Partial attenuation of hemodynamic responses to rapid sequence induction and intubation with labetalol

The effectiveness of labetalol (a combination nonselective beta and alpha-1-adrenergic receptor antagonist) in modifying hemodynamic responses associated with rapid sequence induction and tracheal intubation was evaluated. In a double-blind study, 24 ASA physical status I or II male patients scheduled for elective surgery were given either IV labetalol, 0.25 mg/kg (n = 8) or 0.75 mg/kg (n = 8), or a saline placebo (n = 8). Five minutes later, patients were given oxygen by mask and IV vecuronium, 0.01 mglkg. Ten minutes after giving labetalol or placebo, cricoid pressure was applied and anesthesia was induced with IV sodium thiopental (4 mg/kg) and succinylcholine (1.5 mg/kg) 1 minute prior to intubation. The mean duration of laryngoscopy was 17 ± 3 seconds. Prior to induction, the 0.25 mg/kg and 0.75 mg/kg) doses of labetalol significantly (p < 0.05) reduced mean arterial pressure by 4.4 ± 1.9 and by 8.6 ± 2.0 mmHg, respectively, but did not significantly alter heart rate or cardiac output. The 0.75 mg/kg) dose of labetalol also significantly (p < 0.05) decreased total peripheral resistance by 10.1 ± 3.0%. Within 30 seconds after intubation, patients in all three groups exhibited increases in heart rate, mean arterial pressure, total peripheral resistance, and rate pressure product and a decrease in stroke volume. However, patients in the 0.25 and 0.75 mg/kg) labetalol groups, compared to those in the placebo group, had significantly lower increases in peak heart rate (33 ± 2 and 27 ± 3 vs. 44 ± 7 beats/minute), peak mean arterial pressure (38 ± 6 and 38 ± 7 vs. 58 ± 7 mmHg), and peak rate pressure product (7,726 ± 260 and 7,215 ± 300 vs. 14,023 ± 250 units). The results show that these doses of labetalol significantly blunt, but do not completely block, autonomic responses to rapid sequence induction and intubation.     

Attenuation of the hemodynamic responses to endotracheal intubation with preinduction intravenous labetalol

Endotracheal intubation following anesthesia induction frequently produces hypertension and tachycardia. This study evaluated the efficacy of preinduction IV labetalol for attenuating the hemodynamic responses to intubation following thiopental and succinylcholine induction of anesthesia. Two hours after diazepam (10 mg by mouth), 60 patients were randomized in a double-blind manner and received IV saline or labetalol at doses of 0.25, 0.5, 0.75, or 1 mg/kg in a parallel design study. Five minutes later, thiopental (4 mg/kg) and succinylcholine (1 mg/kg) were administered, and the trachea was intubated in 2 minutes. Nitrous oxide (70%) anesthesia was maintained for 10 minutes. Hemodynamic parameters were grouped and analyzed for significance (p less than 0.05) by two-way repeated measures analysis of variance and t-test with Bonferroni adjustments. Baseline group demographics and hemodynamics were comparable. All doses of labetalol significantly attenuated the rate-pressure product increase immediately postintubation versus placebo. There was a dose-dependent attenuation of the increases in heart rate and the systolic, diastolic, and mean blood pressures versus placebo following intubation. IV labetalol at doses up to 0.75 mg/kg offers an effective pharmacologic means of attenuating preoperative hemodynamic responses to endotracheal intubation.     

快速顺序诱导气管插管的研究进展

快速顺序诱导气管插管(RSII)是为反流误吸高风险患者气管插管提供的一种保护性措施。经典RSII技术包括：有效的预充氧、快速顺序给予硫喷妥钠和琥珀酰胆碱、环状软骨加压、诱导时避免正压通气、使用带套囊气管导管插管。RSII经历了多次“改良”,但至今临床获益及风险仍未明确。当前技术的发展改变了一些传统观念,如预充氧方式的选择、插管的可视化和正压通气的应用等。本文综述了RSII应用研究进展,旨在为临床RSII实施提供参考。     

A single bolus dose of vecuronium for rapid endotracheal intubation]

The changes in EMG evoked by train-of-four (TOF) stimulation of ulnar nerve were recorded to determine proper single bolus dose of vecuronium for endotracheal intubation in surgical patients. Onset and duration of neuromuscular block were judged by percent depression of EMG. Mean time intervals for 90% depression in TOF seen in 0.10 mg.kg-1 vecuronium group (n = 10), 0.15 mg.kg-1 vecuronium group (n = 10) and 0.20 mg.kg-1 vecuronium group (n = 10), were 181.1 sec, 135.0 sec and 120.0 sec, respectively. Similarly, mean time intervals for 100% depression for each vecuronium group were 240.0 sec, 177.5 sec and 160.0 sec, respectively. Onset time intervals in both 0.15 mg.kg-1 and 0.20 mg.kg-1 groups were significantly shorter than that in 0.10 mg.kg-1 group (P less than 0.05). On the other hand, mean time intervals for 25% recovery in EMG were 53.6 min in 0.10 mg.kg-1 group, 63.3 min in 0.15 mg.kg-1 group and 104.3 min in 0.20 mg.kg-1 group. No statistically significant difference was observed in recovery time between 0.10 mg.kg-1 and 0.15 mg.kg-1 group. These results indicate that the appropriate dose of vecuronium for rapid intubation is considered to be 0.15 mg.kg-1. This dose is allowable for surgical procedures of short duration.     

Modification of the haemodynamic responses to induction of anaesthesia and tracheal intubation with alfentanil,esmolol and their combination

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 patients 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.     

Orotracheal fibreoptic intubation for rapid sequence induction of anaesthesia

We assessed whether flexible fibreoptic-guided orotracheal intubation could be rapidly and successfully achieved during a simulated rapid sequence induction in 30 anaesthetised and paralysed patients. Rapid sequence induction was simulated by applying practised cricoid pressure. Using a flexible fibreoptic laryngoscope with camera and closed circuit television, an anaesthetist experienced with the technique performed orotracheal endoscopy and intubation with a cuffed 7.0-mm Portex tracheal tube through a VBM Bronchoscope Airway. Fibreoptic intubation was successful at the first attempt in 28 patients (93%); two patients required two attempts. Mean (SD) time from removal of the facemask from the patient's face to the appearance of carbon dioxide in the expired breath after intubation was 111 (46) s (median 100 s; range 54-195 s). There were one or more difficulties in 13 patients (43%). These difficulties were largely avoidable and included problems with fibreoptic equipment, the Bronchoscope Airway, copious secretions, cricoid pressure or railroading of the tracheal tube. Flexible fibreoptic-guided orotracheal intubation may have a place in the management of failed intubation during a rapid sequence induction.     

Pulse wave velocity can predict hemodynamic responses to induction of anesthesia and tracheal intubation

BACKGROUND: The degree of aortic stiffness can be evaluated by noninvasive measurement of pulse wave velocity (PWV). We investigated hemodynamic responses to induction of anesthesia and tracheal intubation, and hypothesized that preoperative measurement of PWV might predict these responses. METHODS: PWV was measured before operation by using automatic PWV measurement device. Patients were anesthetized with fentanyl (1 microg x kg(-1)) and propofol (target controlled infusion at 2.5 microg x ml(-1)), and tracheal intubation was facilitated with vecuronium (1.5 mg x kg(-1)). Hemodynamic data were recorded from the start of anesthesia to 5 minutes after the tracheal intubation. RESULTS: Twenty patients completed the study. There was a significant correlation between PWV and percent changes in systolic blood pressure during anesthesia induction. However, a significant correlation between PWV and percent changes in systolic blood pressure after tracheal intubation was found only in the patients without antihypertensive medications. CONCLUSIONS: Preoperative PWV measurement was useful to predict hemodynamic responses to induction of anesthesia and tracheal intubation.     

阿芬太尼和艾司洛尔对气管插管时循环和儿茶酚胺反应的影响

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右美托咪定对全麻患者气管插管时血流动力学变化的影响

目的 探讨右美托咪定对全麻患者气管插管时血流动力学变化的影响.方法 择期手术患者40例,随机分为M1、M2组,M1组麻醉诱导前给予右美托咪定0.5μg/kg,再以0.3 μg/（kg·h）速度持续输注.两组均给予咪达唑仑、芬太尼、丙泊酚、罗库溴铵麻醉诱导,气管插管.记录患者入室后、麻醉诱导前、插管前、插管即刻、插管1、3、5 min后的血压、心率.结果 M1组输注右美托咪定后,HR较基础值明显降低;麻醉诱导后各观察时刻,BP较基础值明显减低;M2组HR插管前低于基础值,插管后1 min大于基础值,BP在插管前与插管即刻明显小于基础值;M1组HR自诱导前各观察时刻、BP自插管时各观察时刻均低于M2组;M1组麻醉药诱导用量明显少于M2组.结论 麻醉诱导前给予右美托咪定0.5 μg/kg可较完善地抑制插管时的心血管反应,减少麻醉药用量.     

Difficult intubation during rapid sequence induction in a parturient with Ehlers-Danlos syndrome, hypermobility type

There have been several reports of resistance to local anaesthetic agents in women with Ehlers-Danlos syndrome, hypermobility type, also known as Ehlers-Danlos syndrome Type III. General anaesthesia with rapid sequence induction was performed for caesarean section due to prolonged second stage of labour, but intubation proved to be difficult. We propose that intubation difficulty probably arose from collapse of fibro-elastic tissues and adjoining C-shaped cartilages of the trachea with appropriately applied cricoid pressure. We found no other case reports of difficult intubation in patients with Ehlers-Danlos syndrome, hypermobility type. There are reports of cervical spine instability and temporomandibular joint dysfunction in patients with this syndrome suggesting a potential for difficult airway management. Additional anaesthetic problems associated with Ehlers-Danlos syndrome involve patient positioning and vascular access.     

A bolus dose of esmolol attenuates tachycardia and hypertension after tracheal intubation

Forty-five patients of ASA physical status I and II undergoing a variety of non-cardiac surgical procedures were studied to determine the effect of bolus administration of esmolol, a new short-acting beta blocking drug, on heart rate and blood pressure responses to induction of anaesthesia and tracheal intubation. Subjects were allocated randomly to receive placebo, 100 mg or 200 mg of esmolol IV as part of an anaesthetic induction technique. The differences in heart rate between the placebo group and both the 100 mg and 200 mg groups were significant prior to intubation (95 +/- 7.9, 82 +/- 9.7, 80 +/- 7.3 beats per min respectively), and also at 0.5 min and 1.5 min following intubation for the 200 mg group. In the 200 mg group there was a significant decrease, compared with placebo, in systolic blood pressure at 0.5 min (144 +/- 32.1 vs 165 +/- 18.7 mmHg) and 1.5 min (154 +/- 25.0 vs 170 +/- 19.5 mmHg) after intubation. In this study, adequate haemodynamic control was obtained following administration of 200 mg of esmolol.     

Attenuation of cardiovascular response to laryngoscopy and tracheal intubation with bolus injection of diltiazem]

Effect of diltiazem on cardiovascular response to laryngoscopy and tracheal intubation was studied in 20 patients without hypertension and 10 patients with hypertension to be operated on under general anesthesia. The patients were divided into three groups: the first group without hypertension (group C, n = 10) received saline as control, the second group without hypertension (group N, n = 10) received bolus injection of diltiazem, and the third group with hypertension (group H, n = 10) received bolus injection of diltiazem. Diltiazem was administered 2 min before intubation at a dose of 0.2 mg.kg-1 as a bolus injection. Changes of mean blood pressure, rate pressure product, pressure rate quotient in group H and N decreased significantly compared with group C. Changes of heart rate were comparable among the three groups. Complications were not remarkable except one case in which systolic pressure decreased to 80 mmHg. The results suggest that bolus injection of diltiazem at a dose of 0.2 mg.kg-1 attenuates cardiovascular response to laryngoscopy and tracheal intubation without serious complications.     

Haemodynamic responses to laryngoscopy and intubation in patients with pregnancy-induced hypertension: effect of intravenous esmolol with or without lidocaine

The pressor response is known to be exaggerated in patients with pregnancy-induced hypertension, which can result in increased morbidity and mortality in both mother and newborn. Various pharmacological agents have been used before induction in an attempt to attenuate the adrenergic response but with varying degree of success. Esmolol, an ultra short-acting cardioselective beta-blocker with rapid onset and short elimination half-life, is an attractive choice for attenuating the adrenergic response in pregnant patients. In a prospective, randomised double blind study we evaluated the efficacy of two bolus doses of esmolol with or without lidocaine, in patients with pregnancy-induced hypertension. Eighty such patients undergoing lower segmental caesarean section were randomly divided into four groups and received the following study drugs before intubation: group I, esmolol 1 mg.kg(-1); group II, esmolol 2 mg.kg(-1); group III, esmolol 1 mg.kg(-1) and lidocaine 1.5 mg.kg(-1); and group IV, esmolol 2 mg.kg(-1) and lidocaine 1.5 mg.kg(-1). In groups II, III and IV, the changes in maternal heart rate, systolic blood pressure and mean arterial pressure in response to laryngoscopy and intubation were attenuated to a comparable degree (P > 0.05). No adverse effects were noticed in mother or baby. We conclude that esmolol 1 mg.kg(-1) with lidocaine 1.5 mg.kg(-1) is effective in attenuating the adrenergic responses to laryngoscopy and intubation in patients with pregnancy-induced hypertension.     

Lack of effect of intravenous lidocaine on hemodynamic responses to rapid sequence induction of general anesthesia: a double-blind controlled clinical trial

A double-blind, randomized trial was conducted in 16 women aged 20-48 yr, to assess the effect of intravenous lidocaine on the circulatory responses to rapid sequence induction of general anesthesia. None of the patients suffered from heart or lung diseases, all were scheduled for hysterectomy, and all were premedicated with 0.3 mg/kg diazepam orally 2 hr beforehand. Induction, preceded by preoxygenation, included simultaneous injection of thiopental and succinylcholine, without starting manual ventilation until the airway was secured with the endotracheal tube. Two minutes before laryngoscopy and intubation half of the patients received lidocaine, 1.5 mg/kg, intravenously (IV). The other half received an equal volume of saline. Cuff blood pressure was measured repeatedly by an automatic recording device, and heart rate and left ventricular ejection fraction (LVEF) were monitored by a portable nonimaging nuclear probe. After laryngoscopy and intubation, mean blood pressure increased 46%, heart rate 57%, and the rate pressure product (RPP) 84% from control values in patients given lidocaine, compared to 45, 66, and 113%, respectively, in the saline group (P greater than 0.05). Pronounced, but similar decreases in LVEF were observed in the two groups, to 0.40 from 0.65 in the lidocaine group and to 0.41 from 0.65 in the saline group. In all patients, RPP reached a level considered potentially dangerous to patients with ischemic heart disease. We conclude that lidocaine, 1.5 mg/kg IV, 2 min prior to laryngoscopy and intubation does not prevent hemodynamic reactions evoked by rapid sequence induction.     

光棒在快速诱导经鼻气管内插管中的应用研究

目的探讨快速诱导麻醉下光棒引导经鼻气管内插管临床效果。方法60例全麻患者随机均分为光棒(LW)组和纤维支气管镜(BF)组,比较两组插管时间、置管成功率和导管通过声门顺利率。结果在规定的3min内,LW组插管成功率显著高于BF组(96.7%vs.70.0%,P<0.05);LW组插管时间明显短于BF组[(38.9±16.2)svs.(133.0±37.9)s,P<0.01]。LW组导管通过声门顺利率高于BF组(96.6%vs.66.7%,P<0.05)。结论光棒引导经鼻气管内插管,是口腔颌面部手术全麻快速诱导建立气道安全、有效、快捷的方法之一。