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 TrialSingle-dose haloperidol for the prophylaxis of postoperative nausea and vomiting after intrathecal morphine.
Postoperative nausea and vomiting (PONV) occurs frequently with the use of intrathecal morphine. We studied the ability of a single, small dose of the inexpensive, long-acting, dopamine receptor-blocking drug, haloperidol, to prevent PONV after spinal anesthesia using local anesthetic with morphine 0.3 mg. One-hundred-eight adult patients undergoing elective lower limb orthopedic or endoscopic urologic procedures under spinal anesthesia were randomized to receive IM haloperidol 1 mg (H1), haloperidol 2 mg (H2), or placebo (P) after an intrathecal injection. Patients were assessed for 24 h after surgery, with treatment failure being defined as nausea >1 on a 10-cm visual analog scale or any vomiting or request for rescue antiemetic. Most treatment failures occurred during the first 12 h (60% overall), and haloperidol led to a dose-dependent decrease in PONV (first 12 h: 76% P, 56% H1, and 50% H2; P = 0.012). A history of PONV was strongly associated with PONV in the current study, regardless of treatment group. There were no dystonic reactions noted to either dose of haloperidol. We conclude that haloperidol reduces the incidence of PONV after intrathecal morphine, although this incidence remains a significant problem even with treatment. ⋯ In this randomized, double-blinded, placebo-controlled trial, a single, small IM dose of haloperidol 1 mg or 2 mg reduced the incidence of postoperative nausea and vomiting after spinal anesthesia with local anesthetic and intrathecal morphine.
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Clinical TrialSkin sensitivity to rocuronium and vecuronium: a randomized controlled prick-testing study in healthy volunteers.
Prick tests are frequently used for the authentication of neuromuscular blocking drugs (NMBDs) as causative drugs for anaphylactic reactions during anesthesia. Unfortunately, the actual threshold concentration for skin testing remains debatable for most NMBDs. We studied the flare and wheal responses to prick tests with rocuronium and vecuronium. Thirty healthy, nonatopic, anesthesia-naive male and female volunteers (14 men and 16 women) from 18 to 40 yr of age were assigned randomly to receive a total of 10 prick tests-4 ascending dilutions (1:1000, 1:100, 1:10, and 1) of rocuronium and vecuronium and 2 controls-on both forearms. An assessor blinded to the assignment monitored systemic and skin responses to NMBDs and measured wheal and flare surfaces immediately after and 15 min after prick tests. None of the volunteers experienced any immediate systemic or cutaneous responses to rocuronium or vecuronium. Although a dilution of 1:1000 of both NMBDs failed to promote any skin response at 15 min, 50% and 40% of the subjects had a positive skin reaction to undiluted rocuronium and vecuronium, respectively. We demonstrated a sex effect related to smaller threshold concentration-induced cutaneous reactions in female volunteers to both muscle relaxants. Our observation questions the reliability of prick testing with undiluted solutions of rocuronium and vecuronium for the diagnosis of allergy. ⋯ Building concentration-skin response curves to prick tests with rocuronium and vecuronium in healthy, nonatopic, anesthesia-naive male and female volunteers demonstrated that the nonreactive concentration for both muscle relaxants is the 1:1000 dilution of the stock solutions. Our observation calls into question the past practice of prick-testing skin for sensitivity to neuromuscular blocking drugs by using undiluted solutions.
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Clinical TrialThe supraclavicular block with a nerve stimulator: to decrease or not to decrease, that is the question.
Portable nerve stimulators for nerve blocks have been available for more than 40 yr. It is generally accepted that seeking a motor response at low outputs increases the chances of success. It is customary to start the procedure at a higher current with the goal of finding the nerve. After an adequate response is elicited, the current is decreased before the local anesthetic is injected. However, how low is low enough and, for that matter, how high is too high have not been adequately determined. Our experience seems to indicate that, in the supraclavicular block, the type of response obtained is as important as the output at which it is elicited, provided that this current is not higher than 1 mA. In this context, it is theoretically possible that our initial seeking current of 0.9 mA could be an adequate injection current if it is combined with an appropriate response. We designed this study to test the hypothesis that a response of the fingers in flexion or extension, elicited at 0.9 mA, could be followed immediately by the local anesthetic injection. We did not intend to compare 0.5 and 0.9 mA as minimum stimulating currents but rather as currents able to elicit an unmistakable motor twitch. Sixty patients were randomly assigned to one of two groups. Group 1 (n = 30) was injected with a motor twitch in the fingers that was still visible at 0.5 mA. Group 2 (n = 30) was injected after a similar response to that in Group 1 was elicited, but at the initial output of 0.9 mA, without any further decrease. The blocks were injected with 40 mL of local anesthetic solution. One patient was excluded from the study for failing to meet protocol criteria. The success rate in the remaining 59 patients was 100%; success was defined as complete sensory blockade at the median, ulnar, and radial nerve territories of the hand that was accomplished in
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Comparative Study Clinical TrialAnalgesic effects of intraarticular sufentanil and sufentanil plus methylprednisolone after arthroscopic knee surgery.
We studied the effect of intraarticular saline, sufentanil, or sufentanil plus methylprednisolone after knee arthroscopic meniscectomy. In a double-blind randomized study, 60 patients undergoing knee arthroscopic meniscectomy were allocated to groups receiving intraarticular saline, intraarticular sufentanil 10 microg, or sufentanil 10 microg plus methylprednisolone 40 mg at the end of arthroscopy during general anesthesia. Postoperatively, pain levels at rest and during movement (i.e., active flexion of the knee) were measured by a visual analog scale and were significantly decreased in the sufentanil and sufentanil plus methylprednisolone groups compared with the control group. Moreover, we found that there was a significant reduction in intraarticular sufentanil and sufentanil plus methylprednisolone in the postoperative consumption of analgesics. We also found that the use of intraarticular sufentanil or sufentanil plus methylprednisolone after knee arthroscopic meniscectomy decreases the amount of supplementary analgesic needed for pain relief during the early postoperative period. In addition, we detected that sufentanil provided prolonged pain relief up to 24 h when compared with control, whereas when we combined sufentanil plus methylprednisolone, we found that it further reduced pain and use of analgesics when compared with sufentanil. ⋯ The combined use of intraarticular sufentanil (10 microg) and methylprednisolone (40 mg) in arthroscopic meniscectomy surgery reduced both postoperative pain scores and the use of additional analgesics.