Descriptive report of the Invention patent for

"OBTURATOR CANNULA FOR PROPHYLAXIS OF PULMONARY ASPIRATION OF GASTRIC CONTENTS AND POSITIVE-PRESSURE VENTILATION".

The present invention is composed of a set of Cannulas to be used in patients undergoing general anesthesia, deep sedation, in those in coma or with upper gastrointestinal bleeding, as well as patients who need surgery, but whose stomach is not empty, either due to recent feeding or decreased digestive capability, to prevent gastroesophageal reflux as well as to allow the institution of positive-pressure mechanical ventilation. Most of the clinical measures used currently are palliative and do not fully prevent gastroesophageal reflux and pulmonary aspiration. Endotracheal intubation with the available endotracheal tubes, which have a distal balloon to prevent pulmonary aspiration, requires the complete blockade of reflexes that protect the airways, and it is in during this interval in which the patient is not protected that most pulmonary aspirations occur. Palliative measures to avoid gastroesophageal reflux include applying pressure on the cricoid cartilage (Sellick maneuver) and elevating the head of the bed. Every year, thousands of people around the world suffer the consequences of pulmonary aspiration, resulting in an increase in hospital stay or even death. In 1987, Frass developed a tube (Combitube) that combined the functions of an esophageal obturator and an endotracheal tube in a double-lumen tube with 2 balloons (proximal oropharyngeal and distal), in which one lumen is similar to the esophageal obturator, with a blocked distal end and lateral perforations in the area of the pharynx, while the other lumen has an opened distal end, similar to conventional endotracheal tubes. The Combitube is introduced blindly and allows the patient to be ventilated regardless of the position of the tube, perilaryngeal or tracheal.

However, although the Combitube is a device that allows the obstruction and ventilation in the area of the esophagus, it does not block the esophageal-gastric transition, and, therefore, it cannot prevent reflux of gastric contents and it does not offer conditions to aspirate the contents of the stomach.

Besides, the Combitube is a bulky device, and at times it causes traumatic complications, such as: pain, dysphagia, edema, lacerations, hematomas in the oropharyngeal mucosa, edema of the tongue, damage of the Pyriform sinus, subcutaneous emphysema, pneumomediastinum, pneumoperitonium, and esophageal laceration, among others, and it is contra-indicated in patients shorter than 1.40 m.

The current invention differs from the Combitube in that it does not have a distal double-lumen, absence of a distal esophageal balloon, opened distal end, and, mainly, by its reduced size due to its smaller diameter; it will be available in different sizes and can be used in patients shorter than 1.40 m, including children, which is not possible with the Combitube.

The present invention could be used in awake patients and in those with preserved protective reflexes of the airways; therefore, patients are protected against gastroesophageal reflux, improving considerably the conditions for mechanical ventilation without the need to access the airways.

Considering that the epithelium of the digestive tract is much more resistant than the respiratory epithelium, this opens up the possibility of perilaryngeal mechanical ventilation, not only in cases of difficult airways, but also routinely, decreasing the complications related with trauma of the airways.

The present invention, better detailed in the attached pictures, was developed considering the problems to be solved, limitations of the currently available Cannulas, as well as the difficulties and inconveniences mentioned above. Its use will be described in more details, along with the attached figures, where:

Figure 1, frontal view of the Naso/Orogastric Cannula with gastric obturator and empty balloons.

Figure 2, frontal view of the Perilaryngeal Cannula with oropharyngeal obturator with empty balloon. Figure 3, posterior view of the same Cannula in figure 1 with its balloons inflated.

Figure 4, posterior view of the same Cannula in Figure 2 with its balloon inflated.

Figure 5, shows the utilization disposition of the

Cannulas, in which one will be inserted inside the other, which will be explained in details ahead.

Figure 6, the same view of Figure 5, transected to show the interior of the Cannula.

Figure 7, illustration of the human orogastric system, from the Mouth to the Stomach. Figure 8, illustrates the use of the present invention.

As can be seen in the attached figures, the main goal of the Naso/Orogastric Cannula (C1) is to prevent gastroesophageal reflux and, consequently, pulmonary aspiration of gastric contents, which causes severe pneumonia that can be life threatening. The perilaryngeal Cannula (C2) has an Oropharyngeal Obturator (03); perilaryngeal ventilation can only be instituted when it is used with the Naso/Orogastric Cannula (C 1). Therefore, the Naso/Orogastric Cannula (C1) can be used isolatedly or in conjunction with the Perilaryngeal Cannula (C2). The Naso/Orogastric Cannula (C 1) has a proximal opening (09) for aspiration of gastric contents, and an upper Esophageal Balloon (20), between its upper (08) and middle (14) portions, connected to a secondary lumen (10) with an external Pilot Balloon (20A). In its lower portion, the Naso/Orogastric Cannula (C1) has two Balloons: the Intragastric Balloon (17) is connected to a secondary lumen (12) with an external Pilot Balloon (17A). The Intragastric Balloon has a sleeve that forms a Transition Balloon (16), which fits in the esophageal-gastric (EG) transition, blocking it. The lower Esophageal Balloon (15) is located just above this sleeve, and it is connected to a secondary lumen with an external Pilot Balloon (15A). The distal end (18) of the Naso/Orogastric Cannula is blocked and has Perforations (19) in its wall through which gastric (E) contents can be aspirated.

On the other hand, the Perilaryngeal Cannula

(C2) has an opening in the Exit Branch (01) and a Connecting Port (05) at the end of the Ventilatory Branch (02). It also has an oropharyngeal balloon (03) connected to a secondary lumen (06) with an external Pilot Balloon (3A) and Perforations (07) in its distal end (esophageal lumen), which is opened (AD) to allow for the insertion of the Naso/Orogastrie Cannula (C 1), which is done in the cauclal-cephalie direction, as illustrated in Figures 5 and 6.

As can be seen in the figure (08), the Naso/Orogastric Cannula (C 1) can be introduced, through the mouth (B) or nose, into the esophagus (ES), until it reaches the Stomach (E), and gastric contents can be aspirated through the distal Perforations (19); afterwards, the Intragastric Balloon (17) is inflated until the Transition Balloon (16) reaches approximately half of its contents, which can be monitored through the external Pilot Balloon (17A); the Naso/Orogastric Cannula (C1) is, then, pulled until the Transition Balloon (16) is securely locked in the Esophageal-Gastric (EG) Transition Channel. The Intragastric Balloon (17) and the Distal Esophageal Balloon (15) are filled while maintaining traction on the Naso/Orogastric Cannula (C1), leading to a complete gastroperilaryngeal blockade, and, therefore, preventing gastroesophageal reflux.

In patients who need mechanical ventilation, the Naso/Orogastric Cannula can precede tracheal intubation or the Perilaryngeal Cannula (C2) can be used for perilaryngeal ventilation. If perilaryngeal ventilation is the main objective, the upper Esophageal Balloon (20) is inflated. The Perilaryngeal Cannula (C2) is inserted orally, using the Naso/Orogastric Cannula as a guide, until the Reference Mark (MR) is aligned with the incisive teeth. The Oropharyngeal Balloon (03) is, then, inflated, the proximal opening 09) is closed, and ventilation is carried out through the Ventilatory Branch (02). If the distal opening (AD) touches the upper Esophageal Balloon (20), the Perilaryngeal Cannula (C2) should be pulled back approximately 1 cm.

After it is properly positioned, the Naso/Orogastric Cannula (C1) is used for the continuous drainage of gastroesophageal contents and to block gastroesophageal reflux. When the patient is no longer at risk for pulmonary aspiration, the Naso/Orogastric Cannula (C1)

can be used as a common nasogastric tube - after the Balloons (15,17, and 20) are deflated. The Perilaryngeal Cannula (C2) is used along with the Naso/Orogastric Cannula (C1), which will be inside that one, and pulmonary ventilation will be achieved through the Perforations (07).

Each one of the Balloons (03, 15, 17, and 20) in the Cannulas (C 1 and C2) has a secondary lumen with an external Pilot Balloon (03A, 15A, 17, and 20A). As the Balloons (03, 15, 17, and 20) are filled, the external Pilot Balloons (3A, 15A ₁ 17A and 20A) are filled in the same.