One-way Valve Research Articles

Dynamic solution of high pressure tubing

In the real environment, the pressure of high-pressure oil pipe is not always stable due to the process of oil in and out. We created a simulation experiment: to set the time for each opening of the one-way valve to change the pressure in the high-pressure tubing, ensuring that the pressure remains relatively stable under the initial pressure condition 100Mpa. By using the simulated conditions, we obtained the relationship between elastic modulus E and pressure P with high fitting degree, and deduced the relationship between pressure P and density temperature. Since the tubing size V is constant, we established the approximate dynamic balance model of fuel mass in high pressure tubing according to the mV mass. Since the opening time of the one-way valve is unknown, the simplified operation method is used to find the approximate solution and then the dichotomy method is used to find the results in this range. Our contribution is that we proposed a method to control the pressure steadily and rapidly in simulation. For each search result, the iterative method is used to obtain the mean pressure of the injection pipe after the pressure is stable, and the objective function is established to make the average pressure reach 150Mpa. Finally, we present the exact solution with MATLAB simulation.

The Pressure Control of High-pressure Tubing

This article mainly studies the pressure control of high-pressure tubing. Based on the theoretical basis of the pressure formula, a pressure variation model based on the pressure formula is established and solved by the enumeration method within the range. In the process of solving the model of the open time of the one-way valve in the problem, first, establish a model of the pressure change of the inlet and outlet oil. Using integral thinking, we get the oil density under each pressure. Based on the tubing pressure requirements in the corresponding time period together with the relationship between the net mass of the inlet and outlet oil per unit time, the relationship between the opening time of the inlet valve and the pressure is obtained by using the principle of the inlet valve opening time to control the inlet mass. The results of the corresponding pressure requirements are obtained through the enumeration method within the range.

One-Way Valve Method for Achieving Effective Flow Reversal on Carotid Artery Stenting.

We report a simplified method of manual transfusion with a one-way valve during carotid artery stenting (CAS) with flow reversal. A 77-year-old man with cervical internal carotid artery stenosis who developed vulnerable plaques was scheduled for CAS using flow reversal. Blood flow reversal was naturally caused by the arteriovenous pressure gradient, and a method with a one-way valve, which enables simplified manual transfusion using a syringe technique, was used for the patient. CAS was completed without distal embolization. Manual transfusion can be simplified using a one-way valve in cases of flow reversal during CAS, which often require complicated procedures.

Ambulatory management of secondary spontaneous pneumothorax: a randomised controlled trial.

Secondary spontaneous pneumothorax (SSP) is traditionally managed with an intercostal chest tube attached to an underwater seal. We investigated whether use of a one-way flutter valve shortened patients' length of stay (LoS).This open-label randomised controlled trial enrolled patients presenting with SSP and randomised to either a chest tube and underwater seal (standard care: SC) or ambulatory care (AC) with a flutter valve. The type of flutter valve used depended on whether at randomisation the patient already had a chest tube in place: in those without a chest tube a pleural vent (PV) was used; in those with a chest tube in situ, an Atrium Pneumostat (AP) valve was attached. The primary end-point was LoS.Between March 2017 and March 2020, 41 patients underwent randomisation: 20 to SC and 21 to AC (13=PV, 8=AP). There was no difference in LoS in the first 30 days following treatment intervention: AC (median=6 days, IQR 14.5) and SC (median=6 days, IQR 13.3). In patients treated with PV there was a high rate of early treatment failure (6/13; 46%), compared to patients receiving SC (3/20; 15%) (p=0.11) Patients treated with AP had no (0/8 0%) early treatment failures and a median LoS of 1.5 days (IQR 23.8).There was no difference in LoS between ambulatory and standard care. Pleural Vents had high rates of treatment failure and should not be used in SSP. Atrium Pneumostats are a safer alternative, with a trend towards lower LoS.

Delivery system can vary ventilatory parameters across multiple patients from a single source of mechanical ventilation.

Current limitations in the supply of ventilators during the Covid19 pandemic have limited respiratory support for patients with respiratory failure. Split ventilation allows a single ventilator to be used for more than one patient but is not practicable due to requirements for matched patient settings, risks of cross-contamination, harmful interference between patients and the inability to individualize ventilator support parameters. We hypothesized that a system could be developed to circumvent these limitations. A novel delivery system was developed to allow individualized peak inspiratory pressure settings and PEEP using a pressure regulatory valve, developed de novo, and an inline PEEP 'booster'. One-way valves, filters, monitoring ports and wye splitters were assembled in-line to complete the system and achieve the design targets. This system was then tested to see if previously described limitations could be addressed. The system was investigated in mechanical and animal trials (ultimately with a pig and sheep concurrently ventilated from the same ventilator). The system demonstrated the ability to provide ventilation across clinically relevant scenarios including circuit occlusion, unmatched physiology, and a surgical procedure, while allowing significantly different pressures to be safely delivered to each animal for individualized support. In settings of limited ventilator availability, systems can be developed to allow increased delivery of ventilator support to patients. This enables more rapid deployment of ventilator capacity under constraints of time, space and financial cost. These systems can be smaller, lighter, more readily stored and more rapidly deployable than ventilators. However, optimizing ventilator support for patients with individualized ventilation parameters will still be dependent upon ease of use and the availability of medical personnel.

Phosphoglucoisomerase Is an Important Regulatory Enzyme in Partitioning Carbon out of the Calvin-Benson Cycle.

Phosphoglucoisomerase (PGI) isomerizes fructose 6-phosphate (F6P) and glucose 6-phosphate (G6P) in starch and sucrose biosynthesis. Both plastidic and cytosolic isoforms are found in plant leaves. Using recombinant enzymes and isolated chloroplasts, we have characterized the plastidic and cytosolic isoforms of PGI. We have found that the Arabidopsis plastidic PGI Km for G6P is three-fold greater compared to that for F6P and that erythrose 4-phosphate is a key regulator of PGI activity. Additionally, the Km of spinach plastidic PGI can be dynamically regulated in the dark compared to the light and increases by 200% in the dark. We also found that targeting Arabidopsis cytosolic PGI into plastids of Nicotiana tabacum disrupts starch accumulation and degradation. Our results, in combination with the observation that plastidic PGI is not in equilibrium, indicates that PGI is an important regulatory enzyme that restricts flow and acts as a one-way valve preventing backflow of G6P into the Calvin-Benson cycle. We propose the PGI may be manipulated to improve flow of carbon to desired targets of biotechnology.

Structure design, mathematical modeling and dynamical performance tests of a new viscoelastic elastomer damper

In order to improve the ride of passive suspension system for the military vehicles in all kinds of roads, a new viscoelastic elastomer damper with one-way throttle valve structure was designed, and its working principle was set forth. A variable rigidity Maxwell fluid model was used to model viscoelastic elastomer damper, and the resistance formulae of elastomer damper in the input process and return process were conducted respectively, the shock experiment proved that the shock experiments proved the reliability of mathematical modeling. Finally, the dynamical performance tests about the continuous impact test, durability test and attenuation performance test were carried out on the elastomer damper, and the experimental results have shown that the elastomer damper has good impact resistance and stability performance.

An evaluation of hard-shell venous reservoir integrated pressure relief valve pressure mitigation performance.

Vacuum assisted venous drainage (VAVD) requires the sealing of the hard-shell venous reservoir, thereby creating circumstances where reservoir pressurization may occur. Manufacturers utilize integrated pressure relief valves (IPRV) to mitigate pressurization risk; however, accidents have been reported even with these devices. We have undertaken a performance evaluation of IPRV's in a large number of hard-shell venous reservoirs. Reservoirs were sealed and gas insufflated while measuring reservoir internal pressure. Linear regression models were developed to depict the association between internal pressure and gas inflow rate. External secondary one-way valves (ESOV) were assessed for pressure mitigation performance. An assisted venous drainage survey was circulated to Canadian Clinical Perfusionists. The reservoirs tested were adult (n = 9, 64%) and pediatric (n = 5, 36%) designs. Significant variability (p < 0.001) in internal reservoir pressures (range: 0.04-161.41 mmHg) was observed across the titrated gas inflow rate (0.5-10.0 l/min). The regression models demonstrate excellent predictive performance (SE: 0.008-0.309). ESOV's reduce the reservoir pressure below that of the IPRV; however, they cannot eliminate reservoir pressurization. The survey showed a majority (91%) of respondents use VAVD, and reservoir pressurization events occur regularly (18%). Significant variability among reservoir's IPRV to mitigate reservoir pressurization exists. The predictive models are extremely accurate at estimating the internal pressure. ESOV performance limitations moderate their utility as a backup pressure mitigation technique. A significant number of reservoir pressurization events are occurring with the use of VAVD. As a result, standardized communication from manufacturers on the purpose and performance of IPRV is recommended in order to delineate the limitations of these devices.

Reduced Calf Muscle Pump Function Is a Risk Factor for Venous Thromboembolism and Mortality

Background: Venous return from the lower extremities is pumped upwards to the right side of the heart in a process that is facilitated by one-way valves and the venous muscle pump, of which the calf muscle pump is a major contributor1-3. Venous plethysmography can quantitatively assess calf pump function (CPF). The association between the CPF and venous thromboembolism (VTE) has not been investigated. Methods: Venous plethysmography (VP) data (strain gauge or air plethysmography) from the Mayo Clinic Vascular Lab database (1998-2015) of CPF (bilaterally reduced, unilaterally reduced, and bilateral normal) were examined in Olmsted County Residents. The Rochester Epidemiology Project (REP) captures the population of Olmsted County and contains demographic information, medical diagnoses, hospital admissions, and surgical procedures as well as validated VTE events and death. Patients with signs of obstructed outflow in either extremity on the venous plethysmography (a possible sign of acute or chronic deep vein thrombosis) study were excluded. Patients with a history of VTE diagnosed before the physiologic study were also excluded. If more than one measurement of calf muscle pump function was performed, only the first measurement was used. The primary outcome was a composite of any VTE, including proximal and distal deep vein thrombosis (DVT) and pulmonary embolism (PE). Results: 1703 Olmsted County residents had venous plethysmography studies performed. MN research authorization was denied in 64 patients and 107 were excluded for any documented VTE preceding index VP study. 1532 patients with recorded CPF (28% air and 72% strain gauge plethysmography) were studied: 591 (38.5%) had normal CPF, 353 (23.0%) had unilateral reduced CPF (rCPF), and 588 (38.3%) had bilateral rCPF. The mean age was 64.4 (SD 18.4), 68.9% were female, and the mean BMI was 29.5 (SD 6.4). Any VTE occurred in 87 patients (5.7%) after a mean follow up of 10.9 years (range 0-22.0 years). Isolated lower extremity DVT (excluding concurrent PE) occurred in 49 patients and PE+/-DVT occurred in 38 patients. Death occurred in 352 patients (23%). Bilateral rCPF compared to bilateral normal CPF was associated with VTE (p=0.007), DVT only (p=0.02) and death (p&amp;lt;0.001) but not PE+/-DVT (p=0.13). Unilateral rCPF compared to bilateral normal CPF was not associated with VTE, but was associated with death (p&amp;lt;0.001). Kaplan-Meier curves for VTE and death are shown in Figure 1. The hazard ratio for bilateral rCPF compared to bilateral normal CPF for VTE was 2.0 (95% CI 1.2-3.4) and for DVT only was 2.2 (95% CI 1.1-4.2). A sensitivity analysis for the main outcome of VTE did not show significant interaction based on the type of plethysmography (strain vs. air), by age stratified at 65 years, sex, or BMI stratified at 30 (p&amp;gt;0.1 for each comparison). Conclusion: In this population-based study of Olmsted County residents with no prior VTE, rCPF function as measured by venous plethysmography is associated with increased risk for VTE, particularly lower extremity proximal DVT. More research is required to understand what additional measures of venous physiology influence these findings and whether CPF could be used in VTE risk stratification. Disclosures No relevant conflicts of interest to declare.

An Experimental Investigation of Synergistic Pulsation Bubble Column with Inverse Fluidized Loop Reactor for Removing Chloroform from Wastewater

In this study, the feasibility of using the developed design for the removal of organic pollutants from wastewater was examined. The design includes the integration of the work of both pulsation bubble column (PBC) and the inverse fluidization airlift loop reactor (IFALR). The experimental podium was fabricated and installed which that consists of a bubble column with a diameter of 5 cm and a height of 210 cm, contains at the top a solenoid valve which is electrically turned via at least two timers, and its connection with the loop reactor by a one-way valve. The loop reactor consists of an outer rectangular tube with dimensions (29 cm long x 15.5 cm wide x 150 cm high) and an internal draft tube with 9 cm diameter and 120 cm long as granular activated carbon is put as an adsorbent in the annulus region between the inner and outer tube. Experiments were conducted using one of the organic pollutants namely chloroform, with a work scenario that includes changing both the airflow rate (2-20) liters/minute, the total survival time of the treatment (5-60) minutes, the molar ratio of the chloroform pollutant to the oxidizing agent of hydrogen peroxide (1/10 - 1/20). The results showed removal efficiency near to 89%, and it gives an indication of the success of the proposed design, with the possibility of recycling the treated water and releasing it to the environment due to the low risk of the organic pollutant in it.

Exploring a New Management Option for Patients With Refractory Ascites: The PeriLeve Device

Abstract Cirrhosis of the liver is often accompanied by refractory ascites, a condition characterized by fluid buildup in the peritoneal cavity that does not respond to diuretics or recurs shortly after therapeutic paracentesis. There are several management strategies in practice including large-volume paracentesis, transjugular intrahepatic portosystemic shunts, peritoneovenous shunting, and liver transplant. However, each of these options come with limitations such as high cost, poor efficacy, and increased risk of complications. This article explores a new management strategy with a novel biopowered shunt, the PeriLeve device, that moves fluid from the peritoneal cavity to the urinary bladder using natural changes in intra-abdominal pressure (IAP). By doing so, PeriLeve shifts the current paradigm of care from the hospital to the home which reduces costs to healthcare providers and patients while improving quality of life. The basic design of the pump consists of two check (i.e., one-way) valves on either side of a fluid filled cavity which is separated from an air cavity by an elastomeric membrane. This article presents benchtop testing results of a prototype PeriLeve pump. The performance of the pump was analyzed along six parameters: change in intra-abdominal pressure, valve opening pressure, membrane thickness, membrane stiffness, membrane surface area, and air cavity volume. Initial results indicate that, with future optimizations, the pump can ultimately move a clinically significant volume of fluid.

Effects of Elevated Downstream Pressure and the Role of Smooth Muscle Cell Coupling through Connexin45 on Lymphatic Pacemaking.

Lymphatic vessels rely on spontaneous lymphatic muscle cell (LMC) contractions and one-way intraluminal valves to efficiently pump lymph and return it into the bloodstream. Intraluminal pressure is known to regulate the contractile function of lymphatics, with pressure elevation leading to increased contraction frequency and decreased amplitude. Contractions are normally initiated by a dominant pacemaker and are highly entrained among strongly coupled LMCs. Previously, we found that connexin45 is the major connexin isoform mediating LMC-LMC electrical coupling. Lymphatics from mice lacking smooth muscle connexin45 display uncoordinated, impaired contractions. Here, we utilized this connexin45-deficient model, pressure myography, and recently developed, novel analytical tools to assess the effects of elevated downstream pressure on the number, location, and frequency of lymphatic pacemakers. Our results show that, in vessels from healthy controls, an increase in downstream pressure resulted in the recruitment/development of new pacemakers and increased contractile frequency while a dominant pacemaker continued to be observed. In contrast, vessels from connexin45-deficient mice displayed significantly more pacemakers, but none were dominant; this worsened with elevated downstream pressure. These results suggest a potential protective mechanism through which the lymphatic vasculature adapts to transient increases in downstream pressure, but which may not be sustained in scenarios with chronic elevated downstream pressure.

CLOSURE OF A BRONCHOPLEURAL FISTULA WITH ONE-WAY ENDOBRONCHIAL VALVES WHILE ON HIGH-FREQUENCY OSCILLATORY VENTILATION

SESSION TITLE: Medical Student/Resident Critical Care Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: A bronchopleural fistula (BPF) is an abnormal sinus tract between the tracheobronchial tree and the pleural space whose presence is associated with increased morbidity, mortality and extended hospital duration. Additionally, a large airway defect can result in refractory hypercapnia rendering periprocedural ventilation exceedingly difficult. Preferred definitive management is surgical resection. However, for the non – surgical candidate a handful of bronchoscopic and pleural interventions, including compassionate placement of one – way valves, have been successfully described for the treatment of a persistent BPF. CASE PRESENTATION: A 25 – year old male with restrictive lung disease secondary to severe muscular dystrophy was admitted to a surgical ICU after a difficult intubation resulting in an emergent cricothyroidotomy and placement of two unilateral surgical chest tubes. The patient’s underlying lung disease combined with intra-parenchymal placement of one of the chest tubes resulted in mixed respiratory failure. Multiple modes of conventional ventilation with neuromuscular blockade were trialed with persistent life threatening hypercapnia prior to being stabilized on a High – Frequency Oscillatory Ventilator (HFOV). His clinical course was complicated by bacteremia, fungemia and a large continuous air-leak. On bronchoscopy, the right upper lobe (RUL) was identified as the anatomic origin of the defect following occlusion with a 5.5 Fr Fogarty Balloon catheter and resolution of the air leak. Definitive management was attempted by placement of four one – way Spriation endobronchial values within the RUL segments while concurrently on HFOV. Significant decrement of the air leak was successfully obtained as well as improvement of his oxygenation and ventilation. DISCUSSION: Chest trauma, including inadvertent intra – parenchymal placement of a chest tube is a rare cause of a bronchopleural fistula. We describe a case of a BPF complicated by a large persistent air leak with initial management via ventilation on a high frequency oscillatory ventilator followed by a novel attempted at definitive treatment with placement of endobronchial values while concurrently on HFOV. CONCLUSIONS: Compassionate placement of endobronchial one – way vales can be safely executed while on HFOV for management of a severe BPF in non – surgical candidates. Reference #1: Gilbert, C. R., Casal, R. F., Lee, H. J., Feller-Kopman, D., Frimpong, B., Dincer, H. E., … Yarmus, L. B. (2016). Use of One-Way Intrabronchial Valves in Air Leak Management After Tube Thoracostomy Drainage. The Annals of Thoracic Surgery, 101(5), 1891–1896. doi: 10.1016/j.athoracsur.2015.10.113 Reference #2: Keshishyan, S., Revelo, A. E., & Epelbaum, O. (2017). Bronchoscopic management of prolonged air leak. Journal of Thoracic Disease, 9(S10). doi: 10.21037/jtd.2017.05.47 Reference #3: Ha, D. V., & Johnson, D. (2004). High frequency oscillatory ventilation in the management of a high output bronchopleural fistula: a case report. Canadian Journal of Anesthesia/Journal Canadien Danesthésie, 51(1), 78–83. doi: 10.1007/bf03018553 DISCLOSURES: No relevant relationships by Rohini Chatterjee, source=Web Response No relevant relationships by Michal Sobieszczyk, source=Web Response No relevant relationships by Bryce Warren, source=Web Response No relevant relationships by Whittney Warren, source=Web Response

Ambulatory management of primary spontaneous pneumothorax: an open label randomized controlled trial

Spontaneous pneumothoraces, those that occur without preceding trauma, have various guideline directed therapeutic options, from observation to needle aspiration, to ultimately thoracostomy tube placement and admission. The average duration of hospital admission for a spontaneous pneumothorax in the United Kingdom is 6-8 days. The purpose of this study was to determine if there is potential benefit in observing pneumothoraces in the ambulatory setting with an intrathoracic catheter which uses a one-way valve, as well as to evaluate the efficacy and safety of a particular ambulatory device.

Inline Positive End-Expiratory Pressure Valves: The Essential Component of Individualized Split Ventilator Circuits.

Background:As resources are overwhelmed with the coronavirus disease 2019 pandemic, multiple approaches to produce individualized split-ventilator designs have emerged. These designs attempt to address the significant limitations and safety concerns of coventilation practices by allowing practitioners to adjust pressure settings for individual patients connected with specialized circuits to a single ventilator. The critical component in virtually all individualized circuit designs is the adjustable inline positive end-expiratory pressure valve.Methods:We reviewed the literature on the mechanics of inline positive end-expiratory pressure valve function, the implications and considerations for advanced application of inline positive end-expiratory pressure valves in individualized circuits, available methods of adapting commercial positive end-expiratory pressure valves in the resource-restricted setting, and major caveats of the use of inline positive end-expiratory pressure valves.Results and Conclusions:The function of adjustable inline positive end-expiratory pressure valves in advanced individualized ventilator circuits has not been described. Adjustable inline positive end-expiratory pressure valves are critical to individualized circuit reliability and patient safety when attempting to extend ventilator capacity in the setting of extreme ventilator shortages. Adjustable inline positive end-expiratory pressure valves provide a means to reduce delivered peak inspiratory pressure to an individual patient circuit, a method to increase positive end-expiratory pressure for an individual patient circuit, and act as an one-way valve to ensure unidirectional gas flow through the divided circuit. Adjustable inline positive end-expiratory pressure valves can be adapted from commercial valves or printed de novo when commercial options are unavailable. Noncommercial sourcing of ventilator components should only be considered in the setting of extreme ventilator shortages under the supervision of a knowledgeable anesthesiologist or intensivist.

Ultrasound Guided Foam Sclerotherapy for the Treatment of Primary Varicose Vein of Lower Limb

Background: Veins have one-way valves that prevent blood from backing up into the legs when we stand or sit. When the valves become incompetent (or begin to have reflux), blood pools and causes an increase in pressure in the leg veins. Leg veins become enlarged and twisted.Aim of the work: The aim of the current study was to evaluate safety and efficacy of ultrasound guided foam sclerotherapy for the treatment of primary varicose vein.Patients and methods: The current trial is a prospective observational cohort study. It had been carried out at Al-Azhar University Hospital (New Damietta), Egypt. It included Fifty patients who had great saphenous vein (GSV) reflux associated with saphenofemoral junction (SFJ) incompetence. They had been offered foam sclerotherapy as an alternative to standard surgical treatment or conservative management. The duration of the study extended between November 2019 to January 2020. Results: results revealed that post intervention; duplex assessment revealed a radiologic success with complete obliteration of GSV and collaterals in 40 patients (80%). six patients (12%) underwent direct re-injection for further one or two injection sessions over the following two weeks until complete occlusion of GSV and collaterals was obtained. Conclusion: Foam Slcerotherapy is effective & safe in treatment of primary varicose veins.

A Novel Adjustable Damper Design for a Hybrid Passive Ankle Prosthesis

Specifications of actuators when interacting with biological systems such as the human body are entirely different from those used in industrial machines or robots. One important instance of such applications is assistive devices and prostheses. Among various approaches in designing prostheses, recently, semi-active systems attracted the interest of researchers. Even more, some commercial systems benefit from designs such as implementing an adjustable damper in the ankle prosthesis to increase range of motion. The main reason for adding damper is to assist amputees’ walking locomotion on slopes (especially downward). In this paper, we introduce a hydraulic damper design for use in the transtibial prosthetic foot. In the fabricated hydraulic prosthetic foot, two one-way flow control valves are exploited to tune the damping ratio in the plantar flexion and dorsiflexion, independently. Using the carbon prosthetic foot in series to a damper and spring could improve mimicking intact foot movement. First, we present the details of the damper and the prosthesis mechanical design. Then, we introduce experiment-based modeling for the damper’s conceptual design in the proposed prosthesis using SIM-Hydraulic and MATLAB. This device is fabricated and tested in a pilot experiment. The compact design with reduced weight and size of the prosthetic foot are additional advantages of the proposed prosthetic foot.

Paying the price for standing tall: Fluid mechanics of prostate pathology.

BackgroundAge‐dependent increase in the incidence of benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are both related to cell proliferation and survival controlled by intraprostatic free testosterone (FT) concentration. Paradoxically, BPH and PCa occur as circulating testosterone levels decrease, so any possible relationship between testosterone levels and development of BPH and PCa remains obscure.ResultsIn BPH the enlarging prostate is exposed to high testosterone levels arriving directly from the testes at concentrations about hundredfold higher than systemic FT. This occurs because venous blood from the testes is diverted into the prostate due to the elevated hydrostatic pressure of blood in the internal spermatic veins (ISVs). Elevated pressure is caused by the destruction of one‐way valves (clinically detected as varicocele), a unique phenomenon related to human erect posture. While standing, human males are ISVs vertically oriented, resulting in high intraluminal hydrostatic pressures—a phenomenon not found in quadrupeds. In this communication, we demonstrate the fluid mechanics' phenomena at the basis of varicocele leading to prostate pathology.ConclusionsSo far, varicocele has been studied mostly for its etiologic role in male infertility and, thus, for its effects on the testes. It is becoming clear that varicocele is a major etiologic factor in BPH and likely also in PCa. Restoring normal testicular venous pressure by treatment of the abnormal ISV's in varicocele has been shown to avert the flow from the prostate with the effect of reducing prostate volume, alleviating symptoms of BPH, and increasing concentrations of circulating FT.

Hypoxic Respiratory Failure Further Complicated During Airway Exchange Catheter Placement.

IntroductionAn airway exchange catheter is a hollow-lumen tube able to deliver oxygen and maintain access to a difficult endotracheal airway. This case report demonstrates an undocumented complication associated with an airway exchange catheter and jet ventilation, particularly in a patient with reduced airway diameter due to thick endotracheal secretions. Due to the frequent use of airway exchange catheters in the intensive care unit, this report highlights an adverse event of bilateral pneumothoraces that can be encountered by clinicians.Case PresentationThis case report describes a 24-year-old female with severe adult respiratory distress syndrome and thick endotra-cheal secretions whose hospital course was complicated by bilateral pneumothoraces resulting from the use of an airway exchange catheter connected to jet ventilation. During the exchange, the catheter occluded the narrowed endotracheal tube to create a one-way valve that led to excessive lung inflation.ConclusionAirway exchange catheters used with jet ventilation in a patient with a narrowed endotracheal tube and reduced lung compliance have the potential risk of causing a pneumothorax. Clinicians should avoid temporary concomitant oxygenation via jet ventilation in patients with these findings and reserve the use of airway exchange catheters for difficult airways.

Anaesthetic management of a dog with a lung laceration: novel use of an oxygen fuel cell

A one‐year‐old male entire Bracco Italiano weighing 29.4 kg presented with a pyothorax secondary to a thoracic foreign body. During the procedure the patient became hypotensive, which stabilised after intervention. After closing the thoracic cavity, negative pressure could not be obtained through the thoracic drain. An oxygen fuel cell was used to quickly and non‐invasively determine that a lung laceration was the source of the pneumothorax. The declining physiological condition of the patient during anaesthesia led to the decision to attach a one‐way valve to the chest drain, and for recovery to position the dog in lateral recumbency with the affected lung on the dependent side. The recovery was uneventful.