**2.2. Manufacturing the CFE® module**

The CFE® module was manufactured aiming to develop a mechanical device, with biocompatible and flexible material, in the shape of an 8 cm long cylindrical balloon, inflatable with gas by a valve system with an approximately 1 cm diameter conduit. The dimension established for length refers, approximately, to the size of the upper third of the esophagus. Incorporated into the module were radiography visualizations and fixing devices, containing within them a barium contrast indicator for controlling the position for x-rays. At one of the ends, there is a thread for fixing the module to a dental crown, which should be attached to the superior molar with the aim of preventing the module from migrating to the stomach in the event of accidental disinflation.

Manufacturing the CFE® module begins with preparing the environment, the raw material and the moulds and then follows a series of steps, such as: immersion of the glass moulds into a container containing liquid latex, drying the moulds in an oven, analyzing the thickness, removing the solidified latex from the moulds, assembly of module and final inspection.

#### **2.3. Cadaver test**

An experimental feasibility study was conducted, testing the placement and removal of the CFE® device in the esophagus of a cadaver at the Institute of Forensic Medicine (IFM). After being applied, the module was inflated with the aid of a manometer adapted to a pressure of 120 mm Hg. Its placement was made with delicate maneuvers aimed at preventing alterations to the module to be examined.

#### **2.4.** *In-vitro* **study**

172 Practical Applications in Biomedical Engineering

**2.1. Latex preparation** 

that glass provides.

**2.3. Cadaver test** 

alterations to the module to be examined.

to suppose that developing the CFE® module may lead to reducing food intake.The objective is to evaluate the possibility of CFE® insertion into the esophagus which causes, during its use, resistance to the passage of food bolus. This makes food ingestion slower due to a reduction in the lumen of the esophagus, resulting in the need for prolonged chewing.

The latex used here had already been through the centrifuging process, with sulfur and resin suspensions, having the objective of providing elasticity and the necessary strength for the final compound. From this preparation process, the latex is configured as a compound which upon contact with the skin, vulcanizes, making it adhesive. To be removed, however, just pure water is used. On glass surfaces, its removal is facilitated due to the low friction

When handling the latex, glass rods were used for mixing, as well as a glass container for storage, plastic wrap to protect it from contact with the air and cotton flannel for cleaning. An important point for any application that uses raw latex is the uniformity of its properties, since this is an essential characteristic. To obtain this characteristic, the latex source should

The CFE® module was manufactured aiming to develop a mechanical device, with biocompatible and flexible material, in the shape of an 8 cm long cylindrical balloon, inflatable with gas by a valve system with an approximately 1 cm diameter conduit. The dimension established for length refers, approximately, to the size of the upper third of the esophagus. Incorporated into the module were radiography visualizations and fixing devices, containing within them a barium contrast indicator for controlling the position for x-rays. At one of the ends, there is a thread for fixing the module to a dental crown, which should be attached to the superior molar with the aim of preventing the module from

Manufacturing the CFE® module begins with preparing the environment, the raw material and the moulds and then follows a series of steps, such as: immersion of the glass moulds into a container containing liquid latex, drying the moulds in an oven, analyzing the thickness, removing the solidified latex from the moulds, assembly of module and final inspection.

An experimental feasibility study was conducted, testing the placement and removal of the CFE® device in the esophagus of a cadaver at the Institute of Forensic Medicine (IFM). After being applied, the module was inflated with the aid of a manometer adapted to a pressure of 120 mm Hg. Its placement was made with delicate maneuvers aimed at preventing

be the same, i.e. the latex should come from trees of the same clone.

migrating to the stomach in the event of accidental disinflation.

**2.2. Manufacturing the CFE® module** 

With the objective of estimating the minimal time to carry out an intervention, in the event that it descends to the stomach and in order that it not cause intestinal obstruction, an experiment was conducted in the Laboratory of Engineering and Innovation – LEI at the Gama Campus of the University of Brasília. This experiment compared the volume of BIB (400 ml to 700 ml) and (CFE 146 ml) with the goal of comparing its volumes and its emptying capacity in the case it is punctured. The calculation employed for obtaining the CFE volume used a technique based on solids of revolution and the time was obtained from simple arithmetic means. There were four CFE modules used as samples and these were immersed into an environment similar to the stomach. The method utilized was to inflate the CFEs with the same pressure to be applied in humans (60 mmHg – minimum), withdrawal of the scalp1 number 27, immersion of the CFE in the environment with the hole made in the sample by the scalp on the upper part of the module thereby forcing partial emptying, since if it were not punctured, it would not empty as in the test done in [7].

#### **2.5. Preparation for clinical trial**

The choice for using a dog – as an animal for testing and for weight loss and/or as a validator of the CFE module – was made in light of findings raised with medical veterinarians. It was verified that the animal would be an excellent subject for analysis in this study keeping in mind the anatomical-physiological similarity between human and canine esophagi. Allied with this, above all, factors that denote affability with such animals and also, the facility of controlling their eating routine, as well as the food ingestion speed of the animal, associated with little chewing and the absence of psychological pressure (as opposed to what a human develops when the goal is losing weight). To conduct the experimental procedure, eight adult dogs, of no specific breed, males and females, with body weights varying between 9.2 and 17.8 kg were selected. Before the experiment, the animals were kept at the Veterinarian Hospital kennel at the Federal University of Goiás to be submitted to quarantine procedures that include: vaccination (Duramune Max, single dosage), application of ecto and endoparasiticides (administered through 100 mg of mebendazole, twice a day for three days), in addition to laboratory exams like blood count, urinalysis, hormonal and blood biochemical evaluations. Furthermore, improvements in the nutritional conditions of the animals was sought, through the implementation of a daily diet of dry dog food, supplemented with semi-moist dog food rich in nutrients (Dudog®). The animals were vaccinated against rabies and DHLPPC (distemper, hepatitis and adenovirus, leptospirosis, parainfluenza, parvovirus, and coronavirus) and dewormed with a broad spectrum dewormer. Ectoparasites were eliminated with a two-dose application of pour-on parasiticide. Blood was taken from all the animals and when hemoparasitoses was present, doxycycline was applied for 21 days, and diminazene in two applications with an interval of 15 days.

<sup>1</sup> The scalps peripheral intravenous comprise: siliconized needle stainless steel bezel with thin walls and biangular and three faceted; wings malleable and flexible, adjustable anatomically as handling (known as "butterfly"); transparent vinyl tube.
