Manual Breathing Devices & Pharyngeal Airways
Objectives - Operate a manual breathing device with one-person and two-person technique, and identify indications, contraindications, hazards, and uses of pharyngeal artificial airways.
Manual Breathing Devices
A manual breathing device is also called a bag-valve-mask, BVM, or artificial manual breathing unit. It is a hand-held device used to provide positive pressure ventilation to patients who are not breathing adequately.
Supplemental oxygen should be attached to the BVM as soon as appropriate and when enough resources are available.
Indications for Manual Ventilation
Manual ventilation is indicated when:
- Spontaneous breathing is absent or insufficient to support adequate ventilation and gas exchange
- Manual ventilation is needed during CPR
- Temporary ventilation is needed for a mechanically ventilated patient
- A mechanically ventilated patient is being transported
- Manual hyperinflation is needed before or after suctioning
Hazards of Manual Ventilation
Positive pressure ventilation can cause important hazards:
| Hazard | Why it matters |
|---|---|
| Decreased cardiac output | Increased intrathoracic pressure decreases venous return. |
| Barotrauma | Too much pressure can damage airways, lungs, and other organs. |
| Gastric insufflation | Increased airway pressure can force air into the stomach, increasing regurgitation and aspiration risk. |
| Volutrauma | Excessive volume can contribute to tension pneumothorax, especially in patients with lung disease. |
Self-Inflating Manual Resuscitation Bag
A manual resuscitation bag has a cushioned mask connected through a one-way valve to a self-inflating compressible chamber.
Advantages:
- Does not need a gas source to operate
- Can deliver 95% to 100% oxygen at 15 L/min
Disadvantage:
- Cannot deliver blow-by oxygen
Additional equipment may include a PEEP valve, especially when the patient has a high ventilator PEEP setting and particularly when PEEP is above 5 cm H2O.
Flow-Inflating Resuscitation Bag
A flow-inflating bag is also called an anesthesia bag. It is mainly used in the operating room by anesthesia and with neonates.
Peak inspiratory pressure is controlled by:
- Flow to the bag
- Adjustment of the flow control valve
- How hard the bag is squeezed
The bag should be kept approximately half-full between breaths. It may include a pressure manometer and a pressure relief port, also called a pop-off valve.
Advantages:
- Always delivers 100% oxygen
- Lung compliance can be felt
- Can provide blow-by oxygen
Disadvantages:
- Inflates only when the gas source is turned on and the bag opening is sealed
- Requires a more experienced user
Pre-Procedure Setup
Gather and check:
- Bag-valve-mask device
- Cushioned air mask
- Oxygen source and flowmeter
- Yankauer suction catheter with vacuum power source
- Nasopharyngeal and/or oropharyngeal airways
- Pulse oximeter
Patient Positioning
Use the head-tilt/chin-lift technique when appropriate:
- Press down on the forehead with one hand
- Pull up on the bony underside of the chin with two or three fingers of the other hand
- Tilt the head past neutral to open the airway
Use the modified jaw-thrust maneuver when head, neck, or spinal injury is suspected:
- Position yourself above the patient's head
- Place one hand on each side of the head with thumbs near the mouth corners
- Slide fingers under the angles of the jaw without moving the head or neck
- Thrust the jaw upward to lift the jaw and open the airway
An OPA or NPA may improve ventilation. Place the mask at the bridge of the nose, then lower it over the nose, mouth, and chin.
Ventilation Rate and Volume
For manual ventilation:
- Give 10 to 12 breaths per minute
- Squeeze about once every 5 to 6 seconds
- Depress the bag for 1 to 2 seconds, then release
- Do not squeeze aggressively
- Watch for chest rise
For an adult, depress the bag about halfway to deliver approximately 400 to 700 mL.
One-Person Technique
Use the EC technique:
- Position at the head of the bed
- Use the hand holding the mask to form a seal
- Lift the patient's jaw up into the mask
- Depress the bag about halfway
- Deliver smooth ventilations that last about 1 second
- Ventilate only until the chest just begins to rise
Two-Person Technique
Provider 1:
- Stands at the head of the bed
- Uses the EC technique with both hands
- Lifts the jaw into the mask
- Maintains the mask seal and an open airway
Provider 2:
- Depresses the bag about halfway
- Delivers smooth 1-second ventilations
- Watches for chest rise with Provider 1
BVM Troubleshooting
Check four areas when ventilation is difficult:
| Area | Questions to ask |
|---|---|
| Equipment | Is the oxygen source on? Is the bag functioning? Is the correct airway in place? |
| Positioning | Does the patient need a repeated chin lift or jaw thrust? |
| Seal | Should the hold be changed to a one- or two-person technique? Is the mask leaking? |
| Oxygenation and ventilation | Are secretions, vomitus, disease process, or anatomy making ventilation difficult? |
Pharyngeal Airways
Oropharyngeal Airway
An oropharyngeal airway, or OPA, is a hard plastic airway designed to prevent the tongue from obstructing the hypopharynx.
Indications:
- Unconscious patient
- Need to maintain a patent airway when the tongue may obstruct the oropharynx
- Bite block use for an intubated patient
Contraindications:
- Conscious or semiconscious patient
- Trauma to the oral cavity, mandible, or maxillary skull areas
- Foreign body obstructing the oral cavity or pharynx
OPA Sizing and Insertion
To size an OPA, place it along the side of the patient's face with the flange even with the mouth. It should measure from the corner of the mouth to the angle of the jaw while following the natural curve of the airway.
First insertion technique:
- Open the mouth using the cross-finger scissor technique
- Insert the OPA upside down with the curvature toward the tongue
- Advance to the uvula
- Rotate 180 degrees
Second insertion technique:
- Insert through the side of the mouth
- Follow the curve of the oral cavity
Nasopharyngeal Airway
A nasopharyngeal airway, or NPA, is a soft plastic or rubber airway inserted through the nostril. The tip rests behind the tongue and creates a groove that allows airflow.
Indications:
- Assist with bagging
- Frequent nasotracheal suctioning
- Help restore airway patency by separating the tongue from the posterior pharyngeal wall
- Bronchoscopy
- Need for an airway that is well tolerated in a conscious patient
Absolute contraindications:
- Trauma to the nasal region
- Foreign object blocking the nasal passages
NPAs are generally used in adults.
NPA Sizing and Insertion
Select the appropriate length by measuring from the patient's earlobe to the tip of the nose.
Insertion steps:
- Tilt the patient slightly backward
- Lubricate with a water-soluble agent
- Position perpendicular to the frontal plane of the face
- Advance slowly through the inferior meatus of either nostril
- Keep the bevel edge facing the septum
If obstruction is felt, gentle twisting may help. If resistance continues, a deviated nasal septum is likely. Try the other naris or use a smaller-diameter NPA.
High-Yield Review
| Concept | Key point |
|---|---|
| BVM purpose | Provides positive pressure ventilation when breathing is absent or inadequate. |
| Self-inflating bag | Does not need a gas source and can deliver 95% to 100% oxygen at 15 L/min. |
| Flow-inflating bag | Requires gas flow and a sealed opening; allows the clinician to feel lung compliance. |
| Adult BVM rate | 10 to 12 breaths/min, about one breath every 5 to 6 seconds. |
| Adult BVM volume | About half a squeeze, or 400 to 700 mL, with visible chest rise. |
| OPA | Best for unconscious patients when the tongue may obstruct the airway. |
| NPA | Better tolerated in conscious patients but contraindicated with nasal trauma. |