Sevoflurane for difficult tracheal intubation

Three patients in whom difficult tracheal intubation was expected but awake fibreoptic intubation was not feasible presented for head and neck surgery. Anaesthesia was induced rapidly and smoothly by inhalation of sevoflurane followed by fibreoptic or conventional tracheal intubation.      

Sevoflurane with remifentanil allows rapid tracheal intubation without neuromuscular blocking agents

PURPOSE: After inhalational induction with sevoflurane, we compared the effects of adding remifentanil 1 microg x kg(-1) or remifentanil 2 microg x kg(-1) on conditions for tracheal intubation without neuromuscular blocking agents. METHODS: Before anesthetic induction, all patients were given 0.2 mg of glycopyrrolate iv to counteract the bradycardic effects of remifentanil. Two minutes after inhalational induction with 8% sevoflurane and 50% nitrous oxide, 56 female patients with normal airways scheduled for gynecologic surgery were randomized to receive remifentanil 1 or 2 microg x kg(-1) in a double-blind fashion. One minute later, laryngoscopy was initiated for tracheal intubation. Conditions for tracheal intubation and hemodynamic response to tracheal intubation were assessed. RESULTS: Tracheal intubation was successful in all patients. The incidence of post-intubation coughing was lower in the remifentanil 2 microg x kg(-1) group compared to remifentanil 1 microg x kg(-1) group (11% vs 39%, P <0.02). Optimal intubation conditions were also higher in the remifentanil 2 microg x kg(-1) group at 89% vs 54% (P <0.01). However, the higher dose of remifentanil also resulted in a greater decrease in mean arterial pressure (P <0.05). CONCLUSIONS: The addition of remifentanil after sevoflurane induction allows for rapid tracheal intubation without neuromuscular blocking agents. The higher dose of remifentanil results in improved conditions for tracheal intubation but also caused a greater decrease in mean arterial pressure. Tracheal intubation using sevoflurane and remifentanil may be an alternative to traditional tracheal intubation with neuromuscular blocking agents.     

Sevoflurane compared with halothane for tracheal intubation in children

We have studied 40 healthy children, aged 3-10 yr, undergoing adenotonsillectomy, in a double-blind, randomized study. Intubating conditions were assessed when the pupils had become small and central after inhalation induction with either 5% halothane and 60% nitrous oxide in oxygen or 8% sevoflurane and 60% nitrous oxide in oxygen. The quality of tracheal intubation was graded according to ease of laryngoscopy, position of the vocal cords, coughing, jaw relaxation and movement of limbs. Fewer children had significant vocal cord movement on laryngoscopy (P < 0.01) and more had ideal intubating conditions when halothane was used (12 of 20 compared with seven of 20; ns). Time to reach the clinical end-point for intubation was reached sooner with halothane (P = 0.015). In all children the trachea was intubated successfully at the first attempt and all remained haemodynamically stable throughout induction.      

Remifentanil with thiopental for tracheal intubation without muscle relaxants

Tracheal intubation may be accomplished with remifentanil and a non-opioid IV anesthetic without a muscle relaxant. In this study, we evaluated in double-blinded, prospective, randomized manner the dose requirements for remifentanil with thiopental without muscle relaxant administration to obtain clinically acceptable intubation conditions and cardiovascular responses. After premedication with midazolam 0.03 mg/kg IV, 105 patients were randomized equally to one of three study groups, each receiving the following: remifentanil 2 micro g/kg (Group I), 3 micro g/kg (Group II), and 4 micro g/kg (Group III). Remifentanil was administered over 30 s, and anesthesia was induced with thiopental 5 mg/kg. Tracheal intubation conditions were assessed by the anesthesiologist performing the intubation as: (a) excellent, (b) satisfactory, (c) fair, and (d) unsatisfactory. There were no statistically significant differences among groups regarding to demographic data. Blood pressure and heart rate did not increase in any group after accomplishing intubation. There was a significant improvement in intubation conditions between Groups I and II, I and III, and II and III (P < 0.001). We conclude that remifentanil 4 micro g/kg administered before thiopental 5 mg/kg provided excellent or satisfactory intubation conditions in 94% of patients and prevented cardiovascular responses to intubation. IMPLICATIONS: We evaluated in a double-blinded manner the dose requirements for remifentanil with thiopental without muscle relaxants for obtaining acceptable intubation condition. Our results show that remifentanil 4 micro g/kg administered before thiopental provided excellent or satisfactory intubation condition in 94% of patients.     

Lightwand tracheal intubation with and without muscle relaxation

BACKGROUND: Lightwand tracheal intubation is a suitable technique for patients who are difficult to intubate but who are receiving effective ventilation. The effect of muscle relaxants on the efficacy of lightwand intubation has not yet been evaluated. The authors conducted a prospective, double-blind, placebo-controlled study to assess the effectiveness and incidence of complications of lightwand tracheal intubation performed during general anesthesia with and without the use of a muscle relaxant in patients with apparently normal airway anatomy. METHODS: One hundred seventy-six patients who required orotracheal intubation were prospectively included. Anesthesia was administered using propofol (2 mg/kg, then 3 mg . kg (-1). h(-1)) and remifentanil (1 microg/kg, then 0.3 microg . kg(-1) . min(-1)). Patients were randomly assigned to one of two groups (n = 88 for each) to receive rocuronium 0.6 mg/kg or saline intravenously. Lightwand orotracheal intubation (Trachlight; Laerdal Medical Inc., Armonk, NY) was attempted after 3 min. The authors recorded the number of successful intubations, the number of attempts and their duration, and events during the procedure. RESULTS: The failure rate of lightwand intubation was 12% in the placebo group and 2% in the rocuronium group (P = 0.021). Patients in the placebo group received more multiple intubation attempts (P < 0.001), required a greater intubation time (77 +/- 65 vs. 52 +/- 31 s; P = 0.002) and experienced a greater incidence of events during intubation (61 vs. 0%; P < 0.001) than patients in the rocuronium group. CONCLUSIONS: The use of muscle relaxants in patients with apparently normal airways is associated with a lower failure rate, decreased intubation time, and fewer attempts when performing lightwand orotracheal intubation.     

Haemodynamic responses to tracheal intubation following etomidate and fentanyl for anaesthetic induction

The haemodynamic response to anaesthetic induction and tracheal intubation was studied in 29 patients undergoing elective myocardial revascularization surgery. All patients included in the study were anaesthetized with etomidate, 0.3 mg.kg-1. The patients were randomized to three groups: Group I received fentanyl, 2.5 micrograms.kg-1; Group II received fentanyl, 5 micrograms.kg-1; and Group III received fentanyl, 10 micrograms.kg-1. Haemodynamic variables were measured at baseline (awake), after anaesthetic induction, and at one, three, five, and ten minutes after tracheal intubation. The number of patients with haemodynamic responses to intubation (> 20% increase in heart rate or mean arterial pressure) was greater (P < 0.05) in Group I than in Groups II and III. Statistically significant, but clinically minor, decreases in mean arterial pressure and cardiac output occurred in all groups at the last three study times. The frequency of involuntary muscle movements was 14%, and all of these events occurred in patients in Group I. In conclusion, the authors recommend using fentanyl, 5-10 micrograms.kg-1 to blunt the haemodynamic response to tracheal intubation following anaesthetic induction with etomidate, 0.3 mg.kg-1.     

七氟烷-咪达唑仑-瑞芬太尼麻醉诱导用于患者无肌松药气管插管的效果

目的 评价七氟烷-咪达唑仑-瑞芬太尼麻醉诱导用于患者无肌松药气管插管的效果.方法 择期全麻手术患者30例,年龄20～55岁,体重50～80 kg,ASA Ⅰ或Ⅱ级.麻醉诱导:静脉注射咪达唑仑0.03 mg/kg,调节七氟烷挥发罐刻度至3%,氧流量5 L/min,预充呼吸环路30 s后,面罩吸入七氟烷,指导患者行肺活量呼吸,每呼吸3次,七氟烷挥发罐刻度增加1%,直至6%.待患者睫毛反射消失时,1 min内缓慢静脉注射瑞芬太尼2 μg/kg,30 s后停止吸入七氟烷,气管插管后行机械通气.于给药前、睫毛反射消失时、气管插管前即刻和气管插管后即刻,记录MAP、HR、SpO2和BIS;记录从开始吸入七氟烷到睫毛反射消失的时间;评估气管插管条件.结果 所有患者一次性顺利完成气管插管,气管插管条件达优率为80%,从开始吸入七氟烷到睫毛反射消失的时间为(210±12)s.气管插管后即刻MAP、HR和SpO2与气管插管前即刻比较差异无统计学意义(P>0.05).气管插管前、后维持BIS 45～55.结论 七氟烷-眯达唑仑-瑞芬太尼麻醉诱导平稳,可用于患者无肌松药气管插管.     

Effect of remifentanil compared with fentanyl on intraocular pressure after succinylcholine and tracheal intubation

Rapid sequence induction using succinylcholine is associatedwith an increase in intraocular pressure (IOP). This may leadto loss of ocular contents in open globe injuries. No methodhas previously been shown to prevent this increase in IOP. Weinvestigated whether remifentanil, an ultra-short-acting opioid,could attenuate this increase in IOP during rapid sequence inductionof anaesthesia. Forty-five patients were randomized blindlyto receive remifentanil 1 µg kg^–1, fentanyl 2 µgkg^–1 or placebo 1 min before thiopental, succinylcholineand tracheal intubation. IOP and haemodynamic variables weremeasured before, 1 min after the test solution, 30 s after thiopental,30 s after succinylcholine, immediately after intubation andthen every 3 min for 9 min. Remifentanil obtunded the increasein IOP after succinylcholine and intubation, so it could besuitable for use in open globe injuries. Br J Anaesth 2000; 85: 785–7 Footnotes ^* Corresponding author     

Sevoflurane EC50 and EC95 values for laryngeal mask insertion and tracheal intubation in children

The laryngeal mask airway (LMA     

Nifedipine versus fentanyl to prevent the pressor response to tracheal intubation

Thirty six patients, ASA I or II, undergoing surgery that required tracheal intubation, were allocated randomly into three groups of twelve. Before induction of anesthesia, they received either saline, nifedipine sublingual 10 mg or fentanyl 1.5 micrograms.kg-1 i.v. Heart rate, systolic blood pressure, diastolic blood pressure and mean blood pressure (MAP) were recorded automatically every minute for 5 minutes before induction of anesthesia, and for 5 minutes after intubation. Nifedipine was better than fentanyl in blocking the pressor response to intubation. The fentanyl dose was too small to abolish this response completely. The increase in HR and blood pressure were most evident in the control group, followed by fentanyl, and the least increase was seen with nifedipine.     

Intubation time required for tracheal intubation with low-dose rocuronium in children with and without atropine

Purpose

The purpose of this study was to determine the intubation time needed to facilitate tracheal intubation (Time_EI) with a low dose of rocuronium (0.3 mg/kg) during propofol induction, and to determine whether this time was reduced by the administration of atropine.

Methods

Forty-six children, aged 3–10 years, were randomly assigned to receive either saline (control group) or atropine 10 μg/kg (atropine group). Anesthesia was induced with alfentanil 10 μg/kg, propofol 2.5 mg/kg, and rocuronium 0.3 mg/kg. Each Time_EI at which tracheal intubation was attempted was predetermined according to the up-and-down method. The values of Time_EI that provided excellent intubation conditions in 50 and 95 % of patients were defined as Time_EI50 and Time_EI95, respectively.

Results

Time_EI50 ± SD was 160 ± 26.2 and 150 ± 13.7 s in the control and atropine groups, respectively. Using isotonic regression, Time_EI95 in the control and atropine groups was 199 s (95 % CI 198.8–200.7 s) and 171 s (95 % CI 171.3–172.1 s), respectively. Time_EI95 was significantly higher in the control group than in the atropine group (P < 0.001). HR was significantly higher in the atropine group than in the control group during the study period.

Conclusions

This study demonstrated that the Time_EI95 of a low dose of rocuronium (0.3 mg/kg) required for excellent tracheal intubation was 199 s during i.v. anesthesia induction using propofol and alfentanil in children. Also, i.v. atropine (10 μg/kg) before anesthesia induction was able to reduce Time_EI95 by 28 s.     

芬太尼或瑞芬太尼复合七氟醚诱导在无肌松条件下插管的应用

目的计算芬太尼或瑞芬太尼复合七氟醚诱导在无肌松条件下插管的半数有效量(ED50),比较抑制气管插管反应的效果。方法择期短小手术患者49例,ASAⅠ或Ⅱ级,年龄20～50岁。按照入室顺序随机分为芬太尼组(F组,n=23)和瑞芬太尼组(R组,n=26)。8%七氟醚肺活量诱导,眼睑反射消失后,维持呼气末七氟醚浓度(CETSev)为3%。按照改良Dixon序贯法调整芬太尼(剂量梯度为0.05μg/kg)或瑞芬太尼的剂量(剂量梯度为0.1μg/kg),静脉注射芬太尼或瑞芬太尼4min后气管插管。记录患者眼睑反射消失时间及气管插管反应。结果芬太尼ED50为1.30μg/kg(95%CI1.25～1.35μg/kg),瑞芬太尼ED50为0.47μg/kg(95%CI0.39～0.53μg/kg)。F组声带活动、呛咳和体动的发生率均明显高于R组(P<0.05)。结论无肌松条件下瑞芬太尼较芬太尼能更好地抑制气管插管反应。