Anesthesia and analgesia
-
Anesthesia and analgesia · May 1996
Randomized Controlled Trial Clinical Trial Retracted PublicationPostarthroscopic meniscus repair analgesia with intraarticular ketorolac or morphine.
Both ketorolac, a nonsteroidal antiinflammatory drug, and morphine, an opioid agonist, provide enhanced patient analgesia after arthroscopic knee surgery when administered via the intraarticular route. This study was designed to determine whether ketorolac or morphine results in better patient analgesia and whether their combination would provide superior analgesia to either drug alone. Patients undergoing arthroscopic knee meniscus repair under local anesthesia with sedation were evaluated. ⋯ This study revealed a significant benefit from the individual intraarticular administration of both morphine and ketorolac. The combination of these drugs did not result in decreased postoperative pain or need for postoperative analgesics, and it did not result in an increased analgesic duration. We conclude that the use of either intraarticular ketorolac or intraarticular morphine improves the comfort in patients undergoing arthroscopic meniscus repair and that their combination offers no advantage over either drug alone.
-
Anesthesia and analgesia · May 1996
Lidocaine plasma concentrations in pediatric patients after providing airway topical anesthesia from a calibrated device.
The aim of this prospective study was to evaluate plasma lidocaine concentrations in infants and children after laryngeal spray using a calibrated device. Twenty-one patients aged 3 to 24 mo requiring laryngoscopy or bronchoscopy were included in the study. Anesthesia was induced via a mask with halothane up to 2% in 100% O2. ⋯ The dose of lidocaine administered ranged between 0.9 and 2.6 mg/kg. Maximum plasma lidocaine concentration (Cmax) was 1.05 +/- 0.55 micrograms/mL (mean +/- SD; range 0.24-2.29 micrograms/mL). With this procedure, we demonstrated the safety of administering lidocaine to children by laryngeal spraying using a 5% sprayer.
-
Anesthesia and analgesia · May 1996
Comparative StudyHemodynamic effects of intravenous isoproterenol versus epinephrine in the chronic maternal-fetal sheep preparation.
Isoproterenol 5 micrograms may be an effective marker of accidental intravascular injection in women in labor; however, before isoproterenol can be incorporated in routinely used epidural test doses, the safety and usefulness should be determined in an animal model. This study was designed to examine the hemodynamic effects of isoproterenol in comparison with epinephrine in the pregnant ewe. Five doses of isoproterenol were tested and compared with two doses of epinephrine in a randomized cross-over fashion. ⋯ A significant increase in the cardiac output was seen after isoproterenol. Neither isoproterenol nor epinephrine affected fetal heart rate (FHR), fetal mean arterial pressure (FMAP), amniotic fluid pressure (Amn-pr), blood gases, or acid base status in the mother and the fetus. Provided that neurotoxic effects are absent, isoproterenol might be a better alternative than epinephrine as a test dose for possible intravenous placement of an epidural catheter in pregnant women.
-
Anesthesia and analgesia · May 1996
The effect of a cyclodextrin vehicle on the cardiovascular profile of propofol in rats.
We studied the aqueous solution of propofol dissolved in hydroxypropyl-beta-cyclodextrin (HP beta CD) 20% to determine whether the cardiovascular profile differed from that measured for propofol prepared in Intralipid 10% (Diprivan). Conscious male rats were given an intravenous bolus of propofol, 5.0 mg/kg, the minimum dose that induces a loss of righting. Immediately severe bradycardia occurred which was the result of a combination of sinus arrest and atrioventricular block; a significant decrease of blood pressure resulted. ⋯ The severe bradycardia produced by propofol in HP beta CD was blocked by both atropine and bilateral cervical vagotomy. Therefore, the effects of propofol in HP beta CD are cholinergic and neurally mediated. These results are consistent with the hypothesis that propofol reduces sympathetic tone prior to reduction in vagal tone, and thereby produces a period of time during which vagal tone is dominant.
-
Anesthesia and analgesia · May 1996
Identification of cytochrome P450 3A1/2 as the major P450 isoform responsible for the metabolism of fentanyl by rat liver microsomes.
The metabolism of fentanyl was investigated using rat liver microsomes to determine whether fentanyl is metabolized by rat liver microsomal cytochrome P450 and, if so, which isoform is responsible for the metabolism. Microsomes isolated from rats pretreated with phenobarbital were more active in metabolizing fentanyl than were microsomes from saline controls. ⋯ Fentanyl metabolism was inhibited by antibodies specific for CYP3A1/2, as well as by chemical inhibitors specific for CYP3A. These results indicate that CYP3A1/2 plays a major role in the oxidation of fentanyl to norfentanyl by rat liver microsomes.