Providing effective ventilation and oxygenation using a bag mask is probably the single most important component of airway management. Bag-mask-ventilation (BMV) refers to the use of a bag-mask unit, most of which but not all have valves (in which case they are referred to as Bag-Valve-Mask units or BVMs) system/device to deliver gas rich in oxygen either passively or actively by manually ventilating the patient using a face-mask interface. Examples of non-valved bag-mask devices include Mapleson E (Jackson Rees Modification of Ayres T-piece) and other t-piece occlude systems. Manual noninvasive ventilation also accurately describes the use of a BMV device to provide positive pressure ventilation (PPV). This should be differentiated from mechanical noninvasive ventilation, which also uses a face-mask interface but provides respiratory effort assistance (PPV) delivered by specialized ventilator.

Is There Still a Role for Bag-Mask-Ventilation in This Advanced World of Difficult Airway Devices?

Definitive airway management has traditionally been defined as the secure placement of an endotracheal tube (ETT) in the trachea. Although few would argue that there has been a philosophical and evidence-based shift away from defining airway management by the method of gas exchange to focus on the goals of resuscitation namely, maintaining patient’s oxygenation and ventilation while preserving hemodynamic status. In other words, ETTs don’t save lives, whereas providing adequate perfusion and gas exchange does. Optimal oxygenation and ventilation may be provided using ETTs, extraglottic devices (EGDs), BMV devices, and surgical methods. Which method is most appropriately employed will depend on patient characteristics, the clinical situation, and practitioner’s skill.

Bag-mask-ventilation particularly in the pre-hospital setting has been shown to be no less effective than endotracheal intubation (ETI) or EGD use.^1–4 In a large prospective population-based study of out-of-hospital cardiac arrest (OHCA) patients (649,654), survivors who received BMV had more favorable neurologic outcomes compared to those who had their airway managed by ETI or EGD.⁵ With increasing controversy regarding the value of pre-hospital ETI, other means of maintaining oxygenation and ventilation including BMV are being reaffirmed as an airway management priority.^6–12

For OHCA, ventilation has been de-emphasized in the early phase of adult non-asphyxia-related resuscitation where oxygen delivery is more dependent on blood flow than on arterial oxygen content. There is consensus that advanced airway management should not be considered a priority over high-quality chest compressions as preformed in cardioplumonary resuscitation (CPR) and defibrillation and has the potential of causing harm by interrupting CPR, from complications of airway management, impairing cerebral perfusion (EGDs), and perhaps inadvertent hyperventilation.^1,11 While there is a theoretical advantage in using EGDs in the context of cardiac arrest where chest compressions can continue uninterrupted, prospective data to support the preferred approach for pre-hospital airway management in OHCA is lacking and awaits further study (AIRWAYS-2 & PART). While the focus of current studies is determining which advanced airway best serves this patient population, large retrospective data sets suggest the need to prospectively compare less invasive techniques of oxygen delivery such as BMV and passive oxygen insufflation to more active invasive airway procedures (ETI, EGD).^13–15

For non-OHCA patients advanced airway management has not consistently shown to be of benefit when compared to a basic approach that includes BMV.^3,4,16 Many believe that pre-hospital airway management outcomes are less related to the device and more to do with the decisions and skills with which these airway devices are employed.^10,11 Worsening hypoxemia and inadvertent hyperventilation occurring during and post advanced airway management placement are thought to be major contributors to the observed poor outcomes in the pre-hospital setting.¹⁷ The technical imperative of succeeding in placement of an advanced airway device may be distracting clinicians away from the homeostatic goal of improving and maintaining oxygen and ventilation status. This goal may often be best achieved with BMV. Most of the existing data comes from North American ground-based ambulance services.

Bag-mask-ventilation can be a challenging skill to learn and perform effectively.^18–20 Despite the advent of numerous alternative devices, just as direct laryngoscopy (DL) remains the current gold standard for ETT placement, BMV still remains the primary method of providing initial basic life support (BLS) oxygenation and ventilation in most resuscitation settings.²¹ Although this may change, there currently is no compelling evidence of superiority of advanced airway techniques over BMV.^13,22–27 Compared to BMV used by relatively inexperienced health care providers, laryngeal mask airways (LMAs) have been reported to be rapidly placed, “easy to use” and effective as ventilation device.²⁸ Similar results have been shown with the laryngeal tube.²⁵ Other reports of EGD “field use” have, however, demonstrated lower than expected success rates and worse outcomes when compared to BMV despite self-reported ease of use.^13,23,29,30 In contrast, there is some evidence that for the neonatal population, EGD use is more effective than BMV during resuscitation efforts.³¹

Success and complications of any airway device are more often related to training and experience than the device itself. Despite its effectiveness in skilled hands, BMV is facing a growing competition from EGDs that even in unskilled hands, are relatively easy to teach, learn, and ultimately deliver as a primary method for oxygenation and ventilation.

What Are the Key Components of a Bag-Mask System?

Also referred to as manual resuscitators, these devices usually employ a bag and an integrated one-way valve connected to an ETT, an EGD, or a mask to manually provide PPV. Despite there being various types of BMV systems, for most part they share common features (Figure 8–1):³²

• 
  

  Universal connector: with a 22-mm outside diameter (OD), which fits standard face-masks, and a 15-mm internal diameter (ID) that connects to standard ETTs, EGDs, and cricothyrotomy or tracheotomy cannulae.

  
  
• 
  

  Non-rebreathing patient valve: to prevent rebreathing while allowing exhalation.

  
  
• 
  

  Self-inflating bag: supplied in adult (1600 mL); child (500 mL); and infant (240 mL) sizes that when manually compressed deliver a corresponding tidal volume; or an oxygen reservoir bag that is inflated by receiving high oxygen flow through an adjacent connector.

  
  
• 
  

  Oxygen inlet valve: providing unidirectional flow from the oxygen reservoir to the self-inflating bag.

  
  
• 
  

  Air intake valve (at reservoir end): a safety valve intended to allow entrainment of room air if supplied oxygen source is disconnected.

  
  
• 
  

  Safety outlet valve (at reservoir end): a flow-limiting valve

  
  
• 
  

  Other features of BMV systems may include: positive pressure relief or “pop-off” valves with the intent of limiting airway pressures to avoid barotrauma when the manual resuscitator is connected to an ETT.

  
  
• 
  

  An expiratory port at the patient connector that allows attachment of a PEEP valve.

  
  
• 
  

  Flow-limiting valve located at the patient end of the self-inflating bag designed to limit inspiratory flow decreasing the risk of both hyperventilation and excessive airway pressures (Smart Bag→).

The face masks used in conjunction with the manual resuscitator vary in material, size, seal type, and transparency. Traditionally, black/opaque rubber masks with an anatomically contoured seal were used in the operating room setting connected to an anesthetic circuit. These have been replaced to a large extent in most environments by transparent silicone, or plastic latex-free non-disposable and single-use masks that provide the added benefit of being able to visualize the mouth/nose-mask interface and therefore react to the presence of vomitus and other secretions. Rather than anatomically conforming to the patients face, the seals in these disposable masks are either made of foam or an air-filled “cushion” that molds to the underlying facial anatomy.

While the unidirectional valves are similar amongst available BMV devices, it is important to appreciate whether the device has a dedicated expiratory valve. This valve provides an unidirectional flow for expired gases and will not allow room air entrainment for the spontaneously breathing patient. If there is an open expiratory port, it usually means there is no dedicated intrinsic expiratory valve and in the spontaneously breathing patient they may entrain room air.³³ This is easily dealt with by adding a PEEP valve.

How Do You Accurately Anticipate Difficult Mask-Ventilation?

Perhaps the simple answer is you can never ensure 100% accuracy when you are trying to predict anything.³⁴ The safest approach is perhaps to “always anticipate the unexpected.” In the anticipated difficult airway, proceeding depends on context. In an elective operating room setting, predicted difficulty will often mean a very different course (including canceling the case) than in an emergency situation in which a choice of not proceeding is usually not an option. In trying to anticipate difficulty, the core two traditional questions that all practitioners should ask themselves prior to proceeding are:

• 
  

  Will I be able to maintain oxygenation and ventilation by BMV if intubation attempts fail? If not, will I be able to oxygenate and ventilate rapidly using a rescue device or technique, such as an EGD or surgical airway?

Early literature on predicting the difficult airway focused on laryngoscopy and intubation.^35–37 Recognizing that maintenance of oxygenation and ventilation is the priority in airway management and that this is often best achieved rapidly and early by BMV, the identification of predictors of difficult mask-ventilation (DMV) has also been a focus of research.^38–43 Most airway management decision algorithms require a “formal” patient assessment focused on identifying predictors of difficulty. This assessment is a major contributor in deciding whether neuromuscular blockade can safely be used to facilitate intubation. While it is important to assess all aspects of the difficult airway, BMV has been considered the most important as this intervention is usually the primary “go to” technique when tracheal intubation attempts to fail. More recently, however, some guidelines suggest either BMV or an EGD following failed tracheal intubation or moving to an EGD instead of BMV at this stage.^44,45 At this point, oxygen desaturation has often already begun and clinical deterioration often follows rapidly. Despite there being numerous alternative rescue options available to the practitioner, BMV is universally available, familiar to most, and very effective.

Earlier data estimated that “cannot intubate/cannot oxygenate” clinical situations occurred at a rate between 0.01 and 2 in 10,000 general anesthetic cases.⁴⁶ More recent data have reported the incidence of DMV in the operating room setting has varied from a low of 0.9 % to a high of 7.8%.^{39–42,47,48} This reported variation likely relates to differences in case definition, outcome criteria, and sample size. A large multi-center study of over 176,000 patients reported and incidence of DMV if 2.5% with an incidence of DMV with concurrent difficult intubation of 0.4%.³⁸ In a previous study of over 50,000 patients, “impossible” BMV defined as an inability to establish BMV using two–hand technique and “multiple airway adjuvants”, occurred in 0.15% of the study population.³⁹

Langeron et al.⁴² prospectively evaluated 1502 patients requiring routine general anesthesia to determine both the incidence and factors associated with DMV. The reported incidence of DMV in this population was 5%. Five independent factors associated with DMV were identified: presence of a beard; age older than 55; body mass index (BMI) > 26 kg·m⁻²; lack of teeth; and a history of snoring. The presence of two of these factors in a patient was 72% sensitive and 73% specific for DMV.⁴²

Other studies involving large patient populations have validated the above findings and identified additional risk factors, including male gender, a history of neck radiation, high Mallampati grade (Grade III or IV), increased BMI (>30 kg·m⁻²), and limited jaw protrusion (Table 8–1).^38–41 In Kheterpal et al.³⁸ study of patients with difficulty for both BMV and DL, Mallampati grade (III or IV), neck radiation or mass, male gender, limited thyromental distance, presence of teeth, and BMI>30 kg·m⁻² were among the more significant risk factors (odds ratio [OR]> 2).

In the study by Kheterpal et al.³⁹ the presence of three or more predictors (neck radiation, male, OSA, Mallampati III or IV, beard) significantly increased the risk of impossible mask-ventilation (IMV) with an OR of 8.9 compared to patients without these risk factors. Another important finding from this study is that of the IMV group, 25% were also difficult to intubate. In a more recent follow-up study examining combined difficult BMV and difficult laryngoscopy, the odds of encountering difficulty increased significantly with the number of risks identified. However, these retrospective data are difficult to apply prospectively. While many airway practitioners may accept inadequacies in terms of positive predictive value, it would be unwise to apply these findings as a negative predictive tool.

These recent reports differentiating DMV from IMV recognize the fact that clinically BMV challenges are part of a continuum from easy to impossible.⁴⁷ A numeric representation this DMV continuum has been proposed; however, it has not been consistently used or accepted to date in the literature.⁴⁹ The difference between DMV and IMV is simply that DMV is usually correctable (i.e., two-hand and two-person technique), whereas IMV represents a failure and the need to abandon BMV in favor of another intervention (DL, or video-laryngoscopy [VL] if not attempted, EGD, or a surgical airway). Another important observation that has caused some degree of controversy is the value of “checking” for BMV difficulty prior to administering a neuromuscular blocking agent. Current evidence seem to support the use of muscle relaxants to facilitate both BMV and laryngoscopy.^48,50–52

It is important to appreciate the fact that these studies did not examine the incidence of DMV in patients requiring emergency airway management. Levitan et al.⁵³ examined the ability to assess for predictors of the difficult airway in emergency department patients requiring intubation and found that only 32% of this population would have been able to be assessed adequately for difficulty because of limitations such as an inability to follow commands or being immobilized for cervical spine (C-spine) precautions.

The incidence of DMV is not known in this population. However, emergency cricothyrotomy outside of the OR (as a marker for cannot intubate, cannot oxygenate) rates have fallen to between 0.1% and .5 %, and may underrepresent the incidence DMV and are still much higher than that reported in the controlled operating room setting.^54–57 Table 8–2 summarizes the likely pathophysiology behind the various predictors of DMV.

What Anatomic Factors Need to be Considered in Providing Safe and Effective BMV?

The primary goal of BMV is to facilitate oxygenation and ventilation by providing an unimpeded transfer of gas (oxygen/carbon dioxide) to and from the lungs. In the unconscious or anesthetized patient with normal anatomy, it has been traditionally thought that obstruction to the easy to-and-fro movement of gas with BMV was primarily related to the effect of a “relaxed” tongue falling back against the posterior pharyngeal wall. Data gathered during fluoroscopy in studies of obstructive sleep apnea (OSA) patients have improved our understanding of the pathophysiology of upper airway dynamics in the sleeping patient. In addition to obstruction caused by the tongue, there is also a loss of velopharyngeal and hypopharyngeal muscle tone.^58,59 This results in soft tissue collapse leading to the posterior displacement of both the soft palate and epiglottis to oppose the posterior pharyngeal wall and contribute to obstruction (velopharyngeal and hypopharyngeal collapse).⁵⁸ The hypopharyngeal site of obstruction is clinically supported by the observation that placement of an OPA without performing an adequate jaw thrust may not alleviate obstruction caused by “normal” upper airway soft tissues.

When a patient is placed in the “sniffing” position, there is flexion in the cervico-thoracic region with extension occipto-cervical region. This position has been traditionally thought to facilitate “alignment” of the axes necessary to visualize the glottic inlet during DL. Although there has been some question as to whether this position provides any advantage over simple head extension, data do support the combination of neck flexion with head elevation in enabling glottic exposure during laryngoscopy.^60,61 It is less clear, however, if this position improves upper airway patency for BMV. There is some evidence that the retropalatal and retroglossal region is enlarged by placing anesthetized non-obese patients with OSA in the sniffing position and mask-ventilation may be improved.^62,63 Collectively these pharyngeal dilator muscles lose their tone with anesthesia thereby increasing the pharyngeal closing pressure. Pharyngeal patency is improved most significantly by maintaining a sitting position coupled with mandibular advancement, and less so head and neck positioning.⁶⁴ In addition, it is well known that obese patients desaturate early, a clinical phenomenon that can be delayed by denitrogenating in the sitting (as opposed to supine) position.⁶⁵ At this point, it is reasonable to state that head and neck repositioning from neutral to a position that involves a degree of neck flexion with head elevation may improve BMV and is appropriate in anticipation to perform DL should it become necessary.

While head and neck positioning may be considered of vital importance for DL, the key anatomic manipulation that facilitates BMV is performing a jaw thrust.⁶⁶ The genioglossus muscle is attached to the mandible and the hyoepiglottic ligament attaches the tongue to the epiglottis. Therefore, translating the mandible anteriorly pulls the tongue and in turn the epiglottis anteriorly and opens the airway. This maneuver originally described over a century ago (Esmarch-Heiberg’s maneuver) has been demonstrated to be superior to “chin lift” and “head tilt” when performed alone, during observations made of anesthetized patients undergoing (pre-procedure) head and neck fluoroscopy.^67,68 Recognizing that obstruction in the unconscious patient is related to more than the tongue falling posteriorly, the “triple airway” maneuver (open mouth, head tilt, jaw thrust) was suggested to be the best approach.^69,70 More recent evidence supports the jaw thrust alone as being equally effective to the triple airway maneuver in relieving obstruction.⁶⁸

What Is the Role of BMV in Difficult Airway Algorithms?

Numerous algorithms have been published to guide practitioners in the management of the difficult airway (see Chapter 2).^44,45,71,72 Most of these guidelines or recommendations are generated using available evidence and expert opinion from specialized “working groups” and/or anesthesiology societies. Historically algorithms have had limitations for being too complicated or impractical for application in emergency situations outside of the operating room, where it is not possible to “cancel” the case or “awaken” the patient.

A difficult airway may be any or all of difficult BMV, difficult laryngoscopy, difficult intubation, difficult EGD use, or difficult surgical airway placement. Most algorithms or approaches separate the anticipated from the unanticipated (or encountered) difficult airway. In the former scenario, predicted difficulty leads a defined, usually more controlled path, whereas in the latter, whether predicted or not, “real-time” difficulty is being experienced and demands an immediate and specific course of action, depending on the type of difficulty encountered.

In approaching the difficult airway, the ability to successfully perform BMV is a critical management junction in most, if not all algorithms. The most prominent place for BMV as part of any difficult airway algorithm is between failed intubation attempts. However, it is important to appreciate the role of BMV even before a first attempt at laryngoscopy and intubation. Assuming the patient can generate sufficient tidal volumes with an adequate respiratory rate, the bag portion of the BMV device does not have to be squeezed to deliver close to 100% oxygen. It is not uncommon (and in some situations is potentially hazardous) that when switching from a non-rebreathing mask (or another mask type) to BMV, positive pressure is often instinctively applied. If assisted BMV is applied without synchrony, gastric insufflation is much more likely to occur.

In the pre-intubation phase of airway management, the use of a BMV device to denitrogenate should be encouraged. This approach offers several advantages:

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  Passive delivery of high concentration of oxygen (approaching 100%)

  
  
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  Opportunity to size the mask properly

  
  
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  Provides “hands-on feel” for predicting DMV

  
  
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  Provides opportunity to improve gas exchange with assisted BMV

Various methods of denitrogenation have been suggested in an attempt to minimize desaturation during laryngoscopy and intubation. This is relatively easy to accomplish in healthy adults with normal pulmonary mechanics and oxygen consumption rates. It should be recognized that flow from the oxygen source will decay by as much as 50% through most BVM devices. While this is not an issue at normal minute ventilations, it can result in dilution of FiO2 by room air entrainment, leaks around the mask, and an open expiratory port in BVMs without a dedicated expiratory valve.^33,73 In the physiologically normal patient (normal lungs, respiratory rate, and tidal volumes), the key to denitrogenation is having a closed delivery system (i.e., a bag-mask unit with an expiratory valve) attached to high flow oxygen for a minimum of 3 minutes.^74,75

In patients with shunt physiology, effective denitrogenation can be improved through the addition of PEEP valve in the spontaneously breathing patient.⁷⁶ With the addition of a second high flow oxygen source applied through nasal prongs (HFNO) under a well-fitted mask, the BVM/PEEP and HFNO combination will provide CPAP and through alveolar recruitment may provide for improved denitrogenation.⁷⁶ While the addition of manual assisted ventilation synchronized with the patient’s inspiration (PPV) may provide only marginal denitrogenation benefit, the addition of a PEEP valve to this sequence in an attempt to replicate ventilator delivered BiPAP may be of value for denitrogenation in certain patient populations.⁷⁷

Ventilation during the apneic patient as part of a rapid sequence induction has been somewhat controversial. This teaching, however, was based more on theory than science. In fact, Sellick’s⁷⁸ original paper stated that manual PPV in combination with cricoid pressure could be done without gastric distention risk. Data have since supported active denitrogenation using a manual resuscitator with or without the application of cricoid pressure as long as “good” technique is used avoiding high airway pressures.^79–81 BMV is in fact clinically indicated during Rapid Sequence Intubation (RSI) in certain patients (obese, hypoxemic, pediatric) who may have low baseline oxygen saturation, high oxygen consumption rates, and/or low functional residual capacity.^77,82,83 Finally, the knowledge of adequate BMV soon after the drugs are given is reassuring, particularly in situations where difficult intubation may be encountered, and represents a common practice.⁸²

What Defines Optimal BMV Technique and How do You Assess the Adequacy of Ventilation?

There are three important components to proper BMV technique: mask seal, airway opening, and ventilation.

Mask Seal

An appropriately sized face mask is attached to the bag-mask device and applied to the patient’s face. The lower border of the mask’s cuff is first applied to the groove between the lower lip and the chin, then the mask can be placed down across the nasal bridge. The thumb and index finger of the airway practitioner’s hand apply sufficient pressure on the face mask to achieve a good seal (Figure 8–2). Note, however, that sealing pressure must be achieved without excessive downward pressure on the patient’s mandible, as this may worsen functional obstruction—rather, the mandible is lifted to meet the mask. Small adjustments to the position of the mask on the patient’s face (e.g., with small movements to left or right) are made as needed to achieve a seal.

Airway Opening

When employing a one-person technique, the ring and long fingers of the nondominant hand grasp the bony ridge of the patient’s mandible, and, if practical, the fifth finger hooks under the angle of the mandible to provide a jaw thrust (Figure 8–2). In the event the airway practitioner has a small hand, the long finger is hooked under the mentum to provide a jaw pull. These three digits provide counter-pressure to the digits applying the mask to the face, but also apply an upward lift to the mandible to help perform an airway opening jaw thrust. Note that these three fingers should not be placed directly under the patient’s chin unless lifting it forward, as midline pressure under the chin can contribute to airway obstruction. This latter directive is particularly important in small children and infants. Concomitantly, the entire hand also attempts to keep the head extended (if no C-spine precautions).

Ventilation

The practitioner’s dominant hand is free to gently squeeze the bag. Volumes should be delivered with attention to the inflating pressure as well as the patient’s status: if apneic, the patient should be carefully ventilated (attached to high flow oxygen) at a rate of 10 to 12 breaths per minute, at a tidal volume of 6 mL·kg⁻¹, or 500 to 600 mL in the average adult.¹ Smaller tidal volumes (e.g., 3–400 mL in the adult) at increased rates (15–18 breaths per minute) may lead to less gastric insufflation. Although adult (1.6 liter) manual resuscitators may deliver varied volumes, excessive and rapid compression of the bag must be avoided. The goal, as stated previously, is to produce visible chest rise. In the patient still demonstrating respiratory effort, assisted BMV should be performed, synchronizing the positive pressure breath to the patient’s inspiratory effort. If the patient is tachypneic, it will be appropriate to simply deliver an assisted ventilation with every third or fourth breath.

How to Respond to Difficult BMV Situations?

With optimal technique, significant difficulty with BMV is rarely encountered in the absence of airway pathology.^39,48 In the acute setting, BMV is often delegated to another health care practitioner while the practitioner prepares for definitive airway management. While this may be appropriate, it is important to accept that BMV is a difficult skill for those who perform it infrequently and vigilance rather than inattention is recommended. Abandoning BMV in the uncommon scenario of failing BMV should only occur after the most experienced “set of hands” has failed.

Difficult BMV (DMV) is often defined as the inability to maintain an acceptable oxygen saturation despite using “good technique.” However, it is the “dynamic” inability to maintain oxygen saturation that is important. Failure to maintain acceptable oxygen saturations or falling saturations demands a change in approach. Although one response to a DMV situation is to proceed to intubation, DMV may itself predict difficulty with laryngoscopy and/or intubation.^39,47,48 Good BMV skills and an approach to DMV are crucial skills in ensuring oxygenation of a patient prior to, or between laryngoscopy attempts.

In the setting of a failed airway in which one is not able to maintain acceptable oxygen saturations, immediate preparation for a cricothyrotomy is mandatory while one simultaneously attempts “better” BMV. Response to DMV requires a staged response that may include the following:

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  Reposition the head by performing an exaggerated head tilt/chin lift (if not contraindicated);

  
  
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  Open the mouth permit anterior translation of the mandible and tongue in concert with an aggressive jaw thrust;

  
  
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  Insert an appropriate size oropharyngeal airway (OPA; see Figure 8–3) and as many as two nasopharyngeal airways (NPAs);

  
  
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  Perform two-person mask ventilation technique;

  
  
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  If cricoid pressure is being applied, ease up on, or release it;

  
  
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  Consider a mask change (size or type) if seal is an issue;

  
  
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  Rule out foreign body in the airway;

  
  
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  Consider a “rescue” ventilation device, for example, an EGD, such as a LMA;

  
  
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  Consider an early attempt at intubation.

Steps A, B, and C, as listed above, should occur almost simultaneously and very early in the DMV situation. DMV is often due simply to the failure to adequately open a functionally obstructed airway. Attempted ventilation against this obstruction results in a leak at the mask/face interface, often resulting in the practitioner’s attempting to remedy the problem by pushing down harder on the mask to attain a seal, though this can aggravate an already obstructed airway. Rather, what must occur is a more pronounced jaw lift or thrust, with resultant airway opening occurring as anterior movement of the mandible elevates the tongue, epiglottis, and soft palate away from the posterior pharyngeal wall. This is best performed with the aid of a second person. Two-person mask-ventilation is easy to perform and is often much more effective than one person BMV.^84,85 As shown in Figure 8–4, the two-person technique can be performed in a number of ways; however, the “thumbs forward thenar eminence” (T-E) grip appears to be more effective than the traditional C-E grip (place the thumb and first finger around the top of the mask, forming a “C,” while using the 3rd, 4th, and 5th fingers, forming an “E,” to lift the angles of the jaw).^86–89