8.1 Basic Airway Adjuncts & Bag-Mask Ventilation

Basic Airway Adjuncts

Basic airway adjuncts play a pivotal role in maintaining airway patency when a patient is unable to do so independently. The two primary basic airway adjuncts used in ACLS are the Oropharyngeal Airway (OPA) and the Nasopharyngeal Airway (NPA). Each has specific indications, contraindications, and insertion techniques that healthcare providers must master to ensure adequate oxygenation and ventilation without causing harm.

Oropharyngeal Airway (OPA)

The OPA is a J-shaped device designed to fit over the tongue and hold it away from the posterior pharyngeal wall, preventing the tongue from occluding the airway—a common cause of airway obstruction in unresponsive patients.

Indications and Contraindications:

• Use: Only in completely unconscious patients who do not possess a gag reflex.
• Contraindication: Conscious or semi-conscious patients. Inserting an OPA in a patient with an intact gag reflex can stimulate vomiting, which carries a severe risk of aspiration, potentially leading to aspiration pneumonitis or airway occlusion.

Sizing and Insertion:

• Measurement: Proper sizing is critical. Measure the OPA by placing it against the side of the patient's face. The flange should align with the corner of the mouth, and the tip should reach the angle of the jaw (mandible).
• Insertion Technique: Clear the mouth of any secretions or debris. Insert the OPA upside down (with the tip pointing toward the roof of the mouth). As the OPA approaches the posterior wall of the pharynx, rotate it 180 degrees so that it drops into the posterior pharynx behind the tongue. Alternatively, use a tongue depressor to move the tongue out of the way and insert the OPA directly.

Nasopharyngeal Airway (NPA)

The NPA, often called a nasal trumpet, is an uncuffed tube made of soft rubber or plastic. It provides a patent airway from the nares to the lower pharynx.

Indications and Contraindications:

• Use: Can be used in conscious, semi-conscious, or unconscious patients. It is particularly useful when an OPA is contraindicated (e.g., patient has a gag reflex, clenched teeth, or oral trauma).
• Contraindication: Caution should be exercised, and it is relatively contraindicated in patients with known or suspected severe basal skull fractures or severe facial trauma, as the tube could inadvertently enter the cranial vault.

Sizing and Insertion:

• Measurement: Measure the NPA from the tip of the patient's nose to the earlobe. Choosing the correct diameter is also important; it should generally match the size of the patient's smallest finger.
• Insertion Technique: The NPA must be well-lubricated with a water-soluble lubricant before insertion. Insert it gently into the nostril (usually the right, as it is typically larger) with the bevel facing the nasal septum. Advance it straight back along the floor of the nasal cavity. If resistance is met, do not force it; withdraw, re-lubricate, and attempt insertion in the other nostril.

Bag-Mask Ventilation (BMV)

Bag-mask ventilation is the standard initial method for providing positive-pressure ventilation to a patient who is not breathing or is breathing inadequately. It is a critical skill that requires practice to ensure a tight seal and adequate tidal volume.

The Two-Rescuer E-C Clamp Technique

The most effective method for BMV involves two rescuers. One rescuer focuses entirely on maintaining an open airway and a tight mask seal, while the second rescuer delivers the ventilations.

• First Rescuer (Mask Seal and Airway): Positioned at the patient's head, this rescuer uses both hands to perform the E-C clamp technique. The thumbs and index fingers of both hands form a 'C' shape to press the mask firmly against the patient's face. The remaining three fingers (middle, ring, and pinky) form an 'E' shape and are placed along the bony margin of the mandible to lift the jaw upward, opening the airway.
• Second Rescuer (Ventilation): Squeezes the bag to deliver breaths.

Delivering Breaths and Preventing Complications

• Volume and Duration: Deliver each breath over exactly 1 second. Provide only enough volume to produce visible chest rise (typically around 500-600 mL for an average adult). Squeezing the bag too forcefully or delivering too much volume is unnecessary and harmful.
• Preventing Gastric Inflation: Delivering breaths too rapidly or with too much volume forces air into the stomach rather than the lungs. Gastric inflation increases the risk of regurgitation and aspiration, and it elevates the diaphragm, which restricts lung expansion and decreases respiratory compliance.
• Avoiding Hyperventilation: Hyperventilation (delivering breaths too quickly or forcefully) must be strictly avoided. It increases intrathoracic pressure, which in turn decreases venous return to the heart. Decreased venous return leads to a dramatic drop in cardiac output and coronary perfusion pressure, severely compromising the effectiveness of CPR and reducing the likelihood of Return of Spontaneous Circulation (ROSC).