Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2002
Randomized Controlled Trial Clinical TrialClinical application of acoustic reflectometry in predicting the difficult airway.
Acoustic reflectometry, a noninvasive test that produces a length versus cross-sectional area map of the airway, has been used to identify difficult-to-tracheally intubate patients in a small retrospective case-control study. A critical airway volume of 40.2 mL separated those patients whose tracheas were impossible to intubate from those who were easily intubated. To determine if this technology was applicable for prospectively predicting difficult intubation and difficult ventilation in routine clinical practice, we performed a double-blinded, prospective cohort study. Our a priori hypothesis was that small airway volumes in adults (<40.2 mL) would predict absolute inability to intubate. We conclude that by use of acoustic reflectometry, there was no relationship between inability to intubate, poor glottic visualization, and multiple laryngoscopies with airway volume. ⋯ Acoustic reflectometry, a noninvasive test that uses sound to produce a length versus cross-sectional area map of the airway, was not able to predict inability to intubate, poor glottic visualization, and multiple laryngoscopies.
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Anesthesia and analgesia · Sep 2002
Randomized Controlled Trial Clinical TrialA randomized controlled trial examining the effect of naproxen on analgesia during the second day after cesarean delivery.
Whereas nonsteroidal antiinflammatory drugs augment spinal morphine on Day l, the analgesia gained by simply combining these drugs with conventional "on request" oral regimens on Day 2 is less clear. In this trial, we randomized 80 women undergoing elective cesarean delivery with spinal morphine (0.2 mg) to receive naproxen (500 mg) or placebo every 12 h after surgery. Both groups received conventional therapy with acetaminophen with codeine (on request) and rescue IM opioids. Incision pain on sitting (IPS), incision pain at rest, uterine cramping, and gas pain were evaluated with visual analog scales (0-100). Worst interval pain (0-10), analgesic use, and side effects were measured over 72 h. At 36 h (primary outcome), naproxen use was associated with reductions in IPS (38.2 +/- 26.0 versus 51.4 +/- 25.7; P = 0.05), incision pain at rest, uterine cramping, and worst interval pain scores. Clinically modest, statistically significant reductions in IPS (P = 0.0001) and opioid use were found over time (P < 0.0l). Reductions in the incidence of inadequate analgesia and improvements in overall pain relief (P = 0.0006) on Day l did not persist on Day 2 (overall pain relief, P = 0.057; inadequate analgesia, 24% naproxen versus 27% controls; P = 1.00). The addition of regular doses of naproxen to conventional oral pain therapy after cesarean delivery leads to reductions in IPS at 36 h and pain over Day 2 but does not reduce the incidence of inadequate analgesia. ⋯ This randomized trial suggests that adding regular doses of naproxen to conventional "on request" acetaminophen and codeine therapy provides small reductions in pain on the second day after cesarean delivery. The greatest effects occur at 36 h, when pain peaks.
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Anesthesia and analgesia · Sep 2002
Randomized Controlled Trial Clinical TrialIntrathecal magnesium prolongs fentanyl analgesia: a prospective, randomized, controlled trial.
Magnesium is a noncompetitive, N-methyl-D-aspartate receptor antagonist that does not effectively cross the blood-brain barrier when given IV. Intrathecal magnesium potentiates opioid antinociception in rats, and the safety of intrathecal magnesium has been demonstrated in animals. This is the first prospective human study evaluating whether intrathecal magnesium could prolong spinal opioid analgesia. Fifty-two patients requesting analgesia for labor were randomized to receive either intrathecal fentanyl 25 micro g plus saline or fentanyl 25 micro g plus magnesium sulfate 50 mg as part of a combined spinal-epidural technique. The duration of analgesia of the intrathecal drug combination was defined by the time of patient request for additional analgesia. There was significant prolongation in the median duration of analgesia (75 min) in the magnesium plus fentanyl group compared with the fentanyl alone group (60 min). There was no associated increase in adverse events in the group that received intrathecal magnesium. Larger doses of intrathecal magnesium were not studied in this group of patients because of the limitations on cephalad spread when hyperbaric solutions are injected in the sitting position. Our data indicate that intrathecal magnesium prolongs spinal opioid analgesia in humans and suggest that the availability of an intrathecal N-methyl-D-aspartate antagonist could be of clinical importance for pain management. ⋯ Magnesium occurs naturally in the spinal cord and blocks the NMDA glutamate channel. In animal studies, intrathecal magnesium sulfate improves spinal morphine analgesia. For patients receiving spinal analgesia for labor, the addition of magnesium sulfate to the opioid fentanyl prolonged analgesia with no increase of side effects.
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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 TrialThe dose-sparing effect of clonidine added to ropivacaine for labor epidural analgesia.
To determine the effects of clonidine with ropivacaine during epidural labor analgesia, we studied 66 nulliparous women in early active labor. Women were randomized to receive ropivacaine 0.1% 8 mL plus 75 microg of clonidine (Group 1), ropivacaine 0.2% 8 mL plus 0.5 mL of NaCl 0.9% (Group 2), or ropivacaine 0.2% 8 mL plus 75 microg of clonidine (Group 3) 5 min after a bupivacaine 7.5 mg with epinephrine 15 microg test dose. Upon request, additional analgesia with ropivacaine 0.1% 8 mL followed by ropivacaine 0.2% 8 mL/h was administered. With clonidine, duration of analgesia was increased (132 +/- 48 min [Group 1] and 154 +/- 42 min [Group 3] versus 91 +/- 44 min [Group 2]; P < 0.05), and total ropivacaine dose over the first 4 h was significantly reduced (40.5 +/- 15 mg [Group 1] and 47.0 +/- 16 mg [Group 3] versus 72.5 +/- 18 mg [Group 2]; P < 0.01). The incidence of more profound motor block was more frequent in Group 2 (P < 0.05). Although there was a trend for more women receiving clonidine to require ephedrine for treatment of hypotension, this did not seem to have an impact on fetal outcome or incidence of cesarean deliveries for nonreassuring fetal heart rate tracings. This study demonstrates the dose-sparing effect of clonidine when added to ropivacaine. ⋯ The effect of adding 75 microg of clonidine to ropivacaine for epidural labor analgesia was studied. Clonidine increased analgesia duration and produced dose sparing compared with ropivacaine alone. Despite a tendency for hypotension in women receiving clonidine, there was no apparent effect on delivery mode or neonatal outcome.