Characteristics and functions of oropharyngeal airways

An oropharyngeal airway, also known as an oropharyngeal tube, is a commonly used artificial airway adjunct. This rigid, flattened tube-shaped artificial airway is typically made of elastic rubber or plastic. Its primary purpose is to maintain the patency of the patient's upper airway in medical emergencies, during anesthesia, or in cases of impaired consciousness.

1. Simple Structure: Typically a curved, tubular or channel-shaped device made of rigid plastic or rubber, designed to conform to the anatomical structure of the oral cavity and pharynx.
2. Diverse Models: Available in various sizes to suit patients of different ages and body types (from infants to adults). Choosing the appropriate size is crucial.
3. Optimized Design:
• Hollow tube: Allows air passage and can be connected to a suction catheter for secretion aspiration.
• Bite block: Prevents the patient from biting down on the tube or biting their tongue, and also prevents biting on the endotracheal tube.
• Flange or wing: Located outside the lips, preventing the tube from slipping deep into the oral cavity and facilitating fixation.
4. Non-invasive: Compared to tracheal intubation, its placement is simpler and faster, requires no specialized equipment, and is a non-invasive procedure.

1. Maintaining airway patency: This is the most crucial function. When patients experience muscle relaxation due to loss of consciousness, deep sedation, general anesthesia, head injury, or cardiopulmonary resuscitation, the tongue and epiglottis are prone to falling back and obstructing the pharynx. An oropharyngeal airway physically props open this area, creating a clear passage for air to enter and exit the lungs.
2. Preventing tongue prolapse: It directly supports the base of the tongue, pushing it away from the posterior pharyngeal wall.
3. Facilitating suctioning of secretions: Its hollow design allows for the passage of a suction catheter to clear secretions, blood, or vomit from the oral cavity and pharynx, maintaining a clear airway.
4. Protective function: As a bite block, it prevents the patient from injuring their tongue, lips, or medical tubing (such as an endotracheal tube) during seizures or biting.
5. Facilitating other procedures: During mask ventilation, it provides a better seal and improves ventilation efficiency. It also sometimes provides better visibility and space for laryngoscopy and endotracheal intubation.

• Prerequisites for Use: This device is only suitable for patients without a gag reflex (e.g., those in deep coma or under anesthesia). It is strictly prohibited for use in patients who are lightly comatose or conscious, as placement may trigger severe nausea, vomiting, laryngospasm, or even aspiration or airway obstruction.
• Correct Placement: Proper placement technique is crucial; incorrect placement (such as pushing the tongue towards the pharynx) can worsen the obstruction. Common methods include the reverse rotation insertion method or the tongue depressor assisted method.
• Size Selection: The size is usually determined by measuring the distance from the corner of the patient's mouth to the earlobe or mandibular angle. Too short will be ineffective, while too long may stimulate the larynx and trigger reflexes or push the epiglottis towards the glottis.
• Temporary measure: It cannot completely prevent aspiration, nor can it provide a reliable seal for positive pressure ventilation. Tracheal intubation or the use of a supraglottic airway device is necessary when advanced airway protection or prolonged ventilation is required.
• Monitoring and care: After placement, the effectiveness of ventilation must be closely monitored, and the device should be regularly checked and cleaned to prevent obstruction by secretions.

The oropharyngeal airway is a simple, effective, and crucial emergency and anesthesia device, primarily used to temporarily maintain an open airway in unconscious patients, buying time for rescue and treatment. However, it requires correct selection, placement, and use, and an understanding of its limitations.