Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Comparative Study Clinical TrialA randomized, double-blind comparison of rocuronium, d-tubocurarine, and "mini-dose" succinylcholine for preventing succinylcholine-induced muscle fasciculations.
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Clinical TrialEpidural fentanyl reduces the shivering threshold during epidural lidocaine anesthesia.
Epidural local anesthetics and IV opioids both decrease the core temperature that triggers shivering. However, the effect of epidural opioids on shivering thresholds has not been assessed. In this study, we tested the hypothesis that adding epidural fentanyl to epidural lidocaine decreases the shivering threshold compared with epidural lidocaine alone. Fourteen healthy male patients undergoing extracorporeal shockwave lithotripsy under epidural anesthesia were randomly assigned to receive either epidural lidocaine or epidural lidocaine plus epidural fentanyl. Ice-cold lactated Ringer's solution was given IV before epidural blockade, and the core temperature that triggers shivering was established. Then epidural anesthesia was induced, and the shivering threshold was established again after lithotripsy. Results were analyzed using paired or unpaired t-tests. Reduction in the shivering threshold by epidural anesthesia was significantly greater when fentanyl was added to lidocaine than when lidocaine was used alone (mean +/- SD: -0.6+/-0.4 degrees C versus -0.1+/-0.4 degrees C; P < 0.02). We conclude that patients are at increased risk of hypothermia when fentanyl is added to epidural lidocaine. ⋯ Fentanyl is often added to lidocaine to improve the quality of epidural blockade and to reduce side effects. However, this study shows that patients are at increased risk of hypothermia when fentanyl is added to lidocaine.
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Comparative Study Clinical TrialIntrathecal ropivacaine for labor analgesia: a comparison with bupivacaine.
Ropivacaine has less potential for central nervous system and cardiovascular toxicity than bupivacaine; in pregnant patients and volunteers, it produces less motor block in equianalgesic doses than bupivacaine. We compared two doses of intrathecal ropivacaine combined with sufentanil with a standard dose of intrathecal bupivacaine plus sufentanil for labor analgesia using a combined spinal-epidural (CSE) technique. In a prospective, randomized, double-blind fashion, 48 patients requesting labor analgesia received either 2.5 mg of intrathecal bupivacaine plus sufentanil 10 microg (B), 2 mg of intrathecal ropivacaine plus sufentanil 10 microg (R2), or 4 mg of intrathecal ropivacaine plus sufentanil 10 microg (R4). Duration of analgesia and side effects, such as motor block, pruritus, hypotension, ephedrine requirements and fetal bradycardia, were recorded. Duration of analgesia (mean +/- SD) was 79+/-30 min for R2, 98+/-19 min for R4, and 92+/-38 min for B (P = not significant). No differences in motor block or side effects were detected among the groups. We conclude that ropivacaine, when combined with sufentanil, is effective for providing CSE labor analgesia and offers no advantage over bupivacaine in the studied doses. ⋯ In this study, we compared a standard dose of intrathecal bupivacaine with sufentanil for combined spinal epidural analgesia with two doses of the new local anesthetic ropivacaine. Both local anesthetics provided similar labor analgesia duration with equivalent side effect profiles in the doses studied.
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Clinical TrialEsmolol potentiates reduction of minimum alveolar isoflurane concentration by alfentanil.
Esmolol, a short-acting beta1-receptor antagonist, decreases anesthetic requirements during propofol/N2O/morphine anesthesia. This study was designed to determine whether esmolol affects the volatile anesthetic (isoflurane) required to prevent movement to skin incision in 50% patients (minimum alveolar anesthetic concentration [MAC]) with or without an additional opioid (alfentanil). One hundred consenting adult patients were randomly divided into five treatment groups: isoflurane alone (I), I with continuous large-dose (250 microg x kg(-1) x min(-1)) esmolol (E), I with alfentanil (effect site target of 50 ng/mL) via a continuous computer-controlled infusion (A), A plus continuous small-dose (50 microg x kg(-1) x min(-1)) esmolol (A1), or A plus large-dose esmolol (A2). Anesthesia was induced via a face mask, and steady-state target end-tidal isoflurane concentrations were maintained before incision. The MAC of isoflurane alone was 1.28% +/- 0.13%. Large-dose esmolol did not significantly alter the isoflurane MAC (1.23% +/- 0.14%). Alfentanil alone significantly decreased isoflurane MAC by 25% (0.96% +/-0.09%). Adding small-dose esmolol did not further decrease MAC with alfentanil (0.96% +/- 0.13%). However, large-dose esmolol significantly decreased isoflurane MAC with alfentanil (0.74% +/- 0.09%). Esmolol and alfentanil both significantly reduced the increases in heart rate and mean arterial pressure associated with endotracheal intubation and incision. The mechanism of this effect is unknown. ⋯ Most anesthetic techniques rely on a balance of several highly selective medications. The current results define a new anesthetic-sparing effect when volatile anesthetic, analgesic, and beta-adrenergic blocking drugs are combined.
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Anesthesia and analgesia · Sep 1998
Clinical TrialThe laryngeal mask airway reliably provides rescue ventilation in cases of unanticipated difficult tracheal intubation along with difficult mask ventilation.
In 1995, our department of anesthesiology established an airway team to assist in treating unanticipated difficult endotracheal intubations and an airway quality improvement (QI) form to document the use of emergency airway techniques in airway crises (laryngeal mask airway [LMA], flexible fiberoptic bronchoscopy, retrograde intubation [RI], transtracheal jet ventilation [TTJV], and cricothyrotomy). Over a 2-yr period, team members and staff anesthesiologists completed airway QI forms to document the smallest peripheral SpO2 during an airway crisis, the number of direct laryngoscopies (DL) performed before using an emergency airway technique, and the emergency airway technique that succeeded in rescue ventilation. Team members agreed to use the LMA as the first emergency airway technique to treat the difficult ventilation/difficult intubation scenario. A SpO2 value < or =90% during mask ventilation defined difficult ventilation. Inability to perform tracheal intubation by DL defined difficult intubation. An increase in the SpO2 value >90% defined rescue ventilation. Review of airway QI forms from October 1, 1995 until October 1, 1997 revealed 25 cases of difficult ventilation/difficult intubation. Before airway rescue, the median SpO2 was 80% (range 50%-90%), and there were four median attempts at DL (range one to nine). The LMA had a success rate of 94% (95% confidence interval [CI] 77-100). Flexible fiberoptic bronchoscopy, TTJV, RI, and surgical cricothyrotomy had success rates of 50% (95% CI 0-100), 33% (95% CI 0-100), 100% (95% CI 37-100), and 100% (95% CI 37-100), respectively. LMA insertion as the first alternative airway technique was useful in dealing with unanticipated instances of simultaneous difficulty with mask ventilation and tracheal intubation. ⋯ Twenty-five cases of simultaneous difficulty with mask ventilation and tracheal intubation occurred after the induction of general anesthesia during the study period. The laryngeal mask was used in 17 cases, and it provided rescue ventilation without complication in 94% of these cases (95% confidence interval 77-100).