Anesthetic considerations for microlaryngeal surgery

Introduction: Microlaryngeal surgery encompasses a wide range of laryngeal procedures. Patients presenting for microlaryngeal surgery frequently have a difficult airway. The chosen approach to this airway depends on the pathology and the patient’s symptoms. The Aim of the study is to determine the risk factors and anesthetic problems during microlaryngeal surgery.Materials and Methods: A prospective cohort study including 100 patients undergoing microlaryngeal surgery in the Department of Otorhinolaryngology at the University Hospital „Queen Giovanna“ – ISUL, Sofia, in the period 2020–2021; Medical University-Sofia. Preoperative examination of the larynx is performed in all patients by Storz 8402 ZX fiber optic laryngoscope with video capability.Results and discussion: In 69% of the patients the tumor mass causing obstruction is localized in the area of the larynx, and in 31% of them the tumor mass is localized in the area of the hypopharynx. From the patients with tumor mass causing laryngeal obstruction 42% are with 1st degree of obstruction, 29% are with 2nd degree, 27% are with 3rd degree and 2% are with respiratory failure at rest. Twenty six percent (26%) of the patients had pulse rate<45 beats per minute during putting on the tube of Kleinsasser. This is very dangerous reflex reaction of the heart, which we believe is caused by parasympathetic nervous system. The rate of difficult endotracheal intubation among patients presenting for microlaryngeal surgery is higher than among the general surgical patient population. Difficulties during endotracheal intubation in our study are due to higher percent of laryngeal obstruction and pharyngeal restriction because of the intraoral masses.Conclusion: Anesthesia for microlaryngeal surgery has always been demanding, as often pathology interferes with the anesthesiologist’s field of work

Design and Optimisation of a Microwave Reactor for Kilo-Scale Polymer Synthesis

Current industrial production of polymer resins is generally undertaken in large multi-tonne stirred tank reactors. These are characterised by relatively slow heating and cooling cycles, resulting in long vessel cycle times and extended production campaigns. In this work we present a design for a hybrid microwave/oil jacket proof of concept system capable of producing up to 4.1 kg of polymer resin per batch. By exploiting rapid volumetric heating effects of microwave energy at 2.45GHz, we have optimised the synthetic regime, such that a 3.7 kg batch of polyester resin pre-polymer can be made in only 8 hours 20 minutes, with higher molecular weight (Mn 2,100) compared to the conventional process taking 22 hours 15 minutes (Mn 1,200), yielding an increase in synthesis rate of at least 265. The increase in polymer molecular weight also suggests a higher conversion was achieved over a shorter time scale

Design and optimisation of a microwave reactor for kilo-scale polymer synthesis

Current industrial production of polymer resins is generally undertaken in large multi-tonne stirred tank reactors. These are characterised by relatively slow heating and cooling cycles, resulting in long vessel cycle times and extended production campaigns. In this work we present a design for a hybrid microwave/oil jacket proof of concept system capable of producing up to 4.1?kg of polymer resin per batch. By exploiting rapid volumetric heating effects of microwave energy at 2.45?GHz, we have optimised the synthetic regime, such that a 3.7?kg batch of polyester resin pre-polymer can be made in only 8?h 20?min, with higher molecular weight (Mn 2100) compared to the conventional process taking 22?h 15?min (Mn 1200), yielding an increase in synthesis rate of at least 265%. The increase in polymer molecular weight also suggests a higher conversion was achieved over a shorter time scale

Investigation of the sup 9 sup 3 Nb neutron cross-sections in resonance energy range

The results of gamma-ray multiplicity spectra and transmission measurements for sup 9 sup 3 Nb in energy range 21.5 eV-100 keV are presented. Gamma spectra from 1 to 7 multiplicity were measured on the 501 m and 121 m flight paths of the IBR-30 using a 16-section scintillation detector with a NaI(Tl) crystals of a total volume of 36 l and a 16-section liquid scintillation detector of a total volume of 80 l for metallic samples of 50, 80 mm in diameter and 1, 1.5 mm thickness with 100% sup 9 sup 3 Nb. Besides, the total and scattering cross-section of sup 9 sup 3 Nb were measured by means batteries of B-10 and He-3 counters on the 124 m, 504 m and 1006 m flight paths of the IBR-30. Spectra of multiplicity distribution were obtained for resolved resonances in the energy region E=30-6000 eV and for energy groups in the energy region E=21.5 eV- 100 keV. They were used for determination of the average multiplicity, resonance parameters and capture cross-section in energy groups and for low-laying resonances of sup 9 sup 3 Nb. Standard capture cross-sections of sup 2 sup 3 sup 8 U and experimental gamma-ray multiplicity spectra were also used for determination of capture cross section sup 9 sup 3 Nb in energy groups. Similar values were calculated using the ENDF/B-6 and JENDL-3 evaluated data libraries with the help of the GRUKON computer program. Within the limits of experimental errors there is observed an agreement between the experiment and calculation, but in some groups the experimental values differ from the calculated ones