In humans, the trachea refers to the tube extending from the larynx to the bronchi. It is important for conveying air to and from the lungs. An endotracheal tube (ETT) is a flexible plastic tube that is inserted into a patient's trachea through the mouth or nose. This article discusses endotracheal tube types.   Use of an endotracheal tube An endotracheal tube maintains an open airway and facilitates ventilation (The endotracheal tube can be connected to a ventilator. A ventilator is a medical device designed to replace spontaneous breathing in patients who are unable to breathe adequately on their own). The endotracheal tube doesn’t always have to be used with a ventilator, for instance, in a bronchoscopy procedure, the patient can be allowed to breathe spontaneously, and the doctor will insert an endotracheal tube into the patient's trachea through the mouth or nose to secure an open airway for the passage of the instruments. The following illustrates what an ETT is.  Endotracheal tube types There are various types of endotracheal tubes. Common types of ETT are discussed as follows. 1. Type classification based on where the ETT is inserted A. An oral endotracheal tube is inserted into the trachea through the mouth. It is typically made of polyvinyl chloride (PVC) or other flexible, durable materials. It has a cuff, which is an inflatable balloon near the distal tip of the tube. When inflated, it seals the trachea to prevent air leaks and protect against aspiration. It has markings that indicate the insertion depth and position within the trachea. B. The primary difference of a nasal endotracheal tube from an oral one is that it is inserted into the trachea through the nose rather than the mouth. It allows oral access and keeps the mouth free for surgeries, dental work, or other procedures. 2. Type classification based on material  A. Rubber endotracheal tube: this type of tube is relatively hard and less flexible, so there is a risk of damaging the nasal passages, vocal cords, or tracheal mucosa during insertion. B. PVC endotracheal tube: it is softened by the warmth of the upper respiratory tract, which helps ease tube passage.  C. Silicone endotracheal tube has flexibility, which reduces friction with mucosal tissues and lowers the risk of injury. 3. Type classification based on function A. Double-lumen endotracheal tube has two separate lumens, one for each lung. This allows independent ventilation of the right and left lungs. Double-lumen endotracheal tube is typically used in: 1) Thoracic surgery to facilitate lung isolation to operate on one lung while maintaining ventilation in the other. 2) Lung protection, namely to prevent contamination of healthy lung tissue during procedures on diseased lungs. B. Irrigatable endotracheal tube has an irrigation port that introduces sterile solutions to wash away secretions. It also has a drainage channel that directs secretions out of the airway. Its benefits include reducing the risk of ventilator-associated pneumonia and maintaining airway hygiene in critically ill patients. Irrigatable endotracheal tube has applications such as: 1) When used in critical care, the tube minimizes the accumulation of secretions in patients requiring prolonged ventilation. 2) When used in infection control, it helps prevent respiratory infections by maintaining cleanliness within the airway. C. Reinforced (armored) endotracheal tubes: this type of tube contains a spiral wire or plastic coil embedded in the tube wall. The benefits are being flexible and resistant to kinking. Its applications are as follows. 1) Used to provide a stable airway during procedures that require significant head or neck positioning, for instance in head and neck surgery. 2) Used in patients requiring extended ventilation support to prevent tube obstruction. D. Standard endotracheal tube is designed for general airway management during anesthesia, critical care, and emergencies. It has the following features:  1) A single channel for air passage. 2) Its cuff is an inflatable balloon near the distal tip of the tube. When inflated, it seals the trachea to prevent air leaks and protect against aspiration. The uncuffed version is suitable for children aged 5 and below or for cases where the inner diameter of the tube is less than 5.5mm. The following is an illustrative image of cuffed and uncuffed endotracheal tubes. Cuffed and uncuffed endotracheal tubes from Bever Medical Devices  3) Murphy Eye is a side hole near the distal end to ensure airflow even if the main opening is blocked. The standard endotracheal tube has the following applications. 1) When a patient is under anesthesia, the use of the tube provides a secure airway during surgical procedures. 2) It can be used in critical situations such as respiratory failure or cardiac arrest, to provide an open airway. 3) It can be connected to a ventilator to support breathing in intensive care units. Concluding comments Each endotracheal tube type offers unique features to meet specific clinical needs. Healthcare providers choose the appropriate endotracheal tube type for individual patient situations to maintain safe and effective airway patency.  There are other medical devices designed for airway patency purposes too, for example, nasopharyngeal airways. When you are considering the kind of products that are used for airway patency management you can think of endotracheal tubes and nasopharyngeal airways. The nasopharyngeal airway is a flexible tube typically made of soft plastic or rubber. It is inserted through a nostril and extends into the nasopharynx. It is useful in cases where the tongue or soft tissues obstruct the pharynx. The following image shows a typical nasopharyngeal airway. Nasopharyngeal airway from Bever Medical Devices.

It is essential to avoid inserting the suction catheter too deeply to prevent trauma and discomfort, while ensuring it's inserted far enough to effectively clear secretions. Below are guidelines for how far to insert suction catheter in different suctioning situations.   1) Endotracheal Tube Suctioning   Insertion Depth: The catheter should be inserted until mild resistance is felt, which indicates it is near or just above the carina (the point where the trachea divides into the left and right bronchi). Once resistance is felt, withdraw the catheter slightly (1–2 cm) before applying suction.   Avoid forceful insertion beyond the point of resistance to prevent trauma to the bronchial walls.   2) Tracheostomy Suctioning   Insertion Depth: The catheter is typically inserted to a depth that matches the length of the tracheostomy tube. Many tracheostomy tubes have a specific depth guideline (marked in centimeters) to ensure safe suctioning. If resistance is encountered, slightly withdraw the catheter before applying suction.   Measure the catheter length against the tracheostomy tube to prevent over-insertion. For most adult patients, suctioning should not extend into the bronchi unless medically indicated.   3) Nasopharyngeal or Oropharyngeal Suctioning   Insertion Depth: For nasopharyngeal or oropharyngeal suctioning (through the nose or mouth), insert the catheter until it reaches the back of the throat. In oropharyngeal suctioning, you usually insert until the patient coughs or gags slightly.   Ensure the catheter doesn't go deeper than necessary to avoid stimulating the gag reflex excessively or causing trauma to the mucosal lining.   4) General Guidelines   Catheter Size: Ensure the catheter size is appropriate for the patient. For example, in children and infants, use smaller-sized catheters (typically measured in French gauge). The size affects how far and easily the catheter can be inserted. Therefore in the next section we explain how to determine suction catheter size.   How to Determine Suction Catheter Size   Suction Catheter Size   Let’s first understand the term “suction catheter size”. “suction catheter size” refers to suction catheter diameter, measured in French gauge (Fr).   The suction catheter diameter is typically measured in French gauge (Fr). The French gauge system is used to specify the catheter's outer diameter, where one French gauge unit is equal to 1/3 mm in diameter.   A. French Gauge to Diameter Conversion   1 Fr = 1/3 mm in diameter Diameter (mm) = French gauge (Fr) ÷ 3   B. Example Conversions 8 Fr = 8 ÷ 3 = 2.67 mm 12 Fr = 12 ÷ 3 = 4 mm 14 Fr = 14 ÷ 3 = 4.67 mm   C. Common Suction Catheter Sizes and Their Diameters   1) Small Sizes (e.g., for neonates and infants)   5 Fr: Diameter of approximately 1.67 mm (using formula: Diameter (mm) = French gauge (Fr) ÷ 3. Same formula is used in below calculations.)   6 Fr: Diameter of approximately 2 mm   8 Fr: Diameter of approximately 2.67 mm   2) Medium Sizes (e.g., for children):   10 Fr: Diameter of approximately 3.33 mm   12 Fr: Diameter of approximately 4 mm   3) Larger Sizes (e.g., for adults):   14 Fr: Diameter of approximately 4.67 mm   16 Fr: Diameter of approximately 5.33 mm   D. Choosing the Appropriate Diameter   Neonates and Infants: Smaller diameters (5–8 Fr) are used to avoid trauma to delicate airways.   Children: Medium diameters (8–10 Fr) are suitable for their larger airways but still require gentle suctioning.   Adults: Larger diameters (10–16 Fr) are often used for effective suctioning of thicker secretions.   How to Determine Suction Catheter Size Correctly   Suction catheter sizes are typically measured in French Gauge (Fr), where a larger number indicates a wider catheter diameter. In the passages below we discuss how to determine the correct size.   1) Endotracheal or Tracheostomy Tube Suctioning   To determine the size of the suction catheter for a patient with an endotracheal tube (ETT) or tracheostomy tube, a common rule is that the catheter's outer diameter should be less than half the inner diameter of the tube. This prevents the catheter from completely blocking the airway during suctioning, allowing airflow and oxygenation.   2) Age-Based Suction Catheter Sizing   In pediatric and neonatal patients, suction catheter size is often determined based on age or weight, as smaller catheters are required to prevent trauma to the delicate airways.   A. Neonates: 5–6 Fr   B. Infants: 6–8 Fr   C. Children: 8–10 Fr   D. Adults: 12–16 Fr   In general, Smaller patients (neonates and infants) require catheters between 5–8 Fr; Larger pediatric patients and adults typically require catheters between 10–16 Fr.   3) Clinical Context and Secretion Type   The thickness and volume of secretions also play a role in catheter size selection.   A. Thick Secretions: Larger catheters (12–16 Fr) may be needed to clear thicker or more viscous secretions.   B. Thin Secretions: Smaller catheters (6–10 Fr) are generally effective for thinner secretions.   4) Closed Suction Systems   When using a closed suction catheter (in-line suctioning) with a ventilator, catheter size should still be based on the endotracheal tube’s inner diameter, using the same formula. Closed systems often come in predetermined sizes (e.g., 10 Fr or 12 Fr), which match standard ETT sizes.   5) General Guidelines for Catheter Selection   A. Adults (General Use): 12–16 Fr   B. Children (Pediatrics): 8–10 Fr   C. Infants: 6–8 Fr   D. Neonates: 5–6 Fr

What is a Suction Catheter?   A soft suction catheter is a medical device used to remove fluids, secretions, or other substances from the body by suction. It typically consists of a flexible tube (the catheter) that is connected to a suction source, such as a vacuum pump or suction machine.   Suction catheters have many applications. In this article we are focused on the application of it to help patients experiencing respiratory issues.   A suction catheter used for removing fluids, secretions, or other substances from the respiratory tract plays a crucial role in medical care, particularly for patients experiencing respiratory issues.   When the respiratory tract becomes clogged with mucus, sputum, or other secretions, these substances can impede normal breathing processes, leading to difficulties in breathing, hypoxemia, and other serious problems. In such cases, the use of suction catheters becomes imperative.   The suction catheter is then gently inserted into the patient's respiratory tract, and the negative pressure is applied to aspirate the mucus or secretions.   Types of Suction Catheters   1) Whistle Tip Suction Catheter   Key Feature: Side-opening tip that minimizes airway trauma by preventing direct suction at the catheter’s distal end.   Applications: Used in endotracheal and tracheostomy suctioning, particularly in sensitive airway scenarios like neonatal and pediatric care or post-surgical recovery.   2) Yankauer Suction Catheter   Key Feature: A rigid, curved catheter with a large, rounded tip and multiple openings, designed for oral and oropharyngeal suctioning.   Applications: Common in surgeries and emergency situations for suctioning fluids (blood, mucus, etc.) from the mouth and throat.   3) Coude Tip Suction Catheter   Key Feature: Angled or curved tip designed for precise suctioning in specific areas of the airway, such as the left or right bronchus.   Applications: Ideal for targeted suctioning in areas that are harder to reach, particularly in patients with tracheostomy or endotracheal tubes.   4) Closed Suction Catheter (In-Line Suction Catheter)   Key Feature: Enclosed in a sterile sheath that remains attached to the ventilator, allowing suctioning without disconnecting the patient from the ventilator.   Applications: Used in ICU and critical care settings for continuous ventilation while suctioning, reducing infection risk and maintaining lung volume.   5) Open Suction Catheter   Key Feature: A standard, flexible suction catheter used in open suction systems where the ventilator is temporarily disconnected for suctioning.   Applications: Commonly used for tracheal and endotracheal suctioning in routine airway clearance.   Whistle Tip Suction Catheter and Its Applications   What is a Whistle Tip Suction Catheter?   The whistle tip suction catheter gets its name because its tip resembles the shape of a whistle. The catheter has a side-opening near the distal end, which functions similarly to the opening in a whistle. This design allows suction to be applied through the side port rather than directly from the end, reducing the risk of airway trauma by preventing direct suction against the walls of the trachea or bronchi.   The side hole creates a safer and more controlled suction mechanism, and the resemblance to a whistle in terms of structure is why it’s called a Whistle Tip Suction Catheter.   Therefore the suction catheter whistle tip is its key design characteristic.   Whistle Tip Suction Catheter Applications   A Whistle Tip Suction Catheter is most often used to safely and effectively remove respiratory secretions (like mucus, saliva, or blood) from a patient's airway in situations where the airway is sensitive or at risk of trauma. Its characteristic application is in the following situations.   1) Pediatric and Neonatal Suctioning   The Whistle Tip's gentler design makes it ideal for neonates and pediatric patients, whose airways are more delicate. The side-opening reduces the risk of airway trauma, which is especially important in these vulnerable populations.   2) Used for Airway Clearance after Surgeries   After surgeries, especially in the post-anesthesia recovery period, patients often need airway clearance due to the buildup of mucus. The whistle tip suction catheter is used to carefully suction secretions without irritating the airway tissues.   3) Used in ICU Settings   In ICU settings, it is used regularly in mechanically ventilated patients to keep the airways free of obstructions caused by secretions, ensuring continuous airflow and proper oxygenation.   4) Used in Patients with Endotracheal Tubes or Tracheostomy Tubes   The catheter is frequently used in patients with endotracheal tubes or tracheostomy tubes to clear secretions from the trachea and lower airways. This is vital for preventing airway obstructions and maintaining adequate ventilation.