Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1997
Randomized Controlled Trial Clinical TrialThe relationship between cytochrome P4502E1 activity and plasma fluoride levels after sevoflurane anesthesia in humans.
We determined whether the perianesthetic plasma fluoride levels after sevoflurane anesthesia in humans were correlated with the metabolic ratio (MR) of 6-hydroxychlorzoxazone to chlorzoxazone, an in vivo probe for cytochrome P4502E1 (CYP2E1) activity. Thirty ASA physical status I or II patients scheduled for extraabdominal surgery were randomized to a chlorzoxazone (n = 20) or a control group (n = 10). Patients in the chlorzoxazone group received 500 mg chlorzoxazone orally on the morning of the day of surgery. Chlorzoxazone and its 6-hydroxymetabolite concentrations were measured in plasma 2 h after drug administration. Anesthesia was induced with propofol, fentanyl, and atracurium intravenously and maintained with sevoflurane (inspired concentration 1-3 vol%). Plasma fluoride concentrations were determined before the induction of anesthesia, at the cessation of sevoflurane, and 2, 4, 6, 10, and 24 h thereafter. The area under the plasma fluoride concentration-time curve (AUC) was calculated up to 24 h after sevoflurane cessation. MR correlated significantly with the plasma fluoride AUC (r2 = 0.28, P < 0.025), the elimination constant calculated for the postanesthetic 10- to 24-h period (r2 = 0.30, P < 0.025), and the plasma fluoride levels 24 h after the cessation of sevoflurane (r2 = 0.48, P < 0.05). A comparison between groups indicated that the administration of chlorzoxazone itself did not alter the postanesthetic fluoride kinetics. Thus, the interindividual variability in perianesthetic plasma fluoride levels after sevoflurane anesthesia is reflected by differences in the MR of chlorzoxazone and hence is related to the interindividual variability in CYP2E1 activity. We conclude that although the predictive value is limited, this study provides a reasonable basis for examining renal function after sevoflurane anesthesia in a subgroup of patients with a high preoperative metabolic ratio of chlorzoxazone. ⋯ CYP2E1 metabolizes sevoflurane as measured by the metabolic ratio of chlorzoxazone. Patients with a high ratio may be used to justify examining renal function in patients receiving sevoflurane.
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Anesthesia and analgesia · Oct 1997
Randomized Controlled Trial Comparative Study Clinical TrialEpidural bolus clonidine/morphine versus epidural patient-controlled bupivacaine/sufentanil: quality of postoperative analgesia and cost-identification analysis.
We compared the costs, quality of analgesia, and side effects of postoperative patient-controlled epidural analgesia (PCEA) with bupivacaine/sufentanil versus an epidural bolus (BOLUS) of clonidine/morphine in 68 patients with pancreatic surgery. Postoperative pain treatment was performed over 4 days: the PCEA pump was filled with bupivacaine 0.25% and sufentanil 2 micrograms/mL and set to 3-mL bolus and 10-min lockout time. BOLUS patients received injections of clonidine 150 micrograms plus morphine 2 mg on demand. Visual analog scale (VAS) score at rest and during coughing, heart rate (HR), systolic arterial pressure (SAP), incidence of postoperative nausea and vomiting, pruritus, duration of intestinal paralysis, hospital treatment, and costs for personnel and material were recorded. VAS scores during coughing (3 +/- 2.5 vs 5 +/- 3, P < 0.001) was higher, and HR (79 +/- 13 vs 89 +/- 15, P < 0.001), and SAP (110 +/- 18 vs 124 +/- 23, P < 0.001) were lower, in the BOLUS compared with the PCEA group. The incidence of hypotension (SAP < 80 mm Hg) was greater (6 vs 0, P < 0.001) in the BOLUS group. The incidence of all other side effects was comparable. The costs of personnel ($204 +/- $40 vs $166 +/- $38, P < 0.001) were higher in the BOLUS group, but the costs of material ($51 +/- $17 vs $87 +/- $18, P < 0.001) were higher in the PCEA group. Total costs ($62 +/- $9 vs $62 +/- $11 per day, P = 0.9) were comparable. We conclude that because of superior analgesia and reduced side effects at analogous costs, PCEA is preferable to the BOLUS technique for the treatment of postoperative pain. ⋯ An epidural clonidine/morphine bolus technique resulted in inferior analgesia, more side effects, and comparable costs compared with a bupivacaine/sufentanil patient-controlled regimen in a randomized controlled trial after abdominal surgery.
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Anesthesia and analgesia · Oct 1997
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of the effect of intrathecal and extradural fentanyl on gastric emptying in laboring women.
We studied gastric emptying, using acetaminophen absorption, in 105 women in labor divided into three equal groups of 35 each, after intrathecal (i.t.) (25 micrograms, Group S) or extradural (50 micrograms, Group E) fentanyl in combination with bupivacaine and compared with a control group (Group C) receiving extradural bupivacaine only. The time to maximal acetaminophen concentration (tCamax), maximal acetaminophen concentration (Camax), and areas under the acetaminophen concentration-time curve at 90 and 120 min (AUC90 and AUC120, respectively) were determined. Median (range) tCamax values were 120 (15-180), 82.5 (15-180), and 90 (15-180) min in Groups S, E, and C, respectively (P < 0.05). Mean +/- SD Camax was 13.4 +/- 8.82, 17.9 +/- 8.06, and 15.0 +/- 6.22 micrograms/mL in Groups S, E, and C, respectively (P < 0.05). Mean +/- SD AUC90 and AUC120 were also significantly smaller in Group S than in the other two groups (430 +/- 616, 736 +/- 504, and 672 +/- 453; and 649 +/- 592, 1063 +/- 627, and 1053 +/- 616 micrograms.mL-1.min-1 in Groups S, E, and C, respectively). We conclude that the administration of fentanyl 25 micrograms i.t. delays gastric emptying in labor compared with both extradural fentanyl 50 micrograms with bupivacaine and extradural bupivacaine alone. ⋯ We examined emptying of the stomach in women in labor after administration of analgesics by the spinal or the epidural route. We observed that the analgesic, fentanyl, administered by the spinal route, although relieving pain rapidly, may delay emptying of the stomach. In theory, delayed gastric emptying may increase the chance of vomiting and aspiration of gastric contents.
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Anesthesia and analgesia · Oct 1997
Randomized Controlled Trial Clinical TrialPressure support ventilation augments spontaneous breathing with improved thoracoabdominal synchrony in neonates with congenital heart disease.
In neonates, during spontaneous breathing with demand-type continuous positive airway pressure (CPAP), high airway resistance caused by small endotracheal tubes, time delay for triggering, and rapid respiratory frequency may result in patient-ventilator asynchrony. Such asynchrony may alter normal breathing patterns and thoracoabdominal synchrony. We, therefore, studied whether pressure support ventilation (PSV) could augment spontaneous breathing and improve synchrony between the rib cage (RC) and the abdominal (AB) motions in nine postoperative neonates with congenital heart disease. Three successive levels of PSV (0, 5, and 10 cm H2O) were used randomly. With increasing levels of PSV, the tidal volume (VT) increased and the respiratory frequency decreased, associated with an increase in minute ventilation. To assess thoracoabdominal synchrony, maximum compartment amplitude (MCA)/VT (MCA = AB + RC) and the phase delay of the RC-to-AB motion during inspiration (the ratio of the time delay to the inspiratory time) were measured using respiratory inductive plethysmography. When the motions of the RC and AB were out of phase, MCA/VT exceeded 1.0. MCA/VT decreased significantly from 1.3 +/- 0.3 without PSV to 1.0 +/- 0.0 with PSV of 10 cm H2O. The phase delay and paradoxical motion of the RC observed in seven of the nine cases without PSV also disappeared with PSV of 10 cm H2O. In conclusion, PSV can effectively augment spontaneous breathing with better thoracoabdominal synchrony in neonates. ⋯ Assisting spontaneous ventilation in a neonate is often difficult. Because pressure support ventilation facilitates coordination between the patient and ventilator in adults and children, we thought it might be effective in neonates. Our study supports this conclusion.
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Anesthesia and analgesia · Oct 1997
Randomized Controlled Trial Clinical TrialUltrasonographic guidance improves sensory block and onset time of three-in-one blocks.
The use of ultrasound reduces the onset time, improves the quality of sensory block, and minimizes the risks associated with the supraclavicular approach for brachial plexus and stellate ganglion blockade. The present study was designed to evaluate whether ultrasound also facilitates the approach for 3-in-1 blocks. Forty patients (ASA physical status II or III) undergoing hip surgery after trauma were randomly assigned to two groups. In the ultrasound (US) group, 20 mL bupivacaine 0.5% was administered under US guidance, whereas in the control group, the same amount and concentration of local anesthetic was administered with the assistance of a nerve stimulator (NS). After US- or NS-based identification of the femoral nerve, the local anesthetic solution was administered, and the distribution of the local anesthetic solution was visualized and recorded on videotape in the US group. The quality and the onset of the sensory block was assessed by using the pinprick test in the central sensory region of each of the three nerves and compared with the same stimulation on the contralateral leg every 10 min for 60 min. The rating was performed using a scale from 100% (uncompromised sensibility) to 0% (no sensory sensation). Heart rate, noninvasive blood pressure, and oxygen saturation were measured at short intervals for 60 min. The onset of sensory blockade was significantly shorter in Group US compared with Group NS (US 16 +/- 14 min, NS 27 +/- 16 min, P < 0.05). The quality of the sensory block after injection of the local anesthetic was also significantly better in Group US compared with Group NS (US 15% +/- 10% of initial value, NS 27% +/- 14% of initial value, P < 0.05). A good analgesic effect was achieved in 95% of the patients in the US group and in 85% of the patients in the NS group. In the US group, visualization of the cannula tip, the femoral nerve, the major vessels, and the local anesthetic spread was possible in 85% of patients. Incidental arterial puncture (n = 3) was observed only in the NS group. We conclude that an US-guided approach for 3-in-1 block reduces the onset time, improves the quality of the sensory block and minimizes the risks associated with this regional anesthetic technique. ⋯ The onset time and the quality of a regional anesthetic technique for the lower extremity is improved by ultrasonographic nerve identification compared with older techniques.