Does Increasing the Bend Angle of a Stylet to 90° Increase the Nasotracheal Intubation Success Rate?

BACKGROUND: Video-stylet-guided nasotracheal intubation (NTI) is an effective technique for airway management. However, the impact of the bend angle on the success rate of intubation remains unclear. PURPOSE: Does increasing the bend angle of a stylet to 90° increase NTI success rate?. STUDY DESIGN, SETTING, SAMPLE: This prospective randomized controlled trial was conducted in the operating room of a population-based hospital. Adult patients requiring NTI were recruited. PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE: The primary predictor variable is the choice of stylet bend angle (90° vs 70° bend) in NTI. MAIN OUTCOME VARIABLE(S): The primary outcome variables were success rates of NTI, defined as the proportion of successful intubation cases to total cases. COVARIATES: Demographics, intubation time, the distance from the thyroid prominence to the nostril, additional maneuvers applied during intubation, and cases of epistaxis were recorded. ANALYSES: The student's t-test was used to compare continuous variables between groups. Ordinal data (intubation attempts, head extension, and epistaxis) were analyzed using the Wilcoxon rank-sum test. As appropriate, frequency (external pharyngeal pressure) was analyzed using the χ2 test or Fisher's exact test. A P value of <.05 was considered statistically significant. RESULTS: Of the 103 subjects assessed for eligibility, 98 were enrolled in the study. The mean age (27.0 ± 6.9 years vs 27.0 ± 4.1 years, P = .972) and sex differences (male/female: 9/40 vs 7/42, P = .136) were comparable between groups. The overall success rate in the 70° group was significantly lower than that in the 90° group (91.8 vs 100%, P < .001). The intubation time in the 70° group was significantly longer than that in the 90° group (43.2 ± 15.8 s vs 33.7 ± 7.3 s, P < .001). CONCLUSIONS AND RELEVANCE: A 90° bend angle of the stylet significantly improves the likelihood of successful NTI.

Comparison of the supraglottic airway device BlockBusterTM and laryngeal mask airway Supreme in anaesthetised, paralyzed adult patients: a multicenter randomized controlled trial.

BACKGROUND: This multicenter prospective, randomized controlled clinical trial compared the clinical performance of supraglottic airway device (SAD) BlockBusterTM and laryngeal mask airway (LMA) Supreme for airway maintenance in anesthetized, paralyzed adult patients. METHODS: A total of 651 adult patients scheduled for elective surgery in 13 hospitals were randomly allocated into BlockBuster group (n = 351) or Supreme group (n = 300). The primary outcome was oropharyngeal leak pressure (OLP). Duration and ease of insertion, fiberscopic view of positioning, airway manipulations, and complications were also assessed. RESULTS: The OLP was significantly higher in BlockBuster group compared with Supreme group (29.9 ± 4.2 cmH2O vs 27.4 ± 4.3 cmH2O, p < 0.001). Success rate of insertion at the first attempt (90.2% vs 85.1%, p = 0.027), rate of optimal fiberscopic view (p = 0.002) and satisfactory positioning of SAD (p < 0.001) were significantly increased in BlockBuster group. CONCLUSIONS: Both SAD BlockBusterTM and LMA Supreme are safe, effective, and easy-to-use devices for airway maintenance in anesthetized, paralyzed adult patients, but the SAD BlockBusterTM is superior to LMA Supreme in terms of OLP, success rate at the first attempt, and fiber-optic view of positioning. TRIAL REGISTRATION: The trial is registered at www.chictr.org.cn (ChiCTR-ONC-16009105).

Comparison of the Efficacy and Safety of Dexmedetomidine Administered in Two Different Modes Under Procedural Sedation and Analgesia in Plastic Surgery.

Background: Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, is now widely used in procedural sedation and analgesia. This study was designed to observe and compare the efficacy and safety of DEX administered in two different modes. Methods: In total, 100 patients were randomly divided into two groups to receive intravenous DEX 1 µg/kg over 15 min followed by 0.4-0.7 µg/kg/h infusion or DEX 1 µg/kg over 30 min followed by 0.4-0.7 µg/kg/h infusion. Heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), bispectral index (BIS), Ramsay Sedation Scores (RSS scores), the lowest respiratory rates (LRR), incidences of respiratory adverse events and frequencies of body movements were recorded. Recovery time, recall of intraoperative events, pain scores in PACU and satisfaction of patients and surgeons were assessed. Results: The BIS at time points from 5 min after anesthesia to the end of surgery in the intervention group were significantly higher (p < 0.05). The RSS scores at time points from 5 min after anesthesia to immediately after induction with DEX were significantly higher in the intervention group (p < 0.05). The HR at time points from the beginning of surgery to 30 min after local anesthesia, the MAP at time points from 30 min after local anesthesia to the end of surgery, and the RR at time points from 5 min after anesthesia to the end of surgery were significantly higher in the intervention group (p < 0.05). Patients in the intervention group had higher LRR, lower incidences of respiratory adverse events, and shorter recovery time (p < 0.05). Conclusions: Dexmedetomidine infused with a loading dose over 30 min had less impact on patients' hemodynamics and respiration and could shorten the recovery time after anesthesia in procedural sedation and analgesia. Clinical Trial Registration: ClinicalTrials.gov, identifier: ChiCTR1900027958.

Effects of multiple exposures to general anesthesia on the sleep quality of children after plastic surgery in Beijing, China: a cohort study.

To assess the effects of the number and duration of general anesthesia exposure on the sleep quality of 6-15-year-old school children who underwent plastic surgery. The study was conducted on 688 children who underwent plastic surgery between the ages of 6 and 15 years using the Sleep Disorder Scale for Children (SDSC). The children were divided into two groups according to their exposure to general anesthesia: No General Anesthesia (NGA) and General Anesthesia (GA) groups. The GA group was further divided into three subgroups according to the number of exposures: Single-exposure, Double-exposure, and Multiple-exposure groups. The GA group was also subdivided into two groups according to the cumulative total time of anesthesia exposure: < 3 h and ≥ 3 h groups. Multivariate logistic regression analysis was used to confirm the potential factors that affect children with sleep disturbance (SDSC scores > 39) after general anesthesia exposure. Linear regression was used to analyze the correlation of the factors with the SDSC scores. The SDSC scores were higher in the GA group [35.4 ± 4.3 vs. 34.0 ± 3.6, P < 0.0001] as compared to the NGA group. The number of children with SDSC scores > 39 was also higher in the GA group [80 (17.5%) vs. 17 (7.4%), P < 0.0001]. More anesthesia exposure was correlated with higher total SDSC scores [34.5 ± 4.3 for single exposure vs 35.1 ± 3.9 for double exposure vs 37.5 ± 4.5 for multiple exposures, P < 0.0001] and a higher proportion of SDSC scores > 39 [24 (12.0%) for single exposure vs 24 (15.5%) for double exposure vs 32 (31.1%) for multiple exposures, P < 0.0001]. Longer anesthesia exposure was also correlated with higher total SDSC scores [34.4 ± 4.5 for < 3 h vs. 35.8 ± 4.2 for ≥ 3 h, P = 0.002]. The number of exposures to general anesthesia was a potential factor in sleep disturbance among children, determined based on logistic regression. Children who underwent plastic surgery between the ages of 6 and 15 years with general anesthesia exposure might have worse sleep quality and a higher incidence of sleep disorders. More frequent anesthesia exposure leads to worsened sleep quality and a higher incidence of sleep disorders. This study also confirmed that a longer duration of cumulative anesthesia exposure also leads to worse sleep quality.

Efficient synthesis strategy of folate-modified carboxymethyl chitosan/CaCO3 hybrid nanospheres and their drug-carrying and sustained release properties.

Folate-modified carboxymethyl chitosan (FCMC) was made by folate acid as targeted group and attaching folate to carboxymethyl chitosan, and then, targeted FCMC/CaCO3 hybrid nanosphere were formed by self-assembly of calcium carbonate in FCMC solution. The physicochemical properties of the nanospheres were investigated by Fourier transform infrared spectroscopy, X-ray diffraction analysis, Brunauer-Emmett-Teller measurement and thermogravimetric analysis (TGA). The results showed that the FCMC/CaCO3 hybrid nanospheres were composed of calcite, vaterite and polysaccharides, and the content of organic compounds was 12.17%. Also, the structure performance of the hybrid nanospheres was analyzed. Besides, the effects of the hybrid nanospheres on the encapsulation efficiency, the drug loading content and the release behavior were also analyzed with the metformin (MET) as a model drug. Scanning electron microscope, Zeta potential analysis and UV-Vis were used to characterize the hybrid nanospheres. Under the conditions of FCMC/Ca2+ molar ratio of 4: 1 and reaction for 24 h, the achieved results showed that the spherical aggregates with regular morphology were obtained and the average particle size of the nanospheres was 207 nm. The specific surface area of the hybrid nanosphere is 27.06 m2·g-1 and the average pore diameter of the sample is 3.84 nm, indicating the presence of mesoporous structure in the sample. This mesoporous structure can supply potential space for adsorption of anticancer drugs. Additionally, the surface charge of the nanoparticles was positive and the entrapment efficiency was 83.32%. The hybrid nanospheres have a capability of effective pH-sensitivity controlled drug release. All the drug loaded hybrid nanospheres successfully sustained the release of MET at pH 7.4, only about 44.58% of the drug released in 6 days. While under acidic condition (pH 5.0) drug release was significantly accelerated, being over 98.85% of the drug released. The hybrid nanospheres demonstrated an excellent smart drug delivery behavior.

Structural Flexibility of DNA-RNA Hybrid Duplex: Stretching and Twist-Stretch Coupling.

DNA-RNA hybrid (DRH) duplexes play essential roles during the replication of DNA and the reverse transcription of RNA viruses, and their flexibility is important for their biological functions. Recent experiments indicated that A-form RNA and B-form DNA have a strikingly different flexibility in stretching and twist-stretch coupling, and the structural flexibility of DRH duplex is of great interest, especially in stretching and twist-stretch coupling. In this work, we performed microsecond all-atom molecular dynamics simulations with new AMBER force fields to characterize the structural flexibility of DRH duplex in stretching and twist-stretch coupling. We have calculated all the helical parameters, stretch modulus, and twist-stretch coupling parameters for the DRH duplex. First, our analyses on structure suggest that the DRH duplex exhibits an intermediate conformation between A- and B-forms and closer to A-form, which can be attributed to the stronger rigidity of the RNA strand than the DNA strand. Second, our calculations show that the DRH duplex has the stretch modulus of 834 ± 34 pN and a very weak twist-stretch coupling. Our quantitative analyses indicate that, compared with DNA and RNA duplexes, the different flexibility of the DRH duplex in stretching and twist-stretch coupling is mainly attributed to its apparently different basepair inclination in the helical structure.

Effect of Intravenous Dexmedetomidine Injection(1 µg/kg)on the Intubating Conditions without Muscle Relaxants in Children after Inhalation Induction with Sevoflurane.

Objective To investigate the effect of intravenous dexmedetomidine injection(1 µg/kg)on the intubating conditions after inhalation induction with sevoflurane 8% and nitrous oxide(N2O)50% in children. Methods Totally 122 patients aged 4-10 years with an American Society of Anesthesiologists physical statusⅠ undergoing elective plastic surgery under general anesthesia were randomly divided to dexmedetomidine group(intraveneously injected with dexmedetomidine 1µg/kg)and control group(injected with normal saline)by using the random sampling table.On arrival of the operating room,anesthesia was induced with sevoflurane 8% and N2O 50% in oxygen 50%.When the patient became unconscious,the intravenous cannula 24# was inserted on the dorsum of hand.One minute later,laryngoscopy and tracheal intubation were performed.The intubating conditions were assessed by the scoring system in the previous study. Results The rates of acceptable conditions were 97% and 90% in dexmedetomidine group and in control group(P=0.143),and the rates of excellent conditions were 82% and 67%(P=0.04),respectively.In dexmedetomidine group,there were no signifi-cant differences of mean arterial presser and heart rate between the time-point of before intubation and the time-point of immediately after intubation.Conclusion Intravenous bolus of dexmedetomidine(1 µg/kg)can effectively improve the intubating conditions after inhalation induction of sevoflurane 8% and N2O 50% in children and make the hemodynamics more stable during tracheal intubation.

Comparison of Sedative Effects of Two Spray Administration of Intranasal Dexmedetomidine Doses for Premedication in Children.

Objective To compare two spray administration of intranasal dexmedetomidine (DEX) doses for premedication in children. Methods In this prospective,randomized,double-blind study,41 children aged 3-6 years were enrolled. Children were assigned to receive either spray administration of intranasal DEX 1 µg/kg (Group D1) or 2 µg/kg (Group D2). The Ramsay Sedation Scale scores were evaluated at 5 min intervals. Sedation status at separation from patient was also evaluated. Heart rate (HR) and saturation of peripheral oxygen (SpO2) were recorded before and every 15 min after drug administration. Results The median sedation onset time was 30 min and 20 min in group D1 and group D2,respectively. Compared with the children in group D1,those in group D2 were significantly more sedated when they were separated from their parents (61.9% vs. 95.0%,respectively)(χ2=5.549,P=0.010). In Group D2,the HR decreased by 15.8% (t=2.415,P=0.021) 30 min after the spray administration of intranasal DEX. Compared with the baseline values,there was no significant difference in both groups in terms of SpO2(t=-1.426,P=0.162;t=-1.096,P=0.280)and HR in group D1 (t=-0.299,P=0.767) 30 min after the spray administration of intranasal DEX. Conclusion Spray administration of intranasal DEX 2 µg/kg provides superior sedation in children.

Effects of Two Intranasal Dexmedetomidine Doses as Premedication on Sevoflurane EC50 for Successful Laryngeal Mask Airway Placement in Children.

Objective To observe the effects of two different intranasal dexmedetomidine doses as premedication on the EC50 of sevoflurane for successful laryngeal mask airway placement in children. Methods Children aged 3-6 years, of American Society of Anesthesiologists physical status 1, and scheduled for plastic surgery were enrolled in this study. Children were assigned to receive either spray administration of intranasal dexmedetomidine 1 µg/kg (group D1, n=21) or 2 µg/kg (group D2, n=20) approximately 30 minutes before anesthesia. Anesthesia was induced with sevoflurane up to 8% in 100% O2, with fresh gas flow set to 6 L/min. After the pupil fixed to the middle position, sevoflurane dial setting was reduced to 5% and fresh gas flow reduced to 3 L/min. The endtidal sevofluran (ETsevo) concentration for laryngeal mask airway insertion sustained for 10 minutes after vein intubation, which was determined according to the Dixon's up and down method. The initial endtidal sevoflurane concentration in each group was set at 2%. ETsevo was increased/decreased (1:1.2) in the next patient according to the response to laryngeal mask airway insertion. Bispectral index, mask acceptance, all response to laryngeal mask airway insertion, and ETsevo of laryngeal mask airway insertion of children were recorded. Results The bispectral index value was 77.4±3.6 in group D2, which was significantly lower than that (87.4±1.9) in group D1 when children entered operation room (P<0.05). Mask acceptance was 76.2% in group D1 and 90.0% in group D2. The EC50 of sevoflurane for laryngeal mask airway insertion was 1.09% (95% CI=0.89%-1.28%) in group D2, which was lower than 1.59% (95% CI=1.41%-1.78%) in group D1 (P<0.05). Conclusion Compared with the dose of 1 µg/kg, spray administration of intranasal dexmedetomidine 2 µg/kg as premedication can reduce the sevoflurane EC50 for successful laryngeal mask airway placement in children.

Dexmedetomidine Improves Intubating Conditions Without Muscle Relaxants in Children After Induction With Propofol and Remifentanil.

BACKGROUND: Anesthesia induction using propofol (3 mg/kg) and remifentanil (2 µg/kg) without the use of muscle relaxants has been associated with a lower incidence of successful intubation. Dexmedetomidine has been found to effectively decrease the requirements for propofol and remifentanil and to attenuate the hemodynamic response to intubation. Therefore, in this study, we examined intubating conditions and hemodynamic changes in children after induction with dexmedetomidine (1 µg/kg) combined with propofol (3 mg/kg) and remifentanil (2 µg/kg). METHODS: This randomized, double-blinded, and placebo-controlled study included 60 ASA physical status I children aged 5 to 10 years. The children were randomly allocated to a dexmedetomidine group (group D) or a placebo group (group P). After IV administration of atropine (0.01 mg/kg), anesthesia was induced with an infusion of dexmedetomidine (1 µg/kg) over 2 minutes for group D, whereas normal saline was infused for group P. Propofol (3 mg/kg) was then injected IV over 20 to 30 seconds, followed by an infusion of remifentanil (2 µg/kg) over 1 minute for both groups. One minute later, laryngoscopy and tracheal intubation were performed. RESULTS: For group D and group P, tracheal intubation was successful in 90% (27/30) and 53% (16/30) of patients (P = 0.0034), respectively. Excellent conditions were present in 22 of 27 and 8 of 16 of intubations, respectively, resulting in an overall incidence of excellent conditions of 73% (22/30) and 27% (8/30), respectively (P = 0.0007). Systolic blood pressure significantly increased after the IV injection of dexmedetomidine compared with baseline readings (P = 0.012, with a confidence interval of 2-22 mm Hg). CONCLUSIONS: A single dose of dexmedetomidine (1 µg/kg) improved intubation conditions in children after induction with propofol (3 mg/kg) and remifentanil (2 µg/kg) without muscle relaxants. Dexmedetomidine did not affect the hemodynamic response to intubation.

[Comparison of Cookgas and Fastrach intubating laryngeal mask airway with fiberoptic bronchoscope in anticipated difficult airway management].

OBJECTIVE: To compare the clinical effectiveness of fiberoptic bronchoscope (FOB)-guided intubation through the Cookgas intubating laryngeal airway(CILA)and the Fastrach intubating laryngeal mask airway (FT-LMA) in the management of anticipated difficult airways. METHODS: Sixty patients with all three difficult intubation criterion (thyromental distance<60 mm, interincisor distance<35 mm, and Mallampati class 3 or 4) undergoing elective plastic surgery under general anesthesia were randomly allocated into CILA group (n=30) and FT-LMA group (n=30). After anesthesia being induced and CILA or FT-LMA being inserted, the patients were treated with FOB-guided intubation through CILA or FT-LMA. The success of the intubating laryngeal airway(ILA)insertion and FOB-guided intubation, the number of attempts, and the duration of the successful attempt were recorded. RESULTS: The ILA was inserted successfully in 30 patients from CILA group and 27 patients from FT-LMA group. Three failed cases in FT-LMA group were inserted successfully with CILA. In CILA group, the first FOB-guided intubation attempt succeeded in 26 patients, and 4 cases were intubated at the second attempt. In 27 patients of FT-LMA group, 20 cases were intubated successfully at the first attempt, 4 cases at the second attempt, and 3 cases failed; of these three failed patients, two patients were intubated smoothly with FOB through CILA at the first attempt, one was intubated by FOB via CILA at the second attempt. The duration of FT-LMA insertion [(35.3±12.8)s] was significantly longer when compared with CILA [(23.9±17.5)s] (P<0.05). However, the duration of FOB-guided intubation through CILA and FT-LMA [(48.6±13.5)s vs.(53.2±14.2)s] and the time of ILA removal [(40.4±10.2)s vs. (38.5±11.3)s] were not significantly different between these two groups (P>0.05). The adverse events during and after intubtion were not significantly different between these two groups. CONCLUSIONS: FOB-guided intubation through CILA and FT-LMA is safe and feasible for the management of anticipated difficult airways. However, in patients with severe scar contracture of face and neck and those with huge expander in neck, the CILA insertion and FOB-guided intubation via CILA is superior to FT-LMA.

[Application of conscious sedation with midazolam, propofol and sufentanil for patients in plastic surgery].

OBJECTIVE: To observe the effectiveness of conscious sedation with midazolam, propofol and sufentanil for patients in plastic surgery. METHODS: 81 patients, scheduled for plastic surgery, were randomly selected to receive conscious sedation with midazolam 0.05 mg x kg(-1) and sufentanil 0.1 microg x kg(-1) intravenously, following by a continuous infusion of midazolam-propofol-sufentanil combination (midazolam 5 mg + propofol 200 mg + sufentanil 10 microg, a total of 23 ml). The initial infusion rate was 0.2 ml x kg(-1) x h(-1), and was adjusted (in 20% of initial infusion rate increment) to maintain OAA/S score as 11 during the operation. The patients' vital signs, discomfort and level of sedation were evaluated at 5 to 10 min intervals until the end of the surgery. The complications (i. e. anoxemia, apnea, restlessness, nausea and vomiting), anesthesia duration and drug consumption were recorded. The drug infusion was discontinued at 5 - 10 min before the end of the surgical procedure. On the first postoperative day, patients were asked to rate their satisfaction with the anesthetic management and whether they would choose to receive the same anesthetic technique if necessary in the future. RESULTS: The OAA/S score decreased from 20.0 +/- 0 to 11.9 +/- 2.6 after midazolam and sufentanil IV (P < 0.05), and was maintained as 10.5-11.1 during the procedure. At the end of the procedure, the OAA/S score returned to 16.0 +/- 2.2, which was also lower significantly compared with baseline value (P < 0.05). The induction of sedation produced a significant decrease in SBP and DBP (P < 0.05) and no significant changes in heart rate (P > 0.05). At the end of the procedure, SBP, DBP and HR returned to the baseline value. The anoxemia happened in 11 cases, apnea in 5 cases and restlessness in 2. No nausea and vomiting occurred. The anesthesia duration and consumption of midazolam, propofol and sufentanil were (101.1 +/- 42.5) min, (8.4 +/- 3.7) mg, (189.1 +/- 88.7) mg and (18.2 +/- 5.6) microg respectively. In an interview on the first postoperative day, 96% (78/ 81) of the patients were satisfied with their anesthesia and were willing to receive the same anesthetic technique if necessary in the future. CONCLUSION: Conscious sedation with midazolam, propofol and sufentanil is an effective anesthetic technique for patients in plastic surgery.

[Application of the fibreoptic intubating laryngeal mask airway CTrach in face and neck scar contracture patients].

OBJECTIVE: To evaluate the feasibility of the fibreoptic intubating laryngeal mask airway (LMA) CTrach (CTrach) in anticipated difficult airway caused by face and neck scar contracture. METHODS: Totally 33 patients undergoing selective face and neck scar plastic surgery and requiring general anesthesia were enrolled in our study. After anesthesia induction, the CTrach was inserted and the viewer was attached, which allowed fibreoptic visualization of the larynx before and during passage of the tracheal tube through the vocal cords. The duration and the success rates of CTrach insertion, tracheal intubation, and CTrach removal were recorded. The view of glottis on viewer and the adjusting maneuvers for improving the laryngeal view were recorded. Noninvasive blood pressures and heart rates were recorded before and after anesthesia induction and at CTrach insertion, tracheal intubation, and CTrach removal. RESULTS: The CTrach was successfully inserted in all patients, among whom 4 patients succeeded at the second attempt. The full view of glottis were shown in 10 patients, while partial view and no view of glottis were shown in 8 and 15 patients, respectively. The good view of glottis was achieved by adjusting manoeuvres. Tracheal intubation via the CTrach was successful in 27 patients at the first attempt and in 6 patients at the second attempt. Hemodynamic changes during the performance with the CTrach were minimal. CONCLUSIONS: The CTrach can be easily inserted, with clear view and high success rate of tracheal intubation. Therefore, it is an effective way to resolve difficulty intubation caused by face and neck scar contracture.

[Inductions and intubating conditions with sevoflurane and different doses of remifentanil without muscle relaxant in children].

OBJECTIVE: To observe the clinical effectiveness of inductions and tracheal intubating conditions with 3% sevoflurane and different doses of remifentanil without muscle relaxant in children. METHODS: Totally 120 peadiatric patients (aged 4-10 years, American Society of Anesthesiologists grade I for inhalational induction) were randomly allocated into group I (remifentanil 1 microg/kg), group II (remifentanil 2 microg/kg), group III (remifentanil 3 microg/kg), and control group (vecuronium bromide 0.1 mg/kg). After inhalational induction with 3% sevoflurane and 60% nitrous oxide in 40% oxygen for 2 minutes, remifentanil 1 microg/kg, 2 microg/ kg, and 3 microg/kg were intravenously injected over 1 minute into patients in group I , group II, and group III, respectively. After remifentanil administration and manual ventilation for 1 minute, the trachea was intubated. In the control group, 2 minutes after intravenous administration of vecuronium bromide 0.1 mg/kg, tracheal intubation was attempted. Agitation, intubating satisfactoriness, and the circulation changes after tracheal intubation and anesthesia induction were observed. RESULTS: In these four groups, agitation occurred in 37.5% of patients during sevoflurane induction. Satisfactory intubation rate was 70.0% in group I, 86.7% in group II, 90.0% in group III, and 93.3% in the control group. Compared with the control group, the impact of tracheal intubation on the circulatory system was smaller in group I , II , and III. CONCLUSIONS: Induction with 3% sevoflurane combined with remifentanil can be smoothly performed, followed by the successful tracheal intubation. The intubating conditions are more satisfactory with 3% sevoflurane combined with remifentanil 2 microg/kg or 3 microg/kg.