QT interval of the ECG, heart rate and arterial pressure during anaesthetic induction: comparative effects of alfentanil and esmolol

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% m the other groups.     

The effect of intravenous lidocaine on QT changes during tracheal intubation

Laryngoscopy and tracheal intubation may provoke changes of cardiac repolarisation. The aim of this study was to assess the effect of intravenous lidocaine on the ECG changes induced by laryngoscopy and tracheal intubation. Forty-three female patients were randomly allocated to receive lidocaine (1.5 mg.kg⁻¹) or placebo immediately after induction of anaesthesia and changes in the ECG and arterial blood pressure were recorded. Correction of QT interval was calculated using Bazett's formula (QTcb), Fridericia's correction (QTcf), and Framingham formula (QTcF). Transmural dispersion of repolarisation (TDR) was determined as Tpeak-Tend time. There were no changes in the QTc value in the lidocaine group. In the placebo group, significant increases in QTcb, QTcf and QTcF values were observed after intubation compared to either control measurements or to comparative measurements in the lidocaine group. There were no significant differences in TDR either between or within the groups. Lidocaine diminishes prolongation of QTc, induced by tracheal intubation but there is no effect of intubation on TDR.     

Evaluation of intubating conditions with rocuronium and either propofol or etomidate for rapid sequence induction

We have assessed the effect of two induction agents on tracheal intubating conditions after rocuronium 0.6 mgkg⁻¹ in unpremedicated patients undergoing simulated rapid sequence induction. Following pre-oxygenation, anaesthesia was induced with propofol up to 2.5 mgkg⁻¹ ( n  = 35) or etomidate 0.3 mgkg⁻¹ ( n  = 36), and further increments as required. After loss of verbal contact, cricoid pressure was applied and rocuronium was injected. Laryngoscopy was performed at 45 s and intubation attempted at 60 s after rocuronium had been given. Ninety-four per cent of patients in the propofol group had clinically acceptable (good or excellent) intubating conditions compared to only 75% in the etomidate group (p = 0.025). Owing to coughing, one patient in the etomidate group could not be intubated on the first attempt. A greater pressor response also followed intubation after induction with etomidate. We conclude that etomidate and rocuronium alone cannot be recommended for intubation at 60 s under rapid sequence induction conditions.     

Comparison of rocuronium and suxamethonium for use during rapid sequence induction of anaesthesia

This study was designed to compare the tracheal intubating conditions during a rapid sequence induction of anaesthesia using rocuronium 0.6 ( n  = 61) or 1.0 mg.kg⁻¹ ( n  = 130) or suxamethonium 1.0 mg.kg⁻¹ ( n  = 127) as the neuromuscular blocking drugs. Anaesthesia was induced with fentanyl 1–2 μg.kg⁻¹ and thiopentone 5 mg.kg⁻¹ (median dose) and intubating conditions were assessed 60 s after the administration of the neuromuscular blocking drug by an observer unaware of which drug had been given. Intubating conditions were graded on a three-point scale as excellent, good or poor, the first two being considered clinically acceptable. The study was carried out in two parts. At the end of the first part a comparison between the two doses of rocuronium was carried out when at least 50 patients had been enrolled in each group. The results showed the intubating conditions to be significantly superior with the 1.0 mg.kg⁻¹ dose of rocuronium (p < 0.01). Final comparison between the 1.0 mg.kg⁻¹ doses of rocuronium and suxamethonium showed no significant difference in the incidence of acceptable intubations (96 and 97%, respectively). The incidence of excellent grade of intubations was, however, significantly higher with suxamethonium (80% vs. 65%; p = 0.02). It is concluded that rocuronium 1.0 mg.kg⁻¹ can be used as an alternative to suxamethonium 1.0 mg.kg⁻¹ as part of a rapid sequence induction provided there is no anticipated difficulty in intubation. The clinical duration of this dose of rocuronium is, however, 50–60 min.     

Intubating conditions using cisatracurium after induction of anaesthesia with thiopentone

We studied tracheal intubation conditions produced by the muscle relaxant, cisatracurium, following induction of anaesthesia with fentanyl (2 μgkg⁻¹) and thiopentone (6 mgkg⁻¹). Sixty patients were randomly assigned to receive cisatracurium in a single bolus dose of either 0.15 or 0.20 mgkg⁻¹. Tracheal intubation was commenced 120 s after injection of the relaxant. The mean (SD) time taken to achieve intubation was significantly shorter in the 0.20 mgkg⁻¹ group (137 (16) s) than the 0.15 mgkg⁻¹ group (149 (12) s; p < 0.05). The intubating conditions were better after the larger dose. Our results suggest that when anaesthesia is induced using thiopentone, a dose of 0.20 mgkg⁻¹ of cisatracurium is recommended to ensure satisfactory intubating conditions.     

Intramuscular dexmedetomidine premedication—an alternative to midazolam-fentanyl-combination in elective hysterectomy?

Sedation, anxiolysis, intubation responses and fentanyl anaesthetic requirements were investigated in a double-blind, randomized study in twenty ASA I-II elective hysterectomy patients. Ten patients received dexmedetomidine 2.5 μg kg^-1 i.m. 60 min before induction and saline placebo i.v. 2 min prior to induction (= DP group). Ten patients received midazolam 0.08 mg kg^-1 i.m. 60 min and fentanyl 1.5 μg kg^-1 i.v. (= MF group) 2 min before induction of anaesthesia with thiopentone 4 mg kg^-1. Anaesthesia was maintained with 70% nitrous oxide in oxygen and with fentanyl 2 μg kg^-1 i.v. increments according to predetermined criteria. Both premedications induced sedation ( P < 0.01 in both groups) and anxiolysis ( P < 0.01 in DP vs <0.05 in MF group) without any differences between the groups. Haemodynamic changes following tracheal intubation did not significantly differ between the groups. Intraoperatively systolic and diastolic arterial pressure were 15% and 13% lower in DP group ( P < 0.01 and P < 0.05 for drug effect), the mean heart rate was approximately 9 beats min^-1 lower in DP group (n.s.). Fentanyl was required more often in MF group: median 3.5 (QD 1.5) vs. 2.5 (QD 0.5) times in DP group ( P < 0.05), the total amount being 57% smaller in DP group: 0.03 (QD 0.01) vs. 0.07 (QD 0.02) μg kg^-1 min^-1 ( P < 0.05). Postoperative course and analgesic requirements were similar in both groups. Dexmedetomidine premedication may offer an alternative to current anaesthesia practice in elective hysterectomy.     

Ketamine or alfentanil administration prior to propofol anaesthesia: the effects on ProSeal™ laryngeal mask airway insertion conditions and haemodynamic changes in children

This study was designed to compare the effects of ketamine and alfentanil administered prior to induction of anaesthesia with propofol, on the haemodynamic changes and ProSeal laryngeal mask airway^® (PLMA) insertion conditions in children. Eighty children, aged between 3–132 months, were randomly allocated to receive either alfentanil 20 μg.kg⁻¹ (alfentanil group) or ketamine 0.5 mg.kg⁻¹ (ketamine group) before induction of anaesthesia. Ninety seconds following the administration of propofol 4 mg.kg⁻¹, a PLMA was inserted. In the ketamine group, heart rate and mean arterial pressure were higher during the study period compared with the alfentanil group (p < 0.05). The time for the return of spontaneous ventilation was prolonged in the alfentanil group (p = 0.004). In conclusion, we found that the administration of ketamine 0.5 mg.kg⁻¹ with propofol 4 mg.kg⁻¹ preserved haemodynamic stability, and reduced the time to the return of spontaneous ventilation, compared with alfentanil 20 μg.kg⁻¹ during PLMA placement. In addition, the conditions for insertion of the PLMA with ketamine were similar to those found with alfentanil.     

Influence of anaesthesia and muscle relaxation on intubating conditions and sympathoadrenal response to tracheal intubation

Background : The study aimed to assess the relative influence of anaesthesia and muscle relaxation on intubating conditions and the haemodynamic and catecholamine responses to tracheal intubation.
Methods : Sixty ASA 1 or 2 patients were randomly assigned to one of four groups (15 patients each) that differed in the depth of anaesthesia (thiopentone plus fentanyl 2.5 μg kg^-1 or thiopentone alone) and the degree of vecuronium–induced neuromuscular block (100% or _>: 65%) at intubation. Muscle relaxation was measured at 0.1 Hz by means of mechanomyography. Heart rate (HR) and mean arterial blood pressure (MAP) were measured before and after induction of anaesthesia, and 1 min and 5 min following intubation, while adrenaline (A) and noradrenaline concentrations (NA) were determined from arterial blood samples.
Results : Intubating conditions were improved primarily by providing complete muscle relaxation at the adductor pollicis muscle (P<0.001) and to a lesser extent by adding fentanyl to thiopentone (P=0.04). The response of HR and MAP to tracheal intubation was attenuated mainly by fentanyl (P<0.001). Complete muscle relaxation further diminished the response of MAP to intubation (P=0.03). Changes in A and NA were dependent on the depth of anaesthesia only (P =>0.01).
Conclusion : The results of the study demonstrate that the sympathoadrenal response to intubation is attenuated by adding fentanyl (2.5 kg^-1) to an induction regimen with thiopentone, whereas provision of complete muscle relaxation at the adductor pollicis muscle is necessary to attain smooth intubating conditions.     

Effect of esmolol on the heart rate, arterial pressure and electrocardiographic changes during laryngomicroscopy

Background: Laryngomicroscopy causes considerable haemo-dynamic and ECG changes and therefore requires high doses of anaesthetic agents, which prolong recovery. In this double-blind randomized work, we studied the effect of esmolol, a short-acting beta-adrenergic receptor-blocking agent, on haemodyn-amic and ECG changes during laryngomicroscopy under thio-pental-alfentanil-isoflurane-suxamethonium anaesthesia.
Methods: Forty ASA class I-II patients (mean age 43±11 yr) were allocated to receive either esmolol 1 mg·kg^-1+200 μg·kg^-1· min^-1 (the esmolol group) or saline (the control group). Heart rate and arterial pressure were measured non-invasively and ECG was analyzed with the aid of a microcomputer. Comparisons between the groups were performed using two-way analysis of variance with repeated measures and the Student's t -test.
Results: In the presence of esmolol, neither the heart rate nor the QTc interval of the ECG increased significantly when com pared with the baseline values, with the exception that the QTc interval was increased after intubation. The increase in arterial pressure after insertion of the operating laryngoscope was not prevented in esmolol-treated patients. No cardiac arrhythmias occurred in either of the groups.
Conclusions: On the basis of the present study, esmolol-bolus +infusion during alfentanil-isoflurane anaesthesia in healthy, middle-aged patients is a useful treatment in circumstances where an increase of the heart rate, prolongation of the QTc interval and cardiac arrhythmias should be avoided.     

艾司洛尔对患者麻醉诱导气管插管时脑电双频谱指数的影响

Objective To evaluate the effect of esmolol on bispectral index (BIS) in patients undergoing orotracheal intubation during induction of anesthesia and to investigate the mechanism of inhibiting the cardiovascular responses to tracheal intubation.Methode Forty patients in physical status of ASA Ⅰ or Ⅱ and aged 20-60 years were randomly divided into 2 groups ( n = 20 each): esmolol group (group E) and control group (group C). Anesthesia was induced with midazolam 0.1 mg/kg, fentanyl 5 μg/kg and vecuronium 0.1 mg/kg. In group E, esmolol 1 mg/kg was given intravenously before anesthesia induction and followed by an infusion of esmolol 250 μg· kg- 1·min-1, while a comparable volume of saline was given for group C. Mean arterial pressure (MAP), heart rate (HR) and BIS were recorded before esmolol administration, before induction of anesthesia, before orotracheal intubation, and at 1, 2 and 5 min after intubation, respectively.Results There were no significant differences in HR, MAP and BIS between the two groups before tracheal intubation. HR and MAP significantly increased after tracheal intubation in both groups, but BIS only in group C significantly increased after intubation.HR, MAP and BIS were significantly lower after intubation in group E than in group C ( P＜ 0.05).Conclusion Esmolol can decrease BIS during tracheal intubation and its antinociceptive property is related to the mechanism of inhibiting cardiovascular responses to tracheal intubation.     

The effect of bolus administration of remifentanil on QTc interval during induction of sevoflurane anaesthesia

Stimulation of the sympathetic nervous system associated with tracheal intubation causes corrected QT (QTc) interval prolongation. We postulated that the use of remifentanil during induction of anaesthesia might prevent this. Sixty unpremedicated, ASA grade 1 patients were selected and randomly allocated to receive either saline (group S), remifentanil 0.5 microg x kg(-1) (group R 0.5) or remifentanil 1.0 microg x kg(-1) (group R1.0) 1 min before laryngoscopy. The QTc interval was significantly prolonged immediately following intubation in group S and group R0.5, but it remained stable in group R1.0, compared with the QTc interval just before laryngoscopy. It is concluded that the administration of remifentanil 1.0 microg x kg(-1) before intubation can prevent the prolongation of the QTc interval associated with tracheal intubation during induction of anaesthesia with sevoflurane.     

Optimal remifentanil dosage for providing excellent intubating conditions when co-administered with a single standard dose of propofol

This dose–response study aimed to determine the dose of remifentanil combined with propofol 2.5 mg.kg⁻¹ which provided excellent intubation conditions in 95% of patients. Ninety premedicated female ASA 1 and 2 patients were randomly allocated to five remifentanil dose groups (1, 2, 3, 4 or 5 μg.kg⁻¹). Induction of anaesthesia was performed with a blinded dose of remifentanil infused over 60 s simultaneously co-administered with propofol 2.5 mg.kg⁻¹ infused over 45 s. Tracheal intubation was attempted 150 s after the beginning of induction. Intubating conditions were assessed with the Copenhagen score. A probit analysis was performed to calculate the intubating efficient doses (IED) of remifentanil in 95% of patients (IED₉₅). Our data revealed that the IED₉₅ of remifentanil was 4.0 (95% CI: 3.4–5.6) μg.kg⁻¹, which was associated with a maximum decrease in heart rate and mean arterial pressure of < 30%, a finding which also applied to the other groups.     

The optimum bolus dose of remifentanil to facilitate laryngeal mask airway insertion with a single standard dose of propofol at induction in children

The purpose of this study was to determine the optimal bolus dose of remifentanil required for the successful insertion of the laryngeal mask airway during propofol induction in children without a neuromuscular blocking agent. Twenty-six paediatric patients, aged 3–10 years, requiring anaesthesia for short ambulatory surgery were recruited. A predetermined bolus dose of remifentanil was injected over 30 s, followed by propofol 2.5 mg.kg⁻¹ over 10 s. The bolus dose of remifentanil was determined by a modified Dixon's up-and-down method, starting from 0.5 μg.kg⁻¹ (0.1 μg.kg⁻¹ as a step size). Laryngeal mask insertion was attempted 90 s after the end of remifentanil injection and the response of patients was classified as either 'movement' or 'no movement'. The bolus dose of remifentanil at which there was a 50% probability of successful laryngeal mask insertion (ED₅₀) during induction with 2.5 mg.kg⁻¹ propofol was 0.56 (0.07) μg.kg⁻¹ in children without a neuromuscular blocking agent. From probit analysis, the ED₅₀ and ED₉₅ of remifentanil were 0.52 μg.kg⁻¹ (95% confidence limits, 0.42–0.62 μg.kg⁻¹) and 0.71 μg.kg⁻¹ (95% confidence limits, 0.61–1.40 μg.kg⁻¹), respectively.     

Paediatric laparoscopic surgery: anaesthetic management

Summary
Total intravenous anaesthesia (TIVA) has been performed in 54 paediatric patients undergoing laparoscopic surgery. A loading dose of propofol 2.5 mg·kg⁻¹ and fentanyl 2 μg·kg⁻¹ were used for induction while a continuous infusion of propofol 9 mg·kg⁻¹·h⁻¹ and atracurium 0.5 mg·kg⁻¹·h⁻¹ in O₂/Air were used for maintenance. Intraoperative cardiorespiratory stability, prompt recovery, painless postoperative period show that TIVA is a valid and safe technique for laparoscopic surgery in children.     

Comparison of computer-controlled administration of propofol with two manually controlled infusion techniques

Ninety women were studied in order to compare dose requirements and quality of anaesthesia between target-controlled infusion and two manually controlled infusion schemes for propofol administration: group I received target-controlled infusion for induction (4 μg.ml⁻¹ target blood concentration, increased by 2 μg.ml⁻¹ after 3 min if consciousness not lost), groups II and III received an induction bolus of propofol at infusion rates of 1200 or 600 ml.h⁻¹, respectively, until loss of consciousness. Anaesthesia was maintained with propofol target-controlled infusion in group I or by constant rate infusion in the other two groups. Computer simulations were used to calculate blood and effect-site propofol concentrations. Mean induction times (SD) were 78 (65) s in group I versus 51 (10) s and 62 (12) s in groups II and III, respectively (p < 0.05 between groups II and III). Mean induction doses were: 1.31 (0.44), 2.74 (0.56) and 1.77 (0.43) mg.kg⁻¹ and mean maintenance doses were 13.4 (3.55), 9.32 (1.71) and 9.97 (1.53) mg.kg⁻¹.h⁻¹ in groups I, II and III, respectively (p < 0.05 between all groups). There was a lower incidence of apnoea in group I than in groups II and III. There were no significant differences between the groups in other objective parameters of anaesthetic quality studied. Computer simulations showed an 'overshoot' in propofol blood and effect-site concentration with manual induction and significantly higher maintenance levels with target-controlled infusion.     

Partial attenuation of the cardiovascular responses to tracheal intubation with oral manidipine

We conducted a placebo–controlled, randomized, and double–blinded study to evaluate the efficacy of manidipine given orally in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation. Thirty normotensive patients (ASA physical status 1) undergoing elective surgery were allocated to one of three groups (n= 10 for each); placebo, 5 mg manidipine, and 10 mg manidipine groups. These tablets were orally administered 3 h before induction of anaesthesia. Anaesthesia was induced with thiopentone 5 mg kg^-1 iv , and tracheal intubation was facilitated with vecuronium 0.2 mg–kg^-1. Laryngoscopy lasting 30 sec was attempted 2 min after induction of anaesthesia. Patients receiving placebo showed a significant increase in systolic and diastolic blood pressure associated with tracheal intubation. These increases following tracheal intubation were significantly reduced in patients receiving manidipine 10 mg compared with patients receiving placebo or manidipine 5 mg ( P < 0.05). Oral administration of manidipine 10 mg before induction of anaesthesia is a simple and effective method for attenuating pressor response to laryngoscopy and tracheal intubation. We stressed that the potential beneficial effect of a reduced haemodynamic reaction to intubation might be obtained at the expense of hypotension later on.     

Comparison of sevoflurane and ketamine for anesthetic induction in children with congenital heart disease

Background:  Sevoflurane is widely used in pediatric anesthesia for induction. Ketamine has been preferred in pediatric cardiovascular anesthesia. Aim of this study was to compare the hemodynamic effects and the speed of ketamine and sevoflurane for anesthesia induction in children with congenital heart disease.
Materials and methods:  Children with congenital heart disease undergoing corrective surgery were included in the study. After oral premedication with midazolam (0.5 mg·kg⁻¹), anesthesia induction was started with 5 mg·kg⁻¹ intramuscular ketamine (group K). In the second group, induction was achieved with sevoflurane (group S); the first concentration was 3% and increased after every three breaths. Intravenous access time and intubation times were enrolled for each child. Hemodynamic data and oxygen saturation were recorded every 2 min and any event during induction period was also noted.
Results:  Forty-seven children were included in the study; 23 in group K and 24 in group S. Heart rates and oxygen saturation values were similar between groups during the study. No difference was found between intravenous access time and intubation times. However, blood pressure levels were significantly lower in group S after recording baseline values till the intubation time (at 4, 6, and 8 min). Respiratory complications observed during the study were mild and were less frequent in group K than in group S (4 vs 13).
Conclusion:  Ketamine appears a good alternative for induction in patients with congenital heart disease. It permits preservation of hemodynamic stability with minimal side effects.     

Comparison of the incidence and severity of cough induced by sufentanil and fentanyl: a prospective, randomised, double-blind study

We compared the incidence and severity of cough following a bolus of sufentanil with that following fentanyl in 510 patients, randomly allocated to receive sufentanil 0.3 μg.kg⁻¹, fentanyl 3 μg.kg⁻¹ or 5 ml sterile water intravenously over 5 s. Coughing was graded depending on the number of coughs as mild (1–2), moderate (3–5) and severe (> 5). The incidence of coughing was higher after sufentanil (26/165; 15%) and fentanyl (54/169; 32%) than in the control group (0/168; p < 0.001). Sufentanil was also associated with a lesser severity (p  =  0.039) of coughing compared with fentanyl. We conclude that equipotent boluses of sufentanil and fentanyl increase the incidence of cough, although the incidence and severity of coughing with sufentanil are less than those with fentanyl.     

艾司洛尔对依托咪酯诱导气管插管时脑氧供需平衡和能量代谢的影响

目的:观察艾司洛尔对依托咪酯诱导气管内插管时脑氧供需平衡和能量代谢的影响。方法:将24例择期腹部手术患者随机分为艾司洛尔(A)组和对照(B)组,每组各12例。A组全麻诱导应用依托咪酯、咪达唑仑、芬太尼和维库溴铵,并在插管前30s静注艾司洛尔1mg/kg;B组除不用艾司洛尔外,其他与A组相同。分别于全麻诱导前、气管插管后即刻采集颈内静脉和桡动脉血,检测血糖、血乳酸盐及血气,记录MAP和HR;并计算脑动-静脉血氧含量差(Da-jvO2),脑氧摄取率(CERO2),葡萄糖摄取率(GluER),脑动-静脉血乳酸盐浓度差(Da-jvLac)。结果:与诱导前比较,A组插管后即刻MAP、HR无显著变化(P0.05),SjvO2增高、Da-jvO2和CERO2降低(P均0.05);B组插管后即刻MAP、HR及SjvO2明显增高(P0.01),Da-jvO2和CERO2显著降低(P0.01)。B组插管后即刻MAP、HR及SjvO2水平明显高于A组(P0.01),而Da-jvO2和CERO2水平明显低于A组(P0.05)。两组GluER和Da-jvLac无显著变化(P0.05)。结论:麻醉诱导时给予艾司洛尔1mg/kg可减轻依托咪酯诱导气管内插管对脑氧供需平衡的影响,但不影响脑的能量代谢。     

Bolus administration of esmolol for controlling the haemodynamic response to tracheal intubation: the canadian multicentre trial

A multicentre trial was designed to determine the dose-response and side-effects of esmolol when administered as a single iv bolus prior to induction of anaesthesia for controlling the haemodynamic response to tracheal intubation. Five hundred and forty-eight patients from 12 university-affiliated centres across Canada were randomized prospectively to receive either placebo (PLAC) or esmolol (E) in a dose of 100 mg (E100) or 200 mg (E200). Study medication was given immediately before induction of anaesthesia with thiopentone 3-5 mg.kg-1 and succinylcholine 1.5 mg.kg-1. Low-dose narcotic (fentanyl 2-3 micrograms.kg-1 or sufentanil 0.3 micrograms.kg-1) or moderate dose narcotic (fentanyl 4-7 micrograms.kg-1) was also given at five of the participating centres, whereas patients in the remaining seven centres received no narcotic. Patients who received PLAC and no narcotic had greater HR and SBP values after tracheal intubation than patients who received either E100 or E200 (P less than 0.005). The proportion of patients whose maximum HR exceeded 110 min-1 was also greater in the PLAC group (22/180) than in either the E100 (10/187) or E200 (9/181) groups (P less than 0.05), but was not different when comparing E100 with E200. Esmolol was less effective in controlling blood pressure, but, in combination with low-dose narcotic, esmolol suppressed the SBP response to tracheal intubation. In the presence of moderate-dose narcotic, however, a decrease in SBP occurred in all three groups following induction of anaesthesia (P less than 0.003), with the largest decrease (17 +/- 4%) occurring in patients who had received E200. The overall incidence of hypotension (SBP less than 90 mmHg) was greater in the E200 group (33%) than either the E100 (25%) or PLAC (16%) groups (P less than 0.05). Other side-effects, such as bradycardia, bronchospasm or pain on injection, occurred no more frequently in either esmolol group than with placebo. It is concluded that a 100 mg bolus of esmolol is safe and effective for controlling the haemodynamic response to tracheal intubation. This dose of esmolol combined with a low dose of narcotic (fentanyl 2-3 micrograms.kg-1 or equivalent) results in effective control of both heart rate and blood pressure, while avoiding important side-effects.