Single Ventilation Research Articles

CFD numerical simulation of tunnel dust pollution control using a negative pressure double extraction ventilation system

To effectively control the dust pollution problem in tunneling, we studied the dust control and removal effect of a novel negative pressure double extraction ventilation system. We first investigated the spatial and temporal evolution law of wind flow and dust under single-pressure entry ventilation conditions, and found that the dust diffused to the tunnel exit within 150s. The average dust concentrations at the driver’s location, the front of the tunnel, and the back of the tunnel were 339.26, 278.39, and 232.43mg/m3, respectively, and the average dust concentration in the tunnel was 243.74mg/m3. Subsequently, based on the principle of air extraction and dust control, a negative pressure double extraction dust control system was constructed. The spatial and temporal evolution of wind flow and dust at different locations of the exhaust duct was investigated. When the exhaust duct A was 3.0m away from the floor of the roadway, CA=3.0m, and when the exhaust duct B was 4.0m away from the left wall of the roadway, CB=4.0m, the average dust concentrations at the driver’s location, the front of the tunnel, and the back of the tunnel were 45.62, 164.58, and 5.21mg/m3, respectively. Compared with single pressure-entry type ventilation, the dust prevention effect of the system improved by 86.55%, 40.88%, and 97.76%, respectively, and this installation position was determined to be the optimal position for dust removal.

Optimization of ventilation efficiency in tunnel-type underground spaces using response surface methodology: a case study of Yunlong Mountain civil defense in Xuzhou

Civil defense projects, designed as wartime underground spaces, often lack effective natural ventilation and have considerable depth, which complicates their use as public spaces in peacetime. However, the application of passive ventilation technologies can create effective airflow channels within these structures, significantly enhancing ventilation efficiency and thus improving the overall thermal comfort level. For this study, air age, along with average wind speed, temperature, and relative humidity as stipulated by the “Requirements for Environmental Sanitation of Civil Air Defense Works during Peacetime Use” (GBT 17216-2012), were selected as evaluation metrics. This paper compares the ventilation effectiveness between single ventilation shafts and multiple ventilation shafts under positive and negative pressure conditions in underground civil defense structures. The results indicate that negative pressure ventilation in multiple shaft configurations performs optimally across various ventilation approaches. Subsequently, the Response Surface Methodology (RSM) was utilized to further optimize the positioning of multiple ventilation shafts. The study examined the impact of three ventilation shaft locations on average wind speed, temperature, relative humidity, and air age, leading to an optimized design. Specifically, the optimal positions are 54.76 m for Shaft A, 51.45 m for Shaft B, and 79.85 m for Shaft C, achieving an average wind speed of 0.222 m/s, a temperature of 26 °C, a relative humidity reduction to 85.47%, and an average air age of 10.57 s. This research provides practical insights for the optimization of ventilation in underground civil defense facilities.

Experimental evaluation of alternative ceiling-based ventilation systems for long-range passenger aircraft

Alternative ventilation technology bricks, such as ceiling-based, sidewall-based or floor-based ventilation, are of high interest in terms of manufacturing and customization benefits for passenger aircraft. Two novel ventilation systems and state-of-the-art Mixing Ventilation (MV) were experimentally investigated under static conditions in a ground-based research facility. In case of Micro-Jet Ventilation, a perforated ceiling brings the air into the cabin as localized micro-jets with high momentum. Further, Low-Momentum Ceiling Ventilation characterized by a low-momentum air supply through planar and large-surface inlets is investigated. The measurement techniques and the test matrix were designed in order to quantify and evaluate thermal comfort, local air quality and energy efficiency of the ventilation concept. The results proved that there is not one single ventilation concept which optimizes all challenges: air quality, thermal comfort and energy efficiency. Both advantages and disadvantages were found for each ventilation system. In terms of technology bricks, the following main results were found: The average local age-of-air was between 5 and 14%, depending on the boundary conditions. It was lower for the ceiling-based concepts compared to state-of-the-art MV. At the same time the average CO2 concentration decreased by 7–14% for the ceiling-based concepts compared to MV. The local velocities in the vicinity of the passengers were similar for cruise conditions, whereas they decreased by up to 38% in case of hot-day-on-ground conditions for ceiling-based ventilation compared to MV. On the other hand, the heat removal efficiency was low for all concepts and the temperature stratification increased in case of ceiling-based ventilation.

To observe the clinical effect of lipoic acid combined with continuous positive airway pressure ventilation in treating obstructive sleep apnea-hypopnea syndrome and its effect on peripheral blood γ-aminobutyric acid and melatonin levels.

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common respiratory disease with potential lethality. At present, the commonly used treatment method is continuous positive airway pressure ventilation, but with the prolongation of the course of the disease, the effect of single ventilation on the improvement of oxidative stress levels is not good. Lipoic acid is a commonly used antioxidant in clinics. In this paper, lipoic acid combined with continuous positive airway pressure ventilation is used to explore whether it has a better therapeutic effect on patients. To probe into the clinical efficacy of lipoic acid combined with continuous positive airway pressure ventilation in the therapy of OSAHS. 82 patients with OSAHS who were cured in our hospital from March 2021 to September 2022 were prospectively collected as subjects. Based on different treatment methods, patients were grouped into a control group (43 cases) and an observation group (39 cases). The control group was treated with continuous positive airway pressure (CPAP), and the observation group was treated with lipoic acid based on control group. The therapeutic effects were measuredby apnea hypopnea index (AHI), oxygen saturation (SpO2), mean oxygen saturation (MSpO2), serum malondialdehyde (MDA), superoxide dismutase (SOD), hypoxia inducible factor-1α (HIF-1α) levels, peripheral blood γ-aminobutyric acid, melatonin levels. The clinical effectiveness of the observation group was better (P < 0.05). After treatment, AHI, the levels of MDA and HIF-1α in the observation group were lower and SpO2, MSpO2 and the level of SOD, γ- aminobutyric acid, and melatonin were higher than those in the control group (P < 0.05). The levels of γ- aminobutyric acid and melatonin were negatively correlated with the severity of symptoms, ESS, and AIS scores (P < 0.05). The clinical effect of lipoic acid combined with CPAP in the treatment of OSAHS is better, and it has a positive effect on the levels of γ-aminobutyric acid and melatonin in peripheral blood. Lipoic acid was added to the original method for treatment, and the therapeutic effect was greatly improved.

Development and evaluation of a mechanical ventilator-sharing system.

During the COVID-19 pandemic surge in the hospitalization of critically ill patients and the global demand for mechanical ventilators, alternative strategies for device sharing were explored. We developed and assessed the performance of a system for shared ventilation that uses clinically available components to individualize tidal volumes under a variety of clinically relevant conditions. The feasibility of remote monitoring of ventilators was also assessed. By using existing resources and off-the-shelf components, a ventilator-sharing system (VSS) that ventilates 2 patients simultaneously with a single device, and a ventilator monitoring system (VMS) that remotely monitors pulmonary mechanics were developed. The feasibility and effectiveness of VSS and VMS were evaluated in benchtop testing using 2 test lungs on a single ventilator, and then performance was assessed in translational swine models of normal and impaired lung function. In benchtop testing, VSS and VMS delivered the set individualized parameters with minimal % errors in test lungs under pressure- and volume-regulated ventilation modes, suggesting the highest precision and accuracy. In animal studies, the VSS and VMS successfully delivered the individualized mechanical ventilation parameters within clinically acceptable limits. Further, we found no statistically significant difference between the target and measured values. The VSS adequately ventilated 2 test lungs or animals with variable lung conditions. The VMS accurately displayed mechanical ventilation settings, parameters, and alarms. Both of these systems could be rapidly assembled for scaling up to ventilate several critically ill patients in a pandemic or mass casualty disaster situations by leveraging off-the-shelf and custom 3D printed components.

Study of highly efficient control and dust removal system for double-tunnel boring processes in coal mines

To reduce coal dust pollution during double-tunnel boring processes in coal mines, an efficient control and dust removal system has been established and studied by combining theoretical analysis, experimental investigations, numerical simulations, and on-site measurements. The self-developed new spiral air curtain generator can quickly form multiple axial and radial dust control air curtains that cover the entire tunnel section. When combined with a wet-type dust removal fan, they form an efficient dust control and elimination system for double-tunnel boring in coal mines. The airflow and dust control effects of the highly efficient dust control and removal system, single press-in ventilation, and ventilation with dust removal fans were compared. The results show that with the proposed system, the dust concentrations in the boring tunnel and supporting tunnel can be controlled within 18 and 15 m distances from the working face, respectively. The dust control efficiency is increased by 82 % and 85 %, respectively. Hence, the dust concentrations in the coal mine are effectively reduced.

Effect of different multichannel ventilation methods on aerobic composting and vegetable waste gas emissions.

Aerobic composting, especially semipermeable membrane-covered aerobic fermentation, is known to be an effective method for recycling and reducing vegetable waste. However, this approach has rarely been applied to the aerobic composting of vegetable waste; in addition, the product characteristics and GHG emissions of the composting process have not been studied in-depth. This study investigated the effect of using different structural ventilation systems on composting efficiency and greenhouse gas emissions in a semipermeable membrane-covered vegetable waste compost. The results for the groups (MV1, MV2, and MV3) with bottom ventilation plus multichannel ventilation and the group (BV) with single bottom ventilation were compared here. The MV2 group effectively increased the average temperature by 19.06% whilst also increasing the degradation rate of organic matter by 30.81%. Additionally, the germination index value reached more than 80%, 3 days in advance. Compared to those of the BV group, the CH4, N2O, and NH3 emissions of MV2 were reduced by 32.67%, 21.52%, and 22.57%, respectively, with the total greenhouse gas emissions decreasing by 24.17%. Overall, this study demonstrated a multichannel ventilation system as a new method for improving the composting efficiency of vegetable waste whilst reducing gas emissions.

A Single 10-Minute E-cigarette Vapor Exposure Reduces Tidal Volume and Minute Ventilation in Normoxia and Normobaric Hypoxia in Adult Rats.

The present study investigated the effects of a single 10-minute exposure to e-cigarette vapor on ventilation in adult male Long-Evans rats. Ventilation was recorded using awake, unrestrained whole-body plethysmography. Baseline recordings were taken the day before full-body exposure to either room air (n = 9; air control group) or e-cigarette vapor (n = 9; treatment group). Post-exposure recordings were taken immediately after the 10-minute room air or vapor exposure. As part of the ventilation protocol, in addition to recording the subject's ventilation in room air, the subjects were also exposed to 10% oxygen (balanced with nitrogen) to assess the effects of e-cigarette vapor on an increased drive to breathe. Ventilation data were analyzed using a 2x2x2 mixed-model ANOVA measuring treatment (vape vs. air) x time (baseline vs. post-treatment) x condition (normoxia vs. hypoxia) for breathing frequency, tidal volume, and minute ventilation. Breathing frequency increased in both treatment groups (air and vape) with exposure to normobaric hypoxia (p < 0.001), with no effect of time (baseline vs. post-treatment) for either group. Tidal volume increased in both treatment groups (air and vape) with exposure to normobaric hypoxia (p < 0.001), and an effect of time (baseline vs. post-treatment) was observed (p = 0.010) for the vape group. Minute ventilation increased in both treatment groups (air and vape) with exposure to normobaric hypoxia (p < 0.001), and an effect of time (baseline vs. post-treatment) was observed (p < 0.001) for the vape group. In conclusion, immediately following a single 10-minute e-cigarette vapor exposure, both tidal volume and minute ventilation were reduced during normoxia and normobaric hypoxia, indicating a decrease in ventilation after a single 10-minute e-cigarette vapor exposure. Furthermore, this exposure also blunted the physiological response to acute hypoxia exposure. Subjects in the vape group, while breathing more rapidly as expected, experienced shallower breathing than the air group during hypoxia. The findings in this study confirm that vaping could result in reduced lung function.

Re-Evaluating Cross-Contamination: Additional Trials on Co-Ventilation

BackgroundMedical equipment can become scarce in disaster scenarios. Prior work has reported that four sheep could be ventilated together on a single ventilator. Others found that this maneuver is possible when needed, but no one has yet investigated whether cross-contamination occurs in co-ventilated individuals. ObjectiveOur goal was to investigate whether an infection could spread between co-ventilated individuals. MethodsFour 2-L anesthesia bags were connected to a sterilized ventilator circuit that used heat and moisture exchange filters and bacterial and viral filters, as would be expected in this dire scenario. Serratia marcescens was inoculated into “lung” no. 1. After running for 24 h, each lung and three additional points in the circuit were cultured to see whether S. marcescens had spread. These cultures were examined at 24 and 48 h to assess for cross-contamination. This entire procedure was performed three times. ResultsS. marcescens was not found in lung no. 2, 3, or 4 or the three additional sites on the expiratory limb at 24 and 48 h in all three trials. ConclusionsCross-contamination does not occur within 24 h using the described ventilator circuit configuration.

Housing Adaptations to Climate: Vernacular Settlements on the Kahayan Riverbank at Palangka Raya, Indonesia

Producing buildings that can adapt to climatic conditions is one of the notable abilities of people who improve the quality of their houses. Lake Tundai is a residential area in Palangka Raya, Indonesia, occupied by a fishing community, isolated and only accessible through the Kahayan River. People prefer wood materials for house construction, and with a largely impoverished population, they remain in those houses they have inherited from the past. However, it is an example of a village resistant to the effects of global climate change, because their houses are climate-friendly, although natural breeze is the only thermal comfort enjoyed by the inhabitants of Lake Tundai. Using thermal performance simulation on the Tundai Lake houses, this research presents four types applied to four variable elements through the Ecotect analysis program to ascertain how the houses deal with the climate. Based on the climatic conditions in Lake Tundai. Type 2 with stilts, light roof, light walls, single ventilation, and ceiling is the most suitable model condition in Tundai Lake. The research concluded in 2023 that the influence of the building floor height from the ground may affect the thermal comfort in the room. If the floor height over the water level is below 1.2 meters. This study proposes an example of housing adaptation using wood materials nearby the water.

Ventilator management and risk of air leak syndrome in patients with SARS-CoV-2 pneumonia: a single-center, retrospective, observational study

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia is reportedly associated with air leak syndrome (ALS), including mediastinal emphysema and pneumothorax, and has a high mortality rate. In this study, we compared values obtained every minute from ventilators to clarify the relationship between ventilator management and risk of developing ALS.MethodsThis single-center, retrospective, observational study was conducted at a tertiary care hospital in Tokyo, Japan, over a 21-month period. Information on patient background, ventilator data, and outcomes was collected from adult patients with SARS-CoV-2 pneumonia on ventilator management. Patients who developed ALS within 30 days of ventilator management initiation (ALS group) were compared with those who did not (non-ALS group).ResultsOf the 105 patients, 14 (13%) developed ALS. The median positive-end expiratory pressure (PEEP) difference was 0.20 cmH2O (95% confidence interval [CI], 0.20–0.20) and it was higher in the ALS group than in the non-ALS group (9.6 [7.8–20.2] vs. 9.3 [7.3–10.2], respectively). For peak pressure, the median difference was -0.30 cmH2O (95% CI, -0.30 – -0.20) (20.4 [17.0–24.4] in the ALS group vs. 20.9 [16.7–24.6] in the non-ALS group). The mean pressure difference of 0.0 cmH2O (95% CI, 0.0–0.0) (12.7 [10.9–14.6] vs. 13.0 [10.3–15.0], respectively) was also higher in the non-ALS group than in the ALS group. The difference in single ventilation volume per ideal body weight was 0.71 mL/kg (95% CI, 0.70–0.72) (8.17 [6.79–9.54] vs. 7.43 [6.03–8.81], respectively), and the difference in dynamic lung compliance was 8.27 mL/cmH2O (95% CI, 12.76–21.95) (43.8 [28.2–68.8] vs. 35.7 [26.5–41.5], respectively); both were higher in the ALS group than in the non-ALS group.ConclusionsThere was no association between higher ventilator pressures and the development of ALS. The ALS group had higher dynamic lung compliance and tidal volumes than the non-ALS group, which may indicate a pulmonary contribution to ALS. Ventilator management that limits tidal volume may prevent ALS development.

Maintaining an acceptable indoor air quality of spaces by intentional natural ventilation or intermittent mechanical ventilation with minimum energy use

Ventilation is essential for maintaining good indoor air quality (IAQ). However, many buildings continue to suffer from inadequate ventilation due to a lack of either sufficient natural ventilation or proper operation of mechanical ventilation. During the pandemic of COVID-19, several Chinese guidelines have suggested that the household rooms for isolating infected persons and the classrooms that are not equipped with mechanical ventilation should open the windows for at least 30 min twice a day. This study first investigated whether this way of natural ventilation could ensure an acceptable IAQ. Then, the relationships between ventilation duration, ventilation frequency, and IAQ under different air change rates per hour (ACH) were examined to understand how to optimize ventilation design and operation in an efficient manner. When the ACH is ≥ 6 h−1, an acceptable IAQ can be achieved under the recommended ventilation frequency. An increase in ACH would improve the IAQ and reduce the IAQ difference caused by different CO2 generation rate per unit volume (Gr/V) values. Furthermore, simply increasing single ventilation duration while maintaining constant ventilation frequency is not an effective way to improve IAQ, as the improvement decreases as the ventilation duration is increased. Finally, when total ventilation duration is constant, increasing ventilation frequency can significantly improve the ventilation efficiency and thus IAQ, laying the groundwork for ventilation design that balances IAQ and energy use. The findings provide feasible and economical solutions for ventilation of buildings where conventional mechanical ventilation systems are not affordable.

COVID, Co-Ventilation, and Cross-contamination

Introduction:During the COVID-19 pandemic, consideration was given to co-ventilating multiple patients on a single ventilator. Prior work had shown that this procedure was possible by ventilating four adult-size sheep for twenty-four hours, and other groups had performed this maneuver during dire circumstances. However, no investigation had examined the safety regarding cross-contamination. The purpose of our studies was to investigate if an infection could spread between individuals who were being co-ventilated.Method:Four sterile two-liter anesthesia bags were connected to a sterilized ventilator circuit to simulate the co-ventilated patients’ “lungs.” The circuit utilized Heat and Moisture Exchange filters and bacterial/viral filters, which were strategically inserted to prevent the transmission of infectious droplets. Serratia marcescens was inoculated into “lung” number one. The circuit was then run for 24 hours, after which each “lung” and three additional points in the circuit were cultured to see if S. marcescens had spread. These cultures were examined at 24 and 48 hours to assess for cross-contamination. This entire procedure was performed a total of four times.Results:S. marcescens was not identified in lungs two, three, or four or the three additional sampling sites on the expiratory limb of the tubing at 24 and 48 hours in all four trials.Conclusion:Cross-contamination between co-ventilated patients did not occur within 24 hours utilizing the described ventilator circuit configuration.

Mechanical ventilation in dogs and cats with tick paralysis.

Respiratory failure from tick paralysis (TP) is an important cause of mortality in cats and dogs in Australia, occurring from a combination of respiratory muscle paralysis, upper respiratory tract obstruction and pulmonary disease. Patients may require positive-pressure ventilation in management of any combination of hypoxemia, hypoventilation or respiratory fatigue, but may also require airway management due to laryngeal paralysis. No single ventilation strategy is recommended due to the heterogenous disease presentations. Lung protective ventilation should be used in patients with pulmonary disease. Due to local and systemic effects of TP, patients are at higher risk of complications such as aspiration pneumonia and corneal ulceration and may have additional intravenous fluid and nutritional considerations. Treatment with hyperimmune serum is associated with improved outcomes. Prognosis is considered good with documented survival to discharge (STD) of 52.6-77% for animals with TP ventilated with lung disease and 90.5% for animals without lung disease. Median reported duration of ventilation for TP ranges from 23 to 48 h (range 3 h-10 days). The severity of individual neuromuscular signs and the presence of associated conditions such as aspiration pneumonia and laryngeal paralysis may necessitate longer periods of mechanical ventilation. This review aims to summarize the current recommendations regarding indications, management and prognosis of cats and dogs undergoing MV for TP and to identify areas for future research.

Simultaneous mechanical ventilation of several patients with a single ventilator.

Simultaneous mechanical ventilation of several patients with a single ventilator might reduce the deficit of these devices for the care of patients with acute respiratory failure due to Covid-19. To communicate the results of a mechanical ventilation exercise with a ventilator in a lung simulator, and simultaneously in two and four. No statistically significant differences were observed between programmed, recorded and measured positive end-expiratory pressure, mean airway pressure and peak pressure, except when simultaneously ventilating four lung simulators. Simultaneous mechanical ventilation should be implemented by medical personnel with experience in the procedure, be restricted to two patients and carried out in the intensive care unit.

The Transport of Respiratory Distress Syndrome Twin Newborns: The 27-Year-Long Experience of Gaslini Neonatal Emergency Transport Service Using Both Single and Double Ventilators

ObjectiveTwin pregnancy rates have increased in the past 30 years. We describe the experience of the Neonatal Emergency Transport Service of the Gaslini Hospital, Genoa, Italy, in the transport of twin newborns. MethodsThis was a retrospective study (1996-2021); 7,852 medical charts from the Neonatal Emergency Transport Service were reviewed. We included all twin newborns who were transported with respiratory distress syndrome in the study. We split the included patients into 2 groups (group A and group B) based on if they were simultaneously ventilated by a single ventilator or by 2 different ventilators, and then each group was split by the different types of ventilation (nasal continuous positive airway pressure or intermittent positive pressure ventilation). The pH level, base excess, O2 saturation, Pco2, body temperature, plasma glucose, and Transport Risk Index of Physiologic Stability score were recorded at departure and arrival. ResultsOne hundred thirty-six patients were included (68 pairs of twins); group A consisted of 92 newborns and group B 44 newborns. Although some significant differences were observed (statistic), none of these had real clinical significance. ConclusionTransporting respiratory distress syndrome twin newborns is challenging. Our study provided a 27-year experience in the field. Transporting twins by a single ventilator is possible, but, in our opinion, using 2 ventilators mounted on the same transport module is the best possible choice in terms of clinical performance, logistics, and cost.

A Multivent System for Non-Invasive Ventilation: Solving the Problem of Ventilator Shortage During the COVID-19 Pandemic

The COVID-19 pandemic has caused a severe global problem of ventilator shortage. Placing multiple patients on a single ventilator (ventilator sharing) or dual patient ventilation has been proposed and conducted to increase the cure efficiency for ventilated patients. However, the ventilator-sharing method needs to use the same ventilator settings for all the patients, which cannot meet the ventilation needs of different patients. Therefore, a novel multivent system for non-invasive ventilation has been proposed in this study. The close loop system consists of the proportional valve and the flow-pressure sensor can regulate the airway pressure and flow for each patient. Multiple ventilation circuits can be combined in parallel to simultaneously meet patients’ ventilation demands. Meanwhile, the mathematical model of the multivent system is established and validated through experiments. The experiments for different inspired positive airway pressure (IPAP), expired positive airway pressure (EPAP), inspiratory expiratory ratio (I:E), and breath per minute (BPM) have been conducted and analyzed to test the performance of the multivent system. The results show that the multivent system can realize the biphasic positive airway pressure (BIPAP) ventilation mode in non-invasive ventilation without interfering among the three ventilation circuits, no matter the change of IPAP, EPAP, I:E, and BPM. However, pressure fluctuation exists during the ventilation process because of the exhaust valve effect, especially in EPAP control. The control accuracy and stability need to be improved. Nevertheless, the novel designed multivent system can bring innovation to the current mechanical ventilation system and solve the problem of ventilator shortage for major, new, and emerging respiratory infectious diseases in the future.

Automatic air volume control system for ventilation of two patients using a single ventilator: a large animal model study

The COVID-19 pandemic outbreak led to a global ventilator shortage. Hence, various strategies for using a single ventilator to support multiple patients have been considered. A device called Ventil previously validated for independent lung ventilation was used in this study to evaluate its usability for shared ventilation. We performed experiments with a total number of 16 animals. Eight pairs of pigs were ventilated by a ventilator or anesthetic machine and by Ventil for up to 27 h. In one experiment, 200 ml of saline was introduced to one subject’s lungs to reduce their compliance. The experiments were analyzed in terms of arterial blood gases and respiratory parameters. In addition to the animal study, we performed a series of laboratory experiments with artificial lungs (ALs). The resistance and compliance of one AL (affected) were altered, while the tidal volume (TV) and peak pressure (Ppeak) in the second (unaffected) AL were analyzed. In addition, to assess the risk of transmission of pathogens between AL respiratory tracts, laboratory tests were performed using phantoms of virus particles. The physiological level of analyzed parameters in ventilated animals was maintained, except for CO2 tension, for which a permissive hypercapnia was indicated. Experiments did not lead to injuries in the animal’s lungs except for one subject, as indicated by CT scan analysis. In laboratory experiments, changes in TV and Ppeak in the unaffected AL were less than 11%, except for 2 cases where the TV change was 20%. No cross-contamination was found in simulations of pathogen transmission. We conclude that ventilation using Ventil can be considered safe in patients undergoing deep sedation without spontaneous breathing efforts.

Use of a novel "Split" ventilation system in bench and porcine modeling of acute respiratory distress syndrome.

Split ventilation (using a single ventilator to ventilate multiple patients) is technically feasible. However, connecting two patients with acute respiratory distress syndrome (ARDS) and differing lung mechanics to a single ventilator is concerning. This study aimed to: (1) determine functionality of a split ventilation system in benchtop tests, (2) determine whether standard ventilation would be superior to split ventilation in a porcine model of ARDS and (3) assess usability of a split ventilation system with minimal specific training. The functionality of a split ventilation system was assessed using test lungs. The usability of the system was assessed in simulated clinical scenarios. The feasibility of the system to provide modified lung protective ventilation was assessed in a porcine model of ARDS (n = 30). In bench testing a split ventilation system independently ventilated two test lungs under conditions of varying compliance and resistance. In usability tests, a high proportion of naïve operators could assemble and use the system. In the porcine model, modified lung protective ventilation was feasible with split ventilation and produced similar respiratory mechanics, gas exchange and biomarkers of lung injury when compared to standard ventilation. Split ventilation can provide some elements of lung protective ventilation and is feasible in bench testing and an in vivo model of ARDS.

Thoracic and diaphragmatic endometriosis: an overview of diagnosis and surgical treatment.

Thoracic endometriosis is a rare disease that can lead to a variety of clinical manifestations. There are currently no guidelines for optimal diagnosis and management of the disease. The purpose of this review is to provide an overview of the diagnosis and surgical treatment of thoracic endometriosis. Various imaging modalities, including computed tomography (CT), MRI and ultrasound, have been reported in the detection of thoracic endometriosis. MRI is the most sensitive imaging study and may aid in preoperative planning. Histopathology of a biopsied lesion remains the gold standard for diagnosis. Surgical management of thoracic endometriosis may involve laparoscopy and/or thoracoscopy, and surgical planning should include preparation for single ventilation capability. A multidisciplinary approach involving a gynaecologic surgeon and thoracic surgeon may be considered. Repairing diaphragm defects and pleurodesis are shown to decrease recurrent symptoms. Although optimal diagnostic testing remains uncertain, a high clinical suspicion for thoracic endometriosis is critical to ensure prompt diagnosis and treatment in order to prevent recurrent symptoms and progression to more serious sequalae. Minimally invasive surgical techniques are becoming increasingly utilized and allow for thorough evaluation and treatment of thoracic endometriosis.