Endotracheal and Gastrointestinal Tubes

• This lecture is about endotracheal tubes
• The lecture was given by Ghazi Gasmalla Mohamed on March 1, 2025

Learning Objectives

• The objective is to describe the different types of endotracheal and tracheostomy tubes
• The objective is to demonstrate knowledge of the uses and complications of these devices

Gastrointestinal Tubes

• Gastrointestinal tubes can pass through the nose or mouth into the stomach or intestine
• They can pass through the rectum into the intestine, or be surgically inserted gastrostomy (feeding) tubes
• Intestinal tubes are placed for decompression of the GI tract, such as in intestinal obstruction
• Other reasons for placement include lavage to wash out the stomach, gavage for feeding, compression to control bleeding, and diagnosis via analysis of GI contents
• Short tubes pass through the nose into the stomach
• Medium tubes pass through the nose to the duodenum and the jejunum and are used for feeding
• Long tubes pass through the nose, esophagus, and stomach into the intestines, used for decompression
• A nasogastric tube (NGT) is a feeding tube inserted via the nose, exiting the stomach
• Adult NGT's are usually 90-100 cm long

Tracheal Tubes

• Tracheal tubes secure the patient's airway for spontaneous and controlled ventilation
• Disposable plastic tubes are made of polyvinyl chloride (PVC), available in clear, ivory, or siliconized options
• They have a radio-opaque line for position determination on chest X-rays, as plastic is not radio-opaque
• Siliconized PVC aids suction catheter passage
• Older tracheal tubes were rubber, reusable after cleaning & autoclaving

Tracheal Tube Sizes

• Tracheal tube sizes vary based on age, weight, and length
• Neonates require sizes 2.5-3.5 ID (mm) with a length of 10-12cm
• 1-6 month olds require sizes 4.0-4.5 ID (mm) with a length of 12-14cm & weigh 4-6(kg)
• 6-12 month olds require sizes 4.5-5.0 ID (mm) with a length of 14-16cm & weigh 6-10(kg)
• 1-3 year olds require sizes 5.0-5.5 ID (mm) with a length of 16-18cm & weigh 10-15(kg)
• 4-6 year olds require sizes 5.5-6.5 ID (mm) with a length of 18-20cm & weigh 15-20(kg)
• 7-10 year olds require sizes 6.5-7.0 ID (mm) with a length of 20-22cm & weigh 25-35(kg)
• 10-14 year olds require sizes 7.0-7.5 ID (mm) with a length of 22-24cm & weigh40-50(kg)
• The formula for internal diameter is age in years/4 + 4
• The standard tracheal tube position is within the trachea
• If the tube is too far, it may enter the right main bronchus

Tracheal Tube Cuffs

• Tracheal tubes come in cuffed and uncuffed form
• Inflated cuffs provide an airtight seal between the tube and tracheal wall
• The narrowest point in a child's airway is the cricoid cartilage
• A correctly sized uncuffed tube fits well in children
• Post-extubation subglottic oedema can be a problem because of the narrow upper airway in children
• To minimize risk, a small leak around the tube at an airway pressure of 15 cm H20 is ideal
• Cuffs come in can high or low pressure/volume configurations

High vs Low Volume Cuffs

• High-pressure/low-volume cuffs can prevent the passage of vomitus, secretions, or blood into the lungs
• However, they exert high pressure and if left in position for long periods, can cause necrosis of the tracheal mucosa
• Low-pressure/high-volume cuffs exert minimal pressure on the tracheal wall, allowing it remain inflated for longer periods
• Low-pressure/high-volume cuffs are less capable of preventing aspiration due to wrinkle formation
• Cuff pressure should be checked frequently and regularly, maintaining the pressure of 15–20 mmHg (20–30 cm H2 O)

Tube Insertion

• Nasal intubation is indicated for surgeries needing mouth access, such as ENT or dental operations
• Other indications for nasal include long-term ventilated patients on intensive care units because they tolerate a nasal tube better
• Long-term nasal tubes can cause sinus infection
• In children avoid nasal tube up to the age of 8-11 years as it can cause profuse bleeding
• Ivory PVC nasotracheal tubes cause less trauma to the nasal mucosa

Tracheal Tube Connectors

• Connectors connect tracheal tubes to the breathing system or catheter mount
• Designs vary and are made of plastic or metal
• Should have a suitable ID to reduce the gas flow resistance

Tube Problems

• Tracheal tube issues: obstruction by kinking, cuff herniation, occlusion by secretions, foreign body
• Other Tube issues : tube bevel lying against the tracheal wall
• Tube issues also include: Oesophageal or bronchial intubation and Trauma and injury to tissues during and after intubation

Tube Cuffs

• Low-pressure/high-volume cuffs vs high-pressure/low-volume cuffs and potential risks/benefits need to be understood

Special Tracheal Tubes

• Oxford and armoured/reinforced tracheal tubes are available along with the Polar and Ring, Adair and Elwyn (RAE) tracheal tubes
• Armoured tracheal tubes are made of plastic or silicone rubber, used in anaesthesia for head and neck surgery
• Incorporates a spiral for flexibility and strength, with an introducer stylet aiding intubation
• The RAE tube has a preformed shape to fit the mouth or nose without kinking
• It has a bend located just as the tube emerges, at the chin or forehead level, preventing surgical access interference
• RAE tubes are north or south-facing, cuffed or uncuffed

Tracheostomy Tracheal Tubes

• These tubes are curved plastic tubes usually inserted through the second, third and fourth tracheal cartilage rings
• An introducer is used for insertion, fixed in place with a ribbon or suture
• Designs include an adjustable flange for varying subcutaneous tissue thicknesses
• They are usually cuffed of uncuffed and may have a pilot balloon
• The proximal end has a standard 15mm connector

Cannula

• The cannula tip is usually cut square not bevelled, reducing obstructions against the tracheal walls
• New designs incorporate an additional suctioning lumen above the cuff
• This cuff shape design allows secretions above to be suctioned via this lumen

Tracheostomy Indications

• These include: Long-term intermittent positive pressure ventilation, Upper airway obstruction that cannot be bypassed with an oral/nasal tracheal tube and Maintenance of an airway
• Other Indications for Tracheostomy include: protecting lungs in those with impaired pharyngeal/laryngeal reflexes, long term control of secretions, facilitating ventilator weaning that is better tolerated due to a reduction in the sedation required

Tracheostomy Benefits

• Benefits include: increased patient comfort, less need for oral hygiene, improved oral hygiene, ability to provide nutrition, bronchial suctioning assistance, reduced dead space, reduced airway resistance and reduced glottic trauma

Intubation Problems

• Tube Problems in practice and safety features exist: surgical tracheostomy has a mortality rate of under 1%, but a high complication rate of 40%
• Complication rates are higher in the intensive care unit (ICU) and emergency patients
• Immediate complications include: hemorrhage, tube misplacement (e.g into main bronchus), occlusion of tube by cuff herniation/, occlusion of the tube tip against carina, pneumothorax
• Delayed complications include: blockage of the tube by secretions, infection of the stoma, over inflation of the cuff leading to Ulceration and distension of the trachea, mucosal ulceration from cuff pressure and tube migration
• Late complications include: Granulomata of the trachea causing respiratory difficulty after extubation, persistent sinus at the tracheostomy site, tracheal dilatation, tracheal stenosis at the cuff site, scar formation

Double Lumen Endobronchial tubes

• During thoracic surgery, one of the patients lungs needs to be deflated or isolated. Using with Double lumen endobronchial tubes that allow for the anaesthetist to selectively deflate one lung while maintaing standard ventilation of the other.

Double Lumen Components

• These tubes have two separate color-coded lumens, with each color ending with the bevel. One lumen ends in the trachea and the other ending in one main bronchus. Each cannal has its own cuff. The proximal end of these tubes is connected to a ‘Y’ connection mount on the patient.

Action

• There are differing bronchus anatomy which means there needs to be a tube for both bronchi

• When tubes are correctly placed, the anaesthetist can selectively ventilate one lung, so that the other lung is ventilated in operations where the right lung is deflated

• The left double lumen tube is preferred over right for patients with upper bronchus damage as the left cuff length allows more coverage and lower risk

Monitoring

• Post tube placement should be monitored. Auscultation should be performed immediately post intubation and bronchoscopy is encouraged.