Oropharyngeal Airway (OPA) / Guedel Airway 

1. Definition

An oropharyngeal airway (OPA) is a curved rigid plastic device inserted into the mouth that sits between the tongue and posterior pharyngeal wall to prevent airway obstruction caused by the tongue.

Core Functions

1. Maintains upper airway patency
2. Prevents tongue fall-back
3. Facilitates bag-mask ventilation
4. Acts as bite block
5. Allows suctioning of secretions

2. Historical Background

The device was introduced by Arthur Guedel, an American anesthesiologist.

Arthur Guedel developed the airway as part of airway management during early anesthesia practice.

3. Anatomy of the OPA

An OPA has three major parts.

1. Flange

• Flat proximal portion outside the mouth
• Prevents device from slipping into airway
• Provides surface for fixation

2. Body

• Curved portion following tongue anatomy
• Holds the tongue away from posterior pharyngeal wall

3. Channel / Lumen

• Central hollow portion
• Allows airflow and suction catheter passage

4. Bite Block

• Prevents biting of endotracheal tube during ventilation

4. Principle of Action

The most common cause of airway obstruction in unconscious patients is posterior displacement of the tongue.

Mechanism:

1. Loss of muscle tone in unconsciousness
2. Tongue falls backward
3. Obstructs oropharynx

OPA displaces the tongue anteriorly, restoring airflow.

5. Indications in ICU

1. Unconscious patient with airway obstruction

2. Bag-mask ventilation

3. Prevent tongue obstruction

In conditions like:

• Deep sedation
• General anesthesia
• Coma

4. Bite block for intubated patients

5. Facilitation of suction

6. Contraindications

Absolute Contraindication

Conscious or semi-conscious patient with intact gag reflex

Why?

Insertion causes:

• Vomiting
• Aspiration
• Laryngospasm

Relative Contraindications

1. Oral trauma
2. Trismus
3. Severe facial fractures
4. Active vomiting

7. Size Selection 

Correct size prevents complications.

Measurement Method

Measure distance between:

Corner of mouth → Angle of mandible

OR

Incisor teeth → earlobe

Size Chart

Size 3 and 4 most commonly used in adults.

8. Insertion Technique

Two techniques exist.

Technique 1: Standard Rotation Technique (Adults)

Steps

1. Open mouth
2. Insert airway upside down (concavity upward).
3. Advance until soft palate reached.
4. Rotate 180°
5. Advance until flange rests on lips.

Reason:

Rotation prevents pushing tongue posteriorly.

Technique 2: Tongue Depressor Technique (Children)

In children rotation can cause trauma.

Steps:

1. Use tongue depressor
2. Insert airway directly concave side down
3. Advance gently.

9. Complications

1. Gagging and vomiting
2. Aspiration

3. Dental injury

From insertion trauma.

4. Oral mucosal injury

Especially in prolonged use.

5. Airway obstruction

If:

• Size too small → pushes tongue backward
• Size too large → epiglottis obstruction

5. Laryngospasm

Especially in semi-conscious patients.

10. Comparison: OPA vs NPA