Positive Pressure Ventilation Using a Bag Valve Mask

Original Editor - Arnold Fredrick D'Souza Top Contributors - Dinalize Purcell and Kim Jackson

Introduction

A bag valve mask (BVM), sometimes referred to as an Ambu bag, is a handheld tool that is used to deliver positive pressure ventilation to any subject with insufficient or ineffective breaths. It consists of a self-inflating bag, a one-way valve, a mask, and an oxygen reservoir.

Method of Use

The following steps must be followed to ensure correct use of the BVM:

An oropharyngeal airway may be inserted to prevent airway occlusion when the patient is supine.

The rescuer should be at the patient’s head. A good seal must be achieved with the mask and the face. The pointed end of the mask must be over the nose and the curved end just below the lower lip.

A one-person technique requires the "E-C seal" method where the first and second digits form a "C" over the mask with the thumb pressing down by the nasal bridge, the second digit over the bottom of the mask by the mouth, and the remaining three digits forming an "E" over the mandible to hold the mask tight. There should be no gaps between the mask and the face. You can also perform the “head-tilt chin lift” maneuver or a “jaw-thrust” if indicated to maintain airway patency.

In a two-person technique, the second rescuer squeezes the bag while the first rescuer uses the same E-C technique with both hands. This is more effective in delivering the required tidal volume and also creates a better seal.

Ensure that the soft tissue around the neck is not compressed by the rescuer's fingers.

The following are signs to look for appropriate ventilation: chest rise, skin color, electronic vital signs, and resistance on the bag squeeze

Indications

It is indicated for hypercapnic respiratory failure, hypoxic respiratory failure, apnea, or altered mental status with the inability to protect the airway. Its usage is advocated while delivering breaths during cardiopulmonary resuscitation. Also, patients undergoing general anesthesia for elective surgery may require bag-mask ventilation.

Contraindications

There are no contraindications for bag-mask ventilation.

Limitations

Research has shown that providers can deliver excessive volume and pressure, which can lead to lung injury and secondary complications. In a study from Culbreth and Gardenhire they found that providers that were more confident in their technique, tended to deliver higher peak pressures and flow rates. Considering these limitations it is important to continue with training and education and use assistive technologies to ensure safe and optimal ventilation.