Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2004
Randomized Controlled Trial Comparative Study Clinical TrialTime-related cuff pressures of the laryngeal tube with and without the use of nitrous oxide.
The Laryngeal tube (VBM Medizintechnik, Sulz, Germany), a new supraglottic airway, consists of an airway tube, two cuffs, and two distal apertures between the two cuffs. One concern with the use of this device is ischemic change to the oropharyngeal mucosa. We studied the time-course change of the intracuff pressure (which reflects the pharyngeal pressure) of the laryngeal tube during anesthesia with and without nitrous oxide. After insertion of a laryngeal tube, 24 patients were randomly allocated to 1 of 2 groups. In one group (group N or nitrous oxide group), 66% nitrous oxide was used, whereas in the other group nitrous oxide was not used (group A or air group). In both groups, sevoflurane was used to maintain anesthesia. Time-course changes of the intracuff pressure and postoperative airway complications were recorded. In group N, the intracuff pressure significantly increased over time (P < 0.001; the maximal pressure: 120 cm H(2)O), whereas in group A the intracuff pressure remained stable. The intracuff pressure was significantly higher in group N than in group A (P < 0.0001; 95% confidence intervals for difference: 6-20 cm H(2)O at 30 min). Postoperatively, two patients in group A and one patient in group N complained of mild sore throat. ⋯ Nitrous oxide may increase pharyngeal pressure by the cuffs of the laryngeal tube, and thus it is advisable to monitor and adjust the intracuff pressure of the laryngeal tube during anesthesia to minimize possible ischemic changes to the oropharynx.
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Anesthesia and analgesia · Jun 2004
Comparative StudyHeparinase-modified thrombelastography in term and preterm neonates.
Thrombelastography (TEG) appears to be a promising test to assess coagulation in infants and children. TEG enables a rapid assessment of hemostatic function with only 300 microL of whole blood and provides information about plasmatic coagulation, platelet function, and fibrinolysis. In this study, we used TEG to assess the coagulation system of preterm and term neonates to determine the effects of their deficient coagulation factor levels on global hemostatic function. Heparinase-modified TEG, platelet and red blood cell count, plasma fibrinogen, and prothrombin time were assessed in four groups of clinically stable infants: severely preterm (gestational age [GA], 27-31 wk), moderately preterm (GA, 32-36 wk), term (GA, 36-40 wk), and former preterm (corrected GA, 34-40 wk). Healthy adult volunteers served as a control group. When compared with the adult group, thromboelastography revealed no defects in coagulation from groups of clinically stable infants, documenting the functional integrity of coagulation despite, in part, decreased conventional coagulation variables. Because clinically stable preterm and term infants show a relatively small incidence of bleeding, despite prolonged conventional coagulation tests, TEG may better reflect the hemostatic potential of these patients compared with conventional coagulation tests. ⋯ This study assessed the coagulation of preterm and term infants by thrombelastography and found functional integrity of coagulation despite, in part, decreased conventional coagulation variables.
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Anesthesia and analgesia · Jun 2004
Case Reports Comparative StudyReversal of direct thrombin inhibition after cardiopulmonary bypass in a patient with heparin-induced thrombocytopenia.
We treated persistent hemorrhage after cardiopulmonary bypass in a heart transplant recipient who had received anticoagulation with the direct thrombin inhibitor bivalirudin by a combination therapy aimed at reducing the plasma concentration of the thrombin antagonist (hemodialysis and modified ultrafiltration), increasing the concentration of thrombin at bleeding sites (recombinant factor VIIa), and increasing the plasma concentration of other coagulation factors (fresh frozen plasma and cryoprecipitate). The bleeding was controlled, and there was no thrombotic complication. ⋯ A combination of modified ultrafiltration, hemodialysis, and the administration of recombinant factor VIIa, fresh frozen plasma, and cryoprecipitate may reverse the anticoagulant effect of bivalirudin.
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Anesthesia and analgesia · Jun 2004
A simple, fast, easy method to identify the evidence base in pain-relief research: validation of a computer search strategy used alone to identify quality randomized controlled trials.
Clinicians need a simple, fast, reliable, and inexpensive way of identifying the evidence base relevant to their clinical practice. It is often believed that the only way to identify all relevant evidence is to perform hand-searches of the literature to supplement computer searches; this is complex and labor intensive. However, most of quality randomized controlled trials cited in systematic reviews in pain medicine are listed in computer databases. We performed two studies to investigate the efficiency-in terms of sensitivity, specificity, and precision-of three computer search strategies: Optimally Sensitive Search Strategy, which is used by the Cochrane Collaboration; RCT.pt, a standard MEDLINE strategy; and DBRCT.af, which is a new single-line computer algorithm based on the assumption that double-blinded, randomized controlled trials would be indexed with "double-blind," "random," or variations of these terms in MEDLINE and EMBASE. DBRCT.af was found to be highly sensitive (97%) in identifying quality randomized controlled trials in pain medicine. The precision (ratio of randomized controlled trials to the number of nonrandomized trials identified) was 82%, and the specificity in excluding the nonrandomized controlled trials was 98%. We conclude that clinicians can now use DBRCT.af to update and conduct de novo systematic reviews in pain-relief research. ⋯ Quality evidence about what is good clinical practice in pain treatment is buried in the medical literature among large quantities of other information. This article describes how any clinician with access to the Internet can identify those quality studies reliably, quickly, and inexpensively.
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Anesthesia and analgesia · Jun 2004
Comparative StudyTreatment of uncontrolled hemorrhagic shock after liver trauma: fatal effects of fluid resuscitation versus improved outcome after vasopressin.
In a porcine model of uncontrolled hemorrhagic shock, we evaluated the effects of vasopressin versus an equal volume of saline placebo versus fluid resuscitation on hemodynamic variables and short-term survival. Twenty-one anesthetized pigs were subjected to severe liver injury. When mean arterial blood pressure was <20 mm Hg and heart rate decreased, pigs randomly received either vasopressin IV (0.4 U/kg; n = 7), an equal volume of saline placebo (n = 7), or fluid resuscitation (1000 mL each of lactated Ringer's solution and hetastarch; n = 7). Thirty minutes after intervention, surviving pigs were fluid resuscitated while bleeding was surgically controlled. Mean (+/- SEM) arterial blood pressure 5 min after the intervention was significantly (P < 0.05) higher after vasopressin than with saline placebo or fluid resuscitation (58 +/- 9 versus 7 +/- 3 versus 32 +/- 6 mm Hg, respectively). Vasopressin improved abdominal organ blood flow but did not cause further blood loss (vasopressin versus saline placebo versus fluid resuscitation 10 min after intervention, 1343 +/- 60 versus 1350 +/- 22 versus 2536 +/- 93 mL, respectively; P < 0.01). Seven of 7 vasopressin pigs survived until bleeding was controlled and 60 min thereafter, whereas 7 of 7 saline placebo and 7 of 7 fluid resuscitation pigs died (P < 0.01). We conclude that vasopressin, but not saline placebo or fluid resuscitation, significantly improves short-term survival during uncontrolled hemorrhagic shock. ⋯ Although IV fluid administration is the mainstay of nonsurgical management of trauma patients with uncontrolled hemorrhagic shock, the efficacy of this strategy has been discussed controversially. In this animal model of severe liver trauma with uncontrolled hemorrhagic shock, vasopressin, but not saline placebo or fluid resuscitation, improved short-term survival.