Preliminary evaluation of SaCoVLM™ video laryngeal mask airway in airway management for general anesthesia.

BACKGROUND: To preliminary evaluate the application of SaCoVLM™ video laryngeal mask airway in airway management of general anesthesia. METHODS: We recruited 100 adult patients (ages 18-78 years, male 19, female 81, weight 48-90 kg) with normal predicted airway (Mallampati I ~ II, unrestricted mouth opening, normal head and neck mobility) and ASA I-II who required general anaesthesia. The SaCoVLM™ was inserted after anesthesia induction and connected with the anesthesia machine for ventilation. Our primary outcome was glottic visualization grades. Secondary outcomes included seal pressure, success rate of insertion, intraoperative findings (gastric reflux and contraposition), gastric drainage and 24-h complications after operation. RESULTS: The laryngeal inlet was exposed in all the patients and shown on the video after SaCoVLM™ insertion. The status of glottic visualization was classified: grade 1 in 55 cases, grade 2 in 23 cases, grade 3 in 14 cases and grade 4 in 8 cases. The first-time success rate of SaCoVLM™ insertion was 95% (95% CI = 0.887 to 0.984), and the total success rate was 96% (95% CI = 0.901 to 0.989). The sealing pressure of SaCoVLM™ was 34.1 ± 6.2 cmH2O and the gastric drainage were smooth. Only a small number of patients developed mild complications after SaCoVLM™ was removed (such as blood stains on SaCoVLM™ and sore throat). CONCLUSIONS: The SaCoVLM™ can visualize partial or whole laryngeal inlets during the surgery, with a high success rate, a high sealing pressure and smooth gastroesophageal drainage. SaCoVLM™ could be a promise new effective supraglottic device to airway management during general anesthesia. TRIAL REGISTRATION: ChiCTR, ChiCTR2000028802 .Registered 4 January 2020.

Comparison of the ED50 propofol requirements during the insertion of laryngeal mask airway Ambu AuraFlex with Ambu AuraOnce in children undergoing strabismus surgery.

WHAT IS KNOWN AND OBJECTIVE: Optimal airway management is crucial in strabismus surgery due to the inaccessibility of the airway throughout the procedure. Laryngeal mask airway offers advantages over tracheal intubation in ophthalmic surgery as it does not increase the intraocular pressure. The purpose of this study was to determine the median effective dose of propofol required, when combined with 0.2 µg/kg of sufentanil, for smooth insertion of Ambu AuraFlex in the first attempt in children undergoing strabismus surgery, and to compare it with that for Ambu AuraOnce. METHODS: Forty-three paediatric patients undergoing strabismus surgery under general anaesthesia were recruited. For induction, the initial dosage of propofol was 2 mg/kg in the AuraOnce group or 3 mg/kg in the AuraFlex group. In accordance with Dixon's up-and-down method, the dose of propofol for consecutive patients in each group was adjusted in increments or decrements of 0.25 mg/kg based on the previous patient's "three-point, six-category scale" response to the first attempt of insertion of the randomized device. Insertion of the device was attempted when the bispectral index was ≤60 for 5 s after propofol administration without the use of neuromuscular blocking agents. RESULTS AND DISCUSSION: The median effective dose (95% confidence interval) of propofol was significantly lower in the Ambu AuraOnce group than in the Ambu AuraFlex group (1.92 [1.50-2.32] mg/kg vs. 2.98 [2.49-3.94] mg/kg; p = 0.002). The incidence of dislodgement of the device was significantly higher with the use of the Ambu AuraOnce than with the use of AuraFlex (p = 0.023), whereas insignificant differences were observed between the two groups in the incidence of other perioperative adverse events. WHAT IS NEW AND CONCLUSION: Ambu AuraFlex requires a significantly higher dose of propofol for insertion and provides more effective and stable airway management in strabismus surgery than AuraOnce.

Prospective, Randomized Comparison of the i-gel and the Self-Pressurized air-Q Intubating Laryngeal Airway in Elderly Anesthetized Patients.

BACKGROUND: Age-related changes in upper airway anatomy may affect the overall performance of supraglottic airways significantly. The clinical performance of the i-gel and the self-pressurized air-Q intubating laryngeal airways with noninflatable cuffs for elderly populations remains unknown, unlike in children. Thus, we performed a prospective, randomized comparison of these 2 supraglottic airways in elderly patients undergoing general anesthesia. METHODS: We recruited 100 patients, 65-90 years of age, who were scheduled for elective surgery under general anesthesia with muscle relaxation. The enrolled patients were allocated to the i-gel or self-pressurized air-Q group. We assessed oropharyngeal leak pressure as the primary outcome and fiberoptic view after placement and fixation of the airway and at 10 minutes after the initial assessment. The fiberoptic view was scored using a 5-point scale as follows: vocal cords not visible; vocal cords and anterior epiglottis visible, >50% visual obstruction of epiglottis to vocal cords; vocal cords and anterior epiglottis visible, <50% visual obstruction of epiglottis to vocal cords; vocal cords and posterior epiglottis visible; and vocal cords visible. We also investigated success rate and ease of insertion, insertion time, and manipulations during insertion as insertion variables, complications during maintenance and emergence periods, and postoperative pharyngolaryngeal complications including sore throat, dysphagia, and dysphonia. RESULTS: After assessing for eligibility, 48 patients were allocated to each group. Oropharyngeal leak pressures were significantly higher in the i-gel group than in the self-pressurized air-Q group (P < .001) at the 2 measurement points. The raw mean difference at initial assessment and the median difference after 10 minutes were 5.5 cm H2O (95% confidence interval, 3.3-7.6 cm H2O) and 5.0 (95% confidence interval, 2.0-7.0 cm H2O), respectively. The initial scores of fiberoptic view were similar in the 2 groups. However, the self-pressurized air-Q supraglottic airway provided a significantly improved fiberoptic view at 10 minutes after initial assessment (P = .030). We found no statistically significant differences in insertion variables and complications between the 2 groups. CONCLUSIONS: The i-gel provided better sealing function than the self-pressurized air-Q supraglottic airway according to the high oropharyngeal leak pressures in elderly patients during general anesthesia. The self-pressurized air-Q supraglottic airway had improved fiberoptic views in elderly patients during general anesthesia.

Gentle facemask ventilation during induction of anesthesia.

BACKGROUND: To determine the level of inspiratory pressure minimizing the risk of gastric insufflation while providing adequate pulmonary ventilation. METHODS: In this prospective, randomized, double-blind study, patients were allocated to one of the two groups (P10, P15) defined by the inspiratory pressure applied during controlled-pressure ventilation: 10 and 15 cm H2O. Anesthesia was induced using propofol and sufentanil; no neuromuscular-blocking agent was administered. Once loss of eyelash reflex occurred, facemask ventilation was started for a 2-min period. The cross-sectional antral area was measured using ultrasonography before and after facemask ventilation. Respiratory parameters were recorded. RESULTS: Forty patients were analyzed. Mean tidal volume was about 7 ml/kg in group P10, and was >11 ml/kg in group P15 in the same period. As indicated by ultrasonography test, the antral area in P15 group was markedly incresed compared with P10 group. CONCLUSION: Inspiratory pressure of 10 cm H2O allowed for reduced occurrence of gastric insufflation with proper lung ventilation during induction of anesthesia with sufentanil and propofol in nonparalyzed and nonobese patients.

Ambu® Aura Gain™ versus Ambu® Aura Once™ in children: a randomized, crossover study assessing oropharyngeal leak pressure and fibreoptic position.

PURPOSE: The Ambu® Aura Gain™ is a new second-generation supraglottic airway device that-because of a wider curvature and a wide airway tube-allows fibreoptic intubation. The purpose of this study was to assess the oropharyngeal leak pressure of the Ambu® Aura GainTM compared with the Ambu® Aura Once™. METHODS: In this randomized non-blinded crossover trial with 50 patients aged 18 months to six years (10-20 kg), we compared the Ambu® Aura Gain™ and the Ambu® Aura Once™ for airway maintenance in anesthetized, non-paralyzed participants. Our primary outcome was oropharyngeal leak pressure. Time of insertion, success rates for each device, evaluation of fibreoptic view and ventilation quality during anesthesia, as well as possible complications (e.g., blood staining) were assessed. RESULTS: There were no differences in first and overall insertion attempt rates (Ambu® Aura Once™ 50/50 (100%) vs Ambu® Aura Gain™ 50/50 (100%). Mean (standard deviation) oropharyngeal leak pressure was found to be significantly higher for Ambu® Aura Gain™ than it was for Ambu® Aura Once™ [21 (7) vs 19 (6) cmH2O, respectively; mean difference [MD] - 2 cmH2O; 95% confidence interval [CI], - 3.8 to - 1.0; P = 0.001]. Mean (SD) insertion time was faster for Ambu® Aura Once™ than for Ambu® Aura Gain™ [8 (3) vs 10 (4) seconds, respectively; MD, - 2 sec; 95% CI, - 2.9 to - 1.2; P < 0.001]. There were no differences in ventilation quality, fibreoptic view, or blood staining. CONCLUSION: We conclude that Ambu® Aura Gain™ is a good alternative to the Ambu® Aura Once™ and an efficient device for children in this age group. TRIAL REGISTRATION: www.clincaltrials.gov (NCT02811042). Registered 23 June 2016.

A comparison of blind intubation with the intubating laryngeal mask FASTRACH™ and the intubating laryngeal mask Ambu Aura-i™ a prospective randomised clinical trial.

BACKGROUND: The intubating laryngeal mask Fastrach™ is considered a gold standard for blind intubation as well as for fibreoptic guided intubation via a laryngeal mask. Recently, a single use version of the mask has been introduced. We compared the Fastrach single use with the new, low-priced single use intubating laryngeal mask Ambu Aura-i™. We hypothesised that the LMA Ambu Aura-i and the LMA Fastrach are comparable with respect to success rates for mask placement and blind tracheal intubation through the LMA device. METHODS: A prospective, randomised clinical trial. University Hospital Schleswig-Holstein, Campus Kiel, from April 2011 to April 2012. Eighty patients undergoing general anaesthesia with planned tracheal intubation were randomised and enrolled in the study. Blind intubation was performed with either laryngeal mask using two different tracheal tubes (Rüsch Super Safety Silk™ and LMA ETT™). A crossover-design was performed after an unsuccessful procedure. Primary outcome measure was the overall success rate of blind intubation. Secondary outcome measures were the time to the first adequate ventilation, a subjective handling score, and a fibreoptic control of placement, as well as the success rate of mask placement, time for mask removal after successful intubation, differences in airway leak pressure, and the incidence of postoperative sore throat and hoarseness. RESULTS: The success rate of tracheal intubation with the Fastrach for the first and second attempt was significantly better compared with the Ambu Aura-i. Tracheal intubation was also significantly faster (14.1 s. ±4.4 versus 21.3 s. ±9.0; p < 0.01), and the time interval for mask removal after successful intubation was significantly shorter using the Fastrach device (24.0 s. ±8.2 versus 29.4 s. ±7.5; p < 0.001). There were no significant differences between groups regarding the incidence of postoperative sore throat and hoarseness. CONCLUSION: Both laryngeal mask devices are suitable for ventilation and oxygenation. Blind intubation remains the domain of the LMA Fastrach, the Ambu Aura-i is not suitable for blind intubation. TRIAL REGISTRATION: Clinicaltrials.gov Identification Number NCT03109678 , retrospectively registered on April 12, 2017.

Evaluation of the Augmented Infant Resuscitator: A Monitoring Device for Neonatal Bag-Valve-Mask Resuscitation.

BACKGROUND: Annually, 6 million newborns require bag-valve-mask resuscitation, and providing live feedback has the potential to improve the quality of resuscitation. The Augmented Infant Resuscitator (AIR), a real-time feedback device, has been designed to identify leaks, obstructions, and inappropriate breath rates during bag-valve-mask resuscitation. However, its function has not been evaluated. METHODS: The resistance of the AIR was measured by attaching it between a ventilator and a ventilator tester. To test the device's reliability in training and clinical-use settings, it was placed in-line between a ventilation bag or ventilator and a neonatal manikin and a clinical lung model simulator. The lung model simulator simulated neonates of 3 sizes (2, 4, and 6 kg). Leaks, obstructions, and respiratory rate alterations were introduced. RESULTS: At a flow of 5 L/min, the pressure drop across the AIR was only 0.38 cm H2O, and the device had almost no effect on ventilator breath parameters. During the manikin trials, it was able to detect all leaks and obstructions, correctly displaying an alarm 100% of the time. During the simulated clinical trials, the AIR performed best on the 6-kg neonatal model, followed by the 4-kg model, and finally the 2-kg model. Over all 3 clinical models, the prototype displayed the correct indicator 73.5% of the time, and when doing so, took 1.6 ± 0.9 seconds. CONCLUSIONS: The AIR is a promising innovation that has the potential to improve neonatal resuscitation. It introduces only marginal resistance and performs well on neonatal manikins, but its firmware should be improved before clinical use.

Can Transesophageal Echocardiography Be Performed Safely Using a Laryngeal Mask Airway During Atrial Fibrillation Ablation?

OBJECTIVE: To investigate the feasibility and safety of using a laryngeal mask airway (LMA) compared with a cuffed oral endotracheal tube (COETT) for atrial fibrillation (AF) ablation with transesophageal echocardiography (TEE). DESIGN: Prospective, cohort study. SETTING: A single-center inner-city hospital. PARTICIPANTS: The study comprised adult patients undergoing elective AF ablation with periprocedural TEE over a 3-year period. INTERVENTIONS: Patients were treated with either an LMA or a COETT before undergoing a standardized protocol for TEE and AF ablation. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the need for conversion from an LMA to a COETT. Between January 2014 and January 2017, 346 patients underwent AF ablation. Of those, 126 procedures were performed with a COETT (36.4%) and 220 (63.6%) with an LMA. There were no differences between groups in terms of baseline characteristics, including age, sex, body mass index, and American Society of Anesthesiologists grade. An adequate airway seal was unable to be maintained in 3 patients in the LMA group (1.4%), and those patients were converted to a COETT. No episodes of airway complications occurred in either group. No difference was found in mean propofol (2%) dose between COETT and LMA (385 mg/h v 374 mg/h; p = 0.127). However, the mean remifentanil dose (100 µg/mL) was reduced significantly in the LMA group compared with the COETT group at 355 µg/h and 939 µg/h, respectively (p < 0.001). CONCLUSIONS: LMA use is safe and feasible in the vast majority of patients undergoing AF ablation with TEE and is an acceptable alternative to COETT. A significantly reduced rate of remifentanil was required to maintain anesthesia in the LMA group.

Comparison of the laryngeal mask airway supreme and the i-gel in paralysed elderly patients: A randomised controlled trial.

BACKGROUND: The laryngeal mask airway supreme (LMA-S) and i-gel are both popular second-generation supraglottic airway devices that have been widely studied in surgical patients, but their differences in clinical performance in the elderly are not clear. OBJECTIVE: We compared the efficacy and safety of the LMA-S and i-gel in anaesthetised and paralysed elderly patients. DESIGN: A randomised study. SETTING: Single-centre trial, study period January 2014 from to October 2016. PATIENTS: One hundred and six elderly patients who underwent urological or orthopaedic surgery with an expected duration less than 2 h. INTERVENTION: Patients were allocated to either the LMA-S (n = 53) or i-gel (n = 53) group. All insertions were performed in a standardised manner according to the manufacturers' instructions. MAIN OUTCOME MEASURES: Our primary endpoint was the rate of successful insertion at the first attempt. The adequacy of positive pressure ventilation and airway sealing, fibreoptic laryngoscopy grades and stability of airway maintenance during anaesthesia were also assessed. RESULTS: Although the rate of successful insertion at the first attempt was similar between the two groups (94.3 vs. 82.7%, P = 0.072), more patients required device manipulation during insertion with the LMA-S than the i-gel (42.3 vs. 18.9%, P = 0.011). Good fibreoptic laryngoscopy grades were significantly more common with the i-gel than the LMA-S (79.3 vs. 55.8%, P = 0.042), and peak inspiratory pressures were lower in the i-gel group both immediately after insertion and at the end of surgery. Leak pressures were significantly higher in the i-gel group than the LMA-S group, both immediately after insertion and at the end of surgery (25.8 vs. 23.0, P = 0.036; and 28.1 vs. 23.7, P < 0.001, respectively). CONCLUSION: Both the LMA-S and i-gel were used successfully and safely in elderly patients. However, the i-gel demonstrated better airway sealing than the LMA-S at insertion and during maintenance of anaesthesia. TRIAL REGISTRATION: NCT02026791 at clinicaltrial.gov.

Comparison Between the Cobra Perilaryngeal Airway and Laryngeal Mask Airways Under General Anesthesia: A Systematic Review and Meta-analysis.

The complication rate and efficacy of the Cobra Perilaryngeal Airway (CobraPLA) and laryngeal mask airways (LMAs®) have been evaluated in the published literature, but the conclusions have been inconsistent. The aim of this systematic review and meta-analysis was thus to assess the performance of the CobraPLA and LMAs under general anesthesia. We searched PubMed, Embase, and the Cochrane Library for randomized controlled trials comparing the CobraPLA with LMAs under general anesthesia. The LMAs used for comparison were the classic LMA (CLMA) and the unique LMA (ULMA). The random effect model was used if heterogeneity was observed, otherwise the fixed effect model was used. Seventeen randomized controlled trials were included; number of studies analyzed for each result are different and were up to 10. The current result suggests that no significant difference between the devices in the insertion success rate at the first attempt. The success rate of first insertion of the CobraPLA was not different from the rates for the CLMA and the ULMA (relative risk: 0.95, 95% confidence interval [CI], 0.91-1.00). CobraPLA insertion was not different from CLMA and ULMA insertion. The CobraPLA provided an oropharyngeal leak pressure higher than that provided by the CLMA (weight mean difference: 3.90, 95% CI, [1.59-6.21] cmH2O) and ULMA (weight mean difference: 6.57, 95% CI, [4.30-8.84] cmH2O). We also found a higher likelihood of blood staining in the airway with the CobraPLA than with the CLMA. In our research, the principal finding of our meta-analysis is that the success rate of first insertion of the CobraPLA was not different from the rate for each of the CLMA and the ULMA, which featured a short learning curve implying its ease of insertion. There was also no significant difference in the incidence of the best view (with a score of 4) obtained with the CobraPLA compared with the other 2 devices. The CobraPLA does seem to be superior to the CLMA and ULMA in providing a higher oropharyngeal leak pressure. The data were insufficient to establish differences in airway adverse events between the groups except for blood staining in the devices, although mucosal trauma occurred more frequently with the Cobra PLA device than with the CLMA and the ULMA.

Comparison of the Supreme™ and ProSeal™ laryngeal mask airways in infants: a prospective randomised clinical study.

BACKGROUND: The Supreme™ and ProSeal™ laryngeal mask airways (LMAs) are widely used in paediatric anaesthesia; however, LMA use in infants is limited because many anaesthesiologists prefer to use tracheal intubation in infants. In this study, we compared the Supreme and ProSeal LMAs in infants by measuring their performance characteristics, including insertion features, ventilation parameters, induced changes in haemodynamics and rates of postoperative complications. METHODS: Infants of ASA physical status I scheduled for elective, minor, lower abdominal surgery were divided into two groups: the Supreme LMA group and the ProSeal LMA group. Times and ease of LMA insertion were noted. The percentages of tidal volume leakage as well as peak, mean and leakage pressures for all infants were measured. Heart rate (HR), oxygen saturation (SpO2) and end tidal carbon dioxide (EtCO2) values were recorded before and after LMA insertion and before and after extubation. After extubation, complications and adverse effects were noted. RESULTS: Demographic and surgical data were similar between the two groups. LMA insertion times were shorter for the ProSeal group than for the Supreme group (P < 0.002). The mean HR value for the ProSeal group was lower than for the Supreme group (P < 0.011). Both the peak pressure and the leakage percentage for the ProSeal group were statistically lower than for the Supreme group. The leakage pressure for the ProSeal group was statistically higher than for the Supreme group (P < 0.001). CONCLUSIONS: The ProSeal LMA is superior to the Supreme LMA for use in infants due to the ease of insertion, high oropharyngeal leakage pressure and fewer induced changes in haemodynamics. TRIAL REGISTRATION: ClinicalTrial.gov, NCT03251105 , retrospectively registered on 15 Aug 2017.

Pediatric supraglottic airway devices in clinical practice: A prospective observational study.

BACKGROUND: Supraglottic airway devices (SGA) are commonly used in pediatric anesthesia and serve as primary or back-up devices for difficult airway management. Most SGA are marketed without proper clinical evaluation. The purpose of this study was to evaluate the performance of the pediatric LMA Supreme™, Air-Q® and Ambu® Aura-i™. METHODS: This prospective observational study was performed at Bern University Hospital, Switzerland. With ethics committee approval and a waiver for written informed consent 240 children undergoing elective surgery with an ASA class I-III and a weight of 5-30 kg were included. Three different pediatric supraglottic airway devices were assessed: The LMA Supreme™, Air-Q® and Ambu® Aura-i™. Primary outcome parameter was airway leak pressure. Secondary outcome parameters included first attempt and overall success rate, insertion time, fiberoptic view through the SGA, and adverse events. The primary hypothesis was that the mean airway leak pressure of each tested SGA was 20 cmH2O ± 10%. RESULTS: None of the SGA showed a mean airway leak pressure of 20 cmH2O ± 10%, but mean airway leak pressures differed significantly between devices [LMA Supreme™ 18.0 (3.4) cmH2O, Air-Q® 15.9 (3.2) cmH2O, Ambu® Aura-i™ 17.3 (3.7) cmH2O, p < 0.001]. First attempt success rates (LMA Supreme™ 100%, Air-Q® 90%, Ambu® Aura-i™ 91%, p = 0.02) and overall success rates (LMA Supreme™ 100%, Air-Q® 91%, Ambu® Aura-i™ 95%, p = 0.02) also differed significantly. Insertion times ranged from 20 (7) seconds (Air-Q®) to 24 (6) seconds (LMA Supreme™,

Determination of the optimal inspiratory pressure providing adequate ventilation while minimizing gastric insufflation using real-time ultrasonography in Chinese children: a prospective, randomized, double-blind study.

BACKGROUND: During facemask ventilation, gastric insufflation is defined as appearance of a comet-tail or an acoustic shadow on ultrasonography. Ultrasonographic measurement of antral cross-section area (CSA) may reflect an insufflated antrum and provide interesting semi-quantitative data in regard to the gastric insufflation. This study aimed to determine the appropriate level of inspiratory pressure sufficient to provide adequate pulmonary ventilation with a lower occurrence of gastric insufflation during facemask pressure-controlled ventilation using real-time ultrasonography in paralyzed children. METHODS: Ninety children, ASA I-II, aged from 2 to 4 years, scheduled for general anesthesia were enrolled in this randomized and double-blinded study. Children were randomized into one of the five groups (P8, P10, P12, P14, and P16) defined by the applied inspiratory pressure during facemask ventilation: 8, 10, 12, 14, and 16 cm H2O. Anesthesia induction was conducted with fentanyl and propofol. Rocuronium was administrated as a muscle relaxant. After rocuronium administration, facemask ventilation was performed for 120 s. Gastric insufflation (GI+) was detected by ultrasonography, and the antral CSA before and after facemask ventilation were also measured using ultrasonography. Respiratory variables were monitored. RESULTS: Gastric insufflation was detected in 32 children (3/18 in group P8, 5/18 in group P10, 7/18 in group P12, 8/16 in group P14, and 9/14 in group P16). The antral CSA after facemask ventilation statistically increased in subgroups P14 GI+ and P16 GI+ for whom gastric insufflation was detected by ultrasonography, whereas it did not change statistically in other groups. Lung ventilation was inadequate for group P8 or P10. CONCLUSION: We concluded that an inspiratory pressure of 12 cm H2O is sufficient to provide adequate ventilation with a lower occurrence of gastric insufflation during induction of general anesthesia in paralyzed Chinese children aged from 2 to 4 years old. TRIAL REGISTRATION: ( ChiCTR-IPR-16007960 ). Registered 21 February 2016 Conclusion heading: Ultrasound for determining gastric insufflation.

Appropriate Size of Laryngeal Mask Airway in Thai Children: Is It Age or Weight that Better Correlated.

Background: Clinicians are divided regarding laryngeal mask airway (LMA) size selection for pediatric patients, primarily whether age or body weight is an appropriate predictor. Objective: Determine if body weight and/or age are reliable predictors in LMA size selection in Thai children. Material and Method: Retrospective review of patient medical records was conducted between October 1, 2012 and December 31, 2013. Seven hundred forty one patients, aged 0 to 8 years, were evaluated for the present study. Age and weight correlation for LMA size selection was determined. Appropriate LMA size was identified by successful LMA insertion after induction of anesthesia. Results: Our findings indicate that size 1 LMA for patients weighing less than 7 kilograms, size 1.5 LMA for patients weighing 7 to 11 kilograms, size 2 LMA for patients weighing 11 to 17 kilograms, and size 2.5 LMA for patients weighing 15 to 28 kilograms is appropriate. There was poor correlation between children's age and LMA size. Conclusion: LMA size selection should be based on patient's weight. Our findings revealed applicable and specific weight range for LMA selection in Thai pediatric patients

Occupational Chronic Sevoflurane Exposure in the Everyday Reality of the Anesthesia Workplace.

BACKGROUND: Although sevoflurane is one of the most commonly used volatile anesthetics in clinical practice, anesthesiologists are hardly aware of their individual occupational chronic sevoflurane exposure. Therefore, we studied sevoflurane concentrations in the anesthesiologists' breathing zones, depending on the kind of induction for general anesthesia, the used airway device, and the type of airflow system in the operating room. Furthermore, sevoflurane baselines and typical peaks during general anesthesia were determined. METHODS: Measurements were performed with the LumaSense Photoacoustic Gas Monitor. As we detected the gas monitor's cross-sensitivity reactions between sevoflurane and disinfectants, regression lines for customarily used disinfectants during surgery (Cutasept®, Octeniderm®) and their alcoholic components were initially analyzed. Hospital sevoflurane concentrations were thereafter measured during elective surgery in 119 patients. The amount of inhaled sevoflurane by anesthesiologists was estimated according to mVA = cVA × V × t × ρVA aer. RESULTS: Induction of general anesthesia stopped after tracheal intubation with the patient's expiratory sevoflurane concentration of 1.5%. Thereby, inhalational inductions (INH) caused higher sevoflurane concentrations than IV inductions (mean [SD]: (Equation is included in full-text article.)[ppm] INH 2.43 ± 1.91 versus IV 0.62 ± 0.33, P < 0.001; mVA [mg] INH 1.95 ± 1.54 versus IV 0.30 ± 0.22, P < 0.001). The use of laryngeal mask airway (LMA™) led to generally higher sevoflurane concentrations in the anesthesiologists' breathing zones than tracheal tubes ((Equation is included in full-text article.)[ppm] tube 0.37 ± 0.16 versus LMA™ 0.79 ± 0.53, P = 0.009; (Equation is included in full-text article.)[ppm] tube 1.91 ± 0.91 versus LMA™ 2.91 ± 1.81, P = 0.057; mVA [mg] tube 1.47 ± 0.64 versus LMA™ 2.73 ± 1.81, P = 0.019). Sevoflurane concentrations were trended higher during surgery in operating rooms with turbulent flow (TF) air-conditioning systems compared with laminar flow (LF) air-conditioning systems ((Equation is included in full-text article.)[ppm] TF 0.29 ± 0.12 versus LF 0.13 ± 0.06, P = 0.012; mVA [mg/h] TF 1.16 ± 0.50 versus LF 0.51 ± 0.25, P = 0.007). CONCLUSIONS: Anesthesiologists are chronically exposed to trace concentrations of sevoflurane during work. Inhalational inductions, LMA™, and TF air-conditioning systems in particular are associated with higher sevoflurane exposure. However, the amount of inhaled sevoflurane per day was lower than expected, perhaps because concentrations in previous measurements could be overestimated (10%-15%) because of the cross-sensitivity reaction.

Comparisons of clinical performance of Guardian laryngeal mask with laryngeal mask airway ProSeal.

BACKGROUND: The Guardian Laryngeal Mask Airway (G-LMA) is a new silicone-based single-use extraglottic device with the drainage port and a cuff pilot valve with pressure indicator. The aim of this study is to compare the clinical performance of this laryngeal mask airway with ProSeal laryngeal mask airway (P-LMA). METHODS: In this prospective randomized study, we included adult patients with ASA grading I and II scheduled for elective surgery requiring supine position under total intravenous anesthesia. The patients were randomly allocated to two groups, 40 in each. G-LMA and P-LMA were used in groups G and P respectively. The cuff of each device was air inflated to 60 cmH2O. The primary outcome was to compare the airway sealing pressure and the secondary outcome was to compare the efficacy and safety of these two devices with respect to insertion success, insertion time, ease of insertion, volume of air for cuff inflation to 60 cmH2O, intracuff pressure measurement, gastric tube insertion attempt, gastric tube insertion time, Fiberoptic laryngeal view, and postoperative pharyngolaryngeal morbidity. RESULTS: The airway sealing pressure at 60 cmH2O cuff pressure was significantly greater in G-LMA than P-LMA (p = 0.04).The first successful attempt of both groups were comparable (p = 1.000). Insertion time was significantly shorter in G-LMA than P-LMA (p < 0.0001). The first successful attempt for the gastric tube insertion in both groups was comparable (p = 0.431). Gastric tube insertion time was less in G-LMA than in P-LMA (p < 0.0001). The volume of air for cuff inflation to 60 cmH2O was more in G-LMA than in P-LMA (<0.0001). The intracuff pressure measurement at 30, 60, 90 and 120 minutes were comparable (p = 0.823, 0.182, 0.870, 0.658).We did not find differences in ease of insertion (p = 0.60); Fiber-optic positions of airway devices were comparable (p = 0.83). In addition, blood staining (p = 1.00), sore throat and dysphagia at 1, 2 and 24 hour (p = 1.00) were comparable in both groups. CONCLUSION: The Guardian laryngeal mask airway was associated with high airway sealing pressure with a quicker insertion of the device as well as gastric tube. TRIAL REGISTRATION: Clinical Trial.gov Identifier: NCT02063516. Date: June 2013.

Multicentre validation of manufacturers' weight-based recommendations for laryngeal mask airway size choice in anaesthetic practice: A retrospective analysis of 20,893 cases.

BACKGROUND: Manufacturers' weight-based recommendations for laryngeal mask airway (LMA) sizes are not scientifically founded and have never been validated clinically. OBJECTIVE: The validation of manufacturers' weight-based recommendations in clinical practice and whether other patient variables such as sex and age may influence LMA size choice. DESIGN: A retrospective study. SETTING: Four Israeli hospitals (two tertiary and two secondary hospitals). METHODS: Data on LMA use were retrieved from the Anaesthesia Information Management System (AIMS). Multinomial logistic regression analysis including weight, sex and age amongst adults, adolescents and children was used to identify predictors of LMA size used (development data set). Concordance between the size of LMA used and that predicted according to the model and the manufacturers' recommendations was assessed (validation data set). RESULTS: LMA insertions were analysed in 13,743 (65.8%) adults, 1807 (8.6%) adolescents and 5343 (25.6%) children. Suitability of manufacturers' recommendations was higher in children [4075/5343 (76.3%)] than adults [5200/13743 (37.8%)] or adolescents [885/1807 (49.0%); P < 0.001 for children vs. adults or adolescents]. Sex influenced LMA size in adults and adolescents, but not in children. Age had no influence. Amongst adults and adolescents, LMA size was better predicted by the regression model than by manufacturers' recommendations [adults: anaesthetists/model 61.7%, 95% confidence interval (95% CI) 60.1 to 63.2, anaesthetists/manufacturer 38.4%, 95% CI 36.0 to 39.0, P < 0.001; adolescents: anaesthetists/model 68.1%, 95% CI 64.1 to 72.0, anaesthetists/manufacturer 46.9%, 95% CI 42.7 to 51.1, P < 0.001]. In children, the regression model and manufacturers' weight-based recommendations performed equally (anaesthetists/model 78.0%, 95% CI 75.9 to 80.0, anaesthetists/manufacturer 75.7%, 95% CI 73.6 to 7.8, P = 0.126). CONCLUSION: Manufacturers' weight-based recommendations for LMA size reflect clinical practice in children, but not in adults and adolescents. In these age groups, choice of LMA size is influenced by sex and weight, although with wider ranges than those recommended by manufacturers.

Best position and depth of anaesthesia for laryngeal mask airway removal in children: A randomised controlled trial.

BACKGROUND: There is a wide variation in clinical practice amongst clinicians in the process of removal of the laryngeal mask airway (LMA) in children. Some of the airway complications during recovery are associated with the position of the child as well as the depth of anaesthesia and are potentially avoidable. OBJECTIVES: We wished to determine whether removal of the LMA in the lateral position reduces the incidence of airway complications, either in a deep plane of anaesthesia or awake. DESIGN: A randomised trial. SETTING: A tertiary children's hospital. PATIENTS: The study population comprised 216 American Society of Anesthesiologists (ASA) 1 to 2 patients aged 1 to 16 years scheduled for elective surgery under general anaesthesia using an LMA. Exclusion criteria were children less than 1 year old, ASA 3 or above, presence of congenital heart disease or gastro-oesophageal reflux, anticipated difficult airway and patients undergoing airway or dental surgery. INTERVENTION: We randomly allocated 212 children into one of four groups for LMA removal, deeply anaesthetised or awake in either the lateral or supine position. Various airway complications were recorded after removal of the LMA. MAIN OUTCOME MEASURES: The primary outcome measure was the number of patients experiencing one or more complication in each group. We also devised a novel 'Clinical Importance' score on the basis of the clinical relevance of airway complications. RESULTS: There were significant differences among groups (P = 0.001); the fewest complications occurred when the LMA was removed in a deep plane of anaesthesia in the lateral position. There was a significant difference among groups in the 'Clinical Importance' scores (P < 0.001); the greatest risk occurred when the LMA was removed in deeply anaesthetised supine patients. CONCLUSION: The results of the present study suggest that lateral positioning of children for removal of the LMA provides the safest conditions if the LMA is to be removed at a deep plane of anaesthesia. Sheffield Children's NHS Foundation Trust Study number CA08014.

The effect of changing the sequence of cuff inflation and device fixation with the LMA-Supreme® on device position, ventilatory complications, and airway morbidity: a clinical and fiberscopic study.

BACKGROUND: The conventional sequence when using supraglottic airway devices is insertion, cuff inflation and fixation. Our hypothesis was that a tighter fit of the cuff and tip could be achieved with a consequently lower incidence of air leak, better separation of gastrointestinal and respiratory tracts and less airway morbidity if the device were first affixed and the cuff then inflated. METHODS: Our clinical review board approved the study (public registry number DRKS00003174). An LMA Supreme® was inserted into 184 patients undergoing lower limb arthroscopy in propofol-remifentanil anaesthesia who were randomly assigned to either the control (inflation then fixation; n = 92) or study group (fixation then inflation; n = 92). The cuff was inflated to 60 cmH2O. The patients' lungs were ventilated in pressure-controlled mode with 5 cmH2O PEEP, Pmax to give 6 ml kg-1 tidal volume, and respiratory rate adjusted to end-tidal CO2 of 4.8 and 5.6 kPa. Correct cuff and tip position were determined by leak detection, capnometry trace, oropharyngeal leak pressure, suprasternal notch test, and lube-tube test. Bowl and cuff position and the presence of glottic narrowing were assessed by fiberscopic examination. Postoperative dysphagia, hoarseness and sore throat were assessed with a questionnaire. Ventilatory impairment was defined as a tidal volume < 6 ml kg-1 with Pmax at oropharyngeal leak pressure, glottic narrowing was defined as an angle between the vocal cords under 16 degrees. RESULTS: The incidence of incorrect device position (18% vs. 21%), failed ventilation (10% vs. 9%), leak pressure (24.8 vs. 25.2 cmH2O, p = 0.63), failed lube-tube test (16.3% vs. 17.6%) and glottic narrowing (19.3% vs. 14.1%, p = 0.35) was similar in both groups (control vs. study, resp.). When glottic narrowing occurred, it was more frequently associated with ventilatory impairment in the control group (77% vs. 39%; p = 0.04). Airway morbidity was more common in the control group (33% vs. 19%; p < 0.05). CONCLUSIONS: Altering the sequence of cuff inflation and device fixation does not affect device position, oropharyngeal leak pressures or separation of gastrointestinal and respiratory tracts. It reduces the incidence of glottic narrowing with impaired ventilation and also perioperative airway morbidity.

Prehospital use in emergency patients of a laryngeal mask airway by ambulance paramedics is a safe and effective alternative for endotracheal intubation.

BACKGROUND: In Dutch ambulance practice, failure or inability to intubate patients with altered oxygenation and/or ventilation leaves bag-valve mask ventilation as the only alternative, which is undesirable for patient outcome. A novel Laryngeal Mask Airway Supreme (LMA-S) device may be a suitable alternative. AIM: To evaluate the effectiveness and suitability of the LMA-S for emergency medical services in daily out-of-hospital emergency practice. METHODS: After a period of theoretical and practical training of ambulance paramedics in the use of the LMA-S, prospective data were collected on the utilisation of LMA-S in an observational study. Procedures for use were standardised and the evaluation included the number of direct intubation attempts before using LMA-S, attempts required, failure rate and the adequacy of ventilation. Data were analysed taking patient characteristics such as age and indication for ventilatory support into account. RESULTS: The LMA-S was used 50 times over a period of 9 months (33 involving cardiorespiratory arrest, 14 primary and three rescue). The LMA-S could be applied successfully in all 50 cases (100%) and was successful in the first attempt in 49 patients (98%). Respiratory parameters showed adequate oxygenation. All paramedics were unanimously positive about the utilisation of LMA-S because of the easiness of the effort of insertion and general use, and emphasised its value as a useful resource for patients in need. CONCLUSIONS: Ensuring ventilation support by using LMA-S by paramedics in prehospital emergency practice is safe and effective.