thiopental and esmolol

To compare the effects of four techniques for preventing or blunting the hypertensive response to the insertion of Mayfield headrest skull pins: intravenous (IV) alfentanil (ALF), esmolol (ESM), thiopental sodium (TPL), and local anesthesia using plain lidocaine (Xylocaine; XYL).. Randomized open study.. 40 adult patients undergoing intracranial or spinal surgery requiring the use of Mayfield headrest skull pins for head positioning and immobilization.. 20 minutes after anesthetic induction, and 2 to 3 minutes prior to the insertion of headrest skull pins, one of three drugs was administered IV: ALF 10 mcg/kg, ESM 1 mg/kg, or TPL 1.5 mg/kg. The fourth drug, XYL, was administered by injection into the scalp.. Blood pressure and heart rate (HR) were recorded immediately prior to and after pin insertion with balanced general anesthesia, and at 30, 60, 120, and 180-second intervals after pin insertion. The measurements were compared with the immediate preinsertion values. In the ALF and XYL groups, there was no significant increase in mean arterial pressure (MAP) or HR for any of the measurement periods. MAP was elevated immediately on pin insertion and for up to 2 minutes in the TPL group, and for up to 3 minutes in the ESM group (p < 0.05). HR changes were seen in the TPL group for up to one minute (p < 0.05). Increases in systolic blood pressure were seen in the TPL and ESM groups for up to 3 minutes, and in diastolic blood pressure for up to 2 minutes (p < 0.05). No other significant changes were observed.. IV ALF and local injection of XYL in the scalp prevent the hemodynamic response to the insertion of skull pins in anesthetized patients. Neither ESM nor TPL prevented the hypertensive response. Local anesthetic injection into the scalp requires coordination between the anesthesiologist and surgeon, it carries the risk of needle stick injury, and it must be repeated if the surgeon repositions the headrest. The rapid onset and short half-life of ALF, coupled with the absence of hemodynamic effects at the dose used, makes this drug an alternative to the use of XYL injection.

Topics: Adrenergic beta-Antagonists; Adult; Alfentanil; Anesthesia, Intravenous; Anesthetics, Intravenous; Anesthetics, Local; Blood Pressure; Heart Rate; Hemodynamics; Humans; Lidocaine; Middle Aged; Orthopedic Fixation Devices; Propanolamines; Skull; Spine; Thiopental

In a double-blind study the effect of esmolol and alfentanil on the QT interval of the ECG corrected by the heart rate (QTc), heart rate and arterial pressure during anaesthetic induction was studied in 59 oxycodone- and atropine-premedicated ASA class I-(II) patients with a mean age of 26 yr (range 15-50 yr). The patients were randomly allocated to one of the four groups: saline, esmolol 2 mg.kg-1, esmolol 3 mg.kg-1 or alfentanil 0.03 mg.kg-1. Both doses of esmolol prevented the prolongation of the QTc interval after thiopental and suxamethonium, but not after laryngoscopy and intubation. Alfentanil prevented the prolongation of the QTc interval following thiopental, suxamethonium and laryngoscopy but not after intubation. Esmolol did not prevent the increase in the heart rate and arterial pressure in response to laryngoscopy and intubation. No cardiovascular responses to laryngoscopy and intubation occurred in the patients treated with alfentanil. No cardiac arrhythmias occurred in the esmolol 3 mg.kg-1 group, whereas the frequency of ventricular ectopic beats was 40% in the saline group and 13-20% in the other groups.

Topics: Adolescent; Adrenergic beta-Antagonists; Adult; Alfentanil; Anesthesia; Anesthetics, Intravenous; Arrhythmias, Cardiac; Blood Pressure; Double-Blind Method; Electrocardiography; Heart Rate; Humans; Intubation, Intratracheal; Laryngoscopy; Middle Aged; Propanolamines; Succinylcholine; Thiopental

To compare the safety and efficacy of lidocaine, esmolol, and nitroglycerin in modifying the hemodynamic response to laryngoscopy and intubation.. Randomized, placebo-controlled, double-blind study.. University-affiliated VA medical center.. 40 ASA physical status I and II patients undergoing electric surgery with general endotracheal anesthesia.. Anesthesia was induced with thiopental sodium 5 mg/kg, and intubation was facilitated with vecuronium 0.15 mg/kg. Isoflurane (0.5% to 1%) and 50% nitrous oxide in oxygen were used for maintenance of anesthesia. In addition, patients received one of the following four study drugs intravenously (i.v.) prior to laryngoscopy: Group 1 (control) = saline 5 ml; Group 2 = lidocaine 1.5 mg/kg; Group 3 = esmolol 1.4 mg/kg; Group 4 = nitroglycerin 2 micrograms/kg.. Mean arterial pressure (MAP) and heart rate (HR) were recorded every minute for 20 minutes following induction of anesthesia. Following laryngoscopy and intubation, MAP increased significantly in all four treatment groups (control 49% +/- 19%, lidocaine 55% +/- 26%, esmolol 25% +/- 11%, nitroglycerin 45% +/- 21%) compared with preinduction baseline values. In the esmolol-pretreated patients, the increase in HR was significantly lower (20% +/- 3%) compared with the nitroglycerin (37% +/- 8%), lidocaine (52% +/- 8%), and control (29% +/- 4%) groups.. Lidocaine 1.5 mg/kg i.v. and nitroglycerin 2 micrograms/kg i.v. were ineffective in controlling the acute hemodynamic response following laryngoscopy and intubation. Esmolol 1.4 mg/kg i.v. was significantly more effective than either lidocaine or nitroglycerin in controlling the HR response to laryngoscopy and intubation (p < 0.05). Esmolol also was significantly more effective than lidocaine in minimizing the increase in MAP (25% vs. 55%).

Topics: Adrenergic beta-Antagonists; Anesthesia, Intravenous; Blood Pressure; Double-Blind Method; Elective Surgical Procedures; Heart Rate; Humans; Intubation, Intratracheal; Laryngoscopy; Lidocaine; Middle Aged; Nitroglycerin; Placebos; Propanolamines; Thiopental; Vecuronium Bromide

The purpose of this double-blind randomized work was to study the effect of alfentanil and esmolol and their half-dose combination on the increases of heart rate and arterial pressure and on the prolongation of the QTc interval of the ECG occurring during anaesthetic induction. Sixty ASA class I-II patient with mean age ranging from 26 to 32 yr among the groups. Patients were allocated to one of four equal groups to receive saline, esmolol 2 mg.kg-1, alfentanil 0.03 mg.kg-1 and alfentanil 0.015 mg.kg-1+esmolol 1 mg.kg-1. Anaesthesia was induced with thiopentone. Succinylcholine was used to facilitate tracheal intubation. Haemodynamic variables were measured non-invasively and the QTc interval with the aid of a microcomputer. Comparisons between the groups were performed using two-way analysis of variance with repeated measures. Both alfentanil and alfentanil-esmolol prevented the increase of heart rate and arterial pressure caused by intubation whereas esmolol prevented only the increase of the heart rate. None of the treatments prevented prolongation of the QTc interval after intubation and only alfentanil prevented that after succinylcholine. The present results suggest that in the prevention of the haemodynamic responses to tracheal intubation, the half-dose combination of alfentanil and esmolol is as effective as alfentanil and superior to esmolol. The combination is preferable to relatively large doses of either drug in circumstances where side effects, such as respiratory depression due to alfentanil or bradycardia due to both drugs should be minimized.

Topics: Adrenergic beta-Antagonists; Adult; Alfentanil; Analysis of Variance; Anesthesia, Intravenous; Blood Pressure; Bradycardia; Double-Blind Method; Drug Combinations; Electrocardiography; Heart Rate; Humans; Intubation, Intratracheal; Propanolamines; Respiration; Succinylcholine; Thiopental

Esmolol, an ultra-short-acting cardioselective beta-adrenergic blocker, was investigated in a double-blind prospective protocol for its ability to control haemodynamic responses associated with tracheal intubation after thiopentone and succinylcholine. Thirty ASA physical status I patients received a 12-minute infusion of esmolol (500 micrograms X kg-1 X min-1 for four minutes, then 300 micrograms X kg-1 X min-1 for 8 minutes) or saline. Five minutes after the start of the drug/placebo infusion, anaesthesia was induced with 4 mg X kg-1 thiopentone followed by succinylcholine for tracheal intubation. Prior to induction esmolol produced significant decreases in heart rate (HR) (9.3 +/- 1.8 per cent) and rate-pressure product (RPP) (13.1 +/- 1.8 per cent), systolic blood pressure (SAP) (4.3 +/- 1.5 per cent) and mean arterial blood pressure (MAP) (1.7 +/- 2.0 per cent). Increases in HR, SAP and RPP after intubation were approximately 50 per cent less in patients given esmolol compared to patients given placebo. There were highly significant differences in HR (p less than 0.0001), and RPP (p less than 0.0005) and significant differences in SAP (p less than 0.05) when the maximal esmolol post-intubation response was compared to the maximal placebo response. Infusion of esmolol in the dose utilized in this study significantly attenuated but did not completely eliminate cardiovascular responses to intubation.

Topics: Adult; Anesthesia; Blood Pressure; Double-Blind Method; Female; Heart Rate; Humans; Intubation, Intratracheal; Laryngoscopy; Male; Middle Aged; Propanolamines; Succinylcholine; Thiopental

The effects of IV anesthetics are enhanced by increased cerebral blood flow (CBF) because of a greater delivery of drugs to the brain. In contrast, mathematical simulations suggest that a decrease in CBF, by increasing regional drug uptake and decreasing drug washout, enhances the efficacy of intraarterial drugs. We hypothesized that administrating intracarotid anesthetics during cerebral hypoperfusion will significantly prolong the duration of electroencephalographic (EEG) silence. We tested our hypothesis on New Zealand White rabbits. In the first group of 7 animals, we observed that decreasing CBF by approximately 70% attenuated, but did not abolish, EEG activity. Subsequently, 9 animals received 3 intracarotid injections of 3 mg of thiopental (thiopental-1, thiopental + hypoperfusion, and thiopental-2). The first and third injections were made under physiological conditions. The second drug injection was made during cerebral hypoperfusion. Compared with injection of thiopental-1 and -2, thiopental + hypoperfusion resulted in a profound increase in EEG silence (from 45 +/- 5 and 67 +/- 27 s, to 206 +/- 46 s, respectively, n = 9, P < 0.0001). The EEG recovery profile was similar during all three thiopental challenges. The study suggests that modulation of CBF is an important tool for enhancing intraarterial drug delivery to the brain.

Topics: Adenosine; Adrenergic beta-Antagonists; Animals; Body Temperature; Carotid Artery, Common; Cerebrovascular Circulation; Electroencephalography; Hypnotics and Sedatives; Infusions, Intra-Arterial; Propanolamines; Rabbits; Thiopental; Vasodilator Agents

Pulmonary reactivity to methacholine after equipotent beta-blocking doses of propranolol and esmolol was compared in seven basenji-greyhound dogs during thiopental-fentanyl anesthesia. Equipotent doses of esmolol and propranolol were determined by both heart rate effects and by isoproterenol response curves. Propranolol (2 mg/kg) was administered intravenously as a bolus dose and esmolol (0.4-0.5 mg.kg-1.min-1) was administered by continuous infusion. Both esmolol and propranolol significantly decreased heart rate and mean arterial pressure (P less than 0.001). Baseline pulmonary resistance and dynamic compliance did not change after the administration of either propranolol or esmolol. However, propranolol significantly shifted the methacholine dose-response curve to the left so that methacholine (0.3 mg/ml) increased pulmonary resistance by 7.9 +/- 0.97 cmH2O.l-1.s-1 (mean +/- SEM of seven dogs) after pretreatment with propranolol but only 4.4 +/- 0.89 cmH2O.l-1.s-1 (P less than 0.05) without propranolol pretreatment (control). Esmolol, however, did not significantly shift the methacholine dose-response curve. Methacholine (0.3 mg/ml) increased resistance 4.0 +/- 0.89 cmH2O.l-1.s-1 during esmolol administration. This study shows that at equipotent beta 1-blocking doses, propranolol, but not esmolol, produces significant increases in pulmonary reactivity to methacholine.

Topics: Adrenergic beta-Antagonists; Anesthesia, General; Animals; Blood Pressure; Dogs; Dose-Response Relationship, Drug; Drug Interactions; Fentanyl; Heart Rate; Isoproterenol; Lung; Methacholine Chloride; Methacholine Compounds; Propanolamines; Propranolol; Thiopental