Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of ropivacaine and bupivacaine for cervical plexus block.
We compared bupivacaine 0.5% and ropivacaine 0.75% for cervical plexus block (CB). Forty patients scheduled for carotid artery surgery were allocated randomly to undergo superficial and deep CB with 30 mL of one of the two anesthetic solutions. We evaluated the onset of anesthetic block; the requirement for supplementation during the surgery; the patients' satisfaction; postoperative pain on a visual analog scale at 1, 2, and 3 h; and the use of paracetamol as a rescue analgesic medication. Arterial blood was sampled immediately and 1, 3, 5, 10, 15, 30, 45, and 60 min after CB for measurements of bupivacaine or ropivacaine concentrations. Patients in both groups had equivalent onset of CB, local infiltration with lidocaine during surgery, and satisfaction scores. In the Bupivacaine group, visual analog scale scores were lower at 2 and 3 h, and the delay before paracetamol administration was prolonged. Observed peak concentrations were larger in the Ropivacaine group (4.25 [2.07-6.59 mg/L] vs 3.02 [0.98-5.82 mg/L]), but time to reach peak concentrations was comparable (5 [1-15 min] vs 5 [0-45 min] in the Ropivacaine and Bupivacaine groups, respectively). We conclude that ropivacaine has no advantage over bupivacaine for CB. ⋯ Compared with bupivacaine (150 mg), a larger dose of ropivacaine (225 mg) produces comparable features of cervical plexus block but less postoperative analgesia and larger plasma concentrations. There is no reason to favor ropivacaine in such a case.
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Comparative Study Clinical TrialThe influence of intravascular volume therapy with a new hydroxyethyl starch preparation (6% HES 130/0.4) on coagulation in patients undergoing major abdominal surgery.
A new hydroxyethyl starch (HES) preparation with a mean molecular weight of 130,000 daltons and a degree of substitution of 0.4 shows favorable pharmacokinetic properties. We conducted a study of the influence of the new HES specification on coagulation and compared it with another colloidal intravascular volume replacement regimen using gelatin. According to a prospective, random sequence, 42 patients undergoing major abdominal surgery received either HES 130/0.4 (n = 21) or gelatin (n = 21) until the first postoperative day (POD) to keep central venous pressure between 10 and 14 mm Hg. From arterial blood samples, standard coagulation variables were measured, and modified thrombelastogram (TEG) measurements using different activators were performed. A total of 2830 +/- 350 mL of gelatin and 2430 +/- 310 mL of HES 130/0.4 were administered until the morning of the first POD. The use of allogeneic blood/blood products and standard coagulation variables did not differ significantly between the two groups. After induction of anesthesia, all TEG data for both groups were within normal range. Coagulation time and maximum clot firmness did not change significantly in any TEG measurements during the study period. The kinetics of clot formation (clot formation time) significantly increased immediately after surgery, but without showing significant group differences. On the morning of the first POD, the clot formation time returned to almost normal levels, except for aprotinin-activated TEG(R). We conclude that administration of moderate doses of the new HES 130/0.4 preparation in patients undergoing major abdominal surgery results in similar coagulation alterations as those after using an established gelatin-based volume-replacement regimen. ⋯ We compared the effects of infusion of a new hydroxyethyl starch preparation (6% hydroxyethyl starch; mean molecular weight 130,000 daltons; degree of substitution 0.4) on coagulation with a gelatin-based intravascular volume replacement regimen in patients undergoing major abdominal surgery. After moderate doses of hydroxyethyl starch (2430 +/- 310 mL until the morning of the first postoperative day), coagulation monitoring, including modified thrombelastography, did not show impaired hemostasis.
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Clinical TrialDexamethasone for preventing nausea and vomiting associated with epidural morphine: a dose-ranging study.
We conducted a dose-ranging study of dexamethasone for preventing nausea and vomiting within the first 24 h after the administration of epidural morphine. Two hundred twenty-five women (n = 45 in each of the five groups) undergoing simple abdominal total hysterectomy under epidural anesthesia were enrolled in this randomized, double-blind, placebo-controlled study. When the incision closure was completed, patients received IV dexamethasone, 10 mg, 5 mg, or 2.5 mg; IV droperidol 1.25 mg; or saline 2 mL. All patients received epidural morphine 3 mg for postoperative analgesia. We found that patients who received dexamethasone 5 mg or 10 mg or droperidol 1.25 mg were significantly different from those who received saline alone in the following variables: the total incidence of nausea and vomiting, the incidence of more than four vomiting episodes, the number of patients requiring rescue antiemetics, the total number of patients with no vomiting and/or no antiemetic medication (P < 0.05 to P < 0.01). The differences among dexamethasone 10 mg and 5 mg and droperidol 1.25 mg were not significant. Dexamethasone 2.5 mg was ineffective. In conclusion, because dexamethasone 5 mg was as effective as 10 mg as an antiemetic, we recommend the smaller dose for preventing nausea and vomiting associated with epidural morphine. ⋯ We conducted a dose-ranging study of dexamethasone for preventing nausea and vomiting within the first 24 h after the administration of epidural morphine. We found that dexamethasone 5 mg was as effective as 10 mg. We recommend the smaller dose for this purpose.
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Clinical TrialThe effect of the preemptive use of the NMDA receptor antagonist dextromethorphan on postoperative analgesic requirements.
Both central sensitization after peripheral tissue injury and the development of opiate tolerance involve activation of N-methyl-D-aspartate receptors. In this double-blinded, randomized study, we investigated the preemptive versus postincisional effects of dextromethorphan, an N-methyl-D-aspartate receptor antagonist, on postoperative pain management. Sixty ASA I and II patients undergoing elective upper abdominal surgery were randomly allocated to three equally sized groups. The Preincisional group patients received dextromethorphan (120 mg) IM 30 min before skin incision and a placebo (isotonic saline) 30 min before the end of surgery. The Postincisional group received the same dose of dextromethorphan 30 min before the end of surgery and a placebo 30 min before skin incision, and the Control group received a placebo both 30 min before skin incision and 30 min before the end of surgery. A standard general anesthetic technique including fentanyl, propofol, isoflurane, and atracurium was used. Postoperative meperidine patient-controlled analgesia (PCA) was used. There were no significant group differences in the median pain scores except in the visual analog scale at 6 h both at rest and on movement; these were significantly lower in the Preincisional group than the other two groups (P < 0.05). The mean time to initiation of PCA was significantly longer in the Preincisional than in the Postincisional and Control groups (mean [SD]: 10.7 [2.2 h], 5.4 [2.1 h], and 3.7 [1.6 h], respectively; P < 0.001]. The 24-h PCA-meperidine consumption was significantly less in the Preincisional than in the Postincisional and Control groups (mean [SD]: 140 [60 mg], 390 [80 mg], and 570 [70 mg], respectively; P < 0.001]. The incidence of postoperative hypoxemia (SpO(2) < 90%) and nausea was significantly less in the Preincisional group (P < 0.05). In conclusion, preincisional IM 120 mg dextromethorphan compared with the same postincisional dose significantly reduced postoperative meperidine consumption. ⋯ IM administration of preincisional dextromethorphan (120 mg), allowing the use of a larger dose sufficient to block the central sensitization caused by activation of the N-methyl-D-aspartate receptors, provides preemptive analgesia and has a supportive role in postoperative pain relief, as shown by a significant decrease in 24-h meperidine consumption.
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Anesthesia and analgesia · Mar 2001
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of two constant-dose continuous infusions of remifentanil for severe postoperative pain.
We evaluated the analgesic efficacy and safety of two continuous constant-dose infusions of IV remifentanil, without infusion rate increments or the addition of boluses, in patients with severe postoperative pain during the first 4 h after general anesthesia with IV propofol-remifentanil. Thirty patients were randomly assigned to two groups of 15 subjects each according to the remifentanil dose administered: 0.1 microg. kg(-1). min(-1) IV (Group A) or 0.05 microg. kg(-1). min(-1) IV (Group B). Rescue analgesia was provided with meperidine (0.5 mg/kg IV) when pain intensity on the simple verbal scale (SVS) > or =2. The criteria for adequate analgesia (SVS 0-1, respiratory frequency >8/min. and SpO(2) >90%) after 4 h were met by 78% and 75% of the patients in Groups A and B, respectively (P = ns). "Meperidine rescue" analgesia was significantly more in Group B (26%) than in Group A (6%) (P < 0.05). There were no cases of respiratory depression, and nausea and emesis occurred in one patient in each group (6.5%). We conclude that IV remifentanil is an effective and safe opioid for the treatment of postoperative pain at a constant dose of 0.1 microg. kg(-1). min(-1) with a need for rescue analgesia 4 times less than a constant dose of 0.05 microg. kg(-1). min(-1). ⋯ Our study suggests that the use of a constant continuous infusion of remifentanil 0.1 microg.kg(-1).min(-1)IV is an effective alternative in the treatment of severe postoperative pain.