Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1998
Comparative Study Clinical TrialComparison of plasma lidocaine concentrations after injection of a fixed small volume in the stellate ganglion, the lumbar epidural space, or a single intercostal nerve.
We measured the plasma lidocaine concentrations after stellate ganglion block (SGB) and compared them with those after intercostal nerve block (ICNB) and epidural block (EB) using identical doses of lidocaine. Thirty patients undergoing SGB (n = 10), ICNB (n = 10), or EB (n = 10) in our pain clinic participated in this study. Six milliliters of 1% lidocaine was used for all nerve blocks. SGB was performed at the C6 transverse process, ICNB was performed on a single intercostal nerve, and epidural lidocaine was injected through the lumbar epidural catheter. After drug administration, venous blood samples were taken from an indwelling catheter in the arm every minute for the first 10 min and 15, 20, 30, 45, and 60 min thereafter. Plasma lidocaine concentrations were measured by using an enzyme immunoassay method. The SGB group showed significantly higher peak plasma lidocaine concentrations than other groups (SGB 1.65 +/- 0.21 microgram/mL, ICNB 0.89 +/- 0.12 microgram/mL, EB 0.91 +/- 0.19 microgram/mL; P < 0.01). The SGB group reached peak levels significantly faster than the other groups (SGB 3.4 +/- 1.0 min, ICNB 7.9 +/- 1.5 min, EB 6.9 +/- 0.7 min; P < 0.01). We conclude that the plasma lidocaine concentrations after SGB were higher than those after ICNB and EB when using small, equal doses of lidocaine. The high and rapid peak plasma lidocaine concentrations after SGB are probably related to the high vascularity of the injection site. ⋯ Higher plasma concentrations of local anesthetics are reportedly obtained after multiple intercostal nerves blocks compared with those after other types of nerve blocks. Our results, however, showed that the peak plasma concentrations after stellate ganglion block were higher and faster than those after a single intercostal nerve block.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialClonidine added to the anesthetic solution enhances analgesia and improves oxygenation after intercostal nerve block for thoracotomy.
We evaluated the effect of adding clonidine to bupivacaine on postoperative pain control and oxygenation after intercostal nerve blockade (ICB) for thoracotomy, and attempted to distinguish a systemic from a local effect of clonidine. ICB with 2 mg/kg 0.5% bupivacaine was performed in 36 patients undergoing thoracotomy. Patients were randomized to one of three groups: 1) a control group that received bupivacaine with saline for ICB and an IM injection of saline, 2) an IM group that received bupivacaine with saline for ICB and an IM injection of 2 micrograms/kg clonidine, and 3) a block group that received bupivacaine with 2 micrograms/kg clonidine for ICB and an IM injection of saline. Blood gases, visual analog scale (VAS) scores, and analgesic demand were determined hourly for 8 h after arrival in the postoperative care unit (PCU). Patients in the block group had significantly lower VAS scores, higher arterial oxygen tension, and lower analgesic demand for the first 4 h in the PCU, compared with the two other groups. No difference was noted thereafter. We conclude that the addition of clonidine to bupivacaine for ICB leads to a short-term effect enhancing postoperative pain control and improving arterial oxygenation, probably mediated by a direct effect on the nerves. ⋯ Severe pain after thoracotomy can lead to impaired ventilation. We studied the effect of adding clonidine to bupivacaine for intercostal nerve blockade after thoracotomy. Clonidine administered directly on the nerves enhanced analgesia and improved oxygenation for a short time compared with systemic administration or control.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialMagnesium sulfate reduces intra- and postoperative analgesic requirements.
In a randomized, double-blind study with two parallel groups, we assessed the analgesic effect of perioperative magnesium sulfate administration in 46 ASA physical status I or II patients undergoing arthroscopic knee surgery with total i.v. anesthesia. The patients received either magnesium sulfate 50 mg/kg preoperatively and 8 mg.kg-1.h-1 intraoperatively or the same volume of isotonic sodium chloride solution i.v. Anesthesia was performed with propofol (2 mg/kg for induction, 6-8 mg.kg-1.h-1 for maintenance), fentanyl (3 micrograms/kg for induction), and vecuronium (0.1 mg/kg for intubation). Intraoperative pain was defined as an increase of mean arterial blood pressure and heart rate of more than 20% from baseline values after the induction of anesthesia and was treated with bolus fentanyl (1-2 micrograms/kg). Postoperative analgesia was achieved with fentanyl (0.5 microgram/kg) and evaluated using the pain visual analog scale for 4 h. During the intraoperative and postoperative periods, patients in the magnesium group required significantly less fentanyl than those in the control group (control group 0.089 +/- 0.02 microgram.kg-1.min-1 versus magnesium group 0.058 +/- 0.01 microgram.kg-1.min-1; P < 0.05 and control group 0.021 +/- 0.013 microgram.kg-1.min-1 and magnesium group 0.0031 +/- 0.0018 microgram.kg-1.min-1; P < 0.01 for intraoperative and postoperative periods, respectively). We conclude that, in a clinical setting with almost identical levels of surgical stimulation, i.v. magnesium sulfate administration reduces intraoperative and postoperative analgesic requirements compared with isotonic sodium chloride solution administration. ⋯ The perioperative administration of i.v. magnesium sulfate reduces intra- and postoperative analgesic requirements in patients with almost identical levels of surgical stimulus. Our results demonstrate that magnesium can be an adjuvant to perioperative analgesic management.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialThe effect of preoperative dexamethasone on the immediate and delayed postoperative morbidity in children undergoing adenotonsillectomy.
In this prospective, randomized, double-blind, placebo-controlled study, we examined the effect of preoperative dexamethasone on postoperative nausea and vomiting (PONV) and 24-h recovery in children undergoing tonsillectomy. One hundred thirty children, 2-12 yr of age, ASA physical status I or II, completed the study. All children received oral midazolam 0.5-0.6 mg/kg preoperatively. Anesthesia was induced with halothane and nitrous oxide in 60% oxygen and maintained with nitrous oxide and isoflurane. Intubation was facilitated by mivacurium 0.2 mg/kg. Each child received fentanyl 1 microgram/kg i.v. before initiation of surgery, as well as dexamethasone 1 mg/kg (maximal dose 25 mg) (steroid group) or an equal volume of saline (control group). Intraoperative fluids were standardized to 25-30 mL/kg lactated Ringer's solution. All tonsillectomies were performed under the supervision of one attending surgeon using an electrodissection technique. Postoperatively, fentanyl and acetaminophen with codeine elixir were administered as needed for pain. Rescue antiemetics were administered when a child experienced two episodes of retching and/or vomiting. Before home discharge, the incidence of PONV, need for rescue antiemetics, quality or oral intake, and analgesic requirements did not differ between groups. However, during the 24 h after discharge, more patients in the control group experienced PONV (62% vs 24% in the steroid group) and complained of poor oral intake. Additionally, more children in the control group (8% vs 0% in the steroid group) returned to the hospital for the management of PONV and/or poor oral intake. The preoperative administration of dexamethasone significantly decreased the incidence of PONV over the 24 h after home discharge in these children. ⋯ In this double blind, placebo-controlled study, we examined the efficacy of a single large dose (1 mg/kg; maximal dose 25 mg) of preoperative dexamethasone on posttonsillectomy postoperative nausea and vomiting (PONV) in children 2-12 yr of age undergoing tonsillectomy. Compared with placebo, dexamethasone significantly decreased the incidence of PONV in the 24 h after discharge, improved oral intake, decreased the frequency of parental phone calls, and resulted in no hospital returns for the management of PONV and/or poor oral intake.