Use of esmolol during anesthesia to treat tachycardia and hypertension

We evaluated the clinical effectiveness of esmolol, an ultra-short-acting, cardioselective beta-adrenergic receptor blocker, in controlling sinus tachycardia and increased systolic blood pressure occurring perioperatively in 30 ASA physical status II or III patients having elective, non-cardiac surgery. Esmolol 80 mg I.V. bolus (N = 15) or placebo (N = 15) followed by 12 mg/min or placebo were infused in 30 isoflurane-anesthetized patients using a randomized double-blind study design. The bolus plus infusions were given when surgical stimuli caused heart rate to exceed 95 bpm or systolic blood pressure 140 mm Hg. Esmolol significantly decreased heart rate (107 +/- 4, mean +/- SEM to 99 +/- 4, mean +/- SEM bpm) within 45 sec after starting the bolus plus infusion; the placebo had no effect, heart rate being 105 +/- 4 before and 106 +/- 3 bpm after the bolus plus infusion. Patients given esmolol continued to have heart rates significantly lower than patients given placebo injections throughout a six min infusion (Ex., at 5 min 81 +/- 3 vs 91 +/- 4 bpm). The study demonstrated no apparent effect of esmolol on blood pressure but that esmolol is effective in treating perioperative sinus tachycardia.     

A comparison of esmolol and labetalol for the treatment of perioperative hypertension in geriatric ambulatory surgical patients

This is an open randomized study comparing the efficacy and safety of i.v. esmolol and labetalol in the treatment of perioperative hypertension in ambulatory surgery. Twenty-two elderly patients undergoing cataract surgery under local anaesthesia were studied. The main inclusion criteria were development of systolic blood pressure greater than 200 mmHg or diastolic greater than 100 mmHg. Esmolol was given as a bolus 500 micrograms.kg-1 i.v. followed by a maintenance infusion (150-300 micrograms.kg-1.min-1). Labetalol was given as a bolus of 5 mg i.v. followed by 5 mg increments as needed up to a maximum of 1 mg.kg-1. Esmolol and labetalol both produced reductions in systolic and diastolic blood pressure (P less than 0.05) within ten minutes of administration which lasted for at least two hours. Reduction of blood pressure by esmolol was accompanied by a decrease in HR (P less than 0.05). Two patients developed extreme bradycardia (HR less than 50 beats.min-1) and esmolol had to be discontinued. Labetalol, in contrast, induced only a moderate decrease in HR. None of the patients treated with labetalol experienced any prolonged side effects such as orthostatic hypotension. In conclusion, esmolol may produce considerable bradycardia in elderly patients when hypertension is not accompanied by tachycardia. Labetalol was easier to administer in the ambulatory setting and one-tenth the cost of esmolol.     

Esmolol bolus and infusion attenuates increases in blood pressure and heart rate during electro-convulsive therapy

To determine whether a standardized dose of esmolol can effectively attenuate the cardiovascular response to electroconvulsive therapy (ECT), 17 ASA physical status I-II patients were studied in a randomized within-patient, crossover design. Each patient received "no esmolol" during one ECT and three to five days later crossed over to the alternative treatment receiving an esmolol 80 mg bolus followed by 24 mg.min-1 infusion two minutes prior to induction of anaesthesia and continued for five minutes after induction. Esmolol blunted the maximum increases in heart rate (HR) by 26 per cent, mean arterial pressure (MAP) by 14 per cent, and rate pressure product by 37 per cent with significant differences (P less than 0.05) noted at one, two, three and four minutes after ECT (minutes five, six, seven, and eight of the esmolol infusion). There was no significant difference in seizure duration between the two groups and no adverse reactions occurred.     

Esmolol in anesthesiology: pharmacology and indications

Esmolol is a beta-adrenergic receptor antagonist with a relatively specific affinity for beta 1 adrenergic receptors. Its mechanism of action is therefore largely cardioselective and only high doses block beta 2 adrenergic receptors. The pharmacologic features of the drug give it rapid onset of beta-blocking action (distribution half-life = 2 minutes) and a short duration of action due to rapid clearance (clearance half-life = 9 minutes). The rapid metabolism of esmolol allows its beta-blocking activity to be lowered rapidly by changing the rate of infusion and obtaining rapid reversibility of effect in the minutes following interruption of the infusion. The esmolol dose is therefore manageable and individual adjustments can be made in function of a patient's clinical status. Such properties mean that esmolol is indicated for short-term treatment of hypertension and tachycardia during the perioperative period and in clinical situations that require easy unblocking of beta receptors. Hypertension and bradycardia are the most frequent complications associated with the administration of esmolol, such that blood pressure, heart rate and electrocardiographic data must be monitored.     

Cardiovascular effects of esmolol in anesthetized humans

We studied the cardiovascular effects of esmolol, a newly synthesized beta-adrenocepter antagonist, in anesthetized humans. Forty patients (four groups of 10 each) with ischemic heart disease and normal ventricular function were anesthetized with diazepam, pancuronium, and N2O in O2. Esmolol was given by continuous infusion in cumulative doses of 1100 micrograms/kg (group 1), 2000 micrograms/kg (group 2), and 2700 micrograms/kg (group 3); a control group received no esmolol. Infusion of esmolol was begun 3 min prior to and ended 4 min after tracheal intubation. All three doses of esmolol significantly (P less than 0.001) attenuated the heart rate responses to intubation. Rate-pressure products were significantly (P less than 0.001) lower in esmolol-treated patients than in controls after intubation, but ST-segment changes compatible with ischemia occurred in one patient in each group. Increases in heart rate were associated with significant increases in plasma norepinephrine levels (r = 0.45, P = 0.02) in the control group, but not in esmolol-treated patients, a demonstration that esmolol antagonizes the beta-adrenergic effects of norepinephrine. The effect of esmolol on heart rate was absent 5 min after cessation of infusion, and plasma levels of esmolol were undetectable in 26 of 30 treated patients 15 min after the termination of esmolol infusion. Esmolol has a rapid onset and short duration of effect. It can be used safely during anesthesia in patients with normal ventricular function to attenuate cardiac response to sympathetic stimulation.     

Comparison of two esmolol bolus doses on the haemodynamic response and seizure duration during electro-convulsive therapy

Twelve ASA physical status I-III patients were enrolled in a double-blind, prospective, randomized, three-way, within-patient crossover study designed to determine the effect of two standard esmolol bolus doses (100 and 200 mg) on the haemodynamic response and seizure duration during electro-convulsive therapy (ECT). Esmolol or placebo was administered one minute prior to induction of anaesthesia and exactly two minutes before ECT. Both the 100 and 200 mg bolus doses significantly blunted the maximum increase in heart rate (HR) and mean arterial pressure (MAP) following ECT in comparison with placebo. Compared with placebo, esmolol 100 mg decreased maximum HR by 23 +/- 3%, maximum MAP by 17 +/- 7% and maximum rate-pressure product (RPP) by 40 +/- 9%. Esmolol 200 mg decreased maximum HR by 25 +/- 3%, maximum MAP by 19 +/- 3% and maximum RPP by 42 +/- 5%. No significant difference was found between the two esmolol doses at corresponding measurement points before and after ECT. Treatment with esmolol 200 mg resulted in a significantly shorter mean seizure duration than with placebo. As the 200 mg dose caused a shorter seizure duration and the haemodynamic effects of 100 mg and 200 mg doses were similar, it was concluded that the 100 mg esmolol bolus dose was the better dose for ECT.     

Defining the dose range for esmolol used in electroconvulsive therapy hemodynamic attenuation.

We evaluated the clinical effectiveness of esmolol, an ultra-short-acting, beta-adrenergic receptor blocking drug, to control the sinus tachycardia and increase in arterial blood pressure induced by electroconvulsive therapy (ECT). Each of 20 patients, ASA physical status I-III, participated in a double-blind, randomized Latin-Square study involving two matched-pair trials (placebo versus esmolol given as a 500-micrograms/kg bolus followed by either 300 micrograms.kg-1.min-1 [high dose], 200 micrograms.kg-1.min-1 [medium dose], or 100 micrograms.kg-1.min-1 [low dose] infusion of esmolol) during ECT. Each patient acted as his or her own control (total number of ECT procedures were 160). We administered a 1-min bolus of placebo (normal saline) or esmolol at the rate of 500 micrograms.kg-1.min-1 followed by either high-, medium-, or low-dose esmolol or placebo for an additional 3 min. We then induced anesthesia with methohexital (1 mg/kg) and succinylcholine (0.5 mg/kg) IV. Ninety seconds after the administration of succinylcholine, the electrical stimulus was applied to induce seizure. The infusion of placebo or esmolol was discontinued 3 min after the electrical stimulus. Significant decreases were found in mean heart rate from minute 3 until minute 7 and in the maximum heart rate. The mean of each patient's maximum heart rate after seizure changed from 147 +/- 18 bpm in placebo patients to 112 +/- 20 bpm in high-dose esmolol patients; to 121 +/- 23 bpm in medium-dose esmolol patients; and to 124 +/- 20 bpm in low-dose esmolol patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

A single bolus dose of esmolol in the prevention of intubation-induced tachycardia and hypertension in an ambulatory surgery unit

The efficacy of a single bolus dose of esmolol in the prevention of intubation-induced tachycardia and hypertension was studied in a double-blind manner. Thirty patients from the Ambulatory Surgery Unit at Rush-Presbyterian-St. Luke's Medical Center were prospectively randomized to receive a placebo, 100 mg of esmolol, or 200 mg of esmolol immediately prior to induction (2.5 to 3.0 minutes before intubation). The groups were similar in demographic characteristics and with regard to preoperative blood pressure (BP) and heart rate (HR). Anesthetic management was standardized for all patients. Esmolol 100 mg (1.4 +/- 0.3 mg/kg) and 200 mg (2.6 +/- 0.7 mg/kg) significantly (p less than 0.05) blunted the maximum increases in HR and BP following intubation. The average maximum HR increase in the placebo group was 40% as opposed to 16% in the esmolol 100 mg group and 14% in the esmolol 200 mg group. Both esmolol groups blunted the tachycardic response over a 4-minute postintubation time period. The average maximum BP increase was 47% in the placebo group versus 22% and 19% in the esmolol 100 mg and esmolol 200 mg groups, respectively. There were no significant differences between the two esmolol groups. This study demonstrates the efficacy of a single bolus dose of esmolol in blunting the tachycardic and hypertensive responses to laryngoscopy and intubation in an ambulatory surgery setting.     

The effect of esmolol on cerebral blood flow, cerebral vasoreactivity, and cognitive performance: a functional magnetic resonance imaging study

BACKGROUND: Esmolol is often applied perioperatively to maintain stable hemodynamic conditions in neurosurgical patients. Little is known, however, about its effects on cerebral circulation. The authors employed functional magnetic resonance imaging based on blood oxygenation level-dependent contrast to explore the effect of esmolol on the human brain. The purpose of the study was to investigate the effect of esmolol on cerebral blood flow, cerebral vasoreactivity, and cognitive performance. METHODS: Ten healthy volunteers were investigated in two separate experimental sessions using functional magnetic resonance imaging. During the first experimental session, a hyperventilation task and a cognitive task, subjects had to perform both tasks twice, once after administration of an esmolol bolus of 1 mg/kg followed by a continuous infusion of 150 microg.kg.min and once without beta-blockade, in a random order. During the second experimental session subjects were scanned at resting state after administration of esmolol. Furthermore, the effect of the esmolol dose on hemodynamic changes caused by beta-adrenergic stimulation with orciprenaline was investigated. RESULTS: Esmolol decreased heart rate and blood pressure during the various experimental conditions and blunted the increase in heart rate and blood pressure caused by orciprenaline. Infusion of esmolol affects neither the blood oxygenation level-dependent contrast during the functional challenges nor the reaction times during the cognitive task. However, the esmolol bolus caused a brief blood oxygenation level-dependent contrast increase. CONCLUSION: The results indicate that effective beta-blockade with esmolol does not affect cerebral blood flow, cerebrovascular reactivity, or cognitive performance.     

Intraoperative use of bolus doses of esmolol to treat tachycardia

A randomized, double-blind, parallel, placebo-controlled study was conducted to determine the safety and efficacy of intravenous (IV) bolus administration of esmolol in treating intraoperative tachycardia in patients undergoing noncardiac general surgery. Forty-eight ASA II-IV patients were randomized into three equal groups to receive either placebo, esmolol 50 mg, or esmolol 100 mg. Premedication (lorazepam) and anesthetic induction techniques (thiopental sodium and succinylcholine) were identical between groups. Approximately 20 minutes after intubation, during isoflurane/N2O/O2 maintenance anesthesia, patients with systolic pressure (SBP) greater than or equal to 110 mmHg were advanced into a 10-minute study drug period if one of two conditions were met: (1) heart rate (HR) was greater than or equal to 95 beats/minute, or (2) an increase in HR of greater than 20% above preinduction baseline occurred. After two consecutive recordings of HR and blood pressure (BP), the study drug (or placebo) was injected. HR was recorded every 30 seconds and BP was recorded every minute during the ensuing 10-minute period. Compared to placebo responses, HR was significantly reduced with both doses of esmolol within 1 minute of bolus injection and remained below placebo levels for 5 minutes after 50 mg of esmolol and for 9.5 minutes after 100 mg of esmolol. There were, however, only minor differences among groups with respect to SBP, diastolic blood pressure (DBP), and mean blood pressure (MBP) changes. Conclusion: Bolus administration of esmolol can produce a rapid reduction of HR with relatively few adverse effects in an unhealthy surgical population.(ABSTRACT TRUNCATED AT 250 WORDS)     

Esmolol for control of increases in heart rate and blood pressure during tracheal intubation after thiopentone and succinylcholine

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.     

Attenuation of hemodynamic responses to rapid sequence induction and intubation in healthy patients with a single bolus of esmolol

The effectiveness of a single preinduction intravenous (IV) bolus of esmolol in blunting hemodynamic responses to rapid sequence induction and tracheal intubation was evaluated. In a randomized double-blind study, 32 ASA I and II healthy patients scheduled for surgery were monitored with electrocardiography (EKG) lead V5, arterial cannulation, and impedance cardiography. After preoxygenation and a priming dose of vecuronium (0.01 mg/kg), patients received either saline (n = 12), esmolol 100 mg (n = 10), or esmolol 200 mg (n = 10) as an IV bolus (20 ml volume). This procedure was immediately followed by a 5 ml IV saline flush, cricoid pressure, thiopental sodium 5 mg/kg, and succinylcholine 1.5 mg/kg. Patients receiving 200 mg of esmolol had a 50% reduction in the usual tachycardia associated with induction and a greater decline in systolic blood pressure (SP) (by 50%) prior to intubation as compared with the placebo group (p less than 0.05). The increase in diastolic blood pressure (DP) and the reduction in stroke volume (SV) produced by induction and intubation were similar in all the groups. Plasma norepinephrine levels at 1.5 minutes after intubation increased in the esmolol groups about 130% above that measured in the placebo group. This finding was associated with a more gradual return of peripheral resistance to baseline following tracheal intubation. However, both doses of esmolol effectively attenuated heart rate (HR), SP, and rate pressure product (RPP) increases (p less than 0.05 vs placebo) produced by laryngoscopy and tracheal intubation.     

Can esmolol manage surgically-induced tachycardia?

A double-blind, randomised study was conducted to examine the efficacy of a single bolus dose of esmolol in treating surgically-induced tachycardia. Anaesthetic technique was identical in all patients, and consisted of premedication with midazolam and glycopyrronium, induction with thiopentone followed by suxamethonium, tracheal intubation, and maintenance with isoflurane 0.6% (end-tidal) and 60% nitrous oxide in oxygen. Forty-eight patients developed a heart rate of greater than 95 beats/minute or 20% more than pre-induction values at an average time of 34 minutes after tracheal intubation and received placebo (15 patients), esmolol 50 mg (16 patients), or esmolol 100 mg (17 patients). Controlled intervention was instituted if heart rate or blood pressure was not adequate. Both 50 and 100 mg of esmolol resulted in lower heart rates compared to placebo (p less than 0.05), with no difference between the two esmolol groups (p greater than 0.05). Patients who received placebo had more episodes of medical intervention than those given esmolol (p less than 0.05). No adverse effects occurred in any patient.     

Comparison of the efficacy of esmolol and alfentanil to attenuate the hemodynamic responses to emergence and extubation

Study Objective: To define the ability of esmolol and alfentanil to control the hemodynamic changes associated with extubation and emergence.

Design: Randomized, double-blind, placebo-controlled study.

Setting: General surgery operating rooms at a university hospital.

Patients: Forty-two ASA physical status I and II patients without history of cardiac or pulmonary disease undergoing surgery not involving the cranium or thorax.

Interventions: Patients were given either a bolus dose of normal saline followed by an infusion of normal saline, a bolus dose of alfentanil 5 μg/kg followed by an infusion of normal saline, or a bolus dose of esmolol 500 μg/kg followed by an infusion of esmolol 300 μg/kg/min.

Measurements and Main Results: Emergence and extubation resulted in significant increases in heart rate (HR) and blood pressure (BP) in the placebo group. Alfentanil controlled the responses to emergence but prolonged the time to extubation (p < 0.05). Esmolol significantly controlled the responses to emergence and extubation (p < 0.05).

Conclusions: Emergence and extubation after inhalation general anesthesia result in significant increases in BP and HR in healthy patients. An esmolol bolus dose and subsequent infusion significantly attenuated these responses. A small bolus dose of alfentanil minimized the responses to emergence but prolonged the time to extubation and was no longer protective at that point.     

Esmolol and anesthetic requirement for loss of responsiveness during propofol anesthesia.

The administration of esmolol decreases the propofol blood concentration, preventing movement after skin incision during propofol/morphine/nitrous oxide anesthesia. However, interaction with esmolol has not been tested when propofol is infused alone. Accordingly, we tested the hypothesis that esmolol decreases the propofol blood concentration, preventing response to command (CP50-awake) when propofol is infused alone in healthy patients presenting for minor surgery. With approval and consent, we studied 30 healthy patients, who were randomized to esmolol bolus (1 mg/kg) and then infusion (250 microg x kg(-1) x min(-1)) or placebo. Five minutes later, a target-controlled infusion of propofol was commenced. Ten minutes later, responsiveness was assessed by a blinded observer. Oxygen saturation, heart rate, and noninvasive arterial blood pressure were recorded every 2 min. Arterial blood samples were taken at 5 and 10 min of propofol infusion for propofol assay. Results were analyzed with a generalized linear regression model: P <0.05 was considered statistically significant. The probability of response to command decreased with increasing propofol blood concentration (CP50-awake = 3.42 microg/mL). Esmolol did not alter the relative risk of response to command. We conclude that the previously observed effect of esmolol on propofol CP50 was not caused by an interaction between these two drugs. IMPLICATIONS: There is no evidence to suggest that esmolol, an ultra-short-acting cardioselective beta-blocker, affects anesthetic requirement for loss of responsiveness during propofol anesthesia.     

Maternally administered esmolol produces fetal beta-adrenergic blockade and hypoxemia in sheep

Although esmolol may be a useful therapeutic agent in obstetrics and obstetric anesthesia, concerns about fetal safety have limited its use. To assess acute fetal hemodynamic effects of maternally administered esmolol, saline or esmolol (4-200 micrograms.kg-1.min-1 in a stepped manner) was infused into maternal venous catheters in nine chronically prepared pregnant ewes, and the degree of beta-adrenergic blockade was assessed by isoproterenol challenge. In control experiments saline infusion and repeated isoproterenol challenges did not alter measured parameters, although maternally administered isoproterenol (0.1 micrograms) transiently decreased uterine blood flow by 20 +/- 5% (mean +/- SEM; P less than 0.05). Esmolol produced a dose-dependent decrease in maternal blood pressure and fetal heart rate (maternal blood pressure decreased by 22 +/- 8% and fetal heart rate decreased by 27 +/- 7% following esmolol, 200 micrograms.kg-1.min-1; P less than 0.05). Fetal arterial PO2 decreased from 18.2 +/- 1.2 mmHg before to 14.1 +/- 1.5 mmHg following esmolol, 200 micrograms.kg-1.min-1 (P less than 0.05). Maternally administered esmolol produced similar dose-dependent beta-adrenergic blockade in both ewe and fetus, with complete blockade following the 80 and 200 micrograms.kg-1.min-1 doses. Thirty minutes following cessation of esmolol infusion, fetal resting heart rate and maternal and fetal isoproterenol-stimulated heart rate remained below control values. These results suggest that maternally administered esmolol may produce adverse fetal effects, limiting its usefulness in the obstetric setting.     

Postoperative beneficial effects of esmolol in treated hypertensive patients undergoing laparoscopic cholecystectomy

BACKGROUND: In an attempt to decrease haemodynamic instability and early postoperative complications such as nausea, vomiting, and pain, esmolol was added to the routine alfentanil infusion of patients with treated hypertension undergoing laparoscopic cholecystectomy. METHODS: Forty consecutive ASA class II patients with controlled hypertension about to undergo laparoscopic cholecystectomy were randomized into two groups: an esmolol group (Group E, n=20) was given a 1 mg kg(-1) bolus of esmolol and a placebo group (Group P, n=20) was given an identical volume of Ringer's lactate. The rate of esmolol infusion was adjusted to keep the heart rate between 65 and 75 beats min(-1) and was 5-10 microg kg(-1) min(-1) throughout the procedure. After operation, patients reported their nausea using a four-point scale. RESULTS: Esmolol had an opioid-sparing effect intraoperatively (P=0.001). Postoperative requirements for antiemetics were significantly less in the esmolol group, with no antiemetics given to eight patients. In the placebo group, however, all patients required at least one dose of antiemetic (P=0.007). The frequency of PONV did not correlate to the amounts of alfentanil, propofol, postoperative antiemetics consumed, or to female gender, non-smoking status, and history of PONV or motion sickness. Postoperative analgesic consumption in Group E was significantly lower than in Group P (P=0.012). CONCLUSIONS: Esmolol had an opioid-sparing effect in the intraoperative and immediate postoperative period in hypertensive patients undergoing laparoscopy. When combined with alfentanil, it was more effective than placebo in decreasing early PONV.     

The Effect of Esmolol on Cerebral Blood Flow, Cerebral Vasoreactivity, and Cognitive Performance: A Functional Magnetic Resonance Imaging Study

Background: Esmolol is often applied perioperatively to maintain stable hemodynamic conditions in neurosurgical patients. Little is known, however, about its effects on cerebral circulation. The authors employed functional magnetic resonance imaging based on blood oxygenation level-dependent contrast to explore the effect of esmolol on the human brain. The purpose of the study was to investigate the effect of esmolol on cerebral blood flow, cerebral vasoreactivity, and cognitive performance.

Methods: Ten healthy volunteers were investigated in two separate experimental sessions using functional magnetic resonance imaging. During the first experimental session, a hyperventilation task and a cognitive task, subjects had to perform both tasks twice, once after administration of an esmolol bolus of 1 mg/kg followed by a continuous infusion of 150 [mu]g [middle dot] kg-1 [middle dot] min-1 and once without [beta]-blockade, in a random order. During the second experimental session subjects were scanned at resting state after administration of esmolol. Furthermore, the effect of the esmolol dose on hemodynamic changes caused by [beta]-adrenergic stimulation with orciprenaline was investigated.

Results: Esmolol decreased heart rate and blood pressure during the various experimental conditions and blunted the increase in heart rate and blood pressure caused by orciprenaline. Infusion of esmolol affects neither the blood oxygenation level-dependent contrast during the functional challenges nor the reaction times during the cognitive task. However, the esmolol bolus caused a brief blood oxygenation level-dependent contrast increase.     

Low-dose esmolol bolus reduces seizure duration during electroconvulsive therapy: a double-blind, placebo-controlled study

We have measured the effect of a bolus dose of esmolol 80 mg i.v. on heart rate, and systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures during electroconvulsive therapy (ECT). We also assessed seizure duration using both the cuff method and two-lead EEG. We studied 20 patients in a double-blind, placebo-controlled, within- patient blocked randomized study. No patient was receiving psychotherapeutic drugs or had cardiovascular disease. Esmolol significantly reduced heart rate, SAP and MAP before the stimulus, and also significantly reduced the increases in these variables during the convulsion, compared with placebo. However, seizure duration was also significantly reduced, possibly making ECT less effective. The reduction in seizure duration was 5.83 s when monitored clinically and 9.9 s when measured by the EEG. Because of the reduction in seizure duration, routine administration of esmolol is not advisable because it may interfere with the efficacy of ECT, but administration of esmolol during ECT could be useful to reduce tachycardia and hypertension in high-risk patients.      

Test doses: optimal epinephrine content with and without acute beta-adrenergic blockade

The authors studied the optimal epinephrine content of an epidural test dose, and determined criteria to identify intravascular injections in subjects with or without beta-adrenergic blockade. Nine healthy nonpregnant subjects 25-36 years of age were given intravenous infusions of saline or esmolol in random order. During each infusion, they received a series of five injections (3 ml each) of either saline, 1% lidocaine or 1% lidocaine containing 5, 10, or 15 micrograms of epinephrine. Thirty minutes after completing these two infusions, propranolol was administered as a bolus injection, and the series of five injections repeated. All injections were double blind and randomized. During saline infusion, all injections containing epinephrine significantly increased heart rate (HR) by an average of 31-38 beats/min when compared with that following plain lidocaine (P less than 0.05), and increased systolic blood pressure by an average of 17-26 mmHg (P less than 0.05 for the 15-micrograms dose only). During esmolol infusion, epinephrine injections increased HR by an average of 23-31 beats/min (P less than 0.05), and increased systolic blood pressure by an average of 18-30 mmHg (P less than 0.05 for 10 and 15 micrograms). After propranolol injection, epinephrine injections caused a decrease in HR by an average of 21-28 beats/min (P less than 0.05), whereas systolic blood pressure increased by an average of 22-35 mmHg (P less than 0.05 for 10 and 15 micrograms only). Without beta-adrenergic blockade, an increase in HR greater than or equal to 20 beats/min was 100% sensitive and specific for intravascular injection of 10 or 15 micrograms of epinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)