Executive Summary of the Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR) Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management.

The Airway section of the Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) present the Guidelines for the integral management of difficult airway in adult patients. This document provides recommendations based on current scientific evidence, theoretical-educational tools and implementation tools, mainly cognitive aids, applicable to the treatment of the airway in the field of anesthesiology, critical care, emergencies and prehospital medicine. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations and optimization in the progression of the application of strategies to preserve adequate alveolar oxygenation in order to improve safety and quality of care.

TCA Cycle and Its Relationship with Clavulanic Acid Production: A Further Interpretation by Using a Reduced Genome-Scale Metabolic Model of Streptomyces clavuligerus.

Streptomyces clavuligerus (S. clavuligerus) has been widely studied for its ability to produce clavulanic acid (CA), a potent inhibitor of ß-lactamase enzymes. In this study, S. clavuligerus cultivated in 2D rocking bioreactor in fed-batch operation produced CA at comparable rates to those observed in stirred tank bioreactors. A reduced model of S. clavuligerus metabolism was constructed by using a bottom-up approach and validated using experimental data. The reduced model was implemented for in silico studies of the metabolic scenarios arisen during the cultivations. Constraint-based analysis confirmed the interrelations between succinate, oxaloacetate, malate, pyruvate, and acetate accumulations at high CA synthesis rates in submerged cultures of S. clavuligerus. Further analysis using shadow prices provided a first view of the metabolites positive and negatively associated with the scenarios of low and high CA production.

Clavulanic Acid Production by Streptomyces clavuligerus: Insights from Systems Biology, Strain Engineering, and Downstream Processing.

Clavulanic acid (CA) is an irreversible ß-lactamase enzyme inhibitor with a weak antibacterial activity produced by Streptomyces clavuligerus (S. clavuligerus). CA is typically co-formulated with broad-spectrum ß­lactam antibiotics such as amoxicillin, conferring them high potential to treat diseases caused by bacteria that possess ß­lactam resistance. The clinical importance of CA and the complexity of the production process motivate improvements from an interdisciplinary standpoint by integrating metabolic engineering strategies and knowledge on metabolic and regulatory events through systems biology and multi-omics approaches. In the large-scale bioprocessing, optimization of culture conditions, bioreactor design, agitation regime, as well as advances in CA separation and purification are required to improve the cost structure associated to CA production. This review presents the recent insights in CA production by S. clavuligerus, emphasizing on systems biology approaches, strain engineering, and downstream processing.

A Genome-Scale Insight into the Effect of Shear Stress During the Fed-Batch Production of Clavulanic Acid by Streptomyces Clavuligerus.

Streptomyces clavuligerus is a filamentous Gram-positive bacterial producer of the ß-lactamase inhibitor clavulanic acid. Antibiotics biosynthesis in the Streptomyces genus is usually triggered by nutritional and environmental perturbations. In this work, a new genome scale metabolic network of Streptomyces clavuligerus was reconstructed and used to study the experimentally observed effect of oxygen and phosphate concentrations on clavulanic acid biosynthesis under high and low shear stress. A flux balance analysis based on experimental evidence revealed that clavulanic acid biosynthetic reaction fluxes are favored in conditions of phosphate limitation, and this is correlated with enhanced activity of central and amino acid metabolism, as well as with enhanced oxygen uptake. In silico and experimental results show a possible slowing down of tricarboxylic acid (TCA) due to reduced oxygen availability in low shear stress conditions. In contrast, high shear stress conditions are connected with high intracellular oxygen availability favoring TCA activity, precursors availability and clavulanic acid (CA) production.

Characterization of the Metabolic Response of Streptomyces clavuligerus to Shear Stress in Stirred Tanks and Single-Use 2D Rocking Motion Bioreactors for Clavulanic Acid Production.

Streptomyces clavuligerus is a gram-positive filamentous bacterium notable for producing clavulanic acid (CA), an inhibitor of ß-lactamase enzymes, which confers resistance to bacteria against several antibiotics. Here we present a comparative analysis of the morphological and metabolic response of S. clavuligerus linked to the CA production under low and high shear stress conditions in a 2D rocking-motion single-use bioreactor (CELL-tainer ®) and stirred tank bioreactor (STR), respectively. The CELL-tainer® guarantees high turbulence and enhanced volumetric mass transfer at low shear stress, which (in contrast to bubble columns) allows the investigation of the impact of shear stress without oxygen limitation. The results indicate that high shear forces do not compromise the viability of S. clavuligerus cells; even higher specific growth rate, biomass, and specific CA production rate were observed in the STR. Under low shear forces in the CELL-tainer® the mycelial diameter increased considerably (average diameter 2.27 in CELL-tainer® vs. 1.44 µm in STR). This suggests that CA production may be affected by a lower surface-to-volume ratio which would lead to lower diffusion and transport of nutrients, oxygen, and product. The present study shows that there is a strong correlation between macromorphology and CA production, which should be an important aspect to consider in industrial production of CA.

Aspen Plus Simulation Strategies Applied to the Study of Chitin Bioextraction from Shrimp Waste.

Chitin is an aminopolysaccharide of industrial interest commonly obtained from shrimp processing waste through chemical or biotechnological means. Current environmental concerns offer a stimulating perspective for chitin bioextraction with lactic acid bacteria since a considerable reduction in the use of corrosive and pollutant products is possible. Nevertheless, the efficiency of this bioprocess is still a matter of discussion. In this work, the experimental studies of chitin bioextraction from Pacific white shrimp (Litopenaeus vannamei) waste with a mixed culture of Lactobacillus plantarum, Lactobacillus bulgaricus and Streptococcus thermophilus are used in process simulation using Aspen Plus software for the analysis of the potential application of a bioprocess on plant scale. The experimental results of characterization in shake flasks and 1-litre bioreactor indicated that 50 h of fermentation with the mixed culture of lactic acid bacteria was enough to extract more than 90% of minerals and proteins from the shrimp waste. The use of experimental parameters in the simulation allowed a reliable representation of the bioprocess yielding normalized root mean square values below 10%. Simulation was used for the assessment of the impact of the raw material variability on the production costs and gross margin. In this regard, the gross margin of the operation ranged from 42 to 52% depending on the raw material composition and product yield.

Data of clavulanic acid and clavulanate-imidazole stability at low temperatures.

Clavulanic acid (CA) is a ß-lactam antibiotic with a strong inhibitory effect on ß-lactamase enzymes. CA is produced in submerged cultures by the filamentous Gram-positive bacterium Streptomyces clavuligerus (S. clavuligerus). CA is an unstable molecule in aqueous solution and its stability depends strongly on temperature and concentration. In this contribution, the experimental data of CA stability, produced in chemically defined media and exposed to temperatures between -80 and 25 °C, are presented. The chromophore clavulanate-imidazole (CAI) is commonly used for analysis and quantification of CA samples by High Performance Liquid Chromatography (HPLC); nevertheless, this molecule is also susceptible to suffer degradation in aqueous solution, potentially affecting the quantification of CA. Data of CAI concentration for samples conserved at 4 °C and 25 °C are also presented. A reversible-irreversible kinetic model was applied to estimate the degradation rate of CA. Data from numerical simulations of CA degradation using the proposed kinetic model are also graphically presented. The data show the clavulanic acid instability in fermentation broths, in a range of temperatures of interest for bioprocess operation, downstream processing, samples quantification, conservation and storage.

Degradation Kinetics of Clavulanic Acid in Fermentation Broths at Low Temperatures.

Clavulanic acid (CA) is a ß-lactam antibiotic inhibitor of ß-lactamase enzymes, which confers resistance to bacteria against several antibiotics. CA is produced in submerged cultures by the filamentous Gram-positive bacterium Streptomyces clavuligerus; yield and downstream process are compromised by a degradation phenomenon, which is not yet completely elucidated. In this contribution, a study of degradation kinetics of CA at low temperatures (-80, -20, 4, and 25 °C) and pH 6.8 in chemically-defined fermentation broths is presented. Samples of CA in the fermentation broths showed a fast decline of concentration during the first 5 h followed by a slower, but stable, reaction rate in the subsequent hours. A reversible-irreversible kinetic model was applied to explain the degradation rate of CA, its dependence on temperature and concentration. Kinetic parameters for the equilibrium and irreversible reactions were calculated and the proposed kinetic model was validated with experimental data of CA degradation ranging 16.3 mg/L to 127.0 mg/L. Degradation of the chromophore CA-imidazole, which is commonly used for quantifications by High Performance Liquid Chromatography, was also studied at 4 °C and 25 °C, showing a rapid rate of degradation according to irreversible first-order kinetics. A hydrolysis reaction mechanism is proposed as the cause of CA-imidazole loss in aqueous solutions.

A randomised crossover trial comparing the Airtraq ® NT, McGrath ® MAC and Macintosh laryngoscopes for nasotracheal intubation of simulated easy and difficult airways in a manikin / Estudo cruzado e randômico comparando os laringoscópios Airtraq ® NT, McGrath ® MAC e Macintosh para intubação nasotraqueal em simulação de via aérea fácil e difícil em manequim

ABSTRACT OBJECTIVE: Several devices can aid nasotracheal intubation when managing difficult airways. The McGrath MAC and Airtraq NT were compared with a Macintosh laryngoscope when studying the performance of anaesthetists with different levels of experience, in a manikin model of easy or difficult airway scenarios. METHODS: Sixty-three anaesthetists were recruited into a randomised trial in which each performed nasotracheal intubation with all laryngoscopes, in both scenarios. The main endpoint was intubation time. Additional endpoints included laryngoscopic view, intubation success, number of optimisation manoeuvres, audible dental clicks and the force applied to the upper airway. RESULTS: Intubation time was significantly shorter using the McGrath MAC in both scenarios and using the Airtraq in the difficult scenario, when compared with the Macintosh laryngoscope. Both devices gave more Cormack and Lehane grade 1 or 2 views than the Macintosh in the difficult scenario (p < 0.001). The McGrath MAC had the best first-attempt success rate (98.4% vs. 96.8% and 95.8%, p < 0.001 for the Airtraq NT and Macintosh laryngoscopes respectively). The number of optimisation manoeuvres, audible dental clicks and subjective assessment of the degree of force applied were significantly lower for indirect laryngoscopes versus the Macintosh laryngoscope (p < 0.001). CONCLUSION: In a manikin, the Airtraq and the McGrath laryngoscopes appeared superior to the Macintosh laryngoscope when dealing with simulated airway scenarios. Both devices were associated with better views, intubation times and rates of success, especially in a simulated "difficult airway". Overall satisfaction was highest with the McGrath laryngoscope. Similar clinical studies are needed.

RESUMO OBJETIVO: Vários dispositivos podem ajudar a intubação nasotraqueal no manejo de via aérea difícil. Os laringoscópios McGrath MAC e Airtraq NT foram comparados com um laringoscópio Macintosh em estudo do desempenho de anestesistas com diferentes níveis de experiência, em manequim com cenário de via aérea fácil ou difícil. MÉTODOS: Foram recrutados 63 anestesistas para um estudo randômico, no qual cada um fez intubação nasotraqueal com todos os laringoscópios, em ambos os cenários. O desfecho primário foi o tempo de intubação. Desfechos adicionais incluíram vista laringoscópica, sucesso na intubação, número de manobras de aprimoramento, cliques dentais audíveis e força aplicada nas vias aéreas superiores. RESULTADOS: O tempo de intubação foi significativamente menor com o uso do laringoscópio McGrath MAC em ambos os cenários e com o uso do Airtraq no cenário difícil, em comparação com o laringoscópio Macintosh. Ambos os dispositivos obtiveram mais grau 1 ou 2 de Cormack e Lehane para visualização do que o Macintosh em cenário difícil (p < 0,001). O McGrath MAC teve a melhor taxa de sucesso na primeira tentativa (98,4% vs. 96,8% e 95,8%, p < 0,001, para os laringoscópios Airtraq NT e Macintosh, respectivamente). O número de manobras de aprimoramento, os cliques dentais audíveis e a avaliação subjetiva do grau de força aplicada foram significativamente menores para os laringoscópios indiretos versus o laringoscópio Macintosh (p < 0,001). CONCLUSÃO: Em um manequim, os laringoscópios Airtraq e McGrath pareceram superiores ao laringoscópio Macintosh para lidar com cenários das vias aéreas simuladas. Ambos os dispositivos foram associados a melhores visibilidades, tempos de intubação e taxas de sucesso, especialmente em simulação de "via aérea difícil". A satisfação geral foi maior com o laringoscópio McGrath. Estudos clínicos similares são necessários.

A randomised crossover trial comparing the Airtraq(®) NT, McGrath(®) MAC and Macintosh laryngoscopes for nasotracheal intubation of simulated easy and difficult airways in a manikin.

OBJECTIVE: Several devices can aid nasotracheal intubation when managing difficult airways. The McGrath MAC and Airtraq NT were compared with a Macintosh laryngoscope when studying the performance of anaesthetists with different levels of experience, in a manikin model of easy or difficult airway scenarios. METHODS: Sixty-three anaesthetists were recruited into a randomised trial in which each performed nasotracheal intubation with all laryngoscopes, in both scenarios. The main endpoint was intubation time. Additional endpoints included laryngoscopic view, intubation success, number of optimisation manoeuvres, audible dental clicks and the force applied to the upper airway. RESULTS: Intubation time was significantly shorter using the McGrath MAC in both scenarios and using the Airtraq in the difficult scenario, when compared with the Macintosh laryngoscope. Both devices gave more Cormack and Lehane grade 1 or 2 views than the Macintosh in the difficult scenario (p<0.001). The McGrath MAC had the best first-attempt success rate (98.4% vs. 96.8% and 95.8%, p<0.001 for the Airtraq NT and Macintosh laryngoscopes respectively). The number of optimisation manoeuvres, audible dental clicks and subjective assessment of the degree of force applied were significantly lower for indirect laryngoscopes versus the Macintosh laryngoscope (p<0.001). CONCLUSION: In a manikin, the Airtraq and the McGrath laryngoscopes appeared superior to the Macintosh laryngoscope when dealing with simulated airway scenarios. Both devices were associated with better views, intubation times and rates of success, especially in a simulated "difficult airway". Overall satisfaction was highest with the McGrath laryngoscope. Similar clinical studies are needed.

[A randomised crossover trial comparing the Airtraq(®) NT, McGrath(®) MAC and Macintosh laryngoscopes for nasotracheal intubation of simulated easy and difficult airways in a manikin]. / Estudo cruzado e randômico comparando os laringoscópios Airtraq(®) NT, McGrath(®) MAC e Macintosh para intubação nasotraqueal em simulação de via aérea fácil e difícil em manequim.

OBJECTIVE: Several devices can aid nasotracheal intubation when managing difficult airways. The McGrath MAC and Airtraq NT were compared with a Macintosh laryngoscope when studying the performance of anaesthetists with different levels of experience, in a manikin model of easy or difficult airway scenarios. METHODS: Sixty-three anaesthetists were recruited into a randomised trial in which each performed nasotracheal intubation with all laryngoscopes, in both scenarios. The main endpoint was intubation time. Additional endpoints included laryngoscopic view, intubation success, number of optimisation manoeuvres, audible dental clicks and the force applied to the upper airway. RESULTS: Intubation time was significantly shorter using the McGrath MAC in both scenarios and using the Airtraq in the difficult scenario, when compared with the Macintosh laryngoscope. Both devices gave more Cormack and Lehane grade 1 or 2 views than the Macintosh in the difficult scenario (p<0.001). The McGrath MAC had the best first-attempt success rate (98.4% vs. 96.8% and 95.8%, p<0.001 for the Airtraq NT and Macintosh laryngoscopes respectively). The number of optimisation manoeuvres, audible dental clicks and subjective assessment of the degree of force applied were significantly lower for indirect laryngoscopes versus the Macintosh laryngoscope (p<0.001). CONCLUSION: In a manikin, the Airtraq and the McGrath laryngoscopes appeared superior to the Macintosh laryngoscope when dealing with simulated airway scenarios. Both devices were associated with better views, intubation times and rates of success, especially in a simulated "difficult airway". Overall satisfaction was highest with the McGrath laryngoscope. Similar clinical studies are needed.