Although artificial ventilation is taught to us early on and frequently reinforced throughout our careers, proper bag-valve-mask (BVM) ventilation is an art that must be practiced regularly to ensure it remains second nature for anyone called upon to perform this critical intervention. Using a flow-inflating bag isn’t as simple as attaching oxygen tubing to a flowmeter and squeezing the bag. Flow inflating bag masks require more training and experience to operate properly as the provider must simultaneously manage gas flow, suitable mask seal, patient neck position, and proper tidal volume.
Managing gas flow and checking for leaks
Flow inflating bags must have oxygen or compressed air flow to function and in most cases require a higher liter flow than other devices to maintain appropriate pressure. NRP guidelines recommend starting at 10 LPM. The bag should remain fully inflated with the desired PEEP. Unlike self-inflating bags, flow inflating bags will not refill when the oxygen source is empty or detached. The adjustment valve wheel is used to set the desired peep. Turning the valve wheel clockwise opens up the valve and decreases the pressure that you are trying to deliver to the patient. Turning the valve counterclockwise closes the valve, hence, increasing the pressure you are delivering to the patient. Clinicians should always check for leaks and adequate flow control prior to use on the patient. The bag can be tested by setting the preset pressure by occluding the patient outlet and making adjustments to the flow control valve.
Positioning the patient
The best way to set yourself up for airway success is by placing the pediatric patient in the proper position. Proper positioning and manual maneuvers to relieve tongue and soft tissue obstruction of the upper airway are crucial in the pediatric population. Often times laying a child supine may force their chin onto their chest resulting in less than optimal airway positioning. A neutral “sniffing” position without hyperextension of the neck is appropriate for infants and toddlers. Extreme hyperextension in small children will result in airway obstruction. A shoulder roll can help create a simple extension of the neck and bring a child into sniffing position
Selecting the proper size mask is crucial to ventilating the patient. Inflatable masks range from sizes 00 to 5 in the neonatal-pediatric population. When placed on the patient’s face, a properly sized mask will completely cover the nares and mouth without any gaps between the mask and face. The mask should measure from the bridge of the nose to the cleft of the chin. The EC clamp technique of bag-mask ventilation can be utilized with careful hand placement. In the sole rescuer technique, the thumb and index finger hold the mask down over the nose and mouth forming a C while the other three fingers of the hand grasp the patient’s mandible forming an E. It is important to be mindful to minimize pressure on the submental tissue to avoid tongue obstruction. Often times, it is more effective to ventilate with two rescuers. The rescuer who is positioning the airway should seat the mask at the apex of the narrow portion on the bridge of the nose and seal the mask to the patient’s face by positioning the rescuer’s thumbs on each side of the mask, being careful not to push the mask down into the face.
Proper Tidal Volume and Monitoring Pressures
Because the flow inflating bag is soft, you can easily feel lung compliance and respiratory effort. With spontaneous ventilation, the skilled clinician can see and feel the bag partially deflate with each inspiration before it inflates with the gas flow. The amount the bag deflates gives the clinician a good indication of tidal volume. Experienced personnel will know immediately when you have lost a good seal because the bag will go flat and tidal volume will not be delivered. Due to extremely fine control, flow inflating bags are capable of delivering tiny tidal volumes. Monitoring airway pressures while maintaining adequate ventilation is crucial. Many flow inflating bags are equipped with either a pressure manometer or a port to attach an optional manometer. Ventilating with the lowest pressure to achieve appropriate chest rise is key. Targeted pressures of less than 20 cm H20 are ideal. Bags are furnished with a pop-off valve safety feature to ensure patient safety and reduce the effects of ventilation such as barotrauma.
Airway management is a key skill for the respiratory therapist and their team. The airway of the pediatric patient has a number of significant differences when compared to the adult airway and presents some unique challenges. Bag mask ventilation plays a vital role in effective manual ventilation, improving both oxygenation and ventilation as well as buying time while preparations are made for endotracheal intubation.
“Flow inflating bags offer many advantages over self-inflating bags in infants. It is the preferred device for manual ventilation by most neonatal resusitationists. However, you need experience using these devices! It takes practice to assure you maintain PEEP with the flow and the valve wheel and to assure you are giving adequate breaths without over-inflating your bag. If you are inexperienced with a flow inflating bag and are struggling to ventilate an infant, consider switching to a self-inflating bag.”
-Steve Haywood MD.
- Flow inflating bags must have oxygen or compressed air to operate.
- The adjustment wheel sets the desired peep.
- Maintain the sniffing position without hyperextension of the neck in children.
Oliveira, P.M., Almeida-Junior, A., Almeida, C., Ribeiro, M.A., Ribeiro, J. (2013). Neonatal and Pediatric Manual Hyperinflation: Influence of Oxygen Flow on Ventilation Parameters. Respiratory Care, 58, 2127-2133.