INTRODUCTIONDraw-over anaesthesia remains an attractive option for conduct of anaesthesia in austere conditions. The Diamedica Draw-over Vaporiser (DDV) is a modern draw-over vaporiser and has separate models for isoflurane/halothane and sevoflurane.

MATERIALS AND METHODSA laboratory study was done to measure sevoflurane output in an isoflurane/ halothane DDV. We did 3 series of experiments with the isoflurane/halothane DDV. We measured anaesthetic agent output in both push-over and draw-over setups, and at minute ventilation of 6 L/min and 3 L/min. Series 1 experiment was done with isoflurane in the DDV at ambient temperature of 20°C. Series 2 experiment was done with sevoflurane in the DDV at ambient temperature of 20°C. Series 3 experiment was done with sevoflurane in the DDV and with the DDV placed in a water bath of 40°C.

RESULTSThe sevoflurane output was found to be two-thirds of the isoflurane/ halothane DDV dial setting at ambient temperature of 20°C. With the DDV in a 40°C water bath, the sevoflurane output was found to be about the isoflurane/ halothane DDV dial settings.

CONCLUSIONIn our experiment, we show that it is possible to use sevoflurane in an isoflurane/halothane DDV.

Anesthesia, Inhalation ; instrumentation ; methods ; Anesthetics, Inhalation ; administration & dosage ; Halothane ; Humans ; Isoflurane ; Methyl Ethers ; administration & dosage ; Nebulizers and Vaporizers ; Temperature

Objective To observe the effects of two different intranasal dexmedetomidine doses as premedication on the ECof 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% O, 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 (ET) 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%. ETwas 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 ETof 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 ECof 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 ECfor successful laryngeal mask airway placement in children.
Administration, Intranasal ; Anesthesia ; Anesthetics, Inhalation ; administration & dosage ; Child ; Child, Preschool ; Dexmedetomidine ; administration & dosage ; Humans ; Laryngeal Masks ; Methyl Ethers ; administration & dosage

OBJECTIVETo investigate the effect of different fresh gas flows (FGFs) on the pharmacodynamics of isoflurane during anesthesia induction.

METHODSSixty female ASA class I or II patients (aged from 18 to 49 years) scheduled for gynecologic laparoscopic surgery were randomly divided into groups I, II, and III (n=20). The FGFs for group I, II, and III was 1, 2 and 3 L/min, respectively, and each group was further divided into two equal subgroups according to the setting concentrations of isoflurane vaporizer (Co), which was 1% in groups I1, II1, and III1 and 2% in groups I2, II2, and III2. Isoflurane at different setting concentration was administered under different FGF in the patients after tracheal intubation following anesthesia induction. The systolic blood pressure (SBP), diastolic blood pressure (DBP), main arterial blood pressure (MAP), heart rate (HR) and bispectral index (BIS) were recorded before anesthesia induction and every 3 min after tracheal intubation. Patients given ephedrine and atropine were also recorded. The patients' consciousness during anesthesia were followed up and recorded. The inspiratory concentration (CIiso) and expiratory concentration (CEiso) of isoflurane in the airway were monitored and recorded every 3 min. The observation after intubation lasted for 18 min, during which stimulation of the patients was avoided, and the operation began after the observation.

RESULTSThere was a close correlation between BIS and CIiso and between BIS and CEiso (r=-0.904 and -0.893, respectively). The incidence of hypotension was significantly different between groups III and I (P<0.01), and between the subgroups in groups II and I (P<0.05). No bradycardia occurred and no consciousness reported awareness during anesthesia.

CONCLUSIONSBetween the completion of tracheal intubation and beginning of the surgery, 1% or 2% Co under a moderate FGF (1-3 L/min) may guarantee the patients' unconsciousness, but hypotension is less likely under a relatively low flow (1-2 L/min) than a higher flow (3 L/min). Higher FGF and Co result in faster induction of deep anesthesia and higher incidence of hypotension.

Adolescent ; Adult ; Anesthesia, Inhalation ; Anesthetics, Inhalation ; pharmacokinetics ; Female ; Humans ; Isoflurane ; pharmacokinetics ; Middle Aged ; Monitoring, Intraoperative ; methods ; Oxygen ; administration & dosage

OBJECTIVETo observe the clinical effectiveness of inductions and tracheal intubating conditions with 3% sevoflurane and different doses of remifentanil without muscle relaxant in children.

METHODSTotally 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.

RESULTSIn 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.

CONCLUSIONSInduction 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.

Anesthesia, Inhalation ; Anesthetics, Inhalation ; administration & dosage ; Child ; Child, Preschool ; Dose-Response Relationship, Drug ; Female ; Humans ; Intubation, Intratracheal ; adverse effects ; Male ; Methyl Ethers ; administration & dosage ; Piperidines ; administration & dosage

OBJECTIVE: To observe the effect of sevoflurane on the induction and maintenance of anaesthesia in children, and to evaluate its safety and effectiveness. METHODS: Forty child patients who conformed to the selection standard were operated under anaesthesia with intubation.Without premedicant, all the patients inhaled 100% oxygen(1L/min) and sevoflurane by mask, and escalated the concentration of sevoflurane (to the maximum concentration 7%) until the lash reflex disappeared, and the maintenance concentration was controlled under 4%. All the patients were intubated, together with vecuronium 0.1mg/kg. RESULTS: With little tract excretion, the achievement ratio of induction by sevoflurane was 100%, and the children tolerated well. With stable hemodynajmics,1% approximately 4.0% maintenance concentration of sevoflurane during the operation showed effective anaesthesia, no decreased heart rate or blood pressure appeared, and all the patients' body temperature was normal. CONCLUSION Sevoflurane for children induction can bring fewer stimuli in the respiratory tract,less cardiac vascular inhibition and palinesthesia time. Anaesthesia in children induced by sevoflurane is safe and effective.
Anesthesia ; methods ; Anesthesia, Inhalation ; Anesthetics, Inhalation ; administration & dosage ; Child ; Child, Preschool ; Female ; Humans ; Male ; Methyl Ethers ; administration & dosage ; Sevoflurane ; Treatment Outcome

The effects of sevoflurane and subsequent administration of diltiazem on intrapulmonary shunt and oxygenation were studied in pentobarbital anesthetized dogs. After inhalation of 1MAC of sevoflurane and subsequent intravenous administration of clinical dose of diltiazem (loading dose 0.2 mg/kg, maintenance dose 0.01 mg/kg/min), there were no changes in cardiac output, arterial oxygen tension, mixed venous oxygen tension, oxygen transport, oxygen consumption, intrapul-monary shunt ratio, pulmonary vascular resistance, alveolar-arterial oxygen difference. After intravenous administration of diltiazem with bolus (0.4 mg/kg) and maintenance dose (0.02 mg/ kg/min), pulmonary vascular resistance was significantly decreased (p<0.05) but the other parameters indicating pulmonaruy hemodynamics and oxygenation were unchanged. These results suggest that concomittent use of the two classes of drugs is not induce significant changes in pulmonary hemodynamic and oxygenation, and can be used safely in patient with normal cardiopulmonary function when clinical concentration of both were used.
Administration, Intravenous ; Anesthesia* ; Anesthetics ; Animals ; Cardiac Output ; Diltiazem* ; Dogs* ; Hemodynamics ; Humans ; Inhalation ; Oxygen ; Oxygen Consumption ; Pentobarbital ; Vascular Resistance

Adult ; Anesthetics, Inhalation ; administration & dosage ; Desflurane ; Electroencephalography ; methods ; Female ; Humans ; Isoflurane ; administration & dosage ; analogs & derivatives ; Male ; Middle Aged ; Monitoring, Intraoperative ; Nitrous Oxide ; administration & dosage

OBJECTIVETo study the effects of cardiovascular function in dental extraction on hypertensive patients by inhalation 50% nitrous oxide.

METHODSThe 30 hypertensive patients were randomly allocated into two groups: A group inhalation the 50% nitrous oxide and oxygen, B group inhalation the air and O(2). To measured the HR, BP, and SpO(2) in dental extraction.

RESULTSIn a group the changes of blood pressure and heart rate are more smoother than B group. Two groups were significant in HR, BP and SpO(2) (P < 0.01).

CONCLUSIONSInhalation with 50% nitrous oxide can keep the stability of cardiovascular system and it is a valid method in dental extraction on hypertensive patients.

Administration, Inhalation ; Aged ; Anesthetics, Inhalation ; administration & dosage ; pharmacology ; Blood Pressure ; drug effects ; Female ; Heart Rate ; drug effects ; Hemodynamics ; drug effects ; Humans ; Hypertension ; physiopathology ; Male ; Middle Aged ; Nitrous Oxide ; administration & dosage ; pharmacology ; Oxygen ; blood ; Partial Pressure ; Time Factors ; Tooth Extraction

OBJECTIVETo investigate the value of Narcotrend (NT) index monitoring versus standard hemodynamic parameters in predicting the recovery of consciousness in patients undergoing abdominal surgery.

METHODSForty ASA I or II patients undergoing elective abdominal surgery were randomized into two groups to receive sevoflurane-sufentanil anesthesia monitored by NT index or solely by clinical parameters. Anesthesia was induced with the inhalation of 8% sevoflurane and sufentanil target-controlled infusion at 0.2-0.5 ng/ml. The values of NT stage (NTS), NT index (NTI), and hemodynamic parameters (MAP and HR) were recorded during the period of recovery. The prediction probability (Pk) of each parameter was calculated and compared.

RESULTSNTS and NTl were closely correlated to the changes of consciousness during the recovery from general anesthesia. The Pk values of NTS and NTI in predicting eye opening and orientation recovery were 0.95, 0.92, and 0.92, 0.89, respectively, obviously higher than the Pk values of MAP and HR (P<0.05).

CONCLUSIONNT monitoring can be used to effectively predict the recovery of consciousness in patients undergoing abdominal surgery and facilitates a significant reduction of the recovery time and sufentanil dosage during a sevoflurane-sufentanil anesthesia.

Abdomen ; surgery ; Adolescent ; Adult ; Aged ; Anesthesia Recovery Period ; Anesthesia, General ; Anesthetics, Inhalation ; administration & dosage ; Anesthetics, Intravenous ; Electroencephalography ; methods ; Female ; Hemodynamics ; Humans ; Male ; Methyl Ethers ; administration & dosage ; Middle Aged ; Monitoring, Intraoperative ; methods ; Sufentanil ; administration & dosage ; Unconsciousness ; chemically induced ; Young Adult

OBJECTIVE: To evaluate the effects of bispectral index(BIS) and auditory evoked potentials index(AEPindex) monitoring on the depth of anesthesia in inhalation of isoflurane and target-controlled infusion(TCI) of propofol, and to observe the changes of BIS and AEPindex. METHODS: Fourty ASA physical status I - II patients undergoing selective abdominal operations were divided into 2 groups randomly: Group I1(the end-tidal isoflurane concentration was 0.6 MAC, n=20) and Group I2(the end-tidal isoflurane concentration was 1.0 MAC, n=20). Anesthesia was induced with proprofol and vecuroninm. After the tracheal intubation, the patients were ventilated with 0.6/1.0 MAC isoflurane in pure oxygen, and after 20 minutes, propofol was administered with TCI according to the different target plasma concentrations from 1.0 g/mL to 3.0 g/mL(increasing 0.5 g/mL each time). The changes of MAP, HR, BIS and AEPindex were recorded simultaneously. RESULTS: There was no close correlation between MAP, HR and the end-tidal isoflurane concentration, target plasma concentration of propofol. The correlation coefficiencies between BIS, AEPindex and the end-tidal isoflurane concentration were -0.757, -0.819 and -0.832, -0.878 (P<0.001), respectively; those between BIS, AEPindex and the target plasma concentration of propofol were -0.932, -0.888 and -0.920, -0.923 (P<0.001). The correlation coefficiencies between BIS, AEPindex and the stimulation of endotracheal intubation were -0.728 and 0.544, respectively; however, there was no close correlation between BIS , AEPindex and the stimulation of skin incision, and exploration. CONCLUSION BIS and AEPindex are reliable parameters to monitor the depth of anesthesia of isoflurane and propofol combined anesthesia; and in response to the stimulation of tracheal intubation, AEPindex is better than BIS, but BIS and AEPindex can not be used to predict the cardiovascular reaction of skin incision and exploration.
Abdomen ; surgery ; Anesthesia ; methods ; Anesthetics, Combined ; administration & dosage ; Anesthetics, Inhalation ; administration & dosage ; Anesthetics, Intravenous ; administration & dosage ; Blood Pressure ; drug effects ; Electroencephalography ; Evoked Potentials, Auditory ; drug effects ; Female ; Heart Rate ; drug effects ; Humans ; Isoflurane ; administration & dosage ; Male ; Propofol ; administration & dosage ; Vecuronium Bromide ; administration & dosage