Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Comparative Study Clinical TrialBispectral index values at sevoflurane concentrations of 1% and 1.5% in lower segment cesarean delivery.
Inadequate hypnosis in the absence of opioid analgesia may account for the increased incidence of awareness in cesarean delivery. An end-tidal concentration of 0.5 MAC isoflurane in 50% nitrous oxide (N(2)O) during cesarean delivery resulted in bispectral index (BIS) values >60, the threshold below which consciousness is unlikely. Our aim was to determine the BIS values achieved with the equivalent end-tidal concentration of sevoflurane and to determine if a larger concentration would consistently maintain BIS values <60. Twenty ASA physical status I-II parturients were randomized to receive an end-tidal concentration of either 1% sevoflurane or 1.5% sevoflurane delivered in 50% N(2)O throughout surgery. Thiopental 4 mg/kg was used for anesthetic induction. Morphine 0.1-0.15 mg/kg was administered only after delivery. Mean BIS values in the period between skin incision and neonatal delivery were 61 (95% confidence interval, 57-64) in the 1% sevoflurane group, versus 42 (95% confidence interval, 37-47) in the 1.5% sevoflurane group. BIS values were significantly different between groups at skin incision, uterine incision, delivery, and 10 min after delivery, but not thereafter. Indices of maternal and neonatal outcome were similar between groups. ⋯ Bispectral index (BIS) values <60 are consistent with a high probability of unconsciousness. An end-tidal concentration of 1.5% sevoflurane maintained BIS values <60 during cesarean delivery, whereas 1% did not. Adverse effects were not seen with the use of larger concentrations of sevoflurane.
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Clinical TrialPostoperative epidural anesthesia preserves lymphocyte, but not monocyte, immune function after major spine surgery.
Extensive spine surgery is associated with postsurgical pain. Epidural pain therapy may reduce postoperative stress responses and thereby influence immune functions. In a randomized, controlled, double-blinded prospective trial, 54 patients received either conventional patient-controlled IV analgesia (PCIA; morphine 3 mg/15 min) or patient-controlled epidural analgesia (PCEA; 0.125% ropivacaine plus sufentanil 1 microg/mL at a base rate of 12 mL/h and bolus application of 5 mL/15 min). Circulating cytokines, C-reactive protein (CRP), cortisol, and cell-surface receptor expression of immune cells (cluster of differentiation [CD]14, human leukocyte antigen-DR, CD86, CD71, CD3, CD4, CD8, CD16, and CD19) were measured perioperatively to characterize immunological functions. PCEA, compared with PCIA, had no influence on altered levels of circulating cytokines (interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor-alpha, monocyte chemoattractant protein-1, and macrophage inhibitory factor) or indicators of the stress response (CRP and cortisol). Also, no significant difference was found in monocyte numbers or their human leukocyte antigen-DR, CD86, or CD71 expression. In contrast, the postoperative decrease in B lymphocytes and T-helper cells was significant in the PCEA group. Natural killer cells decreased significantly in patients receiving PCEA compared with PCIA. Therefore, postoperative epidural pain therapy has no influence on monocyte functions but reduces natural killer cells and preserves B-cell and T-helper cell populations. Epidural analgesia thus influences the specific rather than the innate immune system and potentially blunts the postsurgical lymphocyte depression, which is relevant for infectious resistance. ⋯ Epidural analgesia affects the immune system. Postoperative epidural analgesia, compared with conventional IV opioid therapy, preserves lymphocyte rather than monocyte functions. An improvement of postoperative immune function by epidural analgesia therefore may improve postoperative resistance to infectious complications or to chronic pain states.
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Clinical TrialA dose ranging study of dexamethasone for preventing patient-controlled analgesia-related nausea and vomiting: a comparison of droperidol with saline.
We designed this study to determine the minimum dose of dexamethasone for preventing nausea and vomiting associated with the use of morphine by patient-controlled analgesia (PCA). Two hundred forty female patients were randomly assigned to receive dexamethasone 2, 4, 8, or 12 mg IV immediately before induction of anesthesia. Droperidol (0.1 mg/mL with morphine 1 mg/mL in PCA pump) and saline were used as controls. The complete response (no postoperative nausea and vomiting and no need for rescue antiemetic for a 24-h postoperative period) rates for dexamethasone 8 mg (72.2%) and 12 mg (78.9%) were significantly more than for saline (42.9%) (P < 0.05). Patients who received dexamethasone 12 or 8 mg also reported higher patient satisfaction than those who received saline (P < 0.05). These results were as effective as adding droperidol 0.1 mg/mL to the morphine PCA without causing drowsiness, restlessness, or arrhythmias. Smaller doses of dexamethasone (4 or 2 mg) were not effective for this propose. The results suggest that dexamethasone 8 mg IV is the minimum effective dose for the reduction of PCA morphine-related nausea and vomiting. ⋯ Morphine administration by patient-controlled analgesia (PCA) is often associated nausea and vomiting. In this double-blind study, the minimum effective dose of dexamethasone for reducing this complication was 8 mg. This was as effective as adding droperidol 0.1 mg/mL to the morphine PCA without causing drowsiness, restlessness or arrhythmias.