The Insertion Tube For Endoscopy
Endoscopy is a procedure that allows doctors to see organs and structures within the body without making big incisions.
Usually, an endoscopy is performed with sedation or anesthesia to help you feel relaxed and comfortable. The type of sedation you get depends on your health and the reason for the procedure.
Air/Water Valve
Endoscopes are used to examine a patient’s gastrointestinal tract for symptoms such as nausea, vomiting, diarrhea, abdominal pain, etc.; diagnose a medical problem such as a cancer or polyp; or provide treatment such as gastrostomy tube placement, cauterizing bleeding vessels, widening a narrow esophagus, clipping off a polyp, and more.
Endoscopic devices are usually made of a flexible tube or an inflatable device that is inserted through the mouth into the gastrointestinal tract. The tube is generally made of a metal tube or a plastic tube with an objective lens at the proximal tip that allows the physician to see the mucosal surface. The tube also includes a nozzle that deflects air or water to clear the lens or pass therapeutic instruments through the endoscope.
Several valves control the flow of air and water through the insertion tube, and these are typically re-usable. After each use, the valves must be cleaned and disinfected to prevent cross-contamination between patients. These processes can be labor intensive, and the valves themselves are often expensive to replace or repair.
Reprocessing re-usable air/water and suction valves in the course of an endoscopic procedure requires staff training, standardization of procedures, and proper cleaning and disinfection techniques. Moreover, reprocessed valves are frequently contaminated with micro-organisms that may pose a threat to the health of patients.
A reprocessing valve must be cleaned and disinfected according to the manufacturer’s instructions, in order to prevent the potential spread of disease to other patients. A reprocessor must be staffed with experienced personnel, and a sufficient number of reprocessors must be available at the facility in order to meet demand for these services.
As mentioned, the reprocessing of valves can be time-consuming and difficult due to their complex structure and multiple parts that must be cleaned and disinfected individually. Therefore, many healthcare facilities do not reprocess valves on a regular basis because of the associated risks to health and safety.
To limit these risks, a disposable air/water valve assembly may be developed for use in an endoscopic device. The valve assembly comprises a housing that fits over an air/water cylinder (e.g., a spool of metal that is affixed to an endoscope or other medical instrument). The housing also contains slots that facilitate engagement with the spool and the air/water cylinder. In addition, a lip seal is provided on the spool that impedes the flow of air from the inlet through the valve cavity.
Suction Valve
A suction valve is a device used to control the suction of a fluid. The valve may have a finger-like push-down motion or it can be activated by an energizing force from a spring.
As shown in FIGS. 1 and 2, a valve casing 102 fitted to a control portion of an endoscope and a valve member 104 are set up so that they make a sliding motion in response to the push-down motion of a button 120. The valve member 104 and the button 120 are each in communication with one another via a side through-hole 110 on the valve member 104, the hole 115 a of the spring seat member 115 and air releasing grooves 122 formed on the outside peripheral surface of the button 120.
In order to improve the airtightness between the valve casing 102 and the active blockade face 116 of the valve member 104, it is preferable that the active blockade insertion tube for endoscopy face 116 has a groove 118 formed in it as shown in FIGS. 5A and 5B (i.e., the groove 118 is wider along the direction of the suction source side path 108 than in the ordinary state of the valve member 104).
According to this constitution, the foreign substances for instance blood and others that stick to the active blockade face 116 of a valve member 104 during the usual operating state of the valve member are moved to and stored in the inside of the groove 118 whenever it is made into a new suction control state. This prevents the slide friction between the valve casing 102 and the valve member 104 increasing due to these foreign substances when the valve member is made into a suction control state.
Moreover, it is preferred that the groove 118 is constituted such that the width of its opening portion is greater than the depth thereof. insertion tube for endoscopy This causes a larger amount of the foreign substances to be caught and removed from the active blockade face 116 during the repeated suction switching operation.
However, this constitution also makes it more difficult for the above foreign substances to be removed from the active blockade face 118 during the overhaul cleaning of the valve member 104. For this reason, it is preferable that the groove 118 is shaped such that it is formed in a spiral-like manner as shown in FIGS. 5A and in a circumference-like manner as shown in FIGS. 6A. This allows the foreign substances to be caught and removed more easily from the active blockade face 116 in the overhaul cleaning of the suction valve 100 than in the ordinary state of the same.
Antireflux Valve
An antireflux valve is a device that prevents reflux through the vent tube when a nasogastric (stomach) tube is inserted into a patient. This prevents stomach contents from refluxing through the vent lumen and contaminating the patient’s clothing and bedding, which could cause infection.
The valve is inserted into the pigtail at the proximal end of the vent lumen before the tube is inserted into the cavity. The pigtail and valve are then held frictionally in place to form an air-tight fit with the vent tube when it is inserted into a patient. When pressure within the body cavity exceeds atmospheric pressure, the valve 27 opens and permits a column of air to enter the vent tube 25.
This air-tight fit ensures that gastric fluids cannot flow through the valve 27 and into the nasogastric tube 1 or into the suction tube 13. When pressure at the distal end of the vent tube 25 is slightly less than ambient, the flexible disc valve 41 immediately blocks the flow of fluids into the vent tube 25.
When the nasogastric tube or the suction tube are removed from the body cavity, the pigtail and valve remain in place and prevent gastric fluids from entering the tube or the suction tube. This enables the endoscopist to remove the tube or the suction tube without worrying about contaminating the patient’s clothing or bedding, as previously described in the preceding section.
The insertion tube for endoscopy is typically made of polymer and has a wire mesh and a plastic coating over the entire length. A pull wire runs the length of this tube and is firmly attached to a ring at the proximal end of the tube (see Fig. 3.2).
A variable stiffness system allows the bending section to be angled in any direction and achieves what is known as “up tip deflection.” This is achieved by a series of four angulation wires running the length of the insertion tube that are firmly attached to the tips of the bending section at the 3 o’clock, 6 o’clock, 9 o’clock, and 12 o’clock positions. When the pull wire in this angulation system is pulled, the bending section curls in the up direction.
Air/Water Channel
The insertion tube for an endoscope is very delicate and contains the air/water channel, instrument channel, angulation wires and fibreoptic bundles. It also has the control sections, which allow the endoscopist to manipulate the angulation of the tip.
Typically, the air valve (shown on left) controls the inflation of the insertion tube and the water valve (shown on right) controls the insufflation and deflation of the insertion tube. The control section of the endoscope is held by the endoscopist’s left hand, and a small knob on the insertion tube (shown on left) is used to regulate angulation.
It’s important to keep the angulation knob of the insertion tube in an upright position. This will prevent the insertion tube from slipping out of the endoscope and injuring the physician’s fingers or the patient. The angulation knob should never be sharply angulated, as this can cause damage to the biopsy channel.
A variety of techniques may be used to control the angulation of the insertion tube. The angulation knob is often controlled by the thumb and first two fingers of the physician’s left hand, while the rest of the fingers grip the instrument.
When a clinician depresses the air/water valve, water flows down the water channel and out the nozzle at the distal tip of the insertion tube. This is used for insufflation, as well as to rinse the optical system of the insertion tube and the soiled endoscope when activated.
The air/water valve is also used to dilate the internal organs of a patient for observation or surgical interventions, or for the purpose of enabling the insertion of the endoscope into a body cavity. This method is particularly useful for a patient who cannot be intubated, such as an elderly patient who does not breathe on his or her own.
Another useful feature of the air/water valve is that it allows the endoscopist to use different activation modes–0–position, air, air and water mixture, or water. This helps in avoiding the risk of overinsufflation of a patient’s GI tract by allowing the operator to stop the pumping of air at any time.
