Optimizing Mask Ventilation
by Tom Trimble, RN
Choosing the Mask:
Although hospitals and EMS providers typically purchase BVMs with the manufacturer's mask, or provide disposable generic masks, for use, there are additional styles that you may encounter or find personally more useful or comfortable. I prefer clear malleable plastic masks with soft air-filled cuffs and a stepped or contoured shell for lower dead space and less fatigue for the hand. A range of sizes should be available. Spares should be available (Dropped masks have a tendency to roll under furniture and into awkward places . Punctured cuffs can occur.---Always send a mask on transports of intubated patients in case of accidental extubation). Hooks and straps should only rarely be used (although, some individuals find hooks useful as a finger rest when manipulating the mask's position).
Holding the Mask:
To successfully ventilate patients with mask-fitting respiratory devices one must do more than "OK".
Make an "OK" sign with your thumb and forefinger around the port or chimney of the mask.
Use your spread lower fingers to span the length of the patient's mandible and its inferior angle.
Fit the nose-notch of the mask's cuff over the bridge of the patient's nose.
Spread and mold the malleable portions of the mask to flare and fit against the patients face. Roll the mask into contact with the face. Open the mouth slightly and bring the lower portion of the mask's cuff to rest in the hollow above the chin's bump and below the base of the teeth.
Do NOT "press the mask onto the face!" PULL the face into the mask! This will provide much closer fit, tauten the tissues which help open the airway, oppose the inherent collapse of the airway from any downward pressure, give you control over the head and neck, and allow you to independently move the mask cuff to block a leak.
Listen and feel for any leak under the cuff. If the leak is on the side opposite the hand, you may need to roll the mask slightly towards the leak to allow better cuff pressure. Compensating for this on the side you are holding with your hand may require you to compress the mask cuff to block the leak with the inner edge of the hand.
Positioning of head, neck, and torso:
Prop and support the patient's shoulders, neck, and head in midline without rotation to align the airway conduit for easy ventilation, less fatigue, and with the neck flexed anteriorly into a "sniffing position" in preparation for invasive airway devices. Elevate the head of the bed thirty degrees for obese or pregnant patients so that gravity will take the weight of the viscera off the diaphragm to lessen the work of ventilation. This elevation and avoidance of neck torsion is likewise beneficial to the head-injured patient with potential for increased intracranial pressure by ensuring good flow dynamics through the neck vessels.
The "Bacon Bunch" for increasing fit and decreasing leak:
Dr A K Bacon, FRCA FANZCA , a Medical Director for the Metropolitan Ambulance Service in Melbourne, Australia states: "It works wonders to use the "Bunching the cheek" technique: the radial edge of the palm is used to push a fold of cheek up towards the mask, then settle the palm down on the face and mask, keeping the palm in contact with the face at all times. The traditional "spread the fingers and get the palm off the face" way looks more elegant, but does not provide such a good seal on all faces."
Mask Ventilation: Wrong Size Mask for Face?:
(This section is reprinted from ENW's Tips & Tricks page)If you must mask ventilate (O2BVM) a small-stature adult or child with a typical "Adult Mask" which is larger than can readily seal on the patient's face, try inverting the mask so that the usual chin portion lies across the nasion and cheek bones and the narrow nasal portion of the mask is used to fit against or around the chin; this may be sufficient adaptation to control the situation until an appropriately sized mask is available.
If the patient is edentulous and has sunken cheeks and hasn't the customary facial architecture to effectively seal the mask: try slipping a "Newborn Mask" (such as a Rendell-Baker-Soucek) in place and then into the patient's mouth. Use your support hand to "cup" the chin and pull upwards stabilizing the mask port within the "OK Sign" of your thumb and index fingers and pinch the nostrils closed. This should allow satisfactory seal and ventilation until a definitive airway can be placed.
An additional solution is to place a nasopharyngeal airway with an endotracheal tube connector in place to which the O2BVM can be attached. Support the chin and pinch the nostrils in the same fashion: continue until a definitive airway is placed. This works well for "One-Man Band" single-rescuer CPR until endotracheal intubation support arrives {the bag just hangs in place at the patient's nose during compressions, and ventilations can be given more quickly this way without changing positions or having to carefully fit a mask}.
Need an "Extra Hand"? Put your chin into it!:
Use two hands to support the mask with all the care and technique with the second hand as the first (delegating bag-squeezing to someone else). Your chin can be used to press slightly on the top of the mask for an extra bit of pressure or tilt (especially with large masks with hard plastic shells that are not malleable).
Have to Ventilate Baby from the side of the bed?:
One way to hold the mask in this position is to "fork" the fingers of your mask hand (this should be the hand nearest the baby's feet) with the port of the mask between the index and middle fingers while the head is tilted gently and the jaw lifted with the thumb and ring fingers There's now plenty of room at the head for the intubator. (Remember the large size of the baby's occiput and place some padding under the shoulders and head. Avoid forceful hyperextension of the neck that can distort or collapse the trachea of the neonate.)
Fatigued or Cramped from Squeezing the BVM?:
Rotate the valve and bag on the mask so that the weight of the bag rests upon the forearm of the hand which is holding the mask. The bag can now be squeezed by pressing against the forearm. (Small hands can now give a full bag volume breath to the patient.). If using an anesthesia bag, or extension tubing can be placed between the valve and the bag, the bag can be squeezed against the bed. A second operator can squeeze the bag and two hands can be used by the first to better fit the mask and support the airway with two-handed Triple Airway Maneuver. If the patient is on the ground, the bag can be squeezed against the rescuer's kneeling leg, or the rescuer can sit, stabilizing the victim's head between the rescuer's knees or thighs, and squeeze the bag against his own knee or thigh.
CPAP (Constant Positive Airway Pressure), with an anesthesia bag, can be used to distend flaccid airway tissues and provide "internal pneumatic splinting" for an open passage. This is especially useful when muscle tone is lost or in the presence of a short thick neck, short jaw, thick tongue, or when there is trouble oxygenating as in acute pulmonary edema or pneumonia. Increase the flow carefully so that the bag stays mostly distended during both inspiratory and expiratory phases of the breathing cycle The bag will decrease size slightly with inspiration but quickly refill, but not over-distend during expiration. (Avoid barotrauma.) A manometer should be connected near the elbow as soon as available to monitor the Peak Airway Pressure and Positive End-Expiratory Pressure.
Airway Devices:
Pharyngeal Airways (nasal/oral): An oropharyngeal airway may now be needed to provide space between the structures of lips, teeth, tongue, palate (hard & soft), base of tongue, and retropharynx; or nasopharyngeal to bypass trismus (clenched jaws, wired jaws, or masseter spasm), provide a conduit for air or suctioning catheters, and to be better tolerated by the patient with varying level of consciousness (e.g., post-ictal)
A new COPA™ -Cuffed Oropharyngeal Airway device from Malinckrodt.may be useful for short term hands-off maskless airway support of the spontaneously breathing patient and for ventilation without endotracheal intubation for brief deep sedation procedures or CT scans. It does not protect the lower airway from aspiration however.
Combitube: An "alternative airway" with two lumena and balloons which can be inserted manually without visualization through which one can ventilate the patient whether the tube is endotracheally or esophageally placed.
Laryngeal Mask Airway: A more invasive ventilatory device is a "glorified face mask" especially shaped to close the area around the tracheal glottis and epiglottis attached to a tube that conveys respiratory gasses which exits the mouth to connect to your breathing circuit or O2BVM. This can provide good ventilation for short periods to several hours with a manual insertion technique without laryngoscopy. It does not completely protect against aspiration, and is best used with the fasted patient. However, there is a role for it in the management of the difficult airway as it can quickly provide ventilation when face mask will not suffice, and endotracheal intubation can then be done through it with a fiberoptic scope, a "tube exchanger" stylet or an Eschmann Gum Elastic Bougie. (c.f., Action Plan For Airway Hell and our Airway Management links)
Sequence of Steps with Difficult Ventilation:
Inspect patient and observe patient's responses continuously. If firmly obstructed at any point, go to Heimlich Maneuver and Finger-sweep, etc., as per Basic Life Support
Align, straighten, and lift neck; tilt head; open mouth slightly.
Make OK sign with mask; fit mask to nose, face, and chin; spread, mold, and clamp mask to face.
With little and ring fingers, pull mandible upwards into mask.
Ventilate. If ventilation inadequate or airway obstructed, recheck head tilt and mask fit, and jaw lift.
Additional airway can be obtained in flaccid patients by displacing the mandibile forward from the TemporoMandibular Joint by continued upward pressure at the ramus with the little finger creating a prognathic appearance (the teeth of the lower jaw in advance of the the upper).
Two-handed mask holding with an assistant to bag ventilate.
If still unable to ventilate, Inspect for obstruction with Direct Laryngoscopy if possible, or finger-sweep digital inspection. Remove any found obstruction.
Use most appropriate available airway adjunct device according to one's training, demonstrated competency and credentialling, and experience.
If adequate airway and ventilation are still not obtained, proceed with the Difficult Airway Algorithm and obtain help as quickly as possible if not already summoned.
This web article is: "Optimizing Mask Ventilation"
[http://ENW.org/MaskVentilation.htm]
from Emergency Nursing World ! [http://ENW.org]
©Tom Trimble, RN [Tom@ENW.org](c.f., Action Plan For Airway Problems From Hell! and our Airway Management links)
