ABSTRACT
Objective To evaluate the efficacy of dexmedetomidine in preventing agitation during recovery from general anesthesia in patients undergoing uvulopalatopharyngoplasty (UPPP).Methods Sixty adults patients with obstructive sleep apnea syndrome,of American Society of Anesthesiology physical status Ⅰ or Ⅱ,aged 24-62 yr,with body mass index of 24-37 kg/m2,undergoing elective UPPP,were divided into dexmedetomidine group (group D) and conventional group (group C) using a random number table method,with 30 patients in each group.Dexmedetomidine was infused in a loading dose of 0.8 μg/kg over 10 min starting from 10 min before anesthesia induction,followed by a continuous infusion of 0.4 μg · kg-1 · h-1 for 30 min in group D,while the equal volume of normal saline was given instead of dexmedetomidine in group C.Anesthesia was induced and maintained by target-controlled infusion of propofol and remifentanil,and bispectral index value was maintained at 40-60 during surgery.Patients were extubated after they restored spontaneous breathing completely,opened eyes on verbal command and responded to verbal command,and then the patients were transferred to the recovery room,and oxygen was inhaled by mask.The emergence time,extubation time and development of agitation were recorded.Verbal rating scale was used to assess pain at 30 min after patients were transferred to the recovery room.Results Compared with group C,the incidence of agitation was significantly decreased,pain was reduced,and the emergence time was prolonged in group D (P＜0.05).There was no significant difference in extubation time between two groups (P＞0.05).Conclusion Dexmedetomidine can effectively prevent the occurrence of agitation during recovery from general anesthesia in patients undergoing UPPP.
ABSTRACT
Objective To evaluate the effects of different anesthetic methods on postoperative acute pain in patients with myasthenia gravis undergoing video-assisted thoracoscopic thymectomy.Methods Fifty-four patients of both sexes,aged 18-64 yr,with body mass index of 20-28 kg/m2,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,scheduled for elective video-assisted thoracoscopic thymectomy,were allocated into 2 groups (n =27 each) using a random number table method:sevoflurane-based anesthesia group (group S) and propofol-based anesthesia group (group P).After routine anesthesia induction in two groups,anesthesia was maintained by inhaling sevoflurane and target-controlled infusion of remifentanil in group S and by target-controlled infusion of propofol and remifentanil in group P.Heart rate and mean arterial pressure were recorded before operation and at 5 and 10 min after extubation (T1.2).The intensity of pain at T2 and visual analog scale (VAS) score and consumption of morphine at 1,2,4,24 and 48 h after operation (T3-7) were recorded.The pressing times of analgesia pump,requirement for rescue analgesia and development of nausea and vomiting were recorded at T7.Results There were no significant differences in heart rate or mean arterial pressure at each time point between two groups (P＞0.05).Compared with group S,the intensity of pain was significantly alleviated at T2,and VAS scores and morphine consumption were decreased at T3,4 in group P (P＜0.05).There were no significant differences between group P and group S in VAS scores or consumption of morphine at T5-7,or pressing times of analgesia pump,requirement for rescue analgesia or incidence of nausea and vomiting at T7 (P＞0.05).Conclusion Propofol-based anesthesia provides better efficacy in alleviating postoperative acute pain in patients with myasthenia gravis undergoing video-assisted thoracoscopic thymectomy.
ABSTRACT
Objective To evaluate the efficacy of laryngeal mask airway (LMA) Guardian for airway management in the patients requiring insertion of nasogastric tube before laparoscopic cholecystectomy.Methods Sixty patients of both sexes,aged 26-64 yr,weighing 48-95 kg,of American Society of Anesthesiologists physical status Ⅰ-Ⅲ,with Mallampati grade Ⅰ-Ⅲ,scheduled for elective laparoscopic cholecystectomy under general anesthesia,were divided into group Ⅰ and group Ⅱ (n =30 each) using a random number table.In group Ⅰ,the nasogastric tube was inserted through the drain tube of LMA Guardian.In group],the nasogastric tube was inserted through the nostril before operation,and after successful LMA Guardian placement,another nasogastric tube was inserted through the drain tube of LMA Guardian.The hemodynamic parameters,SpO2,end-tidal pressure of carbon dioxide and peak airway pressure (Ppeak) were monitored during operation.The fiberoptic laryngoscopy scores were assessed after successful LMA placement,and the nasogastric tube displacement was recorded.The LMA placement time,success rate of LMA placement at first attempt,airway sealing pressure,occurrence of air leakage of LMA and nasogastric tube drainage were recorded.The bloodstains and gastroesophageal reflux were observed after removal of the LMA.The pH values were tested at the tip of LMA and on the dorsal and ventral sides of the body of LMA using pH test papers.The development of adverse reactions in the oropharynx was recorded within 24 h after operation.Results The hemodynamics was stable,the SpO2 and Ppeak were within the normal range during operation,and Ppeak was lower than airway sealing pressure in the two groups (P＞0.05),and there was no significant difference between the two groups.There was no significant difference between the two groups in the LMA placement time,success rate of LMA placement at first attempt,airway sealing pressure,score for exposure of oropharynx,development of adverse reactions in the oropharynx,consumption of anesthetics,development of bloodstains within the body of LMA and gastroesophageal reflux,and pH values at the tip of LMA and on the dorsal and ventral sides of the body of LMA (P＞0.05).Nasogastric tube drainage:the rate of nasogastric tube drainage through the LMA Guardian was 67％ in group Ⅰ;the rate of nasogastric tube drainage through the nostril was 40％,and the rate of nasogastric tube drainage though the LMA Guardian was 50％ in group Ⅱ.No nasogastric tube displacement was found after operation in group Ⅱ.Conclusion For the patients requiring insertion of nasogastric tube before laparoscopic cholecystectomy,insertion of LMA Guardian is easy,and LMA Guardian can assure good airway sealing and adequate ventilation and can be safely and effectively used for airway management in this type of patients.
ABSTRACT
Objective To determine the relationship between neuronuscular block induced by cisatracurium for tracheal intubation during anesthesia induction and types of myasthenia gravis (MG).Methods Sixty-five patients of both sexes with MG,aged 20-75 yr,weighing 53-92 kg,with body height of 155-185 cm,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,undergoing elective videoassisted thoracoscopic thymectomy,were enrolled in the study.Among the 65 patients,there were 8 patients with ocular MG (type Ⅰ),19 patients with mild generalized MG (type]Ⅱ a),33 patients with subacute generalized MG (type Ⅱ b),2 patients with acute MG (type Ⅲ) and 3 patients with late severe MG (type Ⅳ).Neuromuscular monitoring was initiated when the patients lost consciousness after induction of anesthesia.Cisatracurium was administrated with the initial dose of 0.05 mg/kg,and if T1 depression was less than 95％ within 6 min,cisatracurium 0.015 mg/kg was intravenously injected until T1 depression was more than 95％.The patients were then tracheally intubated.The amount of cisatracurium consumed for intubation,onset time (from the beginning of cisatracurium injection to T1 depression ＞95％) and recovery time (recovery of T4/T1 to 25％ of control height) of neuromuscular block were recorded.T1 depression ＞ 95％ within 6 min after administration of 1-fold ED95 cistracuriun was defined as sensitivity to muscle relaxants.The requirement for cistracurium ＞ 1-fold ED95 when T1 depression ＞ 95％ was defined as insensitivity to muscle relaxants.The proportion of sensitivity/insensitivity was calculated.Results There was no significant difference in the amount of cisatracurium consumed for intubation and onset time and recovery time of neuromuscular block between patients with type Ⅰ and those with type Ⅱ a (P＞0.05).Compared with patients with type Ⅰ and type]Ⅱ a,the amount of cisatracurium consumed for intubation was significantly decreased,the proportion of sensitivity/insensitivity was increased,the onset time was shortened,and the recovery time was prolonged in patients with type Ⅱ b (P＜0.05).Conclusion With the severity of MG,the consumption of cisatracurium is gradually decreased when used for tracheal intubation during anesthesia induction,and the sensitivity is gradually increased in the patients with MG.
ABSTRACT
Objective To evaluate the efficacy of different doses of dexmedetomidine combined with propofol for drug-induced sleep endoscopy (DISE) in the patients with snoring.Methods Sixty patients with snoring,aged 24-62 yr,with body mass index of 24-37 kg/m2,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,scheduled for elective DISE,were randomly divided into either group Ⅰ or group Ⅱ,with 30 patients in each group.In Ⅰ and Ⅱ groups,dexmedetomidine was infused over 10 min in a loading dose of 0.4 and 0.8 μg/kg,respectively,followed by an infusion of 0.4 μg · kg-1 · h-1.At 15 min of dexmedetomidine infusion,propofol was given by target-controlled infusion with the initial target plasma concentration (Cp) of 1.0 μg/ml.At 2 min after the target effect-site and plasma concentrations were balanced,the Cp of propofol was increased/decreased by 0.2 μg/ml to maintain the Cp of propofol stable during DISE.Bispectral index (BIS) value was recorded before anesthesia (T1),at 10 and 15 min of dexmedetomidine infusion (T2,3),at 2 min after the target effect-site and plasma concentrations were balanced (T4),at the beginning of DISE (T5),when the fiberoptic laryngoscope was placed at the site of oropharynx (T6),at the end of DISE (T7),at emergence (T8),and while discharge from the examination room (T9).Richmond Agitation Sedation Scale (RASS) scores were recorded at T1-4.Sleep was recorded within 15 min of dexmedetomidine infusion.The emergence time,discharge time,and anesthetics-related adverse events were recorded.Results All the patients completed DISE successfully.BIS values were maintained at 75-90,and RASS scores ≤ 4 during dexmedetomidine infusion.BIS values were maintained at 65-75 during DISE.Compared with group Ⅰ,BIS values were significantly decreased at T4,and RASS scores were significantly increased at T2-4,the sleep rate was significantly increased within 15 min of dexmedetomidine infusion,the Cp of propofol was significantly decreased during DISE,the emergence time was significantly prolonged (P＜0.05),and no significant change was found in the discharge time and anesthetics-related adverse events in group Ⅱ (P＞ 0.05).Conclusion Dexmedetomidine infused at 0.4 μg · kg-1 · h-1 after infusion of a loading dose of 0.8 μg/kg combined with propofol provides better efficacy for DISE in the patients with snoring.
ABSTRACT
OBJECTIVE@#to investigate the origin characters of snore in simple snorers and provide the basis for its treatment.@*METHOD@#Thirty-two simple snorers diagnosed by polysomnography were induced to sleep by propofol and dexmedetomidine, then we observed the vibration sites, pattern and concomitant collapse of soft tissue in pharyngeal cavity by nasendoscopy.@*RESULT@#Thirteen cases showed palatal fluttering only, and 1 case showed vibration of epiglottis only. Six cases showed palatal fluttering with vibration of epiglottis, and 2 cases showed palatal fluttering with vibration of epiglottis and tongue base. Five cases showed palatal fluttering with vibration of pharyngeal lateral wall, and 5 cases showed palatal fluttering with vibration of lateral wall, epiglottis and tongue base together. Palate and pharyngeal lateral wall vibrated strongly and always collapsed with vibrating, but epiglottis and tongue base usually vibrated slightly and seldom collapsed.@*CONCLUSION@#The palatal fluttering is the main source of snoring sounds for most simple snorers, then followed by vibration of palatal and pharyngeal lateral wall together. The site of collapse in pharyngeal cavity is consistent with the main site of vibration.
Subject(s)
Humans , Endoscopy , Epiglottis , Palate , Pharynx , Polysomnography , Propofol , Sleep , Sleep Apnea, Obstructive , Snoring , Diagnosis , TongueABSTRACT
Objective To investigate the neuromuscular block effect of intravenous injection of cisatracurium in myasthenia gravis patients with different ages.Methods Fifteen geriatric patients defined as geriatric group(≥ 65 years old)with ASA Ⅰ-Ⅱ scheduled for video-assisted thoracoscopic (VATS)thymectomy with Ⅱ b MG and fifteen young-middle aged Ⅱ b MG patients defined as youngmiddle aged group (20-50 years) with paired sex,clinical symptoms,duration of symptoms,preoperative treatment regimen,anesthesia management and surgical time were included.Neuromuscular block was monitored with TOF Watch acceleration instrument.After induction of intravenous anesthesia,0.05mg/kg Cisatracurium was administrated intravenously,followed by increments of 0.015 mg/kg until T1/T0 was less than 5％ for each patient.A double-lumen bronchial tube was intubated when T1/T0 was less than5％.0.015 mg/kg cisatracurium was injected during the operation when T4/T1 was achieved to 25％.The dose of cisatracurium,the duration of blockade maintenance,duration of clinical action and neuromuscular block recovery index were obtained.Results There were no significant differences in tracheal doses of cisatracurium [(0.058 ± 0.013)mg/kg vs.(0.053±0.009)mg/kg]and the duration of blockade [(31.5±9.6)min vs.(40.0±19.8)min] between geriatric group and young-middle age group (P＞0.05).The duration of clinical action of cisatracurium [(21.6±6.7)min vs.(33.7±13.4)min]and the time to achieve a TOFr of 25％ were significantly shorter in geriatric MG group than those in young-middle aged MG group (P=0.045,0.037).The geriatric MG group were administrated more increments of ciastracurium than the young middle aged MG group during surgery (P=0.025).There was no significant difference in the time to achieve a TOFr of 70％ [(49.3±16.4)min vs.(57.4±34.7)min] and 90％ [(61.6± 19.2)min vs.(64.3±35.9)min] between geriatric MG group and young-middle aged MG group (P＞ 0.05).Conclusions The duration of clinical action of cisatracurium in geriatric MG patients was shorted than that in young-middle aged MG patients which was different with neuromuscular block effect in normal patients.It is suggested to do more studies to estimate the influence of age on cisatracurium and other muscle relaxants in MG patients.
ABSTRACT
Objective To evaluate the effect of neuromuscular block on the airway sealing pressure of laryngeal mask airway (LMA) i-gel in patients undergoing general anesthesia.Methods Sixty patients scheduled for elective surgery under general anesthesia with LMA i-gel were randomly allocated to one of three groups (n =20 each):control group (group C),rocuronium 0.3 mg/kg group (group R1) and rocuronium 0.6 mg/kg group (group R2).Anesthesia was induced with target-controlled infusion of propofol and remifentanil.The target plasma concentration of propofol was 3.5 μg/ml,and the target effect-site concentration of remifentanil was 3.0 ng/ml.When the patients lost consciousness and after the target plasma and effect-site concentrations were balanced,LMA i-gel was inserted to perform mechanical ventilation.After insertion of LMA i-gel,rocuronium 0.3 and 0.6 mg/kg were injected in R1 and R2 groups,respectively.The airway sealing pressure of LMA i-gel was detected immediately after insertion of LMA i-gel and at 1 min after administration of rocuronium.Results There was no significant difference in the airway sealing pressure of LMA i-gel between groups and within groups(P ＞ 0.05).Conclusion Neuromuscular block has no significant effect on the airway sealing pressure of LMA i-gel in patients undergoing general anesthesia.
ABSTRACT
Objective To assess the efficacy of laryngeal mask airway Supreme (LMA Supreme) used in patients undergoing laparoscopic surgery. Methods One hundred and twenty ASA I or Ⅱ patients of both sexes aged 35-60 yr weighing 48-85 kg undergoing elective laparoscopic surgery were randomized to 2 groups ( n = 60 each): LMA Supreme group (group S) and tracheal intubation group (group T). Mallampati test was performed before operation in both groups. The patients were classified as I - Ⅲ . In group S the LMA Supreme was inserted after induction of anesthesia with sufentanil 0.2 fig/kg, propofol 2-3 mg/kg and vecuronium 0.1 mg/kg. A gastric tube was inserted through the drain tube of the LMA Supreme. In group T the patients were intubated under direct laryngoscopy. The success rate, LMA placement/intubation time, success rate of gastric tube placement, airway seal pressure, SpO2, PETCO2 , peak airway pressure and complications (hypoxemia, nausea and vomiting, choking hoarseness, sore throat and regurgitation of gastric contents) were recorded. The duration of surgery, anesthesia time, extubation time and emergence time were also recorded. Results There was no significant difference in the success rate between the two groups. The placement and removal time and recovery time were significantly shorter in group S than in group T. The airway seal pressure was (25 ±4) cm H2O in group S. SpO2, PETCO2 and peak pressure were within normal range in both groups. The incidence of postoperative hypoxemia, choking and sore throat were significantly lower in group S than in group T. Conclusion LMA Supreme can provide adequate ventilation during operation with less complications and can be used effectively for laparoscopic surgery.
ABSTRACT
Objective To evaluate the efficacy of streamline liner of pharyngeal airway ( SLIPA) in airway management of general anesthesia. Methods Sixty ASA Ⅰ -Ⅱ patients undergoing elective breast surgery were randomized into 2 groups (30 cases each): SLIPA group (group S) and laryngeal mask airway (LMA) classic group (group L). Anesthesia was induced with propofol 2 mg/kg, sufentanil 0.15 μ g/kg and vecurium 0.08 mg/kg. SLIPA or LMA was inserted with digital manipulation. Anesthesia was maintained with 1% - 2% sevofluran and 50% N2O in 50% oxygen. The parameters of controlled ventilation were same in both groups. The attempt times, seal pressure and grade of fiberoptic (FOB ) laryngoscopy were measured. SpO2, PErCO2 and peak airway pressure were monitored every 15 minutes after successful laryngeal mask insertion. The complications such as regurgitation of gastric contents and sore throat were assessed by anesthesiologist after surgery. Surgery time, anesthesia time, extubation time and emergence time were recorded. Results Success rate of LMA insertion in both groups were 100%. The first attempt success rates were 90%( 27/30) in group S and 60%( 18/30) in group L (P< 0.05), the FOB grade 4 were 67%(20/30) in group S and 37% (ll/30)in group L(P< 0.05), the maximum seal pressures were (23.6 ± 4.7)cmH2O (1 cm H2O = 0.098 kPa) in group S and (18.8 ± 4.5) cm H2O in group L (P<0.05). SpO2, PErCO2 and peak airway pressure were within normal ranges. The occurrence of sore throat was similar in group S and group L (7 cases vs 6 cases). No signs of regurgitation were detected. Conclusion The SLIPA proved to be a simple, safe and effective airway instrument with little complications during the course of general anesthesia.
ABSTRACT
Objective To assess the efficacy of the laryngeal mask airway i-gel (LMA i-gel) in patients umdergoing laparoscopic cholecystectomy. Methods One hundred and twenty ASA Ⅰ or Ⅱ patients of both sexes,aged 34-62 yr, weighing 45-90 kg, undergoing elective cholecystectomy using fiberoptic laparoscope, were randomized into 2 groups (n =60 each): LMA i-gel group (group I) and LMA ProSeal group (group P). After induction of anesthesia with sufentanil 0.2 μg/kg, propofol 2.5 mg/kg and vecuronium 0.1 mg/kg, LMA i-gel and LMA ProSeal were inserted in group I and P respectively. A gastric tube was inserted through the drain tube of the LMAs. The number of attempts, success rate, success rate of gastric tube placement, airway seal pressure, SpO2 ,PETCO2, peak airway pressure and complications (hypoxemia, nausea and vomiting, choking hoarseness, sore throat and regurgitation of gastric contents) were recorded. The fiberoptic laryngoscope scores were assessed after sccessful LMA placement. The anesthesia time, duration of surgery, extubation time and emergence time were also recorded. Results There was no significant difference in the anesthesia time, duration of surgery, extubation time and emergence time between the two groups ( P ＞ 0.05). The SpO2, PETCO2 and peak airway pressure were within the normal range during operation in both groups. The first attempt success rate of LMA placement and fiberoptic bronchoscopic scores were significantly higher, and the LMA placement time was significantly shorter in group Ⅰ than in group P (P ＜ 0.05). The success rate of LMA and gastric tube placement was 100% in both groups. The incidence of sore throat was significantly lower in group I than in group P ( P ＜ 0.05). Conclusion LMA i-gel can provide adequate ventilation during operation with less complications and can be used effectively for cholecystic laparoscopic surgery.
ABSTRACT
Objective To investigate the effects of inhalation of different concentrations of sevoflurane on pulmonary inflammatory response in rats. Methods One hundred and twenty adult Wistar rats of both sexes weighing 200-250 g were randomly divided into 4 groups: Ⅰ control group breathing room air (group C, n = 12);Ⅱ oxygen group breathing 40% O2(group O, n = 36);Ⅲ and Ⅳ sevoflurane groups breathing 1.5% and 3.0% sevoflurane in 40% O2 respectively (group S1, S2, n = 36). Group Ⅱ was further divided into 3 subgroups according to the duration of 40% O2 inhalation 4 h, 8 h and 10 h. Group Ⅲ and Ⅳ were further divided into 3 subgroups ( n = 12 each) breathing sevoflurane for 4 h, 8 h and 8 h followed by 2 h O2 (40%) inhalation. The animals were sacrificed at the end of O2 or/and sevoflurane inhalation. Broncho-alveolar lavage was performed in 6 animals in each subgroup. The TNF-α concentration in broncho-alveolar lavage fluid was determined. The TNF-α mRNA expression and MPO activity in the lung tissue were measured in the other 6 animals in each subgroup. Results Inhalation of 1.5% or 3.0% sevoflurane for 4 or 8 h did not induce inflammatory response in the lung as compared with animals breathing room air or 40% O2 . Conclusion Exposure to sevoflurane does not induce pulmonary inflammatory response in rats breathing spontaneously.
ABSTRACT
Objective To investigate the changing and correlation between PaCO2 and PETCO2 during laparoscopic colorectal surgery. Methods Thirty ASA Ⅰ-Ⅱ patients scheduled for laparoscopic colorectal surgery were accepted general anesthesia and trachea cannula. Hemodynamic measurements, respiratory parameters and artery blood gas analysis were drawn at 5 min after intubating, 5 min, 30 min and 60 min after pneumoperitoneum, before the side-incisions were opened and the end of operations. Results The operation time was (216.1±39.1) min, pneumoperitoneum time was (117.3±11.5) min. Comparing to the data after pneumoperitoneum, there were differences among the parameters of circulating dynamics, but the values were acceptable, pH was decreasing with time, except 5 min after pneumoperitoneum, it was significantly decreased 30 min after pneumoperitoneum until the end of operations, compared with pre-intlation value (P<0.01), pH withdrawn a little at the end of the operations. The PETCO2 and PaCO2 at different times after pneumoperitaneum were significantly higher compared with pre-inflation value (P<0.05 or<0.01). They were increasing with the time of pneumoperitoneum, and withdrawn a little at the end of the operations. There was a good correlation between PETCO2 and PaCO2, although the correlation was worst after deflation. Conclusions The circulation dynamics are stable, the correlation of PETCO2 and PaCO2 is good during the laparoscopic colorectal surgery, PaCO2 may exceed the normal value after long-term of penumoperitoneum. It is necessary to monitor the blood gas analysis during such surgeries.
ABSTRACT
Objective To observe the onset time,cardiovascular system reactions and side effects of anesthetic introduction with sevoflurane and to explore its reliability and safety in elderly patients. Methods Sixty American Society Anesthesiologists(ASA)Ⅰ～Ⅲ patients aged 65～78 years who were scheduled for selective operation were selected in the study.They were randomly divided into sevoflurane inhalation induction group(sevoflurane group)and propofol induction group (control group).In sevoflurane group,the concentration of inhaled sevoflurane was regulated according to downgrading method during the induction,and it was decreased by 1% every 30 seconds from the initial concentration of 7% to the maintained concentration of 4%.In control group,propofol was titrated by 1.5～2.5 mg/kg.When bispectral index(BIS)was≤60,sufentanil was administered intravenously and the patients were paralyzed with rocuronium and intubated.The extinction time of lash reflex and the achievement time of BIS≤60 in two groups were recorded.The mean arterial blood pressure(AMBP),heart rate(HR),oxygen saturation(Sp02)and BIS of the basic values before intubation,and 1 min,3 min,5 min after intubation were also recorded,respectively.The side effects during intubation such as laryngeal spasm,body movements,irritating cough,restless movement during intubation were noted.The consciousness during intubation and satisfaction with induction were followed in patients after operation. Results The extinction time of lash reflex and the achievement time of BIS≤60 were significantly longer in sevoflurane group than those in control group (both P＜0.01).In sevoflurane group.there were no differences in MBP and HR between 1 min postintubation and pre-intubation.Whereas,in control group,AMBP and HR were lower before intubation than basic values,and were higher 1 rain post-intubation than pre-intubation(P＜0.05).There were irritating cough cases both in sevoflurane group and in control group(5 vs.3),and there was no laryngeal spasm case.All patients were satisfied with the anesthesia and had no consciousness during intubation. Conclusions Sevoflurane is a safe and effective induction agent and has little side effects.It is an ideal choice for elderly patients.