Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2004
Randomized Controlled Trial Clinical TrialThe effect of epidural bupivacaine on induction and maintenance doses of propofol (evaluated by bispectral index) and maintenance doses of fentanyl and vecuronium.
The growing interest in combining local and general anesthesia has led to studies investigating possible interactions between general anesthesia and local anesthetics administered via spinal, epidural, IV, or IM routes. However, no study has evaluated the effect of local anesthetics on all three components of balanced anesthesia, i.e., hypnosis, analgesia, and muscle relaxation. In this prospective, randomized, double-blind study, we investigated the effect of epidural bupivacaine on the dose requirement of propofol (as evaluated by using the bispectral index [BIS]), fentanyl, and vecuronium for general anesthesia. ⋯ The requirement of propofol for induction and maintenance of anesthesia in the bupivacaine group was 1.3 +/- 0.3 mg/kg and 2.4 +/- 0.9 mg . kg(-1) . h(-1), respectively, compared with 2.4 +/- 0.6 mg/kg and 4.4 +/- 1.6 mg . kg(-1) . h(-1) observed in the control group (P < 0.05). Significant reduction was also observed in the requirement of vecuronium and fentanyl during maintenance in the bupivacaine group (P < 0.05). We conclude that epidural bupivacaine given before induction of anesthesia reduces the requirement of propofol, fentanyl, and vecuronium during general anesthesia.
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Anesthesia and analgesia · Dec 2004
Ventricular fibrillation median frequency may not be useful for monitoring during cardiac arrest treated with endothelin-1 or epinephrine.
In this study, we evaluated whether median fibrillation frequency (MF) and mean fibrillation amplitude (AMP) reflect coronary perfusion pressure (CoPP) and predict successful defibrillation. MF, AMP, and CoPP were measured during prolonged ventricular fibrillation (VF) cardiac arrest and resuscitation in pigs. After 5 min of VF, cardiopulmonary resuscitation was started. ⋯ In a nonparametric spectral analysis of the individual MF versus CoPP and AMP versus CoPP curves, we found no link between the different curves in different animals or therapies. No difference was found in MF in pigs with ROSC (n = 8) compared with animals not achieving ROSC (n = 23) immediately before defibrillation (P = 0.85). Our data suggest that, in prolonged VF cardiac arrest, MF and AMP might not be useful tools to reflect myocardial perfusion.
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Anesthesia and analgesia · Dec 2004
The effect of dilution on plasma coagulation kinetics determined by thrombelastography is dependent on antithrombin activity and mode of activation.
Hemodilution-associated hypercoagulability has been the focus of several investigations because significant morbidity and mortality have been associated with perioperative thrombophilia. Because most investigations implicate imbalances in procoagulant/anticoagulant activity as the etiology of hemodilution-associated hypercoagulability, we determined the effects of dilution on coagulation kinetics and clot strength with thrombelastography (TEG(R)). Control plasma (+/-celite activation) and antithrombin (AT)-deficient (<10% activity) plasma were diluted 0%, 10%, 20%, and 30% with saline. ⋯ Celite activation eliminated dilution-associated changes in R values in control plasma but resulted in linear decreases (R(2) = 0.88-0.96, P < 0.0001) in alpha, A, and G in response to dilution. Thus, our data indirectly support the concept that decreases in AT activity cause dilution-mediated hypercoagulability in plasma. Finally, celite activation permits quantification of dilution with TEG.
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Anesthesia and analgesia · Dec 2004
Case ReportsThe anterior jugular venous system: variability and clinical impact.
The anterior jugular venous system, with its interconnections to the subclavian and deep jugular veins, provides a collateral venous network across the midline of the neck area, which is especially important in unilateral occlusion of an innominate vein. We illustrate the variability of this system and its clinical impact on catheterization by three cases of landmark-guided central venous cannulation. Case 1: Cannulation of the left internal jugular vein with a central venous catheter and of the left innominate vein (LIV) with a pulmonary artery catheter resulted in correctly positioned catheter tips. ⋯ We describe the normal anatomy of the anterior jugular venous system and its role as a major collateral. Correct placement of central venous catheters may be possible via the anterior jugular venous system. Conversely, central venous catheters malpositioned in the anterior jugular vein can increase the risk for complications and should be removed.
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Anesthesia and analgesia · Dec 2004
Randomized Controlled Trial Comparative Study Clinical TrialSevoflurane decreases bispectral index values more than does halothane at equal MAC multiples.
At the minimum alveolar concentration (MAC) of inhaled anesthetics, 50% of subjects move in response to noxious stimulation. Similarly, at MAC-awake, 50% of subjects respond appropriately to command. The bispectral index (BIS) nominally measures the effect of anesthetics on wakefulness or consciousness. ⋯ BIS values in awake patients did not differ between the sevoflurane and halothane groups (96 +/- 2 and 96 +/- 2, mean +/- sd, respectively). At 1 MAC without and with neuromuscular blockade and at 1.5 MAC, BIS values for patients anesthetized with halothane (54 +/- 7, 56 +/- 7, and 49 +/- 7, respectively) exceeded those for patients anesthetized with sevoflurane (34 +/- 6, 34 +/- 6, and 29 +/- 5, respectively) (P < 0.0001). This finding adds to other evidence indicating that BIS is drug specific.