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.

Screening of Lost Circulation Materials for Geothermal Applications: Experimental Study at High Temperature

This study presents a laboratory experimental research to determine the characteristics of lost circulation materials (LCM) capable of addressing thermal degradation, providing bridging, and sealing in geothermal conditions. Eleven different materials were tested; Walnut Fine, Walnut Medium, Sawdust, Altavert, Graphite Blend, Bentonite Chips, Micronized Cellulose (MICRO-C), Magma Fiber Fine, diatomaceous earth/amorphous silica powder (DEASP), Cotton Seed Hulls, and a Calcium Carbonate Blend. The filtration and sealing pressure of the LCMs were measured with HPHT equipment up to 149°C (300°F). Besides, the particle size distribution (PSD) of fine granular materials was measured. The results show that the performance of some LCM materials commonly used in geothermal operations is affected by high temperature. Characteristics such as shape and size made some materials more prone to thermal degradation. Also, it was found that the PSD of LCMs is a key factor in the effectiveness of bridging and sealing fractures. The results suggest that granular materials with a wide particle size distribution PSD are suitable for geothermal applications.

Numerical investigation of tubular expansion and swelling elastomers in oil wells

Solid expandable tubular technology and swelling elastomer seals find extensive use in the repair of aging reservoirs. To improve productivity and cost-effectiveness, they have also become an integral part of new developments such as slim wells and completions with reduced or no cementing. This work reports the use of numerical simulation to investigate the joint use of expandable tubulars and swell packers in various petroleum drilling applications. Material properties of steel tubular and five different swelling elastomers are obtained through mechanical testing. Simulations are performed to study the sealing pressure at the elastomer-formation boundary. Different parameters are studied, such as elastomer material, expansion or compression ratio, seal length, seal thickness, tubular end condition, and formation type. Higher values of rubber elasticity, tubular expansion (expansion ratio), and elastomer compression result in higher seal contact pressure. Contact pressure is higher when the elastomer is pressing against wellbore formation as compared to steel outer casing (zero friction vs. friction), and when the formation is assumed to be rigid as compared to elastic or elastic-plastic. Results of this investigation can be used both for performance evaluation and design enhancement of coupled solid-expandable-tubular and swellable-packer applications.

Comparison of the Jcerity Endoscoper Airway with the LMA Supreme for Airway Management in Patients Undergoing Cerebral Aneurysm Embolization

Background Interventional embolization of cerebral aneurysms often requires anticoagulation and antiplatelet therapy during perioperative period. A new type of laryngeal mask airway (Jcerity Endoscoper Airway)with a unique design may cause less oropharyngeal injury and bleeding for patients receiving perioperative anticoagulation. This study sought to compare the efficacy, safety and complications of Jcerity Endoscoper airwayvs LMA((Laryngeal Mask Airway) Supreme in the procedure of cerebral aneurysm embolization. Methods In this prospective, randomised clinical trial, 182 adult patients with American Society of Anesthesiologists class Ι-II scheduled for interventional embolization of cerebral aneurysms were randomly allocated into the Jcerity Endoscoper airway group and the LMA Supreme group. We compared success rate of LMA implantation, ventilation quality, airway sealing pressure, peak airway pressure, degree of blood staining, postoperative oral hemorrhage, sore throat and other complications between the groups. Results There were no significant differences between the groups in terms of success rate of LMA implantation, ventilation quality, airway sealing pressure or airway peak pressure. The LMA Supreme group showed a significantly higher degree of blood staining than the Jcerity Endoscoper airway group when the laryngeal mask airway was removed (P = 0.04), and there were also more oral hemorrhages and pharyngeal pain than in the the Jcerity Endoscoper airway group (P = 0.03,P = 0.02). No differences were observed between groups in terms of other complications related to the LMA. Conclusions The Jcerity Endoscoper airway can be safely and effectively used for airway management in patients undergoing cerebral aneurysm embolization, which can significantly reduce airway complications related to perioperative anticoagulation.

Prospective, Randomized Comparison of Proseal Laryngeal Mask Airway and Endotracheal Tube in Adults Selected for Elective Laparoscopic Abdominal Surgery

Both PLMA and SLIPA were easy to insert (100% success) and ventilate with maximum sealing pressure of 30cm H2o (P = 0.4) with no muscle relaxant. No significant difference (P = 0.265) in intubation time between PLMA and ETT were observed in the study. A significant SpO2 change (P = 0.804, 0.561, 0.657, 0.248, 0.561) measured Pre op, Pre intubation, lmt, 3 mt and 5mts after intubation and there were no significant EtCO2 changes (P =0.861, 0.251, 0.44) measured after intubation was observed. Blood staining in 1/25 cases with PLMA and 2/25 cases with ETT with a P value of 0.561was seen.

Prewarming i-gel laryngeal mask for mechanical ventilation: a meta-analysis of randomised control trials and trial sequential analysis

ObjectiveTo systematically evaluate the efficiency of prewarming i-gel laryngeal mask for mechanical ventilation by meta-analysis and trial sequential analysis.DesignSystematic review and meta-analysis.Data sourcesCochrane library, Web of Science, Ovid Medline and PubMed were searched from their inception to 31 August 2020. Only articles published in English language were considered.MethodsRandomised controlled trials (RCTs) comparing the efficiency of prewarming i-gel laryngeal mask versus keeping it at room temperature for mechanical ventilation were included. Primary outcome was sealing pressure immediately after successful ventilation. Secondary outcomes were the first-attempt insertion success rate and the incidence of postoperative pharyngeal pain. Two authors independently selected studies. Quality analysis was performed using the modified Jadad Scale. Trial sequential analysis (TSA) was used to control risk of random errors. Sensitivity analysis was done to assess the effect of a single study on the pooled estimates. Publication bias was assessed by funnel plots and Egger’s regression test.ResultsFour RCTs comprising 374 patients were included. The results of meta-analysis showed that compared with the control group, prewarming i-gel laryngeal mask provides a higher sealing pressure immediately after successful ventilation (mean difference 2.19 cm H2O; 95% CI (1.17 to 3.21); p<0.0001; high quality), with firm evidence from TSA and lower publication bias (p=0.7372). No significant difference was observed in the first-attempt insertion success rate (relative ratio (RR) 1.06; 95% CI (1.00 to 1.12); p=0.07; high quality) with lower publication bias (p=0.1378). The TSA indicating further trials are required. No significant difference was assessed in the incidence of postoperative pharyngeal pain (RR 1.0; 95% CI (0.14 to 6.90); p=1.0; high quality).ConclusionPrewarming i-gel laryngeal mask provides higher sealing pressure compared with keeping it at room temperature. But prewarming i-gel laryngeal mask did not increase the first-attempt insertion success rate, nor did it decrease the incidence of postoperative pharyngeal pain.

Finite element analysis of large-sized O-rings used in deep-ocean pressure chambers

A proper criterion to guide how to determine the cross-section diameter of non-standard large-sized O-rings used in deep-ocean pressure chambers (DOPCs) is absent. To design a large-sized O-ring only by scale-up could be a lack of persuasiveness, and it will probably cause the increase of cost. This paper gives a detailed study on the static sealing performance of O-rings by finite element analysis (FEA). The results show that the influence of the inside diameter of O-rings can be ignored, and the O-rings with a large cross-section diameter may not be applicable to the high-pressure DOPCs, but it can allow a larger sealing clearance to be used in the low-pressure DOPCs. The reference values of safe sealing pressure with different cross-section diameters and different sealing clearances are ascertained. An improved criterion to guide how to determine the cross-section diameter of non-standard large-sized O-rings used in DOPCs is proposed. The results obtained in this paper can provide a more convincing guideline for the O-ring sealing design not only in DOPCs but also in the similar pressure vessels.

A design and optimization of a high throughput valve based microfluidic device for single cell compartmentalization and analysis

The need for high throughput single cell screening platforms has been increasing with advancements in genomics and proteomics to identify heterogeneity, unique cell subsets or super mutants from thousands of cells within a population. For real-time monitoring of enzyme kinetics and protein expression profiling, valve-based microfluidics or pneumatic valving that can compartmentalize single cells is advantageous by providing on-demand fluid exchange capability for several steps in assay protocol and on-chip culturing. However, this technique is throughput limited by the number of compartments in the array. Thus, one big challenge lies in increasing the number of microvalves to several thousand that can be actuated in the microfluidic device to confine enzymes and substrates in picoliter volumes. This work explores the design and optimizations done on a microfluidic platform to achieve high-throughput single cell compartmentalization as applied to single-cell enzymatic assay for protein expression quantification. Design modeling through COMSOL Multiphysics was utilized to determine the circular microvalve’s optimized parameters, which can close thousands of microchambers in an array at lower sealing pressure. Multiphysical modeling results demonstrated the relationships of geometry, valve dimensions, and sealing pressure, which were applied in the fabrication of a microfluidic device comprising of up to 5000 hydrodynamic traps and corresponding microvalves. Comparing the effects of geometry, actuation media and fabrication technique, a sealing pressure as low as 0.04 MPa was achieved. Applying to single cell enzymatic assay, variations in granzyme B activity in Jurkat and human PBMC cells were observed. Improvement in the microfluidic chip’s throughput is significant in single cell analysis applications, especially in drug discovery and treatment personalization.

A Randomised Clinical Trial to Compare the Effectiveness of Baska Mask Versus i-gel in Patients Undergoing Laparoscopic Surgeries in a Tertiary Centre

BACKGROUND A wide array of supraglottic airway devices (SAD) are available for the present day anaesthetic practice, each having its own unique features. Laparoscopic surgeries demand meticulous airway maintenance due to the impact of pneumoperitoneum on cardiorespiratory physiology. It thus becomes imperative to have knowledge about the most optimal SAD that can be used for laparoscopic surgeries to provide good quality anaesthesia. The objective of this randomised trial was to compare the airway sealing pressure (ASP) of Baska mask and i-gel and overall success rate in patients undergoing laparoscopic surgeries under general anaesthesia and controlled ventilation. METHODS One hundred and forty patients undergoing laparoscopic surgeries were randomly assigned to either Baska group (Group B) or i-gel group (Group I). Anaesthesia was induced with propofol 2 - 2.5 milligram per kilogram (mg / kg) and relaxation achieved with vecuronium 0.1 mg / kg and SAD was inserted. The primary outcome was airway sealing pressure (ASP) noted after insertion of the device. The secondary outcome measures included the number of attempts and time taken for successful insertion, ASP after gas insufflation of abdomen, Brimacombe grading, hemodynamic changes, airway morbidity (blood on the SAD upon removal, post-operative sore throat, dysphagia and dysphonia) and any other adverse events associated with the use of the devices. RESULTS There were no significant differences in demographic and hemodynamic data. ASP after insertion of the device was significantly higher (p < 0.0001) with Baska than i-gel (41.45 + 4.72 versus 30.29 + 5.76 cm H2O respectively). Brimacombe scoring of grade four was seen in 75.3 % of Baska compared to 18 % in i-gel group. Time taken to insert Baska was significantly more than with i-gel (14.84 versus 11.25 seconds respectively, P < 0.001). However, first time success was more with Baska than with i-gel (147 versus 140 respectively). CONCLUSIONS Both Baska and i-gel can be used safely and effectively in laparoscopic surgeries. Baska provides a better ASP and Brimacombe view than i-gel. However, i-gel offers the advantage of easier insertion in shorter time. KEYWORDS Supraglottic Airway Device, Baska Mask, i-gel, Airway Sealing Pressure

CAE Correlation of Sealing Pressure of a Press-in-Place Gasket

The Press-in-Place (PIP) gasket is a static face seal with self-retaining feature, which is used for the mating surfaces of engine components to maintain the reliability of the closed system under various operating conditions. Its design allows it to provide enough contact pressure to seal the internal fluid as well as prevent mechanical failures. Insufficient sealing pressure will lead to fluid leakage, consequently resulting in engine failures. A test fixture was designed to simulate the clamp load and internal pressure condition on a gasket bolted joint. A Sensor pad using TEKSCAN equipment was used to capture the overall and local pressure distribution of the PIP gasket under various engine loading conditions. Then, the Sensor pad test results were compared with simulated CAE results from computer models. Through the comparisons, it is found that the gasket sealing pressure of test data and CAE data show good correlation for bolt load condition 500N when compared to internal pressure side load condition of 0.138 MPa & 0.276 MPa. Moreover, the gasket cross-sectional pressure distribution obtained by experimental tests and CAE models correlated very well with R2 ranging from 90 to 99% for all load cases. Both CAE and Sensor pad test results shows increase in sealing pressure when internal side pressure is applied to the gasket seal.