Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2002
Randomized Controlled Trial Clinical TrialThe effect of clonidine on the minimum local analgesic concentration of epidural ropivacaine during labor.
On the basis of the determination of minimum local analgesic concentration (MLAC), ropivacaine has been demonstrated to be less potent than bupivacaine during the first stage of labor. In this study we assessed the effect of clonidine on the MLAC of ropivacaine. Seventy-seven parturients of mixed parity requesting epidural analgesia for labor (cervical dilation, 3-7 cm) were included in the study. They received an epidural bolus of either ropivacaine (n = 30), ropivacaine plus clonidine 30 microg (n = 28), or ropivacaine plus clonidine 60 microg (n = 19) in the second part of the study. The concentration of the ropivacaine solution was determined by the response of the previous parturient in that group by using an up-down sequential allocation. A visual analog pain score of < or =10 mm within 30 min after the epidural bolus (20 mL) was considered an effective response. An effective result directed a 0.01% wt/vol decrement for the next patient. An ineffective result directed a 0.01% wt/vol increment. The MLAC of ropivacaine was 0.097% wt/vol (95% confidence interval, 0.085%-0.108%). It was unaffected by a 30-microg dose of epidural clonidine (0.081% [0.045%-0.117%]) but was significantly decreased by a 60-microg clonidine dose (0.035% [0.024%-0.046%]) (P < 0.001). This study documents a decrease in the MLAC of ropivacaine by clonidine, significant for a 60- microg dose. ⋯ Epidural ropivacaine potency in labor can be increased by the addition of epidural clonidine. This study demonstrates that 60 microg of epidural clonidine significantly decreases the minimum local analgesic concentration of ropivacaine during the first stage of labor but is associated with sedation.
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Anesthesia and analgesia · Sep 2002
Randomized Controlled Trial Clinical TrialThe analgesic efficacy of bilateral combined superficial and deep cervical plexus block administered before thyroid surgery under general anesthesia.
In this study we evaluated the analgesic efficacy of combined deep and superficial cervical plexus block in patients undergoing thyroidectomy under general anesthesia. For this purpose, 39 patients undergoing elective thyroid surgery were randomized to receive a bilateral combined deep and superficial cervical block (14 mL per side) with saline (Group 1; n = 13), ropivacaine 0.5% (Group 2; n = 13), or ropivacaine 0.5% plus clonidine 7.5 microg/mL (Group 3; n = 13). Deep cervical plexus block was performed with a single injection (8 mL) at the C3 level. Superficial cervical plexus block consisted of a subcutaneous injection (6 mL) behind the lateral border of the sternocleidomastoid muscle. During surgery, the number of additional alfentanil boluses was significantly reduced in Groups 2 and 3 compared with Group 1 (1.3 +/- 1.0 and 1.1 +/- 1.0 vs 2.6 +/- 1.0; P < 0.05). After surgery, the opioid and non-opioid analgesic requirements were also significantly reduced in Groups 2 and 3 (P < 0.05) during the first 24 h. Except for one patient in Group 3, who experienced transient anesthesia of the brachial plexus, no side effect was noted in any group. We conclude that combined deep and superficial cervical plexus block is an effective technique to alleviate pain during and immediately after thyroidectomy. ⋯ Combined deep and superficial cervical plexus block is an effective technique to reduce opioid requirements during and after thyroid surgery.
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Anesthesia and analgesia · Sep 2002
Randomized Controlled Trial Clinical TrialPropofol-sufentanil anesthesia for thyroid surgery: optimal concentrations for hemodynamic and electroencephalogram stability, and recovery features.
Hypnotics and opioids interact synergistically to block responses to surgery and different dose combinations may be used to provide adequate anesthesia. In this study, we sought to determine the optimal concentrations of propofol and sufentanil, given by target-controlled infusions, to ensure hemodynamic stability, adequate hypnosis (assessed by electroencephalogram bispectral index), and fast recovery for a moderately painful operation. Forty-five patients, ASA physical status I or II, undergoing thyroidectomy, were randomly assigned to a sufentanil target concentration (STC) that was maintained throughout surgery (0.1, 0.2, or 0.3 ng/mL). The propofol target concentration was adjusted to keep mean arterial blood pressure within 30% of a reference value, and bispectral index between 40 and 60. Adequate anesthesia was obtained in all groups. Hypertension and clinically dangerous movements were more frequent with the small STC, and hypotension requiring treatment was more frequent with the large STC. Propofol target concentration during surgery decreased significantly with increasing STC (median at thyroid removal 5.0, 4.0, and 2.5 microg/mL, respectively) as well as the propofol consumption (740, 668, 474 mg/h). The 0.3 ng/mL STC significantly delayed the return of spontaneous breathing. ⋯ Given as a target-controlled infusion for thyroid surgery, sufentanil 0.3 ng/mL for intubation and 0.2 ng/mL during surgery, combined with propofol 4 microg/mL (corresponding to a maintenance infusion rate of approximately 7-10 mg. kg(-1). h(-1)), is recommended to ensure both optimal intraoperative stability and fast recovery.
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Anesthesia and analgesia · Sep 2002
Randomized Controlled Trial Clinical TrialThe use of magnesium sulfate to prevent pain on injection of propofol.
Magnesium sulfate, 2.48 mmol, injected 20 s before the administration of propofol significantly reduced the incidence of pain caused by a propofol injection and may be useful in minimizing this common side effect.