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Position Measurement of Endotracheal Tube during Ventilation

Prof. Prashant B. Patel

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To study available and modern techniques for position measurement of endotracheal tubes.

The need for Instrumentation is to make proper and accurate measurement of various parameters related to medical science. All measurement mainly depends on the detection, acquisition and display of biological signal.

Respiration is to get Oxygen into the body and Waste Gases out of the Body.

The entire process of taking in oxygen from environment, transporting the oxygen to the cells, removing the carbon dioxide from the cells, and exhausting this waste product to the atmosphere must be considered with in the definition of respiration.

1.The Human Respiratory System consists of the Nose, Nasal Cavity, Pharynx, Larynx, Trachea, Smaller conducting passageways (Bronchi and Bronchioles) and lungs.

2. The Respiratory System may be divided into the Upper Respiratory Tract and the Lower Respiratory Tract.

3. The Upper Respiratory Tract consists of the parts outside of the Thoracic (Chest) Cavity: The air passages of the nose, nasal cavities, Pharynx (Windpipe), Larynx (Voice Box), and upper Trachea.

4. The lower Respiratory Tract consists of the parts found in the Thoracic (Chest) Cavity: the Lower Trachea and the Lungs themselves.

5. Air enters the Respiratory System through the Mouth or Nose.

6. Air entering the Nose passes into the Nasal Cavity. The Nasal Cavity is richly supplied with arteries, veins, and capillaries, which bring nutrients and water to its cells.

7. As air pushes back from the Nasal Cavity, it enters the Pharynx. The Pharynx is located in the back of the mouth and serves as a passageway for both air and food. When food is swallowed, a Flap of Cartilage called the Epiglotis, presses down and covers the opening to the air passage (ever have food go “Down the Wrong Way”?).

8. From the Pharynx, the air moves through the Larynx, the upper end of the Trachea, and into the Trachea (windpipe), which leads directly to the lungs.

9. These passageways provide a direct connection between the outside air and some of the most Delicate Tissue in the body.

10. These passageways must filter out dust, dirt, smoke, bacteria, and a variety of other contaminants found in air.

11. The first filtering is done in the nose. The nose will do three things to the air we breathe in:

  • Filter the air
  • Warm the air
  • Provide moisture (water vapor or humidity) to the air.

12. As air passes through the nasal cavities it is warmed and humidified, so that air that reaches the lungs is warmed and moist.

13. The Nasal Airways are lined with Cilia and kept moist by Mucous secretions. The combination of Cilia and Mucous helps to filter out solid particles from the air and Warm and Moisten the air, which prevents damage to the delicate tissues that form the Respiratory System.

14. The moisture in the nose helps to heat and humidify the air, increasing the amount of Water Vapor the air entering the Lungs contains.

15. This helps to keep the air entering the nose from Drying out the Lungs and other parts of our Respiratory System.

16. When air enters the Respiratory System through the Mouth, much less filtering is done. It is generally better to take in air through the Nose.

17. At the top of the Trachea is the Larynx (Voice Box). Inside, and stretched across the Larynx are two highly elastic folds of tissue (Ligaments) called the Vocal cords. Air rushing through the voice box causes the vocal cords to vibrate producing sound waves.

18. From the Larynx, the Warmed, Filtered, and Moistened air passes downward into the Thoracic Cavity through the Trachea.

19. The Walls of the Trachea are made up of C-Shaped rings of tough flexible Cartilage. These rings of cartilage protect the Trachea, make it Flexible, and keep it from Collapsing or over expanding.

20. The Cells that line the trachea produce Mucus; the mucus helps to capture things still in the air (Dust and Microorganisms), and is swept out of the air passageway by tiny Cilia into the Digestion System.

21. Within the Thoracic Cavity, the Trachea divides into two Branches, the Right and Left Bronchi.. Each Bronchus enters the Lung on its respective side. The Lungs are the Site of Gas Exchange Between the Atmosphere and the Blood. The Right Lung has Three Divisions or Lobes, and is slightly larger than the Two Lobed Left Lung. The Lungs are inside the Thoracic Cavity, bounded by the Rib Cage and Diaphragm. Lining the entire cavity and encasing the Lungs are Pleura Membranes that secrete Mucus that decreases friction from the movement of the Lungs during Breathing.

22. The further branching of the Bronchial Tubes is often called the Bronchial Tree.

23. Imagine the Trachea as the trunk of an upside down tree with extensive branches that become smaller and smaller; these smaller branches are the Bronchioles.

24. Both Bronchi and Bronchioles contain Smooth Muscle Tissue in their walls. This muscle tissue controls the size of the Air Passage.

25. The Bronchioles continue to subdivide until they finally end in Clusters of tiny hollow air sacs called Alveoli. Groups of Alveoli look like bunch of grapes. All exchange of gases in the lungs occurs in teh Alveoli.

26. The Alveoli consist of thin, flexible membranes that contain an extensive network of Capillaries. The Membranes separate a gas from liquid. The gas is the air we take in through our Respiratory System, and the liquid is Blood.

27. The Functional Unit of the Lungs is the Alveoli; it is here that the Circulatory and Respiratory Systems come together, for the purpose of gas exchange. All exchange of gases occurs in the lungs in the Alveoli. Each Lung contains nearly 300 Million Alveoli and has a total surface area about 40 times the surface area of your skin.

Available Position Measurement

Techniques for Endotrachael Tube During Ventilation.

  1. Clinical Methods:
    • Chest Expansion,
    • Respiratory Mechanism,
    • Sweating, Etc.
  2. Measurement of O2 (Pulse Oximeter),
  3. Measurement of Blood Pressure,
  4. Measurement of Heart Rate,
  5. Chest X-Ray
  6. Lung Volume

Proposed Modern Techniques.

Acoustic guidance system for position measurement of Endotracheal Tube (ETT). Endotracheal tube is used during intubation.

Ensuring that the end of endotracheal tube (ETT) is properly located with in the trachea, and that the tube is not obstructed by mucus deposition, is a major clinical concern in patient that require mechanical ventilation. A novel acoustic system was developed to allow for the continuous monitoring ETT position. A miniature sound source and two sensing microphones are placed in line between the ventilator hose and the proximal end of the ETT. Reflections of an acoustic pulse emitted in to the ETT lumen and the air way are digitally analyzed to estimate the location and degree of lumen obstruction, as well as the position of the distal end of the tube in the air way. The system estimates tube position and differentiated between proper tracheal, bronchial or esophageal intubation in all cases.

These finding indicates that this miniature technology could improve the quality of care provided to the ventilated adults and infant.