Inhalation Induction Using Sevoflurane in Children, The Single Breath Vital Capacity Technique Compared to Tidal Volume Technique

Introduction: The low solubility as well as the absence ofpungency facilitates rapid induction by facemask, makingsevoflurane the anesthetic of first choice for inhalationalinduction in children. The aim of our study was to comparethe efficacy and tolerance and to compare the inductioncharacteristics of sevoflurane by vital capacity and tidalvolume techniques.Material and methods: Our study included 30 patients eachin both group’s i.e. single breath vital (VC) capacity and tidalvolume groups (TV). The mean age in VC group was 8.76years and in TV group was 8.86 years. We mainly comparedthe Induction time, hemodynamic changes and adverse eventsin both the techniques using sevoflurane.Results: The heart rate, systolic blood pressure, diastolicblood pressure and the mean arterial pressure were comparedbetween both the groups. All these parameters were takenbefore induction, after loss of eyelash reflex and up to 10minutes at 2 minute intervals. There were minimal changesbetween the two groups but clinically, they are not statisticallysignificant in view of mean blood pressure whereas weobserved statistically significant difference in heart rate at8minutes in the post induction period which resolved later. Inour study, we observed an increased incidence of cough andinvoluntary movements in T V. group compared to V C groupbut statistically, there is no significant difference.Conclusion: Sevoflurane Induction improved the speedof induction when compared to tidal volume technique andreduced the incidence of induction complications

A portable inhalational induction device provides co-operative induction of anaesthesia in preanaesthetic area for children / 대한마취과학회지

BACKGROUND: We introduce a new, simple portable inhalational induction device (PD) that provides co-operative inhalational induction of anaesthesia using N2O and subsequent sevoflurane in the preanaesthetic induction area in children. METHODS: Forty-five children (30 to 94 months old age, <35 kg) who were scheduled to undergo simple operations were assigned randomly to one of three regimens. Patients were encouraged by their parents to inhale N2O followed by sevoflurane (PD N2O-sevo group) or sevoflurane (PD sevo group) using a portable inhalational induction device in the preanaesthetic induction area until they were unable to respond to their names. They were then transferred to the operating room while maintaining inhalation of sevoflurane via the device. The control group underwent conventional inhalational induction in the operating room with the parents in attendance. RESULTS: Patients in the PD N2O-sevo group had a higher co-operative inhalation frequency than the patients in the PD sevo or the control group. Anaesthesia induction in the PD N2O-sevo and the PD sevo groups were faster than in the control group. Parent satisfaction score (0-100) was higher for the PD N2O-sevo group than for the control group. CONCLUSIONS: A new portable inhalational induction device allows faster induction in co-operation with parents present in the preanaesthetic induction area compared to conventional inhalational induction in the unfamiliar operating room with the parents in attendance.

The optimal clinical dose of alfentanil for tracheal intubation during inhalation induction with sevoflurane after sedation with ketamine in children

BACKGROUND: The purpose of this study was to determine the clinical effective dose of alfentanil required for successful tracheal intubation during inhalation induction using 5% sevoflurane without neuromuscular blockade in children sedated with ketamine. METHODS: Twenty-one children, aged 3-10 years, undergoing surgeries under general anesthesia were enrolled into the study. All patients were premedicated with 0.004 mg/kg glycopyrrolate intramuscularly 30 min before anesthesia.To facilitate separation of the child from the parents, intravenous 1 mg/kg ketamine was given prior to transfer into the operating room.After inhalation induction with 5% sevoflurane and 100% oxygen, pre-determined dose of alfentanil was injected over 20 sec. The dose of alfentanil was determined by modified Dixon's up-and-down method (2microgramkg as a step size starting from 12microgramkg).The study ended when six independent pairs of patients, who manifested cross over from 'failure' to 'success' for tracheal intubation, were recruited. RESULTS: In 50% of children, the effective bolus dose (ED50) (95% confidence intervals) of alfentanil for successful tracheal intubation was 7.2microgram/kg (6.3-8.1microgram/kg) during sevoflurane inhalation induction.From isotonic regression, 95% effective dose (ED95) (95% confidence intervals) of alfentanil was 9.9microgram/kg (2.2-16.0microgram/kg). CONCLUSIONS: During inhalation induction using 5% sevoflurane without neuromuscular blockade after ketamine sedation, the ED50 and ED95 of alfentanil for successful tracheal intubation were 7.2 microgram/kg and 9.9microgram/kg in children, respectively.

Comparison Between the Effects of High Secoflurance Concentration during Induction of Anaesthesia Using Vital Capacity Breath and Tidal Breathing Techniques in Adults

Introduction: The aims of this randomised study were to compare the induction characteristics of sevoflurane using vital capacity breath technique to that of tidal breathingtechnique in adults undergoing day-care surgery., and to compare patients' acceptance of these two techniques. Methods: Sixty ASA I and II adult patients undergoing day-care surgery were randomly allocated to receive either the vital capacity breath or tidal breathing technique for induction of anaesthesia with 7.5% sevoflurane in nitrous oxide and oxygen. Haemodynamic changes, induction characteristics and patients' acceptance were compared. Results: The mean time for induction was significantly faster with the vital capacity breath technique. There were no significant differences in haemodynamic changes and oxygenation during induction between these two groups. There was a significant increase in incidence of exictatory movement in patients receiving the tidal breathing technique. Either technique was found to be acceptable by most of the patients studied. Conclusion: The vital capacity breath technique appears to be better tolerated with shorter onset time and less movement during induction of anaesthesia. As it is well accepted by the patients and has a stable haemodynamic profile, its use should be encouraged.

Adequate sevoflurane concentrations in inhalation induction of sevoflurane following administration of remifentanil / 대한마취과학회지

BACKGROUND: Currently, sevoflurane and remifentanil are utilized frequently for the inhalation induction of anesthesia. However, there is currently an insufficient amount of clinical data regarding the inhalation induction of sevoflurane after the administration of remifentanil. METHODS: 80 patients undergoing elective surgery were allocated randomly to four groups. Group A inhaled only sevoflurane at 8 vol%. Other groups were administered 3 ng/ml of remifentanil and inhaled sevoflurane at 8 vol% (group B) or 6 vol% (group C) or 4 vol% (group D). All groups also received 0.6 mg/kg of rocuronium. The blood pressure and heart rate were measured at pre-induction, and before and after tracheal intubation. After operation, the patients??levels of satisfaction with the inhalation induction were evaluated. RESULTS: The time to loss of consciousness was substantially longer in group D than in the other groups, but no significant differences were noted among the groups in terms of satisfaction scores. The HR in groups B, C and D increased significantly after pre-intubation as compared to baseline in group A. The HR decreased significantly during induction as compared to group A. The MAP in groups B, C and D decreased significantly at 1 and 2 minutes after tracheal intubation as compared to group A. In group D only, we noted no significant differences in the MAP as compared to baseline at 1, 2 minutes after tracheal intubation. CONCLUSIONS: 4 vol% sevoflurane was a more appropriate concentration for the inhalation induction of anesthesia when coupled with 3 ng/ml of remifentanil.

The Effect of Inhalation Induction with Sevoflurane on Postoperative Emotional Changes in Children / 대한마취과학회지

BACKGROUND: This study was designed to determine whether sevoflurane induction without painful procedures, such as intravenous catheter (IVC) insertion, has any emotional benefit compared with intravenous induction using a prepared IVC. METHODS: Children undergoing outpatient surgery were randomized to 2 groups: inhalation induction with sevoflurane (sevoflurane group, n = 24) or intravenous induction with thiopental sodium (control group, n = 21). In the sevoflurane group an IVC was inserted after chidren had been anesthetized by sevoflurane inhalation, while in the control group, an IVC was placed in the preoperative holding area. Total time and the number of IVC insertion attempts were recorded in both groups. Anesthesia times, agitation scores and the views of medical staff on technique benefits were also noted. Patients and parents were interviewed the following day. RESULTS: Time required for IVC insertion was significantly greater in the control group. No statistically significant differences were found in terms of; the number of attempts required for IVC insertion, anesthesia induction times, extubation times, recovery times, or agitation scores. Though interviews with patients and parents produced similar results in both groups, medical staff satisfaction levels were significantly higher in the sevoflurane group. CONCLUSION: Inhalation induction with sevoflurane had no beneficial effect on postoperative emotional changes. However, this method provides benefit to both children and medical staff because it avoids stressful, time-wasting, painful experiences.

Comparison of Clinical Characteristics in Controlled Ventilation and Spontaneous Breathing during Vital Capacity Inhalation Induction with Sevoflurane / 대한마취과학회지

BACKGROUND: Although controlled ventilation can shorten the induction time during vital capacity inhalation induction (VCII) with sevoflurane, it may associated with decrease in blood pressure and hyperventilation-related hyperdynamic responses such as hypertension and tachycardia. This study was designed to compare the clinical effects between controlled ventilation (CV) within acceptable ranges of PETCO2 and spontaneous breathing (SB) during VCII. METHODS: 100 patients were randomly allocated to the one of two groups. After the loss of consciousness during VCII with sevoflurane, controlled ventilation was applied in CV group within acceptable ranges of PETCO2 and spontaneous breathing was maintained in SB group. Alfentanil 4 mcg/kg was given i.v. 2 minutes prior to intubation. PETCO2, mean arterial pressure (MAP), heart rate (HR), SPO2, and BIS were measured at 1, 2 and 3 minute after the loss of consciousness (LOC). Clinical side effects were evaluated. RESULTS: MAP and HR were significantly decreased and increased in CV group compare to the baseline values at 1 minute after LOC. There were statistical differences of MAP and HR between two groups at 1 and 2 minutes after LOC. 46 of 50 (92%) showed delayed expiration with holding their breath > 20 s in SB group. No differences of other clinical side effects except hypotension between two groups. CONCLUSIONS: We conclude that spontaneous breathing provides a stable hemodynamic status and relatively acceptable ventilation profile compare to controlled ventilation during VCII.

Characteristics of Inhalational Induction with Sevoflurane in Adults / 대한마취과학회지

BACKGROUND: If an inhalation agent has an odor that causes airway irritation and cardiovascular instability, it is important that inhalation induction is performed rapidly and smoothly. So, we studied characteristics of inhalational induction in healthy adults using high inspired concentrations of sevoflurane. METHODS: Fifty-three patients, 19 to 59 years old, received 6 vol% sevoflurane in 66 vol%N2O/28 vol%O2 by face mask for five minutes until endotracheal intubation. Participants exhaled to residual volume and took vital capacity breaths of the gas mixture, thereafter ventilation was manually assisted. Subsequently we recorded the number of breaths before apnea, time to loss of consciousness, the loss of lid-lash reflex, eyeball deviation, the time until BIS reduced to 45, degree of jaw relaxation, and vital signs. After endotracheal intubation without muscle relaxant, ease of intubation and vital signs were observed. RESULTS: Apnea developed after an average three time vital capacity breaths, time to unconciousness was less than one minute. The mean times to loss of lid-lash reflex was 69.0 +/- 8.2 seconds, to eyeball deviation 85.7 +/- 22.2 seconds, and to pupil convergenece 239.5 +/- 31.4 seconds. There was no case of increased secretion or laryngospasm during mask ventilation. The BIS score was significantly lowered after inhalational induction, and the time to a BIS < 45 was 132.3 +/- 19.7 seconds. Mean blood pressures before and after intubation were 75.0 mmHg, and 104.6 mmHg, and heart rates before and after intubation were 77.0 beats/min and 109.8 beats/min, respectively. CONCLUSIONS: The speed of the induction of anesthesia to loss of lid lash reflex in healthy adults approaches that of intravenous induction techniques. No untoward airway responses were noted using the vital capacity breath technique. Healthy adults were successfully intubated with sevoflurane without muscle relaxant.

Effects of Normocapneic Preoxygenation and Air Breathing during Vital Capacity Inhalation Induction with Sevoflurane on the Ventilation / 대한마취과학회지

BACKGROUND: Sevoflurane has been used to provide an inhaled induction by using a vital capacity breath, which is fast and has few side effects. We compared the clinical effects of a vital capacity inhalation induction (VCII) with sevoflurane in patients of preoxygenation or air-breathing before anesthetic induction. METHODS: After IRB approval, patients were randomly assigned to receive preoxygenation (O2 group, 70 patients) or air breathing (Air group, 70 patients) via SIBI (Single Breath Induction) connectorTM before VCII with 8% sevoflurane in 75% N2O/O2 from primed circuit. The clinical characteristics were compared between two groups in respect to prolongation of breath holding after loss of consciousness (response to verbal command) and side effects (airway, hemodynamic, motor) during VCII. RESULTS: O2 group showed lower incidence (60.0% vs. 87.1%, P < 0.05) and shorter duration (27.1 s vs. 36.4 s, P < 0.05) in prolongation of breath holding than Air group. Otherwise, there were no significant differences in clinical effects between two groups. CONCLUSIONS: We found that preoxygenation reduces the incidence and duration of prolongation of breath holding during VCII with sevoflurane compared with air-ventilation before VCII. We suggest that the prolongation of breath holding might be related to Hering-Breuer response to maximal lung inflation during VCII.

Optimal Dose of Rocuronium for Rapid Tracheal Intubation under Sevoflurane Anesthesia / 대한마취과학회지

BACKGROUND: There are situations in anesthesia in which it may be desirable to achieve rapid tracheal intubation. Rapid tracheal intubation with rocuronium has been studied using a probability-based approach. But these studies used intravenous anesthetics for anesthetic induction. Therefore, we aimed to predict doses of rocuronium giving 90% and 95% probabilities of intubation within 60 seconds and to estimate their action durations using sevoflurane for anesthetic induction. METHODS: Anesthesia was induced in sixty patients with sevoflurane. Patients received randomly rocuronium, 0.0, 0.3, 0.6, 0.9 or 1.2 mg/kg (n = 12/dose). Laryngoscopy began 40 seconds later, aiming for intubation at 60 seconds, and conditions were graded as either perfect, acceptable or unacceptable, with the first two conditions being taken as successful intubation. Duration of action was accepted as time until a twitch height recovery of 15%. The dose versus the fraction of patients showing successful intubation was analyzed by logistic regression. Doses giving 90% and 95% (D90 and D95) probabilities of successful intubation were calculated. RESULTS: Of the 12 patients in each group (0.0, 0.3, 0.6, 0.9 or 1.2 mg/kg), intubation was successful in 4, 10, 12, 12 and 12 patients, respectively. The D90 and D95 doses were determined to be 0.34 and 0.43 mg/kg, respectively. CONCLUSIONS: After induction with sevoflurane, rocuronium at 0.43 mg/kg, gives a 95% probability of successful intubaton at 60 seconds.

Intubating Conditions and Responses to intubation after Sevoflurane-N2O-O2 Vital Capacity Rapid inhalation induction without Muscle Relaxant:Comparison with Propofol-N2O-O2-Vecuronium / 대한마취과학회지

BACKGORUND: The objective of this study was to investigate the conditions required for tracheal intubation and the responses to intubation after the administration of a high concentration of sevoflurane- N2O-O2 for vital capacity rapid inhalation induction (VCRii) without muscle relaxant. We compared those with propofol-N2O-O2-vecuronium induction. METHODS:Fifty ASA physical status i or ii adult patients without airway abnormalities who were scheduled for elective surgery requiring endotracheal intubation were randomly allocated to receive either propofol 6g/ml target controlled infusion-N2O 4 L/min-O2 2L/min-vecuronium 0.12mg/kg iv (group PV) or 8% sevoflurane-N2O 4 L/min-O2 2L/min without muscle relaxant (group SO). Vecuronium was injected ninety seconds after starting propofol infusion in group PV. Group SO patients were coached on how to perform vital capacity breathing and the breathing circuit was primed for 2 minutes. Five minutes after the administration of induction agents, intubation was attempted. intubation conditions, arterial blood pressure (BP) and heart rate (HR) changes accompanying both induction techniques were monitored. RESULTS: The time to loss of consciousness for group SO was significantly shorter (41.0+/-15.0 sec vs 81.8+/-25.8 sec, P = 0.000). intubation was successful in 24 out of 25 patients (96%) in group PV and 25 out of 25 patients (100%) in group SO, and clinically acceptable intubating conditions were obtained in 23 of the 25 patients (92%) in group PV and 21 of the 25 patients (84%) in group SO. Significant decreases in BP from baseline were observed before intubation in both groups. The increase in BP at 1min after intubation was significantly greater in group PV. HR did not differ in the two groups. CONCLUSiONS: The intubation conditions after sevoflurane-N2O-O2 without muscle relaxant were similar to those produced after propofol-N2O-O2-vecuronium. Sevoflurane-N2O-O2 VCRii is a useful alternative technique for tracheal intubation when muscle relaxant should be avoided.

Low-Dose Fentanyl Can Improve the Quality of Sevoflurane Induction in Adult Patients with Midazolam Premedication / 대한마취과학회지

BACKGROUND: Although sevoflurane is almost ideal for the ihalation induction of anesthesia, considerable hemodynamic and respiratory effects have been reported during inhalation induction. The goal of this study was to evaluate the effects of low-dose fentanyl on high concentration of sevoflurane induction in adult patients with midazolam premedication. METHODS: 104 healthy patients (16 55 yr) premedicated with midazolam were randomized to receive I.V. fentanyl 0.5mug/kg (F) or placebo (P) before induction. Three vital capacity breathing with 8 vol% sevoflurane/70% N2O was applied to patients after priming of circuit with the anesthetic mixture. A blinded observer recorded the sequence of breaths (1st, 2nd, 3rd) to loss of eyelash reflex, response to verbal command (RVC), side effects, and the intubation time. MAP, HR, respiratory rate (RR), sevoflurane ET%, BIS values, SpO2, and ETCO2 were recorded at 1 minute intervals. Hypotension, tachycardia, and tachypnea were defined as a 30% decrease in MAP, a HR over 100 bpm, and a RR of over 25/min, respectively. Data were analyzed using the Chi-Square Test, ANOVA, and Post Hoc test. Results were considered significant at a P < 0.05. RESULTS: No differences in sevoflurane ET% or overall changes in MAP were observed between the two groups. HR was significantly increased in P compared to F during induction. Loss of RVC was faster in F than in P. Tachycardia and tachypnea were more developed in P than in F. BIS values were increased after intubation to a greater extent in P (from 45.8+/-18.6 to 59.2+/-20.4) than in F (from 36.0+/-9.0 to 39.9+/-10.3). Time to Intubation showed no difference between groups. CONCLUSIONS: We conclude that low-dose fentanyl can reduce the incidence of marked changes in HR and RR, and even in BIS changes at intubation during inhalation induction with sevoflurane. Fentanyl may affect the quality of sevoflurane induction rather than induction speed.

Inhalation Induction of Halothane Using a Vital Capacity Breath / 대한마취과학회지

Inhalation induction of anesthesia is seldom used in a routine adult practice because of the long induction time and the prolonged excitement phase with the risk of laryngospasm and vomiting. So in modern practice, anesthesia is usually administered intravenously and produces unconsclousness pleasantly. However there are situaions where intravenous induction may not be ideal, and where rapid induction is still desired. The author wanted to evaluate the clinical application of inhalation induction of halothane using a vital capacity breath as a substitute for intravenous induction of anesthesia. The patients in this study had an ASA physical status of l or ll and presented no cardiopulmonary disease or abnormal laboratory data. The patients were divided into two group: a control group(n=30) and an experimental group(n=30). Control group: Intravenous induction with thiopental sodium. Experimental group: Inhalation induction with halothane using a vital capacity breath. The results are as follows: 1) The control group consisted of 14 males and 16 females. The mean age was 37.8+/-11.5years, and the ages ranged from 16 to 65 years. The mean body weight was 59.8+/-8.0kg, and body weights ranged from 44 to 75kg. in the experimental group, there were 17 males and 13 females. The mean age was 28.9+/-13.7 years, and the ages ranged from 18 to 65 years. The mean body weight was 57.4+/-8.1 kg, and body weight ranged from 43+/-75kg. 2) In the experimental group, the apnea time ranged from 20 to 105 sec, with a mean of 44.5+/-20.4 sec. The mean induction time was 76.7+/-32.1sec. and induction time ranged from 20 to 150 sec. There was no relationship between apnea time and induction time. 3) The hemodynamic changes were as follows: a. There were significantly greater changes in blood pressure and pulse rate during intubation and postintubation in the control group than in the experimental group(p<0.05). b. There were significant changes in blood pressure and pulse rate in the control group(p<0.05), but seemed not to be hazardous clinically. 4) Induction was impossible in two patients in the experimental group due to profuse secretion or excitement. 5) The side effects in the experimental group included coughs(5 cases), arrythmias(4), excitements(4) and secretion(1), respectively. 6) Postanesthetic comments in the experimental group:27 of the 28 patients remembered the anesthetic smells: 3 pleasantly, 20 moderately and 4 unpleasantly. In conclusion, inhalation induction of halothane using a vital capacity breath is a safe, acceptable and practical alternative to intravenous induction in cooperative adult patients.