Positive Pressure Ventilation Using a Face Mask and Bag-Valve Device

Job #3165

Job Posting Details

Job # 3165 Positive Pressure Ventilation Using a Face Mask and Bag-Valve Device

Posted Date
Mar 18, 2007 @ 12:02
Respond By
Mar 22, 2007
Word Count
0
Language
English (North American)
Gender
Female
Age Range
-
Category
Educational

Job Description

The project is a 10-minute video to teach how to ventilate persons in respiratory failure with a face mask and a bag-valve device. It is a not for profit academic project to be published as streaming video in the New England Journal of Medicine’s website. Thousands of students and physicians will benefit from this tutorial. Although we do not have a formal budget some funds are available. We would appreciate any help you could lend us. To see other similar videos go to www.nejm.org. Thanks.

SCRIPT

Positive Pressure Ventilation Using a Face Mask and Bag-Valve Device
Introduction:
• Providing positive pressure ventilation with a face mask and a bag-valve device can be a life saving maneuver. Although seemingly simple, the technique requires an understanding of the airway anatomy, the equipment, and the indications. Developing manual skills is necessary to provide adequate face mask ventilation. While endotracheal intubation is frequently the definitive airway management approach for patients in respiratory failure, it is not always feasible. In these circumstances, ventilating a patient with a face mask can be an invaluable temporizing measure.
• The purpose of this video is to demonstrate the equipment and technique used to provide positive pressure ventilation with a face mask and a bag-valve device.

Indications
• Face mask ventilation is used in patients with respiratory failure, but who are still spontaneously breathing, and in completely apneic patients.
• Face mask ventilation can be indicated after the induction of general anesthesia, the administration of neuromuscular blocking agents, narcotic overdose, cerebrovascular accidents, cardiopulmonary resuscitation, and other situations in which spontaneous breathing is failing or completely ceases.

Contraindications
• Face mask ventilation is rarely contraindicated in patients with respiratory failure or cardiopulmonary arrest. However, caution is advised in patients with severe facial trauma and open eye injuries. Additionally, foreign material, such as gastric contents and blood in the airway may lead to fatal aspiration pneumonitis. In those circumstances, alternative approaches, including immediate endotracheal intubation or tracheotomy may be necessary.

Equipment
• There are many types of face masks varying in design, size, and construction materials. Transparent masks are preferred because they allow for inspection of lip color, condensation, secretions, or vomitus.
• Face masks consist of three parts: the rim, the body, and the connector.
• The rim of the mask provides the seal with the face. Many masks have an inflatable cushioned rim, which creates a better seal with facial contours.
• Some masks have a malleable body, which can be molded the face, thus reducing dead space.
• Masks equipped with a ring with hooks can be used with a mask strap, to better hold the mask on the face.
• The connector of the mask is a standardized 22 mm diameter orifice and connects the mask to a bag-valve device.
• To maintain a good seal, it is imperative for the mask size and shape to conform to the facial anatomy. This is particularly important in the pediatric population. Thus, several mask shapes and sizes should be readily available.

• There are a variety of bag-valve designs available. All have a self-inflating bag and a non-rebreathing uni-directional valve. The valve is designed to function during both spontaneous and manually-controlled ventilation. Because bag-valve devices can operate without an oxygen source, it is important to ascertain that supplemental oxygen is flowing through the bag valve device when indicated and available. Bag-valve devices can be equipped with an oxygen reservoir of varying design. If the reservoir bag fills, oxygen is flowing. Oxygen flow through bag valve devices with a tube reservoir can be confirmed by listening to the sound of gas flowing. The purpose of these reservoirs is to maximize the delivered oxygen concentration.

• A bag-valve device’s capability for delivering positive pressure ventilation should be tested before use. This can be achieved by sealing the bag-valve device connector with the thumb and squeezing the bag with reasonable force. If it is difficult to compress the bag or if air is forced between the connector and the thumb, positive pressure can be delivered.
• Whenever possible during face mask ventilation, suction should be readily available. Airway management adjuncts such as oral or nasal airways may need to be used.
• Before beginning face mask ventilation, it is prudent to examine the patient’s oral cavity when possible. Smaller dental prosthesis, or other foreign bodies can be swallowed or aspirated. One may consider leaving full dentures in place to provide a better mask seal.

1 Hand Technique

• The most common method to hold the mask consists of placing the thumb and index finger on the body of the mask while the other fingers pull the jaw forward and extend the head. The middle and ring finger are placed on the ridge of the mandible and the 5th finger is placed behind the angle of the mandible.
• The tongue is the most common cause of airway obstruction. It is important to minimize the pressure applied to the submandibular soft tissues as this may further obstruct the airway by pushing the tongue against the palate. Maintaining an adequate seal while extending the head, thrusting the jaw forward, and squeezing the bag with the other hand may require considerable manual strength and coordination. Extreme caution is advised in patients with cervical spine injuries, in which flexion or extension of the neck is contraindicated. In this situation, the jaw thrust maneuver alone without head extension is recommended.

2 Hand Technique
• It may be difficult or impossible to maintain an adequate seal using only one hand. This challenge can occur in obese or edentulous patients, or in those with abundant facial hair. Additionally, large patients may present a challenge for individuals with small hands or with insufficient manual strength or dexterity. In these situations, the mask can be held with two hands, with each hand positioned as described in the one-hand technique. A second person compresses the bag-valve device.

Regardless of the technique used to ventilate the patient with a face mask, adequate ventilation can be assessed by inspecting and auscultating the chest and abdomen. The chest rising and falling and breath sounds synchronous to the delivered tidal volume suggest adequate ventilation. Gurgling epigastric sounds and tympanic abdominal distension indicate gastric insufflation and poor ventilation. Other monitoring tools such as a pulse oximeter and a carbon dioxide detector can be very valuable.

Using Oropharyngeal and Nasopharyngeal airways
Occasionally, it is difficult or impossible to provide ventilation unless an oral or nasal airway is inserted. These devices are most helpful when the cough and gag reflexes are absent. Insertion in patients with intact reflexes may precipitate coughing, vomiting, and laryngospasm. When used, the appropriate-sized device must be selected in order to avoid worsening of the airway obstruction. Too small an oral airway may push the tongue against the oropharynx. Too large an oral airway may push against the epiglottis and trigger laryngospasm. The correct size of an oral airway can be estimated by holding the airway next to the patient’s mouth. The tip should reach the angle of the mandible, and no further.

An oropharyngeal airway can be inserted by depressing the tongue with a tongue blade and advancing the airway towards the base of the tongue. Alternatively, the airway can be inserted upside down and then rotated 180 degrees as it is being advanced posteriorly.

In general, nasopharyngeal airways are better tolerated than oral airways when airway reflexes are present. They are particularly useful when the mouth cannot be opened. The simplest method of estimating their appropriate length is by correlating it with the external anatomy of the face and neck, and taking into consideration the patient’s height. Nasopharyngeal airways should be thoroughly lubricated and advanced perpendicular to the face and parallel to the floor of the nose, not towards the roof of the nose.
They must be used with extreme caution in patients with facial injuries, basilar skull fractures, and coagulopathy, weighing the risk of further injury and bleeding against the need for oxygenation.

Raising the head of a bed may facilitate the delivery of adequate tidal volumes, but may be contraindicated due to hemodynamic instability or may be impossible (e.g., if the patient is on the floor).

When the patient is breathing spontaneously, one must synchronize the delivered tidal volume with the patient’s inspiration. Regardless of the presence of spontaneous respiratory effort, when excessive pressure is delivered to the airway, gastric insufflation may occur. This may lead to a vicious cycle of increased intra-abdominal pressure which requires higher peak inspiratory pressure and can result in further gastric insufflation. This not only reduces effective ventilation but predisposes patients to vomiting or regurgitation.


Complications
Complications other than the inability to ventilate can occur, including corneal abrasions and blindness in the presence of a severe eye injury. Soft tissue injuries, particularly to the bridge of the nose and lips, may result when excessive pressure is applied. Complications such as trigeminal and facial nerve compression have been reported due to continuous, prolonged pressure on the facial structures.

Summary
Discontinuation of face-mask ventilation depends on clinical circumstances. Patients may require a more definitive airway management, such as endotracheal intubation. On other occasions, all that is needed for patients to recover completely is effective face mask ventilation with oxygen. Every physician should be familiar with this potentially life-saving technique.

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