Modelling buccopharyngeal droplet dispersion in an intensive care unit for Covid patients

Author(s):  
Martin Ferrand ◽  
Mathieu Guingo ◽  
Christian Beauchêne ◽  
Maurice Mimoun ◽  
Jean-Pierre Minier

<p>Faced with the first Covid-19 epidemic wave in France, the hospital sector has been forced to considerably increase the number of intensive care beds. To meet this crucial need, some hospital structures have been adapted. This is the case with one of the intensive care sectors of the Burn Treatment Center (CTB) at Saint-Louis Hospital, which has intensive care rooms dedicated to treat burn patients. Beyond the provision and adaptation of these care structures to Covid patients, the hospital has currently an imperative need to progress on the understanding of the dispersion of buccopharyngeal droplets which constitute one of the risk vectors of airborne transmission and as a corollary of manual transmission.</p><p>As part of a partnership between CTB and the EDF Foundation, a CEREA research team provided the hospital with its aeraulics expertise which mainly relies on the digital modelling tool (CFD) code_saturne developed for more than 20 years by EDF-Research and Development. Numerical modelling in fluid mechanics makes it possible to accurately reproduce an architectural ensemble, to describe the air flows and what they carry, and thus to better understand where the risks of airborne contamination lie.</p><p>The objective of the study is to understand the dispersion of the buccopharyngeal droplets in the resuscitation room according to their sizes, identify the areas at risk of deposit, adapt the treatment protocols and optimise the level and the frequency of systematic bio-cleaning of surfaces exposed to deposit of oral-pharyngeal droplets. It should be noted that we are not directly dealing with the spread of the covid-19 virus but with one of the potential vehicles of oral-pharyngeal droplets.</p><p>The methodology consist of a parametric study of poly-dispersion of classes of particles. Each class correspond to a droplet diameter and contains one million of independent droplets for which a Generalized Langevin Model is solved to calculate the instantaneous fluid velocity seen from the particle, the particle velocity and its position. These particles are carried by a turbulent flow using the Reynolds Averaged Navier-Stokes approach, calculating only moments. The specific characteristics of this model allow dealing with poly-dispersed two-phase flow even for particles with very small diameters. The studied parameters are the angle of droplet ejection, the volume of humid air ejected and the time duration of this event and the air flowing activation of the room.</p><p>Expected conclusions are found: the largest particles sediment the fastest and close to the source, the finest droplets follow the streamlines to the air vents. In addition, non-intuitive areas of potential deposit are observed and a major impact of air conditioning on residence time is demonstrated.</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.b43390093fff52971650161/sdaolpUECMynit/12UGE&app=m&a=0&c=4345eb35e27ea319150c5cf3afab9d44&ct=x&pn=gnp.elif&d=1" alt=""></p>

2020 ◽  
Vol 8 (4) ◽  
pp. 103-114
Author(s):  
Ryszard Mądry ◽  
Jerzy Strużyna ◽  
Tomasz Korzeniowski ◽  
Aleksandra Winiarska

Advancements in burn treatment, in the last decades, resulted in a reduction of mortality among burn victims. Increased funding and the creation of regional burn treatment facilities focused on comprehensive therapy of severe burns resulted in improvement of treatment outcomes. Effective functioning and usage of resources in burn centers depends on the organization of prehospital care, proper segregation of patients, triage and prompt transfer to a place where highly specialized care is available. Initial care of a burn injury patient includes actions taken by witnesses of the event and by the emergency medical team during transfer to the emergency department. After evaluating and stabilizing the patient, a decision is made whether or not he should be treated at a specialized burn treatment center to which he may be transferred by land or by air. This paper presents burn patient treatment protocols at each of the following stages: at the burn scene, during transportation, initial hospital treatment and criteria for referring the patient to a burn treatment center.


Author(s):  
Jens A. Melheim ◽  
Stefan Horender ◽  
Martin Sommerfeld

Numerical calculations of a particle-laden turbulent horizontal mixing-layer based on the Eulerian-Lagrangian approach are presented. Emphasis is given to the determination of the stochastic fluctuating fluid velocity seen by the particles in anisotropic turbulence. The stochastic process for the fluctuating velocity is a “Particle Langevin equation Model”, based on the Simplified Langevin Model. The Reynolds averaged Navier-Stokes equations are closed by the standard k-epsilon turbulence model. The calculated concentration profile and the mean, the root-mean-square (rms) and the cross-correlation terms of the particle velocities are compared with particle image velocimetry (PIV) measurements. The numerical results agree reasonably well with the PIV data for all of the mentioned quantities. The importance of the modeled vortex structure “seen” by the particles is discussed.


Author(s):  
Marie Benayoun ◽  
Marie-Charlotte Dutot ◽  
Céline Aboud ◽  
Kévin Serror ◽  
Marc Chaouat ◽  
...  

Abstract Introduction Deep soft tissue defects next to the joints can rapidly lead to irreversible damages and have to be covered urgently and effectively. In severely burned patients the usual approach is to use a flap even though it has its limitations in regards to the extent of the burn and the general condition of the patient. Case report A twenty seven-year-old male was admitted at the Burn Treatment Center for a thermic burn of seventy-two percent of his body surface area. At first he has benefited from several skin grafts and later on a major open right elbow had to be treated urgently to rescue the joint. Results After the burn, a revascularization of the donor site was noticed, sufficient to use the radial forearm pedicled flap as a cover for the elbow. This case reports an innovative approach based on the use of an irrigation and drainage system placed underneath the flap. The elbow was rigidly immobilized with an external fixator in order to facilitate an optimal healing of the flap. Conclusion In this case, the choice of this flap, combined with the irrigation and drainage system and the immobilization by external fixation, provided an original and efficient treatment. Post operatively the healing of the flap and of the donor site was complete. The functional results exceeded the expectations with a complete recovery of the joint amplitude. Thus, in case of no other therapeutic options, it is probably possible to use a variety of flaps recently healed.


2018 ◽  
Vol 25 (6) ◽  
pp. 324-330 ◽  
Author(s):  
Wang Chang Yuan ◽  
Cao Tao ◽  
Zhu Dan Dan ◽  
Sun Chang Yi ◽  
Wang Jing ◽  
...  

Background: For critical patients in resuscitation room, the early prediction of potential risk and rapid evaluation of disease progression would help physicians with timely treatment, leading to improved outcome. In this study, it focused on the application of National Early Warning Score on predicting prognosis and conditions of patients in resuscitation room. The National Early Warning Score was compared with the Modified Early Warning Score) and the Acute Physiology and Chronic Health Evaluation II. Objectives: To assess the significance of NEWS for predicting prognosis and evaluating conditions of patients in resuscitation rooms. Methods: A total of 621 consecutive cases from resuscitation room of Xuanwu Hospital, Capital Medical University were included during June 2015 to January 2016. All cases were prospectively evaluated with Modified Early Warning Score, National Early Warning Score, and Acute Physiology and Chronic Health Evaluation II and then followed up for 28 days. For the prognosis prediction, the cases were divided into death group and survival group. The Modified Early Warning Score, National Early Warning Score, and Acute Physiology and Chronic Health Evaluation II results of the two groups were compared. In addition, receiver operating characteristic curves were plotted. The areas under the receiver operating characteristic curves were calculated for assessing and predicting intensive care unit admission and 28-day mortality. Results: For the prognosis prediction, in death group, the National Early Warning Score (9.50 ± 3.08), Modified Early Warning Score (4.87 ± 2.49), and Acute Physiology and Chronic Health Evaluation II score (23.29 ± 5.31) were significantly higher than National Early Warning Score (5.29 ± 3.13), Modified Early Warning Score (3.02 ± 1.93), and Acute Physiology and Chronic Health Evaluation II score (13.22 ± 6.39) in survival group ( p < 0.01). For the disease progression evaluation, the areas under the receiver operating characteristic curves of National Early Warning Score, Modified Early Warning Score, and Acute Physiology and Chronic Health Evaluation II were 0.760, 0.729, and 0.817 ( p < 0.05), respectively, for predicting intensive care unit admission; they were 0.827, 0.723, and 0.883, respectively, for predicting 28-day mortality. The comparison of the three systems was significant ( p < 0.05). Conclusion: The performance of National Early Warning Score for predicting intensive care unit admission and 28-day mortality was inferior than Acute Physiology and Chronic Health Evaluation II but superior than Modified Early Warning Score. It was able to rapidly predict prognosis and evaluate disease progression of critical patients in resuscitation room.


2020 ◽  
Vol 41 (Supplement_1) ◽  
pp. S135-S135
Author(s):  
Eileen Uberti ◽  
Kathrina Prelack

Abstract Introduction Hair highlighting treatment has become popular at salons across the country. The ubiquity of this beauty treatment gives many people the impression that it is safe. The process of changing hair color differs between hair salons and hair stylists. We describe the cases of two teenage patients who received third degree burns from hair highlighting treatments. Differences in highlighting technique and treatment modality will be compared and contrasted. Methods As part of a quality assurance project looking at variation in scalp burn treatment and outcome, two patients were identified who experienced scalp burn injury due to hair highlighting. Patient 1 received a hot foil hair lighting application. After 5 minutes, the patient experienced tingling in the scalp and removed heat lamp and foils from hair. The first two weeks of treatment were administered by her primary care provider before the patient admitted to our burn facility, where topical collagenase was initiated. Forty two days after initial injury the patient underwent first surgery for debridement, followed by subsequent excision and grafting of scalp. Patient returned for tissue expansion nine months later. Patient 2 received a hair highlighting treatment of bleach and water. Patient 2 complained of burning and immediately her hair was washed out by the hairdresser. The patient was seen two weeks later in our clinic, and treated conservatively with mineral oil and antibacterial topical application. Patient was offered tissue expansion surgery but declined. Results Table 1. compares injury type, treatment and outcome in these two patients. Both injuries required significant time to heal, ranging between 56–70 days. Although similar injuries, mode of treatment differed at this same institution. Both patients made decisions based on school activities and fear or surgery, which prolonged time of conservative treatment. Patient 1 received psychological support and anti-anxiety medication prior to all treatments. After tissue expansion Patient 1 no longer required medication and had no sign of alopecia. Patient 2 has area of alopecia 2x2 cm. Neither patient requires further follow up, however Patient 2 could return for tissue expansion if desired. Conclusions Hair highlighting is a risk for serious scalp burn injury. Conservative treatment (often per patient preference) is associated with prolonged days to healing. Surgical intervention which includes subsequent tissue expansion, combined with psychological support and anxiety management results in good outcome. Applicability of Research to Practice Results from this analysis will be used to develop treatment protocols and staff education on scalp burn injury.


2019 ◽  
Vol 30 (6) ◽  
pp. 878-895
Author(s):  
Mohammad Mehdi Zolfagharian ◽  
Mohammad Hassan Kayhani ◽  
Mahmood Norouzi ◽  
Amir Jalali

In the present work, a new unsteady analytical model is developed for magnetorheological fluid flow through the annular gap which is opened on the piston head of twin tube magnetorheological damper, considering fluid inertia term into the momentum equation. This new unsteady model is based on Stokes’ second problem that is extended for magnetorheological fluid flow between finite oscillating parallel plates under the pressure gradient. A quasi-static analysis is also developed for magnetorheological fluid flow in twin tube damper, to compare its results with present unsteady solution and to show the effect of magnetorheological fluid inertia. The obtained results are validated experimentally and then, a parametric study is presented using both unsteady and quasi-static analysis. The effect of fluid inertia term is investigated on force–displacement and force–velocity loops, magnetorheological fluid velocity profile, pressure drop, phase difference between pressure drop and flow rate and change of plug thickness with time duration. According to the obtained results, quasi-static analysis included considerable error respect to new unsteady analysis as the gap height, magnetorheological fluid density, excitation frequencies and amplitudes are increased and yield stress is decreased. It is found that the plug thickness is considerably affected by inertia term of magnetorheological fluid.


Author(s):  
Flávia Mendonça da Silva Oussaki ◽  
Lilian Denise Mai ◽  
Mariana Sbeghen Menegatti

2019 ◽  
Vol 78 (16) ◽  
Author(s):  
José Aldari Lima ◽  
Roberta Araújo Montana

Introdução: O tratamento das queimaduras é considerado um grande desafi o para os profi ssionais da área de saúde.Cada vez mais, a indústria produz e disponibiliza para o mercado novos produtos com tecnologia inovadora paratratamento de lesões, que permitem redução do número de trocas dos curativos e da dor, maior conforto e queaceleram o processo de reparo tecidual da pele. O objetivo deste estudo foi avaliar o processo de reparo tecidualde queimaduras de 2º grau superfi cial e intermediário em uso de um curativo biológico composto por nitrato decério, colágeno bovino e alginato de cálcio. Método: Trata-se de uma série de seis casos. A coleta de dados foirealizada de dezembro de 2013 a maio de 2014, por médicos e enfermeiros do Centro de Tratamento de Queimadosde um hospital municipal do Rio de Janeiro/RJ. Resultados: Em todos os casos acompanhados as queimadurasapresentaram melhora no processo de reparo tecidual e da dor e não foram evidenciados sinais clínicos de infecçãodurante as trocas de curativos. Conclusão: O uso de um curativo biológico e de alta tecnologia, aliado ao cuidadoespecializado do paciente queimado, trazem mais benefícios para o processo de cicatrização da queimadura e paraa saúde do paciente.Descritores: Queimaduras; Cicatrização; Ferimentos e Lesões. ABSTRACTIntroduction: Burns treatment is still a major challenge for health professionals. Increasingly, industry producesand provides to the market, new products with innovative technology for the treatment of lesions that enablereduction in the number of dressing changes and pain, increase comfort and accelerate the skin tissue repairprocess. The aim of this study was to evaluate the tissue repair process of superfi cial and intermediate 2nddegree burns with the use of a biological dressing composed of cerium nitrate, bovine collagen and calciumalginate. Method: This is a series of 06 cases. Data collection was conducted from December 2013 to May 2014by doctors and nurses from the Burn Treatment Center of a Rio de Janeiro Municipal Hospital. Results: In allcases followed, burns showed improvement in tissue repair process and pain and have not shown clinical signs ofinfection during dressing changes. Conclusion: We conclude that the use of a high technology biological dressingcombined with burned patients specialized care, brings greater benefi ts to the healing process of burns and alsofor patient health.Keywords: Burns; Wound Healing , Wounds and Injuries


2021 ◽  
Vol 72 (3) ◽  
pp. 49-64
Author(s):  
Predrag Stevanović

The coronavirus disease pandemic (2019) has burdened health systems around the world with a large number of severe patients in a short period of time. According to the law of large numbers, a significant number of critically ill COVID-19 patients appear in such conditions which require treatment in the intensive care unit. That percentage of those patients is around 3 - 5% in different countries. It is similar in Serbia; however, every rule has its exceptions. KBC "Dr Dragiša Mišović-Dedinje" in Belgrade has been determined to take care of the most difficult COVID-19 patients since the beginning of the epidemic due to its space, organizational and personnel possibilities. Out of the total number of patients treated in KBC "Dr Dragiša Mišović-Dedinje", about 25% of patients were treated in the intensive care unit for the above mentioned reasons. Guided by valid treatment protocols, Anesthesiology and Intensive Care clinic of the KBC "Dr Dragiša Mišović-Dedinje" has developed its own work protocols for rapid diagnosis, isolation and clinical management of such difficult patients. These protocols are important not only for the treatment of the most severe COVID-19 patients, but also for the best utilization of hospital resources, as well as for the prevention of the spread of the infection to the medical staff. Extensive experience in the treatment of critically ill patients was gained from the entire engagement during the epidemic, experienced doctors, anesthesiologists-intensivists with great knowledge in the field of work in the intensive care unit, but also managers of clinics and institutions, who can share their experience with health care policy makers. It is clear that in the future, the capacities and organization of work in the field of intensive care medicine should be redefined, as well as health workers should be trained to work in the most demanding field of medicine. Expert experience in the form of practical guidelines, derived from over fourteen months of continuous work in the red zone of COVID-19, where they fought for every breath of the patient, in this review are translated into simplified guidelines for orientation of those who find themselves in a similar situation.


2019 ◽  
Vol 41 (1) ◽  
pp. 1-7
Author(s):  
Pramesh S Shrestha ◽  
Moda N Marhatta ◽  
Subhash P Acharya ◽  
Ninadini Shrestha

Introduction: Tracheostomy is one of the frequent surgical procedure carried out in intensive care unit. Percutaneous tracheostomy is becoming increasingly popular compared to conventional open surgical tracheostomy in ICU. Methods: A prospective randomized trial with twenty patients in each group was conducted to compare the outcomes of percutaneous and surgical tracheostomy. Percutaneous tracheostomy was performed using Ciaglia Blue Rhino technique and surgical tracheostomy was performed using established technique. The outcomes were compared in relation to randomization to tracheostomy, completion of procedure, intra operative and post-operative complications, hospital length of stay and cost. Results: There were no major complications in either group. Most variables studied were not statistically significant. The two groups did not differ in terms of basic demographics or APACHE II score. The only variables to reach statistical significance were time duration from tracheostomy randomization to start of procedure and time taken for completion of procedure. It was mean 31.85±15.35 hours in Percutaneous Tracheostomy group and in Surgical Tracheostomy group it was mean 49.10±23.61 hours respectively (p<0.009). Time taken to perform percutaneous tracheostomy was mean 15.50±3.22 minutes and for surgical tracheostomy it was mean 20.30±3.38 minutes. (p<0.001). Conclusion: Percutaneous dilatational tracheostomy is simple, faster to perform and can be done at bedside to avoid considerable delay in the performance of open tracheostomy where there is high demand for elective and emergency procedures in operating room.  


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