Rapid Design of an ICU Ventilator: An Approach Based on Smart Switching of Compressed Air-Oxygen.

Breathing support is provided by regulating volume or pressure of lungs using ventilators. Due to COVID-19 pandemic, there was a sudden shortage of resuscitating devices such as ventilators. Additionally, ventilators being one of the primary critical care devices are also very costly. In order to address this situation, a number of low-cost designs have been proposed, however, many of these lack either an efficient control system or a hardware comparable to a standard ICU ventilator. In this regard, this article presents a comprehensive cost-effective solution that covers all aspects of the ventilator design (named as NED-Vent) such as hardware/pneumatic assembly, electronic design, user interface and control system. The proposed design works on compressed air-oxygen switching via proportional valves to produce basic volume and pressure modes as well as their derivatives such as assist ventilation, intermittent ventilation and spontaneous modes. The NED-Vent also features an interactive single-knob-single-touch user interface along with an automated mechanism for adjusting air-oxygen ratio in breathing gas mixture as an improvement on existing designs. The pressure regulated control is based on two mathematical models of human lungs with dynamic lung parameters estimated using machine learning approach. Additionally, the controller is tuned to optimized stability using Jury's Test and Ziegler-Nichols methods. The obtained results of breath profile are validated for the employed mathematical models (SLSC & SLMC) as well as the tuning methods in compliance with the tolerances provided by international standards.

Trauma dental y lesiones faciales por armas de aire comprimido: reporte de un caso / Dental trauma and facial injuries by airguns: a case report

Las armas de aire comprimido son utilizadas desde hace muchos años con distintos usos que van desde el tiro recreativo hasta el control de plagas. Las más comunes son aquellas que disparan ''balines" o esferas metálicas que pueden llegar a tener capacidad de penetrar tejidos dependiendo del tipo de carga y de la longitud del cañón. Se presenta un caso clínico de un masculino que fue agredido con un arma tipo pistola con carga de CO2 que recibió un impacto a nivel facial y sufrió laceración en piel de labio y fractura dental complicada.

Air guns have been used for many years for a variety of purposes ranging from recreational shooting to pest control. The most common are those that shoot "pellets" or metallic spheres that can penetrate tissues depending on the type of load and the length of the barrel. A clinical case is presented of a male who was assaulted with a CO2-loaded pistol-type weapon, hit at facial level, and suffered laceration of the lip's skin and complicated dental fracture.

Tension pneumoperitoneum following colonic perforation due to barotrauma.

Barotrauma of the colorectum is an uncommon entity that usually occurs after colonoscopy. Perforation of the colon by non-iatrogenic barotrauma of the colon, with tension pneumoperitoneum, is very rare. We present a case of a male patient in his 20s with colon barotrauma caused by industrial compressed air, causing perforation of the transverse colon, with multiple serosal tears throughout the colon. There was also evidence of contusion in the caecum and ascending colon. Primary repair of the perforation and repair of the serosal tears were done along with a covering loop ileostomy.

Colorectal barotrauma following compressed air spray to the perineum.

Colorectal injuries caused by high-pressure air compressors are rare and reported especially among industrial workers. They may appear because of intended or accidental injury. In the present paper, we report a case of colorectal injuries due to air insufflation from a distance towards the anus with the clothes on, as a means of a practical joke. The patient presented one day after the trauma to the Emergency Department with complaints of severe abdominal pain and vomiting. On examination, he had signs of peritonitis. A computed tomography (CT) scan did not show any perforation. Emergency laparotomy was performed with the suspicion of pneumatic pressure-induced lesions. A total resection of the colon was made with enterostomy. The pathologic examination of the resected piece revealed multiple gangrenous areas without perforation associated to signs of peritonitis. Follow up was uneventful. A reversal of the enterostomy was scheduled.

Energy Harvesting Using Thermocouple and Compressed Air.

In this paper, we describe the possibility of using the energy of a compressed air flow, where cryogenic temperatures are achieved within the flow behind the nozzle, when reaching a critical flow in order to maximize the energy gained. Compared to the energy of compressed air, the energy obtained thermoelectrically is negligible, but not zero. We are therefore primarily aiming to maximize the use of available energy sources. Behind the aperture separating regions with a pressure difference of several atmospheres, a supersonic flow with a large temperature drop develops. Based on the Seebeck effect, a thermocouple is placed in these low temperatures to create a thermoelectric voltage. This paper contains a mathematical-physical analysis for proper nozzle design, controlled gas expansion and ideal placement of a thermocouple within the flow for best utilization of the low temperature before a shockwave formation. If the gas flow passes through a perpendicular shockwave, the velocity drops sharply and the gas pressure rises, thereby increasing the temperature. In contrast, with a conical shockwave, such dramatic changes do not occur and the cooling effect is not impaired. This article also contains analyses for proper forming of the head shape of the thermocouple to avoid the formation of a detached shockwave, which causes temperature stagnation resulting in lower thermocouple cooling efficiency.

A pneumatic random-access memory for controlling soft robots.

Pneumatically-actuated soft robots have advantages over traditional rigid robots in many applications. In particular, their flexible bodies and gentle air-powered movements make them more suitable for use around humans and other objects that could be injured or damaged by traditional robots. However, existing systems for controlling soft robots currently require dedicated electromechanical hardware (usually solenoid valves) to maintain the actuation state (expanded or contracted) of each independent actuator. When combined with power, computation, and sensing components, this control hardware adds considerable cost, size, and power demands to the robot, thereby limiting the feasibility of soft robots in many important application areas. In this work, we introduce a pneumatic memory that uses air (not electricity) to set and maintain the states of large numbers of soft robotic actuators without dedicated electromechanical hardware. These pneumatic logic circuits use normally-closed microfluidic valves as transistor-like elements; this enables our circuits to support more complex computational functions than those built from normally-open valves. We demonstrate an eight-bit nonvolatile random-access pneumatic memory (RAM) that can maintain the states of multiple actuators, control both individual actuators and multiple actuators simultaneously using a pneumatic version of time division multiplexing (TDM), and set actuators to any intermediate position using a pneumatic version of analog-to-digital conversion. We perform proof-of-concept experimental testing of our pneumatic RAM by using it to control soft robotic hands playing individual notes, chords, and songs on a piano keyboard. By dramatically reducing the amount of hardware required to control multiple independent actuators in pneumatic soft robots, our pneumatic RAM can accelerate the spread of soft robotic technologies to a wide range of important application areas.

Orbital Compressed Air and Diesel Explosion Injury Resembling Orbital Cellulitis: An Unusual Case.

BACKGROUND In this observational case report, we describe a case of orbital cellulitis caused by blunt trauma from an orbital compressed air and diesel explosion injury. CASE REPORT A 44-year-old man presented to our emergency department with a marked clinical worsening of right upper eyelid swelling, accompanied by pain, fever, and redness. Four days prior, the patient's right eye was struck by a pressurized diesel engine explosion. He sought treatment at another hospital, where an initial examination was conducted and a small laceration was found and immediately treated with irrigation and medication. The wound became progressively worse, and on examination at our hospital, we diagnosed orbital cellulitis, multiple abscesses, and pneumo-orbital formations. There was no indication of infection from the ears, nose, throat, and oral cavity, which usually causes orbital cellulitis. Drainage, debridement, incision, and necrotomy with orbital decompression (canthotomy and cantholysis procedure) was then performed on the patient. CONCLUSIONS Diesel explosion injury can cause orbital cellulitis which can appear to be a simple case at first but has a poor prognosis. Therefore, evaluating the patient's trauma history, computed tomography scan, and histopathological examination are essential in establishing the diagnosis. As early as possible, a diagnosis should be made to prevent tissue damage due to inflammation. Surgical debridement and the administration of a corticosteroid and antibiotic were key to managing the presented case.

Pneumatic Supply System Parameter Optimization for Soft Actuators.

Soft actuators using pressurized air are being widely used due to their inherent compliance, conformability, and customizability. These actuators are powered and controlled by pneumatic supply systems (PSSs) consisting of components such as compressors, valves, tubing, and reservoirs. Regardless of the choice of actuator, the PSS critically affects overall performance of soft robots because it governs the soft actuator pressure dynamics, and thereby, the general dynamic behavior. While selecting and controlling PSS components for meeting desired soft actuator performance, specifications such as PSS mass, volume, and duration of operation must also be considered. Currently, there is no comprehensive study on PSS optimization for meeting dynamic performance and PSS specifications, due to limited understanding of soft actuator pressure dynamics, large solution space for PSSs, and variability in soft actuators. By considering critical parameters of PSS and soft actuators, we introduce and demonstrate PSS parameter optimization. We propose a normalized model for soft actuator pressure dynamics and quantify the relationship between PSS parameters, soft actuator design parameters, and dynamic performance metrics of rise time, fall time, and actuation frequency. After experimental validation, we applied these results and optimally select and control PSS components to meet desired soft actuator performance for a soft exosuit, while minimizing mass of selected components. The measured pressure response with this prototype agrees well with simulations, with root mean square errors <5.2%. This work is a step toward furthering the scope of soft robotics, as it enables PSS modeling and optimization, for meeting the desired soft actuator performance while also addressing PSS specifications.

An Air Recirculation System Based on Bioinspired Soft Re-Air Valve for Highly Efficient Pneumatic Actuation.

Owing to their compliance, lightweight, and high force density characteristics, pneumatic actuation systems have been widely implemented in various soft robots. However, pneumatic actuation systems exhibit low efficiency, poor control performance, and high noise; these make it extremely challenging to widely employ a pneumatic actuation system in mobile robots. To overcome these limitations, many researches were conducted on recycling the compressed air within such systems. However, the proposed approaches do not consider the system efficiency and exhaust performance of pneumatic systems. Therefore, this article proposes a recirculation system using a novel soft re-air valve based on the cardiac structure of fish. In particular, the proposed recirculation system recycles the compressed air to improve the system efficiency and pressurizing performance, and the soft re-air valve simultaneously prevents a decrease in the depressurizing performance. For the validation of the proposed scheme, experiments were conducted to evaluate the system efficiency, control performance, and exhaust noise. In contrast to conventional pneumatic systems, the experimental results revealed that the proposed system increased the overall system efficiency by 47.58%, reduced the position root mean square error by 8.16%, and reduced the exhaust noise by 47.52%.

A review of diving practices and outcomes following the diagnosis of a persistent (patent) foramen ovale in compressed air divers with a documented episode of decompression sickness.

INTRODUCTION: The presence of a persistent (patent) foramen ovale (PFO) increases the risk of decompression sickness (DCS) whilst diving with pressurised air. After the diagnosis of a PFO, divers will be offered a number of options for risk mitigation. The aim of this study was to review the management choices and modifications to diving practices following PFO diagnosis in the era preceding the 2015 joint position statement (JPS) on PFO and diving. METHODS: A retrospective study was conducted of divers sourced from both the Alfred Hospital, Melbourne and the Divers Alert Network Asia-Pacific during the period 2005-2015. Divers were contacted via a combination of phone, text, mail and email. Data collected included: diving habits (years, style and depths); DCS symptoms, signs and treatment; return to diving and modifications of dive practices; history of migraine and echocardiography (ECHO) pre- and post-intervention; ECHO technique(s) used, and success or failure of PFO closure (PFOC). Analyses were performed to compare the incidence of DCS pre- and post-PFO diagnosis. RESULTS: Seventy-three divers were interviewed. Sixty-eight of these returned to diving following the diagnosis of PFO. Thirty-eight underwent PFOC and chose to adopt conservative diving practices (CDPs); 15 chose PFOC with no modification to practices; 15 adopted CDPs alone; and five have discontinued diving. The incidence of DCS decreased significantly following PFOC and/or adoption of conservative diving practices. Of interest, migraine with aura resolved in almost all those who underwent PFOC. CONCLUSIONS: Many divers had already adopted practices consistent with the 2015 JPS permitting the resumption of scuba diving with a lowering of the incidence of DCS to that of the general diving population. These results support the recommendations of the JPS.

Compressed Air-Driven Continuous-Flow Thermocycled Digital PCR for HBV Diagnosis in Clinical-Level Serum Sample Based on Single Hot Plate.

We report a novel compressed air-driven continuous-flow digital PCR (dPCR) system based on a 3D microfluidic chip and self-developed software system to realize real-time monitoring. The system can ensure the steady transmission of droplets in long tubing without an external power source and generate stable droplets of suitable size for dPCR by two needles and a narrowed Teflon tube. The stable thermal cycle required by dPCR can be achieved by using only one constant temperature heater. In addition, our system has realized the real-time detection of droplet fluorescence in each thermal cycle, which makes up for the drawbacks of the end-point detection method used in traditional continuous-flow dPCR. This continuous-flow digital PCR by the compressed air-driven method can meet the requirements of droplet thermal cycle and diagnosis in a clinical-level serum sample. Comparing the detection results of clinical samples (hepatitis B virus serum) with commercial instruments (CFX Connect; Bio Rad, Hercules, CA, USA), the linear correlation reached 0.9995. Because the system greatly simplified the traditional dPCR process, this system is stable and user-friendly.

Arterial gas embolism breathing compressed air in 1.2 metres of water.

Arterial gas embolism (AGE) may result when diving while breathing compressed gas and ascending rapidly or with a closed glottis. Pulmonary over-pressurisation can result in lung stretch injury with entry of bubbles into the pulmonary venous circulation and subsequently the systemic arterial circulation. We present the case of an individual who suffered AGE while breathing compressed air at 1.2 metres' fresh water (mfw) in a swimming pool and discuss the factors determining the depth at which this form of injury may occur. This case serves to underscore the fact that risk of AGE exists at shallow depths.

Urgent Subconjunctival Needle Decompression for Orbital Compartment Emphysema Caused by Compressed Air Injury.

Orbital compartment syndrome is a critical ophthalmic emergency that needs urgent diagnosis and treatment to prevent permanent vision loss caused by optic nerve compression or retinal ischemia. In this article, we present a child with orbital compartment syndrome caused by orbital emphysema as a result of a rare type of ocular trauma and introduce a simple technique to decompress the pressure. The patient was a 4-year-old boy who experienced a compressed air blast to his left eye. He presented to the emergency department with a frozen globe, tight orbit, and chemosis, without any evidence of globe rupture, conjunctival laceration, and orbital bone fracture. Computed tomographic scan demonstrated extensive subcutaneous, intraorbital, and intracranial emphysema. The pressure was immediately relieved under intravenous sedation by inserting a 27-gauge needle into the chemotic subconjunctival space at the lower lid fornix, followed by gentle manipulation of the globe to help the air escape through the needle. Compressed air injury is a rare type of orbital trauma, and this patient constituted the youngest case ever reported in the English literature, to our knowledge. Air decompression through the conjunctiva as described in this article is a useful technique that can be applied by emergency medicine specialists with special caution for patients with orbital compartment syndrome and orbital emphysema caused by compressed air injury.

Doble mecanismo de estrangulación. A propósito de un caso / Double mechanism of strangulation. Apropos of a case

RESUMEN Las asfixias mecánicas son aquellas que resultan del impedimento mecánico a la penetración del aire en las vías respiratorias, suelen clasificarse atendiendo a la naturaleza del medio mecánico que las origina y a su modo de actuar. La estrangulación puede definirse como la constricción del cuello mediante la aplicación de una fuerza activa, ajena al peso del cuerpo, que actúa por intermedio de un lazo, las manos, el antebrazo o cualquier otra estructura rígida. En la estrangulación antebraquial, la constricción del cuello se lleva a cabo normalmente rodeando al individuo con el brazo y el antebrazo. Cuando el mecanismo de la compresión del cuello es lateral, no se afectan las vías aéreas, la compresión de las arterias carótidas hace que se produzca una isquemia cerebral y pérdida de conocimiento en 10-15 segundos. El mecanismo de muerte en estos casos será la anoxia cefálica. Si la compresión del cuello es anterior, actúa ocluyendo las vías aéreas, la presión sobre los cartílagos tiroides y cricoides puede producir fracturas y el mecanismo de muerte será la obstrucción respiratoria. El presente trabajo constituyó un caso poco común de estrangulación, donde se utilizó un mecanismo combinado que llevó al occiso al deceso final. Para la realización de la discusión del caso se tuvo en cuenta los elementos del lugar del hecho, el examen del exterior y el interior del cadáver (AU).

ABSTRACT Mechanical asphyxias are those resulting from the mechanical obstruction of the air penetration in the airways. They are usually classified according to the nature of the mechanical mean producing it and the way it performs. Strangulation may be defined as neck constriction through the application of an active force not proper to the body weight, acting by means of a knot, hands, forearm or any stiff structure. In ante brachial strangulation, neck constriction is normally performed surrounding the individual with the arm and forearm. When the neck constriction mechanism is lateral, the airways are not affected: carotid arteries constriction produces a brain stroke and loss of consciousness in 10-15 s. The death mechanism in these cases will be cephalic anoxia. If the neck compression is anterior, it occludes the airways; the pressure on thyroidal and cricoid cartilages may produce fractures and death mechanism will be respiratory obstruction. The current work deals with an uncommon strangulation case, where a combined mechanism led the person to the final decease. For the case discussion the authors took into account the elements of the place, and the examination of the exterior and the inside of the corpse (AU).

Resolving Reflection and Resolution in 3D Imaging of Fresh Bone.

Structured light scanning is a noninvasive, accurate, and cost-effective 3D imaging technique, but due to reflection issues is yet to be utilized for tool mark analysis on fresh bone. During imaging, reflection from shiny surfaces, such as greasy bone, disrupts image formation. This study tested the David SLS-1 scanner's ability to image saw marks and explored six strategies to reduce reflection by [1] dulling the surface or [2] altering the projected light. The surface was dulled by freezing, talcum powder, dulling spray, or compressed air. The projected light was altered with a diffuser or limited to single pattern-coded. Results demonstrated that the resolution was insufficient for capturing minute details of striae. All six tests failed to reduce reflection sufficiently to produce complete images, but projecting vertical pattern-coded light showed the most promise. Future research is required concentrating on enhancing resolution and exploring the role of pattern-coded light in reducing reflection.

Pressurized IntraPeritoneal Aerosol Chemotherapy with one minute of electrostatic precipitation (ePIPAC) is feasible, but the histological tumor response in peritoneal metastasis is insufficient.

INTRODUCTION: Electrostatic precipitation Pressurized IntraPeritoneal Aerosol Chemotherapy (ePIPAC) has shown superior penetration depth and tissue uptake compared to standard PIPAC. We investigated the feasibility and objective tumor response to ePIPAC with 1 min of precipitation in patients with peritoneal metastasis (PM). MATERIALS AND METHODS: Patients with PM from various abdominal cancers were included in an amendment to the ongoing prospective PIPAC-OPC2 trial. Colorectal and appendiceal PM were treated with oxaliplatin, patients with PM from other primaries were treated with a combination of cisplatin and doxorubicin. Three ePIPAC procedures were planned in each patient including repeated peritoneal biopsies for response evaluation. After emission to the peritoneal cavity, the aerosolized chemotherapeutics were precipitated for 1 min followed by immediate exsufflation and abdominal closure. Histological regression from the first to the third ePIPAC was evaluated according to the Peritoneal Regression Grading Score (PRGS) and compared to data from the PIPAC-OPC1 trial. Complications and toxicities were recorded according to Dindo-Clavien and CTCAE. RESULTS: Sixty-five ePIPAC procedures were performed in 33 patients (median 2, range 1-6). Ten patients were eligible for response evaluation based on biopsies from the first and third ePIPAC procedure. Four patients had disease progression, four patients had regressive disease, and two patients had stable disease according to PRGS. No life threatening adverse reactions and no mortality was observed following ePIPAC. CONCLUSION: One minute ePIPAC was feasible and safe, but the histological tumor response was insufficient compared to standard PIPAC directed therapy with 30 min passive diffusion time.