Lesson 2 – Basic Artificial Ventilation Techniques

BVM Overview

The Bag-Valve-Mask (BVM) is a tool used for artificial ventilation. It consists of a self-inflating bag, a non-rebreather valve, and a mask with a cushioned seal. Many BVMs have an oxygen reservoir to allow for high-concentration oxygen delivery. The one-way valve between the mask and bag ensures only fresh air or oxygen is delivered to the patient by preventing exhaled air from re-entering the bag. The BVM is useful in both single and multiple-rescuer scenarios, allowing for controlled, consistent ventilation.

BVM Assembly

Before using a BVM, make sure it’s correctly assembled. First, connect the mask to the valve assembly and then attach the self-inflating bag. If using supplemental oxygen, connect the oxygen tubing to the appropriate port on the bag or the reservoir. Set the oxygen flow rate to 15 liters per minute (LPM) for adults to ensure a high FiO2 (fraction of inspired oxygen). Test the bag to make sure the valve works correctly by squeezing it and confirming it inflates properly. Proper assembly and correct oxygen connection are essential for effective ventilation.

One-Person BVM Technique

For one-person BVM ventilation, position yourself at the top of the patient's head. Form a "C" shape with your thumb and index finger, using these fingers to hold the mask onto the patient's face, and use your other fingers to lift the jaw to open the airway. With your other hand, squeeze the bag to deliver each breath. This technique requires practice to maintain an effective seal and deliver adequate ventilation. If you’re not getting chest rise, focus on improving your mask seal and airway positioning rather than squeezing the bag harder.

Two-Person BVM Technique

The two-person BVM technique is more effective and is preferred when staffing allows. One rescuer uses both hands to maintain the mask seal and keep the airway open, while the second rescuer squeezes the bag. The rescuer maintaining the seal uses the thenar eminence (base of the thumb) of both hands on the mask, with fingers lifting the jaw. This technique often provides a better seal and more effective ventilation. It’s particularly useful in challenging scenarios such as with bearded patients or during transport.

Ventilation Rates

Ventilation rates are crucial for effective artificial ventilation. For adults, aim for 10–12 breaths per minute. For children, the rate should be 12–20 breaths per minute, and for infants, 20–30 breaths per minute. During CPR, coordinate ventilations with chest compressions according to the current guidelines. These rates are for patients with a pulse. In cardiac arrest, follow the appropriate CPR ratio of compressions to ventilations. Be conscious of not ventilating too quickly in stressful situations, so always control your rate.

Assessing Effectiveness

To assess the effectiveness of your ventilations, the most immediate signs include visible chest rise and fall with each breath. Listen for breath sounds to ensure air is entering the lungs and watch for improvements in the patient’s color, especially a reduction in cyanosis (bluish discoloration of the skin). If pulse oximetry is available, use it to monitor oxygen saturation. Always reassess your patient frequently, as their condition can change rapidly. If ventilation appears inadequate, reassess your technique, reposition the airway, or consider possible obstructions.

Troubleshooting Ventilation

Common issues include inadequate mask seal, which can be resolved by adjusting your hand placement or using the two-person BVM technique. Airway obstruction may require repositioning or suctioning to clear any blockage. Watch for signs of gastric inflation, such as epigastric distention, which can cause vomiting and aspiration. If you encounter high resistance to ventilation, consider causes such as bronchospasm, aspiration, or tension pneumothorax. Always check your equipment if you suspect malfunction. Be ready to troubleshoot and adapt your approach based on the patient’s response.