Inhalational Induction Of Anaesthesia Research Articles

Effective doses of midazolam oral solution for the prevention of preoperative anxiety in paediatric patients.

More than 60% children exhibit anxiety before undergoing an anesthetic-surgical procedure, particularly among pre-school paediatric patients. Oral midazolam can provide procedural sedation for children prior to anesthesia. However, extemporaneous solutions of midazolam are usually prepared from injectable drug solutions, leading to inconsistent efficacy due to variable preparation methods. Xiaoerjing® is the first commercially available oral formulation of midazolam for procedural sedation in children in China. Despite the recommended dosage range of 0.25-0.5 mg/kg, its effective dose is still largely unknown. To determine the 95% effective dose (ED95) of midazolam oral solution (Xiaoerjing®) for alleviating preoperative anxiety in children prior to mask induction of general anesthesia. The study included 61 children between the ages of 1 and 6 years undergoing elective surgery under general anesthesia. The first patient received a single dose of 0.5 mg/kg midazolam oral solution, which was adjusted for subsequent patients using the biased coin design method based on their response to the previous dose. Doses were increased or decreased at the rate of 0.1 mg/kg. An effective response was defined as having a modified Ramsay sedation score ≥3a, separation anxiety score ≤2, and mask acceptance score ≤2 during inhalational anesthesia induction. Fifty-six children were included in the final analysis. Of those, sedation was successful in 50 patients, with a median separation time of 15 (IQR: 25) min. Midazolam oral solution has an ED95 of 0.8254 mg/kg (95% CI: 0.6915-0.8700 mg/kg) for relieving preoperative anxiety in children. No adverse events occurred following drug administration. Midazolam oral solution is a safe and effective medication for relieving preoperative anxiety in children. The ED95 of a single oral dose of midazolam oral solution is 0.8254 mg/kg (95% CI: 0.6915-0.8700 mg/kg).

Topographical Features of Pediatric Electroencephalography during High Initial Concentration Sevoflurane for Inhalational Induction of Anesthesia.

High-density electroencephalographic (EEG) monitoring remains underutilized in clinical anesthesia, despite its obvious utility in unraveling the profound physiologic impact of these agents on central nervous system functioning. In school-aged children, the routine practice of rapid induction with high concentrations of inspiratory sevoflurane is commonplace, given its favorable efficacy and tolerance profile. However, few studies investigate topographic EEG during the critical timepoint coinciding with loss of responsiveness-a key moment for anesthesiologists in their everyday practice. The authors hypothesized that high initial sevoflurane inhalation would better precipitate changes in brain regions due to inhomogeneities in maturation across three different age groups compared with gradual stepwise paradigms utilized by other investigators. Knowledge of these changes may inform strategies for agent titration in everyday clinical settings. A total of 37 healthy children aged 5 to 10 yr underwent induction with 4% or greater sevoflurane in high-flow oxygen. Perturbations in anesthetic state were investigated in 23 of these children using 64-channel EEG with the Hjorth Laplacian referencing scheme. Topographical maps illustrated absolute, relative, and total band power across three age groups: 5 to 6 yr (n = 7), 7 to 8 yr (n = 8), and 9 to 10 yr (n = 8). Spectral analysis revealed a large shift in total power driven by increased delta oscillations. Well-described topographic patterns of anesthesia, e.g., frontal predominance, paradoxical beta excitation, and increased slow activity, were evident in the topographic maps. However, there were no statistically significant age-related changes in spectral power observed in a midline electrode subset between the groups when responsiveness was lost compared to the resting state. High initial concentration sevoflurane induction causes large-scale topographic effects on the pediatric EEG. Within the minute after unresponsiveness, this dosage may perturb EEG activity in children to an extent where age-related differences are not discernible.

Retrospective Survey and Analysis of Anaesthesia and Outcomes in Paediatric Cleft Lip or Palate Surgery in a Tertiary Care Center, Portugal.

Orofacial clefts are the most common craniofacial abnormalities, affecting approximately one in 700 newborns each year. The anaesthetic management of these patients is challenging, including difficulties in airway approach and respiratory complications that have direct implications in the final outcome. The present study aimed to characterize the anesthetic approach to paediatric patients undergoing cleft palate or lip surgical repair and review the perioperative anesthetic complications in a tertiary Portuguese hospital. Data were collected from a retrospective review of thepatient records which included anaesthesia perioperative notes of paediatric patients submitted to cleft surgery repair during a five-year period (2016 to 2021). Demographic, pre-anaesthetic characteristics, anaesthetic management and perioperative complications were recorded. A total of 102 patients were included, with a median age of 1.5 years. Congenital syndromes were present in 14 (13.7%) of the children included. Inhalational induction of anaesthesia with sevoflurane was the preferred approach in 86 cases (84.3%), with neuromuscular blockade being used in 59 cases (57.8%). Intubation was achieved at first attempt in 91 (89.2%) cases with four (3.9%) patients needing three or more attempts. Intraoperative respiratory-related complications were the most frequent, occurring in 22 (21.6%) cases. These include multiple attempts to intubation, desaturation due to bronchospasm or laryngospasm. The average length of stay was two days. Postoperative complications were recorded in 17 (16.7%) of patients. The predominance of airway and respiratory complications occurring in cleft is consistent with previous studies. Care must be taken in order to avoid such complications in the perioperative period by following protocols, having skilled personnel, appropriate monitoring equipment and airway devices available during cleft surgeries to minimise morbidity.

ADV6209 for Premedication in Pediatric Anesthesia: A Double-Blinded, Randomized Controlled Trial.

ADV6209, a new formulation of midazolam with the addition of γ-cyclodextrin for oral use, has recently been licensed as the first pediatric sedative in the European Union. We compared the clinical efficacy of ADV6209 to the standard formulation of midazolam in premedication to reduce anxiety in children before anesthesia induction in a randomized, double-blinded controlled trial. Eighty children (ASA I/II; age: 2–8 years) scheduled for elective surgery were randomized to receive 0.25 mg kg−1 of either conventional midazolam or ADV6209. Assessment tools included the modified Yale Preoperative Anxiety Scale-Short Form (mYPAS-SF) as well as scores for oral acceptance of the premedication and facemask acceptance during inhalational anesthesia induction. Mann–Whitney U and Pearson’s chi-square tests were used for comparisons of outcome parameters. The primary outcome parameter of the study (mYPAS-SF anxiety score 30 min after the drug administration) did not reveal any significant intergroup difference between the ADV6209 group and the conventional midazolam group. Both drugs revealed their efficacy in reducing anxiety and in providing adequate sedation. The premedication dose was accepted by all children in the ADV6209 but rejected by 15% in the conventional midazolam group (p = 0.037). Acceptance of facemask placement was not found to differ significantly. No adverse events related to the study medications were noted. ADV6209 was better orally accepted than the conventional midazolam preparation and proved its efficacy in reducing preoperative anxiety. This clinically interesting preparation may alleviate the premedication process of 2−8 year-old children and obviates off-label drug use.

The association between carotid flow time and fluid responsiveness in children under general anesthesia

Fluid administration in children undergoing surgery requires precision, however, determining fluid responsiveness can be challenging. Ultrasound has been used widely in the emergency department and intensive care units as a noninvasive, bedside manner of determining volume status, but the intraoperative period presents unique challenges as often the chest and abdomen are inaccessible for ultrasound. We investigate whether carotid artery ultrasound, specifically carotid flow time, can be used to determine fluid responsiveness in children under general anesthesia. Prospective observational study of 87 children ages 1-12 years who were scheduled for elective noncardiac surgery. Ultrasound of the carotid artery and heart was performed at three time points: (1) after inhalational induction of anesthesia with the subject spontaneously breathing, (2) during positive pressure ventilation through endotracheal tube or supraglottic airway with tidal volume set at 8ml/kg with PEEP of 10 cmH2 O, and (3) after a 10ml/kg fluid bolus. Carotid flow time and cardiac output were measured from saved images. Corrected carotid flow time (FTc) increased with initiation of positive pressure ventilation in both fluid responders and nonresponders (352.7 vs. 365.3 msec, p=.005 in fluid responders; 348.3 vs. 365.2 msec, p=.001 in nonresponders). FTc increased after fluid bolus in both responders and nonresponders (365.3 vs. 397.6 msec, p < .001 in fluid responders; 365.2 vs. 397.2 msec, p < .001 in nonresponders). However, baseline FTc during spontaneous ventilation or positive pressure ventilation prior to fluid bolus was not associated with fluid responsiveness. Flow time increases with initiation of positive pressure ventilation and after administration of a fluid bolus. FTc may serve as an indicator of fluid status but does not predict fluid responsiveness in children under general anesthesia.

Comparison of induction and recovery characteristics of propofol and sevoflurane in day care adult tonsillectomies

Ambulatory anaesthesia is a rapidly growing subspecialty. Although its history is as old as the history of general anesthesia itself, it has emerged as a recognized concept and is evolving over the past couple of decades. Propofol and Sevoflurane have increased the ability of the anaesthesiologist to provide a successful day-care experience. The aim of the study was to compare the induction and recovery characteristics of Propofol and Sevoflurane when they are used as single induction and maintenance anaesthetic agent in adult day care tonsillectomies. This was a randomized prospective study carried out after obtaining ethical committee and institutional approval. 60 patients were randomly allocated to either the Propofol or the Sevoflurane group by lots. Each group had 30 patients and was named ‘P’ for Propofol and ‘S’ for Sevoflurane. Their age ranged from 13 to 40 years. All the patients were assessed and those with normal clinical, biochemical, radiological and haematological parameters were selected. Despite the low blood gas solubility of Sevoflurane, inhalation induction of anaesthesia was slower than intravenous induction with Propofol. Though the incidence of induction complications was more with Sevoflurane group, it did not compromise tracheal intubation or haemodynamics except for bradycardia observed in three patients.

A study comparing either using intravenous propofol or topical lidocaine over the larynx as adjuncts to inhalational induction of anesthesia for facilitating nasotracheal intubation for pediatric patients undergoing tonsillectomy surgery

Background Nasotracheal intubation in tonsillectomy surgery is used to facilitate surgical exposure. Intubation without muscle relaxant is commonly practiced for pediatric patients in ambulatory surgeries. Using adjuncts to inhalational induction makes more suitable conditions for intubation with hemodynamic stability and less laryngeal morbidities. In this study, lidocaine, 1% was used topically on vocal cords to facilitate nasotracheal intubation in comparison with intravenous propofol after inhalational induction using muscle relaxant only as a rescue medication in case of failure.Patients and methods A randomized controlled study was conducted on 96 patients aged 3–7 years and with American Society of Anesthesiologists physical status I and II scheduled for elective tonsillectomy. Patients were divided randomly into two equal groups, each consisting of 48 patients. Group P patients received inhalational induction using sevoflurane followed by propofol 2 mg/kg. Group L received inhalational induction by sevoflurane followed by topical lidocaine 1% on glottic and supraglottic areas. The intubation conditions, hemodynamic parameters (heart rate, mean blood pressure, and oxygen saturation), respiratory depression, sedation score, and incidence of laryngospasm after recovery were recorded and statistically analyzed.Results The intubation score was statistically significant with a high difference between the two groups. The score mean values were less than 10 with more success of the intubation in the lidocaine group. The success rate of intubation without the use of short-time-acting muscle relaxant was higher in the lidocaine group (88.89%) as compared with the propofol group (79.2%). Hemodynamic stability after intubation in the lidocaine group, was statistically significant. The incidence of postoperative laryngospasm was statistically nonsignificant, but the incidence rate was higher in the propofol group.Conclusion Using lidocaine 1% topically on the larynx can achieve an acceptable condition of the intubation without muscle relaxant in most of the cases, with hemodynamic stability and decreasing incidence of postoperative laryngospasm.

Effects of intravenous and inhalation induction of anesthesia on oxygen delivery in elderly patients undergoing colorectal surgery

Purpose: The induction of anesthesia with direct laryngoscopy and orotracheal intubation are two interventions, which can influence oxygen delivery. Rapid adjustments of treatment to restore oxygen delivery are crucial to improving the outcomes for patients. The aim of this study was to compare the effects of induction of anesthesia with propofol and sevoflurane on oxygen delivery in elderly patients undergoing colorectal surgery. Methods: We studied forty patients with physical status II or III, according to the American Society of Anesthesiology,who were older than 65 years and undergoing elective surgery for resection of colorectal carcinoma. The patients were randomly divided into the propofol group (P-group) and sevoflurane group (S-group), according to the anesthetic received for the induction of anesthesia. Results: After induction of anesthesia, heart rate, mean arterial pressure, cardiac output and the oxygen delivery index significantly decreased in both groups compared to the baselinevalues. Following induction of anesthesia, the decrease in heart rate was significantly more rapid in the P-group. Immediately after orotracheal intubation, heart rate, mean arterial pressure, cardiac output and the oxygen delivery index significantly increased in the S-group, but one minute later these diferences were not statistically significant. Heart rate, meanarterial pressure, cardiac output and the oxygen delivery index were significantly lower after orotracheal intubation in both groups, compared to baseline.Conclusion: Prpofol and sevoflurane are clinically comparable in the induction of anesthesia in elderly patients according to the effect on oxygen delivery.

Inhalational Induction of General Anaesthesia for Elective Caesarean: Ethical Acceptability in Treatment-resistant Needle Phobia?

(Int J Obstet Anesthesia. 2020;43:27–29) This case study describes the cesarean delivery of a woman with a severe needle phobia, which led her to decline regional anesthesia, IV access, or other processes involving needles while awake. The patient previously underwent general anesthesia for an emergency cesarean delivery and requested inhalational induction of anesthesia for her elective repeat cesarean.

Incidence of post-induction hypoxemia in children and the effect of induction gas composition.

Pediatric preoxygenation and inhalation induction of anesthesia can include a mixture of gases. In children, the clinical impact on oxygenation while using other gases with oxygen during an inhalation induction is unknown. We aimed to determine the impact of oxygen, nitrous oxide, and air concentrations added to the volatile agent by recording the incidence of hypoxemia following an inhalation gaseous induction in children. Records from an Automated Information Management System were used to find the incidence of hypoxemia following an inhalation induction of anesthesia. Episodes of hypoxemia (SaO2 <90% sustained for at least 120s) were recorded in the 10min after the 3-min induction period. Nitrous oxide and oxygen concentrations were recorded and nitrogen concentration was deduced. We also considered patient sex, age, and ASA status as covariates. A total of 27258 cases were included in the analysis. The overall incidence of hypoxemia following an inhalation induction of anesthesia was 5.08% (95% CI 4.83 5.35). Hypoxemia was more common in younger patients and those with higher ASA scores. Controlling for those factors and sex, the incidence of hypoxemia increased 1.2-fold when inspired oxygen concentration was less than 60% and hypoxemia was 2.37 times greater than the overall incidence when the inspired oxygen concentration was less than 40%. There was no clear effect of different concentrations of nitrous oxide or nitrogen when those were factored into the model. The risk of hypoxemia following an inhalation induction of anesthesia in children is minimized when the inspired concentration of oxygen is greater than 60%.

Reducing the time to successful intravenous cannulation in anaesthetised children with poor vein visibility using a near-infrared device: A randomised multicentre trial.

During inhalational induction of anaesthesia for children, severe respiratory events can occur but can be rapidly treated once intravenous access is in place. Reducing the time to successful cannulation during inhalational induction for children with poor vein visibility would improve safety. To study the effectiveness of a near-infrared (NIR) vascular imaging device (Veinviewer) to facilitate intravenous cannulation. A prospective, multicentre, randomised, open clinical trial. The operating rooms of three paediatric hospitals in Paris, France, from 1 October 2012 to 31 March 2016. Children up to the age of 7 years, with poor vein visibility requiring general anaesthesia. Inhalational anaesthesia was initiated and intravenous cannulation was performed with the standard approach or with the Veinviewer Vision. The primary outcome was the time to successful intravenous cannulation. A secondary outcome was the proportion of successful first attempts. The mean time to successful intravenous cannulation was 200 (95% CI, 143 to 295) seconds in the Veinviewer and 252 (95% CI, 194 to 328) seconds for the control group: hazard ratio 1.28 (1.02 to 1.60) (P = 0.03). The adjusted hazard ratio for known predictive factors was 1.25 (0.99 to 1.56) (P = 0.06). Success at the first attempt was 64.6% (102/158) in the 'Veinviewer' group vs. 55.6% (85/153) in the 'control' group (P = 0.10). The Veinviewer has limited value in reducing the time to successful intravenous cannulation during inhalational anaesthesia for young children with poor vein visibility. However, there is a strong trend to reducing the delay in some cases and, given its absence of side effects, it could be part of a rescue option for a difficult venous-access strategy. NCT01685866 (http://www.clinicaltrials.gov).

Fasting Duration and Blood Pressure in Children: Comment.

We read with interest the article by Simpao et al.1 regarding the association between clear fluid fasting duration and postinduction low blood pressure in anesthetized children. In this retrospective analysis, the authors reported that, among children (0 to 18 yr) who underwent inhalational induction of anesthesia for elective surgical procedures, longer duration of clear fluid fasting was associated with increased risk of postinduction low blood pressure during the surgical preparation. Despite the clinical relevance of the topic and the elegant study design, certain methodologic issues require clarification.First, although the exposure (fasting duration) was collected as a continuous variable, the authors transformed this continuous variable into categorical groups using some clinically useful, though arbitrary, cutpoints. The statistical limitations of this approach must be highlighted. As elegantly assessed by the authors, the association between clear fasting time and low blood pressure was not linear. In this setting, percentile categorizations can misrepresent the dose–response relationship between the exposure and outcome because instead of accounting for the nonlinearity, the cutpoints are merely identified according to the distribution of the primary predictor.2,3 This may result in the lumping together of subjects with different risks of low blood pressure, thus violating the assumption of no differences in risk of the outcome between groups. For instance, children in the 6- to 8-h group had a 22% (1.55/1.27) relative higher odds of low blood pressure, relative to children in the 4- to 6-h group, yet both groups have been lumped into the 4- to 8-h category. Similarly, children in the 10- to 12-h group had a 17% (1.16/0.99) relative higher odds of low blood pressure, relative to children in the 8- to 10-h group, yet both groups have been lumped into the 8- to 12-h category. These departures of 22% and 17% appear to be meaningful, given the context of the study, because the highest relative excess in the odds ratio was 33%. In addition, the authors adopted an open-ended categorization of patients with clear fasting time greater than 12 h (alternatively greater than 14 h in the sensitivity analysis). This cutpoint of 12 h (14 h in the sensitivity analysis) may be too far from the most extreme value and may hide important effects. For example, the risk of low blood pressure among children with clear fasting time greater than 18 h (corresponding to about 2.5% of the study population) is unknown because it was averaged with those of the other children in the greater than 12-h group.Second, it appears that about 60% of the study cohort received coinduction of anesthesia with propofol or an intravenous opioid, and 12% of subjects received a neuraxial block (type not stated). Given that propofol coinduction and neuraxial anesthesia are known causes of hypotension under anesthesia, the observed associations do not disambiguate the effect of fasting from the expected hypotensive effects of propofol and/or neuraxial anesthesia. Therefore, the interpretation of the authors’ findings would benefit from a sensitivity analysis by separating patients who received propofol from their counterparts who did not receive propofol.In conclusion, we applaud Simpao et al. for adding to the literature on the association of preoperative fasting with intraoperative hypotension. However, the limitations of their exposure and outcome variables must be considered when interpreting the findings of their report.The authors declare no competing interests.

Comparative evaluation of one-handed versus two-handed mask holding techniques in children during inhalational induction of anesthesia: A randomized crossover study.

We aimed to evaluate if two-handed mask airway is superior to one-handed mask airway during inhalational induction of anesthesia in children. A randomized, two period, crossover study was performed on 60 children aged 1-8years, with obstructive sleep apnea due to adenotonsillar hypertrophy, scheduled for adenotonsillectomy. Children were assigned to two study sequences and one control sequence of 20 subjects each. A control sequence was added to evaluate the effect of anesthetic depth. Sequence 1: One-handed followed by two-handed airway, 30seconds each; Sequence 2: two-handed followed by one-handed airway, 30seconds each and Sequence 3: two-handed airway, for 60seconds. The work of breathing indices, phase angle, and labored breathing index were recorded using respiratory inductance plethysmography. Additional outcome measures were tidal volume, minute ventilation, and respiratory rate. A straight comparison and a crossover analysis was performed. The initial comparison revealed that one-handed airway had greater phase angle (mean diff. 17.4; 95% confidence interval [CI] 1.07-33.68; P=.034), greater labored breathing index (mean diff. 0.56; 95% CI 0.16-1.04; P=.004),lower minute ventilation (mean diff. -1567; 95% CI -2695 to -5.4; P=.004),and lower tidal volume (mean diff. -39; 95% CI -2.7 to -5.4; P=.02) than two-handed airway. On crossover analysis, within-subject difference in the phase angle was greater during one-handed than two-handed airway (34.3; 95% CI 8.46-60.14; P=.01) as was labored breathing index (mean diff. 1.2; 95% CI 0.39-2.00; P<.0046).Minute ventilation was lower during one-handed than two-handed airway (mean diff. -3359; 95% CI -4363 to -2355, P<0.0001) as was tidal volume(mean diff. -78; 95% CI -110.4 to -45.8; P<.0001). In children with obstructive sleep apnea due to adenotonsillar hypertrophy, two-handed airway provides superior airway patency that was not influenced by the anesthetic depth.

EC50 of sevoflurane for classic laryngeal mask airway insertion in children at different time points: A randomized blind trial.

Background and Aims:Literature documents EC50 (End-tidal) of sevoflurane for CLMA (Classic Laryngeal Mask airway) insertion between 1.5 and 2% and most of these studies suggest maintaining the required end-tidal sevoflurane concentration for 10-25 minutes before LMA insertion. Waiting for this long interval for blood brain sevoflurane equilibration may not be feasible in children especially during failed ventilation. We aimed to estimate EC50 of sevoflurane for CLMA insertion at equilibration time points of 2.5 min and 5.0 min.Material and Methods:In this randomized trial, children aged 2_8 years of either sex having American Society of Anesthesiologists status I undergoing elective cataract surgery were included. After inhalational induction of general anesthesia with 8% sevoflurane and 100% oxygen, intravenous cannulation was secured. The sevoflurane vaporizer was finely adjusted to maintain an end-tidal sevoflurane concentration at 2% for 2.5 min for first child in group 2.5 and 5 min in group 5.0. This was followed by LMA insertion which was considered to be unsuccessful if there was “movement” and successful if “no movement” occurred. End-tidal concentration was increased/decreased (step-size 0.2%) using Dixon and Massey up and down method in the next patient depending upon the previous patient's response.Results:EC50 of sevoflurane for insertion of classic LMA in children aged 2-8 yrs in 100% oxygen was 1.1% (0.9-1.2) at 2.5 min and 1.6% (1.5-1.7) at 5.0 min. Derived EC95 (95% CI) at 2.5 min was 1.8% (1.5-9.2) and at 5.0 min was 1.8% (1.4-8.8) respectively.Conclusion:We suggest maintaining end-tidal sevoflurane of 1.6% for 2.5 min and 1.8% for 5 min for successful CLMA insertion.

Duration of preoperative clear fluid fasting and peripheral intravenous catheterization in children: A single-center observational cohort study of 9693 patients.

Children routinely undergo inhalational induction of general anesthesia. Intravenous line placement typically occurs after induction of anesthesia and can be challenging, particularly in infants and young children. We conducted a retrospective observational study to determine whether there was an association between clear liquid fasting time and the number of peripheral intravenous catheter insertion attempts in anesthetized children. The secondary aim was to identify factors associated with multiple attempts to insert intravenous lines. After institutional research board approval, we retrieved a data set of all children between 0months and 18years who received general anesthesia at our hospital between January 1, 2016, and September 30, 2017. Data included age, gender, weight, race, ASA status, gestational age, number of peripheral intravenous catheter insertion attempts, any assistive device for insertion, and insertion site. Inclusion criteria were mask induction, ASA status 1 or 2, nonemergency, ambulatory surgical procedures, and placement of a single intravenous line during the anesthetic. A total of 9693 patients were included in the study. Of which 8869 patients required one insertion attempt and 824 underwent multiple insertion attempts. 50% of patients in the single insertion attempt group had clear liquid fasting time <6.9hours compared to 51.8% of patients requiring multiple attempts. Logistic regression model adjusted for age, ASA status, gender, and BMI did not find an association between duration of clear liquid fasting time and rate of multiple insertion attempts for intravenous catheters (OR: 0.99, 95% CI: 0.98-1.01, P=.47). Clear liquid fasting time was not associated with multiple insertion attempts for intravenous line insertion in children receiving general anesthesia. Factors such as patient age, ethnicity, time of day of induction of anesthesia, and American Society of Anesthesiologists Physical Status classification show a greater association with the risk of multiple intravenous line insertion attempts.

A feasibility study of jaw thrust as an indicator assessing adequate depth of anesthesia for insertion of supraglottic airway device in morbidly obese patients.

Background:Jaw thrust has been proven as a useful test determining adequate depth of anesthesia for successful insertion of supraglottic airway device (SAD) in normal adults and children receiving intra-venous or inhalational anesthesia induction. This prospective observational study aimed to determine the feasibility and validity of this test when using as an indicator assessing adequate depth of anesthesia for successful insertion of SAD in spontaneously breathing morbidly obese patients receiving sevoflurane inhalational induction.Methods:Thirty morbidly obese patients with a body mass index 40 to 73 kg/m2 undergoing bariatric surgery in Beijing Friendship Hospital from October 2018 to January 2019 were included in this study. After adequate pre-oxygenation, 5% sevoflurane was inhaled and inhalational concentration of sevoflurane was increased by 1% every 2 min. After motor responses to jaw thrust disappeared, a SAD was inserted and insertion conditions were graded. The anatomic position of SAD was assessed using a fiberoptic bronchoscope.Results:The SAD was successfully inserted at the first attempt in all patients. Insertion conditions of SAD were excellent in nine patients (30%) and good in 21 patients (70%), respectively. The fiberoptic views of SAD position were adequate in 28 patients (93%).Conclusions:Jaw thrust test is a reliable indicator determining adequate anesthesia depth of sevoflurane inhalational induction for successful insertion of SAD in spontaneously breathing morbidly obese patients.Clinical trial registration:ChiCTR1800016868; http://www.chictr.org.cn/showproj.aspx?proj=28646.

Comparison of the Effects of Propofol and Sevoflurane on QT Interval in Pediatrics Undergoing Cochlear Implantation: A Randomized Clinical Trial Study.

BackgroundChildren with sensorineural hearing loss are at risk of cardiac electrophysiologic abnormalities. Inhalational Sevoflurane induction in these children can cause QT prolongation.ObjectivesIn order to evaluate the safety of inhalational induction of anesthesia with sevoflurane in children with sensorineural hearing loss, who are candidates for cochlear implant, its electrophysiologic effects was compared with intravenous induction of anesthesia with propofol.MethodsIn this double-blind randomized clinical trial, 61 children aged between one and eighteen years old, who were candidates for cochlear implantation, were randomly allocated to groups receiving anesthesia with sevoflurane (n = 32) or propofol (n = 29) for induction of anesthesia. Two 12-leads ECG were taken from all of patients before and after induction and QTc, Tp-e interval, and JTc were measured and compared.ResultsTwo cases, who had pre-induction QTc longer than 500 ms were excluded from the study. Patients had similar age (102.58 ± 87 versus 101.46 ± 67 months, P = 0.95) and gender (males: 48.3% versus 56.3%, P = 0.53) distribution. The researchers observed significant post induction difference in QTc values between these groups (propofol 422.5 ± 40, sevoflurane 445.0 ± 29, P = 0.016). There was no significant difference in the percent QTc and Tp-e changes in propofol and sevoflurane groups. Greater percentage of patients with increased Tp-e interval (> 100 ms) in the sevoflurane group than the propofol group was also seen. There was no significant long QTc difference (QTc > 500 ms or more than 60 ms increase from baseline) after induction of anesthesia in the sevoflurane group compared to the propofol group (15.6% versus 13.8%, P = 0.84).ConclusionsAfter electrophysiological evaluations in children with sensorineural hearing loss, in patients whose pre-induction QTc is not longer than 500 ms, propofol seems safer than inhalational sevoflurane for induction of anesthesia.

Sevoflurane EC50 for intravenous cannulation attempt and movement in children.

Intravenous cannulation at lighter planes of anaesthesia can lead to adverse respiratory and haemodynamic events. So far, there is no consensus on optimum end tidal sevoflurane concentration required for intravenous cannulation in children. We aimed to evaluate the optimum end tidal concentration at which an intravenous cannulation can be successfully attempted without movements in paediatric patients after inhalational induction of general anaesthesia. In this clinical trial, paediatric subjects of either sex aged 1-3years, weighing 7-15kg having American Society of Anaesthesiologists physical status I/II of undergoing elective cataract surgery were included. After inhalational induction of general anaesthesia with 8% sevoflurane and 100% oxygen, end tidal sevoflurane concentration was maintained at 2% for 4minutes for the first child. This was followed by intravenous cannulation attempted by an experienced anesthesiologist. The intravenous cannulation was considered to be unsuccessful if there was "movement" and successful if there was "no movement" in response to the stimuli of cannulation. End-tidal concentration was increased/decreased (step-size 0.2% for sevoflurane) using Dixon and Massey up and down method in the next patient depending upon previous patient's response. The sevoflurane EC50 for successful intravenous cannulation is 1.32%±1.0%. Pearson correlation (r) between weight of the child and response to intravenous cannulation was found to be 0.40 with P value of 0.008. Intravenous cannulation can be accomplished without movements at end tidal sevoflurane of 1.3% in children aged 1-3years in 50% of children.

Comparison of the Single Breath Vital Capacity Technique with the Tidal Volume Technique

Introduction: The single breath vital capacity (VC) induction and the tidal volume (TV) breathing induction are currently administered for inhalation of anaesthesia with sevoflurane in children. The aim of this study was to determine whether the vital capacity technique achieves more rapid induction of anaesthesia in children compared to the conventional tidal volume technique.&#x0D; Material and Methods: Sixty ASA physical status 1 or 2 children aged between 5 and 15 years, scheduled to undergo elective urological, orthopaedic or visceral surgery under general anaesthesia using inhalational induction with sevoflurane were recruited and randomized to receive either vital capacity induction or tidal volume induction with 8% sevoflurane at 6L/min of O2 followed by laryngeal mask airway insertion or endotracheal intubation with endotracheal tube. Time required for induction, hemodynamic changes, airway tolerance, side-effects, level of satisfaction using a visual analogue scale (0-100) and Smiley scale (0-10) were documented.&#x0D; Results: Induction time was significantly shorter with the vital capacity induction technique than with the tidal volume breathing induction technique (43.8 ± 13.4 seconds vs 70.8 ± 16.4 seconds; P&lt;0.01). The time to central myosis, haemodynamic changes and respiratory events incidences were similar in both the group. Fewer complications occurred with vital capacity group. More than 94% of the children choose the single Breath Vital Capacity method of induction to the tidal volume technique.&#x0D; Conclusion: For inhalation induction of anaesthesia, the vital capacity induction was faster and produced less complication than that of tidal volume breathing technique.

Induction characteristic of general Anaesthesia in children: A comparative study between sevoflurane and halothane: in 250 Bed Mohammad Ali District Hospital, Bogura, Bangladesh

Background: Inhalational induction of anaesthesia remains of fundamental technique in paediatric anaesthesia. Halothane used most frequently for inhalational induction in children. Halothane is not an ideal induction agent because of its potential to cause bradycardia, hypotension and ventricular ectopy. The pleasant nonpungent order of sevoflurane, faster induction of anaesthesia and stable vital signs during induction suggest that it may be a suitable alternative to halothane for use in paediatric anaesthesia. Objectives: The aim of study is to compare the induction time and haemodynamic response during induction of sevoflurane and halothane. Methods: A total number of 60 patients, age within 1-12 years (ASA grade I & II) were selected randomly into two groups, thirty in each group during March to August 2018 at Sheikh Sayera Khatun Medical College & Hospital, Gopalganj, Bangladesh. Group A induction was done by halothane and Group B induction was done by sevoflurane. Anaesthesia was induced with 60% N2O and 40% O2 and starting inspired concentration of halothane was 1% or sevoflurane was 2% followed by stepwise increases in the inspired concentrations of either sevoflurane (1.5-2% increments) or halothane (0.5-1% increments) every three to four breath until the patients no longer blinked in response to touching the eye lashes. Arterial pressure, heart rate, oxygen saturation (SPO2) were recorded every minute for 3 minutes during induction and induction time was recorded. Results: Induction time was significantly shorter in the sevoflurane group compared to the halothane group (P < 0.001). In haemodynamic profile heart rate and mean arterial pressure were significantly reduced in halothane group while no significant changes were observed in sevoflurane group during induction period (P < 0.001). Conclusion: The study concludes that induction of anaesthesia was faster with sevoflurane than halothane. Vital signs were stable with sevoflurane during induction period.