-root model, square model, and cubic model). The estimated median prolongation of the median QT(c) interval produced by droperidol 0.625-1.25 mg i.v. would vary from 9 +/- 3 to 18 +/- 3 ms. Therefore, this regression analysis suggests that small "antiemetic" doses of droperidol (< or =1.25 mg) would be unlikely to produce proarrhythmogenic effects in the perioperative period. ⋯ Using a square-root curve fit model to evaluate the relationship between the dose of droperidol and QT(c) prolongation, small-dose droperidol (0.625-1.25 mg i.v.) would be expected to produce <30-ms prolongation of the QT(c) interval. Therefore, small "antiemetic" doses of droperidol would not be expected to produce proarrhythmogenic effects when used for prophylaxis in surgical patients.
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Anesthesia and analgesia · May 2004
A survey of orthopedic surgeons' attitudes and knowledge regarding regional anesthesia.
We conducted a survey to explore the surgical attitudes and preferences regarding regional anesthesia among Canadian orthopedic surgeons. Surveys were returned by 468 (61%) of 768 surgeons. Forty-eight percent of respondents directed their patients' choice of anesthetic. Forty percent of surgeons directed their patients to choose regional anesthesia. The principal reasons for favoring regional anesthesia were less postoperative pain (32%), decreased nausea and vomiting (12%), and safety (14%). Reasons for not favoring regional anesthesia were delays in the induction of anesthesia (43%) and an unpredictable success rate (12%). This survey suggests that orthopedic surgeons are supportive of regional anesthesia. Barriers to increased popularity include perceived delays and unreliability. ⋯ Orthopedic surgeons understand the benefits of and are supportive of the use of regional anesthesia in their practices. Barriers to increased popularity include perceived operating room delays and lack of reliability.
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Tissue plasminogen activator (tPA) has a prominent role in physiological fibrinolysis in vivo. Thrombosis has been associated with clinical scenarios (e.g., atherosclerotic disease) known to involve local decreases in tPA activity with concomitant formation of reactive nitrogen species such as peroxynitrite (OONO(-)), a molecule formed from nitric oxide and superoxide. We hypothesized that exposure of tPA to OONO(-) would result in a decrease in tPA activity. OONO(-) was generated with 3-morpholinosydnonimine (SIN-1), a molecule that produces both nitric oxide and superoxide. Recombinant tPA was incubated at 37 degrees C for 60 min with 0 microM SIN-1; 100 microM SIN-1; 100 microM SIN-1 and 4000 U/mL recombinant human superoxide dismutase; or 4000 U/mL recombinant human superoxide dismutase (n = 8 separate reactions per condition). Changes in tPA activity were assessed by addition of tPA samples to tissue factor-exposed human plasma and measuring clot fibrinolysis with a thrombelastograph. Exposure to SIN-1 resulted in a decrease in tPA-mediated fibrinolysis (<1% activity of tPA not exposed to SIN-1) that was significantly (P < 0.001) different from the other three conditions. There were no significant differences between the other conditions. We conclude that tPA is inhibited by OONO(-), and that OONO(-) may have a role in clinical thrombotic scenarios. ⋯ Tissue plasminogen activator (tPA) has a prominent role in fibrinolysis in vivo. Thrombosis has been associated with clinical scenarios involving decreases in tPA activity with concomitant formation of the oxidant peroxynitrite. We determined that peroxynitrite decreased tPA activity via thrombelastography. Peroxynitrite-mediated tPA inactivation may have a role in thrombotic states.
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Anesthesia and analgesia · May 2004
Case ReportsAnesthetic management of a patient in prone position with a drill bit penetrating the spinal canal at C1-C2, using a laryngeal mask.
Airway management in patients with penetrating neck trauma must guarantee cervical spine stability. Moreover, the prone position increases the risk of difficult ventilation and cervical spine injury. A 19-yr-old patient was brought to the emergency room in prone position with a drill bit protruding from the posterolateral aspect of his neck. The bit had entered the spinal canal below the first cervical vertebra, and placed near the odontoid peg. He was referred for surgical removal of the drill. The use of an inhaled induction of anesthesia, avoiding muscle relaxants, and ventilation through a laryngeal mask airway inserted in the prone position seemed to offer a satisfactory approach. ⋯ Management of patients with penetrating neck trauma must guarantee cervical spine stability. Moreover, the prone position increases the risk of difficult ventilation and cervical spine injury. Anesthesia may be induced and the airway can be managed with the patient already in the prone position for surgery.