Boone County Fire District EMS Education-EMT Course...

Boone County Fire District EMS Education-EMT Course Fundamentals Unit-Airway Control and Ventilation Resources

Screencast For lab---sniffing position

● In order for cells to function properly, the circulatory system must deliver oxygen and glucose to the cells. We have discussed the circulatory system in a previous lesson. In that discussion, we saw how the pulmonary circulation interfaces with the inhaled air in the alveoli. All of that circulation must be reasonably intact and functioning in order for oxygen to be delivered from the lungs to the systemic circulation.

● The process of getting gases (O2 and CO2 principally) to interface with the blood is called Oxygenation and is handled in another lesson.

● Right now, we will focus on the process of getting air from the outside into the alveoli where Oxygenation happens. That process of moving fresh air in and exhausting stale air is called Ventilation.

● Those three processes---Circulation, Ventilation and Oxygenation (“CVO”) form the core of our patient assessment because of their critical roles in maintaining life.

● Ventilation requires an intact pathway for air to get from the outside to the alveoli as well as adequate air movement through those pathways. Both are key. Neither is sufficient without the other.

○ Airway Control involves keeping the upper airway pathway open and clear of obstructions.

○ Ventilation involves movement of air through the upper and lower airways to the alveoli.

● Upper airway anatomy of interest and how to control the airway: ○ Tongue---the most common airway obstruction. This is a large and heavy

muscle that can be pulled by gravity in the supine patient to the back (posterior) of the upper airway (pharynx) and create a partial obstruction (snoring sounds) or a complete obstruction (no sounds). Fortunately, the jaw bone (mandible) can act as a handle for the tongue and when the jaw is thrusted forward (anteriorly) using a jaw thrust maneuver, the tongue can be displaced off the posterior pharynx and the airway opened. We will also practice a head tilt-chin lift airway maneuver in Lab in case you are ever alone with a patient and need that technique. The jaw thrust remains our primary manual airway maneuver.

○ Noisy airways are not open airways---usually due to upper airway obstruction---usually due to the tongue being pulled by gravity. Placing the patient in the “recovery” (drainage, coma) position may use gravity to an advantage to displace the tongue anteriorly. This position is of no help when the patient needs positive pressure ventilation or chest compressions. So, we need other tools and techniques.

○ Oropharyngeal airways (oral airways or OPAs) are hard plastic devices designed to hold the tongue off the posterior pharyngeal wall. These must be sized and placed appropriately and patients with a gag reflex still intact won’t tolerate them.

https://www.youtube.com/watch?v=4uW8DdCF1e0


○ Nasopharyngeal airways (nasal airways, nasal trumpets or NPAs) are soft rubber tubes that provide a pathway for air from the nose past the posterior pharynx. Patients with intact gag reflexes can tolerate these airways.

○ OPAs and NPAs can be used together---two NPAs works fine also except you might want to leave a nostril open for medication administration unless you really need both NPAs to keep the airway open.

○ We will practice the use of jaw thrusts, OPAs and NPAs in a Lab Session. ○ OPA-NPA older screencast--short and good to watch (not the best audio).

● Other upper airway obstructions: ○ Swelling from infected tissue or inflamed tissue following a burn or due to an

allergic reaction can create an upper airway obstruction. This obstruction can be partial (air movement still heard) or total (no air movement heard). The high-pitched squeaking or squealing sound made when the upper airway is obstructed is called stridor and can be heard loudest over the Adam’s Apple with a stethoscope (louder there than over the lungs). At the EMT level, there is really not much that can be done for this cause of obstruction other than assisting an allergic reaction patient with his / her prescribed epi-pen (talked about later in the Course).

○ Food / vomit (emesis) / blood in the mouth and pharynx can be inhaled (aspirated) into the lungs and create a lower airway obstruction. Once lodged in the lungs, removal is not possible in the field. Therefore, we must focus on removing these materials from the mouth / pharynx rapidly. Positioning the patient on their side (lateral recumbent) is a relatively quick technique while suction devices are being prepared and while they are in use. This positioning doesn’t work for patients who are requiring chest compressions for CPR. Otherwise, rolling the patient quickly is key. Manual suction devices (such as the V-Vac) use hand powered squeezes to remove liquid matter and some smaller “chunks”. Mechanical suction devices (battery powered) are also just as useful. We will practice the use of these in a Lab Session. Check out those two video links showing how the two devices are just about equal in terms of speed of suctioning. Note on the manual device how we squeeze and “let it eat”--hold the squeeze rather than squeezing rapidly and repeatedly.

○ Patients who are “choking” on objects (food or otherwise) are best managed by having them cough forcefully to expel the object. Once the patient cannot cough, an abdominal thrust is used in the conscious but not supine patient. Once the patient is supine, a chest thrust is used. We will practice these techniques in a Lab Session.

● Advanced airways are used to provide a tube as a pathway for air exchange. Some advanced airways called supraglottic airways or SGA can be used by EMTs. The very best advanced airway, an endotracheal tube (ET tube or ETT) can only be placed by Paramedics in the field. Paramedics can also utilize a surgical airway to cut into the patient’s larynx at the Adam’s Apple area for the most severe cases. We will focus on

https://www.youtube.com/watch?v=CtArbvS-jyk&t=0s&list=PLRhaKQ86JdMFa_SyH4LnEvDxMx5hawlvK&index=4

https://www.youtube.com/watch?v=GyhsZVNWqPA&list=PLRhaKQ86JdMFa_SyH4LnEvDxMx5hawlvK&index=13

https://www.youtube.com/watch?v=GyhsZVNWqPA&list=PLRhaKQ86JdMFa_SyH4LnEvDxMx5hawlvK&index=13

https://www.youtube.com/watch?v=OQhn6_gyx44&t=0s&list=PLRhaKQ86JdMFa_SyH4LnEvDxMx5hawlvK&index=13


SGAs for this EMT Course. Supraglottic refers to “above” (supra) the “glottis” (laryngeal inlet to the trachea)

○ SGAs allow an airway to be placed without directly visualizing the laryngeal inlet (at the vocal cords---entrance to the trachea). These are called “blind insertion” because no direct visualization of the larynx is needed.

○ The SGA that we will teach for our EMT Course is the King LT(S)D. This advanced airway has a large cuff that seals the pharynx and a smaller cuff that seals the esophagus. Air is ventilated through the airway tube to a port that is positioned directly over the laryngeal inlet (opening to the trachea). As long as both cuffs are sealing off effectively, the air is forced into the trachea. Insertion is simple and fast. The King comes in various sizes to fit various patient heights. In a Lab Session, we will work on the sizing, testing, insertion and adjusting of the King including how to handle the three possible situations following insertion:

■ You see good chest rise and the patient is easy to ventilate. (proper placement and proper cuff seal---all good)

■ You see no chest rise and the patient is easy to ventilate.(add air to the cuff to improve your seal)

■ You see no chest rise and the patient is hard to ventilate. (pull the tube back a little bit---the port is not over the laryngeal inlet)

○ Without trying to jump ahead---we should point out that the primary advantage to a SGA in cardiac arrest is that it allows you to perform continuous chest compressions instead of pausing to give a ventilation. For this reason, early use of the SGA in cardiac arrest is key to high-quality CPR---and only EMTs or Paramedics can legally insert the SGA in Missouri.

○ Screencast from the Paramedic Program’s Airway & Breathing Course ● Once the Airway is controlled, Ventilation can be the focus.

○ Assessing Ventilation is based on three criteria---any one of which can cause inadequate ventilation and require intervention:

■ Rate of breathing ● Breathing too slowly (usually 6 or less per minute) simply doesn’t

move enough air in an out to meet the needs of life in most cases. ● Breathing too rapidly (usually 30 or more per minute) may lead to

inadequate air movement due to the shallow nature of those breaths. Patients can be breathing rapidly and deeply (hyperventilation) but usually rapid breathing equals shallow breathing.

■ Effort of breathing ● Patients use their diaphragm as the primary muscle of breathing.

Patients can use accessory muscles of breathing (neck, belly, muscles between the ribs called intercostals). The use of accessory muscles indicates an increase effort of breathing that may require intervention.

https://www.youtube.com/watch?v=lByIU8Unjoc&list=PLRhaKQ86JdMEjKz0Nyg22Lq5PLi8rNfTZ&index=25


● Normal breathing is really with little effort. The only effort that is expended is to inhale---exhalation is passive (not much work needed) in normal cases. When patients are working to exhale as well as inhale, that indicates an increase effort of breathing that may require intervention. If you notice a patient’s breathing---be concerned that it is not normal.

■ Depth of breathing ● Normal breathing depth is NOT maximal breathing depth. Normal

is less than maximum depth and really is not all that obvious. ● Shallow breathing Depth is also not all that noticeable if the

breathing Rate is allow slow. “Low and Slow” is bad and usually indicates the need for intervention.

○ Managing Ventilation is based on providing positive pressure ventilation to either supplement a breathing patients ineffective breaths or replacing their lack of breathing. Humans are negative pressure breathers by design---that is normal. We “suck” in air by creating a small vacuum inside the chest. When positive pressure breathing is required, this is NOT normal for the patient and some bad side effects may happen (a side effect is something we did not intend but are not surprised that it happened):

■ Gastric distention---air blown into a patient’s mouth may go into their lungs via the trachea but the pathway to their stomach via their esophagus is a lot lower pressure and therefore easier for the air to take. Distended (swollen) stomachs full of air tend to release and vomiting is the result.

■ Decreased blood pressure---the increase in pressure inside the chest from positive pressure ventilations makes it harder for blood to return to the heart from the systemic circulation. Decreased amount of blood returning to the heart (preload) causes the heart to struggle to fill and therefore it will be pumping out less (cardiac output). This lowers BP in most cases.

■ Screencast on positive pressure ventilation (older version--audio issues) ○ So...in summary..we prefer for patient’s to maintain their own airway and to

breathe on their own. If their airways need control, we should control them using the least invasive means necessary to do the job. If their ventilation needs assistance (due to a problem with Rate, Effort or Depth), we must use a positive pressure ventilation method until they can breathe on their own effectively. There are side effects to positive pressure ventilation and we should remember them.

○ How to deliver positive pressure breathing: ■ Unless / until you have a SGA in place, you will need a mask sealed over

the patient’s face. Getting the mask to seal is best done in conjunction with a good jaw thrust by using the “two thumbs down” method. You want both your thumbs pointing to the patient’s feet and on top of the mask.

https://www.youtube.com/watch?v=A4dqZiQmZA4&t=4s&list=PLRhaKQ86JdMFa_SyH4LnEvDxMx5hawlvK&index=2


This allows you to use the big muscles of your hand to squeeze the mask to the face while you lift the jaw. We will practice this in a Lab Session.

■ To deliver the breaths, you will either need to blow air from your mouth into the mask (for pocket mask ventilation) or use a bag-valve-mask (BVM) device to blow air into the patient.

● The bag-valve-mask is a TWO PERSON TOOL. The pocket mask is a one-person tool. When you have two persons to assign to the ventilation, use the BVM. When you do not have two persons to assign to the ventilation, use the pocket mask (PM).

● The BVM allows for easy use of supplemental oxygen for your patient as well. You can hook oxygen to some PMs and you can always just put the oxygen tubing under the PM but that makes a good seal very difficult.

■ Regardless of the tools you are using, the RATE OF VENTILATIONS is the same and must NOT be too fast. One breath every six seconds is plenty fast for an adult. Slightly more often for pediatric patient is okay---not more often than once every three seconds though (unless it is a newborn).

■ Regardless of the tools you are using, the DEPTH OF VENTILATIONS is the same and must NOT be too deep---just get normal chest rise. Many adult patients only require ⅓ to ½ the volume of the adult BVM. In fact, some services use the Pediatric BVM for adults to avoid delivering too much volume.

■ Regardless of the tools you are using, the PRESSURE OF VENTILATIONS is the same and must NOT be too forceful. High force / high pressure breaths end up in the stomach almost every time. Only use just enough pressure to get normal chest rise.

■ We will practice ventilation in a Lab Session. ■ Short video on “Two Thumbs Down” bag-mask ventilation.

https://www.youtube.com/watch?v=d3lqhUlVFmo&t=0s&list=PLRhaKQ86JdMFa_SyH4LnEvDxMx5hawlvK&index=3


● Proper mask sizing schematic

Optional stuff: Article on Difficult Mask Ventilation in PDF is attached at the end of this document. Smart Bag flyer on PDF is also included at the end of this document. Links to Screencasts below (slides included at the end of this document) from Paramedic Program’s Airway & Breathing Course x 4--covers Basic Airway Control: Sniffing Position Jaw Thrust-Mask Seal OPA-NPA Bag-Mask Ventilation

https://www.youtube.com/watch?v=Vi1bHsV-McI&t=2s&index=10&list=PLRhaKQ86JdMEjKz0Nyg22Lq5PLi8rNfTZ

https://www.youtube.com/watch?v=oc6SPwophVw&index=10&list=PLRhaKQ86JdMEjKz0Nyg22Lq5PLi8rNfTZ

https://www.youtube.com/watch?v=TJjYOgVMVVM&index=11&list=PLRhaKQ86JdMEjKz0Nyg22Lq5PLi8rNfTZ

https://www.youtube.com/watch?v=C0-xDV-ZKWE&index=12&list=PLRhaKQ86JdMEjKz0Nyg22Lq5PLi8rNfTZ

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Subscribe to ATOTW tutorials by visiting www.wfsahq.org/resources/anaesthesia-tutorial-of-the-week ATOTW 321 – Difficult mask ventilation (8th Oct 2015) Page 1 of 7

G E N E R A L Tutorial 321

Key Points

• Incidence of difficult mask ventilation (MV) is approximately 1.4% and for impossible MV is approximately 0.15%

• It is important to assess patients for difficult MV as well as difficult intubation

• MMMMASK and OBESE are two mnemonics to help remember the risk factors for difficult MV

• Complications are wide-ranging, from trauma to eyes, nose or mouth to hypoxic brain injury and myocardial ischaemia

• When writing your anaesthetic chart it is important to document the ease of MV

• Management of unexpected difficult or impossible MV may benefit from regular airway practice drills or simulation

!DIFFICULT MASK VENTILATION Dr Jonathan Holland Anaesthetics Registrar, Royal Victoria Hospital, Northern Ireland, UK Dr Will Donaldson Consultant Anaesthetist, Antrim Hospital, Northern Ireland, UK Edited by Dr Luke Baitch and Dr Maytinee Lilaonitkul Correspondence to [email protected]

INTRODUCTION Mask ventilation (MV) is an integral skill for all anaesthetists. It forms the starting point of the majority of general anaesthetics and more importantly, it is an essential fall-back technique for maintaining oxygenation during a failed or difficult intubation. Despite its importance, less attention is devoted to MV in research papers and textbooks, with a larger focus on difficult or failed intubation. All anaesthetists require the skill to mask ventilate but more importantly they require the knowledge of how to adjust their management options when faced with a difficult or impossible MV scenario. This tutorial will provide an overview of the definition, incidence, predictors and management of difficult MV. There are some clinical situations when MV is not desirable, such as immediately post trans-sphenoidal surgery, but discussion of these is not within the scope of this tutorial. Definition of difficult mask ventilation Herein lies a central problem with research on difficult MV - over the years there have been various definitions of what constitutes difficult MV. It is an extremely subjective topic because what constitutes difficulty for an anaesthetic trainee beginning their career may be

8th OCT 2015

QUESTIONS Before continuing, try to answer the following questions. The answers can be found at the end of the article, together with an explanation. Please answer True or False: 1. Risk factors for difficult mask ventilation include:

a. A beard b. History of snoring c. BMI > 26kg/m2 d. History of alcohol excess e. Female gender

2. Possible complications of difficult mask ventilation include: a. Hypoxia b. Brachial plexus injury c. Aspiration d. Eye trauma e. Dislocated jaw

3. A patient has been given a long acting muscle relaxant, is impossible to mask ventilate and oxygen saturations have fallen to 88%. Appropriate next steps may include: a. Deepening anaesthesia b. Attempting to wake the patient up c. Attempting laryngoscopy d. Insertion of supraglottic airway device (SAD) e. Performing a surgical airway !


vastly different from an anaesthetic consultant with 25 years’ experience. The American Society of Anesthesiologists (ASA) defined difficult MV as a situation in which: “It is not possible for the anesthesiologist to provide adequate ventilation because of one or more of the following problems: inadequate mask seal, excessive gas leak, or excessive resistance to the ingress or egress of gas.”1

The ASA then goes on to list signs of inadequate ventilation: absent or inadequate chest movement, absent or inadequate breath sounds, auscultatory signs of severe obstruction, cyanosis, gastric air entry or dilatation, decreasing or inadequate oxygen saturation, absent or inadequate exhaled carbon dioxide, absent or inadequate spirometric measures of exhaled gas flow, and haemodynamic changes. This is a very comprehensive definition but in some ways it remains vague and dependent on the operator’s judgment. Other papers have used similar definitions but have specified further criteria. Langeron et al. in 2000 specified inability to maintain saturations above 92%, using the oxygen flush more than twice, requiring 2 operators or a change of operator as indicators for difficult mask ventilation.2 Yildiz et al. in 2005 defined the difficulty depending on the airway manoeuvres used.3 Kheterpal et al. in 2006 defined difficult MV as inadequate MV, or MV requiring 2 operators.4 In each of these definitions the terms used can be interpreted differently, highlighting the difficulty in finding a universal definition. Given that achieving a universal definition is difficult, a way of communicating what worked for a patient would obviously be of benefit. As with many conditions in medicine, MV can be considered as a spectrum with one end being easy MV and the other being impossible MV.5 A definition to represent the various stages of difficulty to allow easier communication between clinicians was described by Han et al.6 It is a grading system 0-4 similar to the Cormack-Lehane grading of views at laryngoscopy, and is shown in Figure 1.

Figure 1: Table showing MV classification and description scale6

Incidence of difficult mask ventilation There has been a range of incidence reported due to lack of consensus in definition; the quoted range is wide at 0.08% to 15%. The most robust data show the incidence of difficult MV is approximately 1.4%,4 and impossible MV is approximately 0.15%.7 Factors affecting mask ventilation Anaesthetic factors Factors that have been shown to affect MV are the experience of the clinician and the use of equipment. The skill of MV is achieved through training and maintained through regular practice. This helps to address common issues such as patient position, airway manoeuvres and sizing of equipment. The use of incorrectly sized oropharyngeal or nasopharyngeal airways are unlikely to improve MV and may cause trauma and bleeding. Furthermore, MV may be difficult due to an improperly sized mask being used or faults with the anaesthetic machine or breathing circuit. Some aspects of general anaesthesia itself are thought to play a role. High dose opioids, inadequate depth of anaesthesia and inadequate muscle relaxation may all lead to increased muscle rigidity, reduced chest wall compliance and difficult MV. The chest wall rigidity associated with high dose opioids is not seen in patients with a tracheostomy. This leads to the suggestion that the resistance to MV is actually due to vocal cord closure, which resolves on administration of a muscle relaxant.8 These factors have led to debate about the timing of administration of muscle relaxant and whether to check if it is possible to mask ventilate the patient prior to administration. Muscle relaxants can make MV easier, by eliminating rigidity and laryngospasm, or more difficult, by causing loss of tone and upper airway collapse. The 4th National Audit Project by the Royal College of Anaesthetists and Difficult Airway Society (DAS) found that in some cases, light anaesthesia and a reluctance to administer muscle relaxants may have caused patient harm.9 The project made the following recommendations:

• “Where facemask or laryngeal mask anaesthesia is complicated by failed ventilation and increasing hypoxia the anaesthetist should consider early administration of further anaesthetic agent and or a muscle relaxant to exclude and treat laryngospasm.”

• “No anaesthetist should allow airway obstruction and hypoxia to develop to the stage where an emergency surgical airway is necessary without having administered a muscle relaxant.”

Classification Description Grade 0 Ventilation by mask not attempted Grade 1 Ventilated by mask Grade 2 Ventilated by mask with oral airway or other adjunct Grade 3 Difficult MV (inadequate, unstable, or 2 person technique) Grade 4 Unable to mask ventilate


Patient factors Being able to anticipate difficult MV can help anaesthetists formulate an airway management plan that is safe for the patient. A simple and reassuring way of assessing the patient is to check their previous anaesthetic chart for any documented difficulties. This highlights the importance of good record keeping and also demonstrates how a reproducible grading system for mask ventilation can play a vital role in standardising communication between clinicians. Patient-specific factors can be the main cause for difficult mask ventilation; these are wide-ranging and can be categorised as shown in Figure 2.

Enlarged soft tissues Abnormal anatomy • Large tongue/epiglottis • Tonsillar hyperplasia • Airway oedema

• Edentulous • Beard • Upper or lower airway tumours • Extrinsic compression of airway • Foreign bodies • Pneumothorax • Bronchopleural fistula • Chest wall deformity • Previous neck irradiation

Physiological reactions • Laryngospasm • Bronchospasm

Figure 2: Patient factors associated with difficult mask ventilation

Other important factors include obesity, increasing age, male gender, Mallampati grading, ability for mandibular protrusion and history of obstructive sleep apnoea. Various BMI values have been used in research papers with one as low as 26kg/m2 being a statistically significant predictor of difficult MV.2 A high neck circumference (>40cm), which is associated with obesity, also increases the probability of difficult MV.10 Increasing age is another risk factor and this is likely due to the loss of elasticity in tissues and presence of lung disease. The mandibular protrusion test gives the assessor an indication of the ability to perform an adequate jaw thrust, and is important in patients at risk of upper airway collapse. Furthermore, it is also a good predictor of difficult intubation. The authors suggest a simple mnemonic to help remember these predictors: MMMMASK. Alternatively, Langeron et al. identified 5 criteria that were independent risk factors (OBESE) for difficult MV.2 Both mnemonics are summarised below.

MMMMASK OBESE M M M M A S K

Male gender Mask seal which is affected by beard or being edentulous Mallampati grade 3 or 4 Mandibular protrusion Age Snoring and obstructive sleep apnoea Kilograms (weight)

OBESE

Obese (BMI>26kg/m2) Bearded Edentulous Snoring Elderly (>55 years)

Figure 3: Two mnemonics helpful for remembering patient factors that are associated with difficult mask ventilation

With respect to impossible mask ventilation, Kheterpal et al. reviewed over 50,000 anaesthetics with an incidence of 0.15% and showed the following independent predictors: neck radiation, male sex, sleep apnoea, Mallampati 3-4, and the presence of a beard.7 Neck radiation was the most significant factor in predicting impossible MV and importantly, it is also a significant risk factor for difficult intubation. Careful consideration of airway plans for patients with previous neck radiation is required as surgical access may also be difficult MANAGEMENT AND COMPLICATIONS Management The management of difficult MV can be split into two scenarios: expected and unexpected. With expected difficult MV, simple measures can be taken such as shaving of beards, weight loss and keeping dentures in situ to improve the seal and removing them immediately prior to intubation. Some anaesthetists find it beneficial to slick down beards with jelly to improve the seal, however optimal management is to remove the beard with patient cooperation. As with all cases an airway plan should be formed and discussed with the anaesthetic assistant to allow for preparation of necessary equipment. Optimal preoxygenation is vitally important with the aim of providing an increased apnoeic time to allow more time for airway management before the patient’s oxygen saturations decline. Proper positioning of the patient helps to improve the apnoeic time by decreasing dependent atelectasis. In obese patients the ear should be at the same level as the sternal notch and so there may be a need to ramp the patient (figure 4). The ramped position helps to improve both ventilation and laryngoscopy view by aligning the oral, pharyngeal and laryngeal axes.


Figure 4: A comparison between supine and ramped position in an obese patient. In a supine position (left), the ear is below the level of the sternal notch. In a ramped position (right), the ear is level with the sternal notch and the face is parallel with the ceiling.

Patel and Nouraei describe an alternate method of maintaining patient oxygenation using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE).11 Continuous high-flow humidified oxygen was delivered transnasally pre- and post-induction of anaesthesia before a definitive airway was secured. This method of apnoeic oxygenation shows promise, however, in their case series they routinely checked that mask ventilation was possible before proceeding. THRIVE only works if the airway remains patent, which is the key to successful MV, so if it is possible to use THRIVE then it should be possible to mask ventilate. In cases where there are signs that suggest difficult MV and a potentially difficult intubation, awake fibreoptic intubation may be the correct choice. If difficult MV is predicted but an easy intubation anticipated, consideration may be given to rapid sequence induction. The benefit of this approach is quicker onset of neuromuscular blockade to facilitate earlier intubation without the need for MV. The risks associated with this are multiple and should be considered on a case-by-case basis. The main risks include desaturation within the time of onset of muscle relaxation and failure to intubate. In elective cases the back-up plan for these risks would be to insert a SAD to provide ventilation but in emergency non-fasted cases, this risks aspiration. Consideration should be given to awake fibreoptic intubation in these patients. The preoperative visit should include discussion of the options and risks with the patient. When MV is unexpectedly difficult the management becomes a dynamic process. There is no agreed adult algorithm but the Association of Paediatric Anaesthetists of Great Britain and Ireland along with the DAS have produced an algorithm for difficult MV in children aged 1-8 years.12 There is a proposed algorithm by El-Orbany and Woehlck detailing the management steps in difficult MV.5 Although major anaesthetic groups have yet to adopt this, it represents a sensible approach to the problem. The first steps in management are: optimising patient position and the use of airway adjuncts such as oropharyngeal and nasopharyngeal airways, the application of continuous positive airway pressure, checking the depth of anaesthesia, muscle relaxation and reducing cricoid pressure. If difficulty remains, i.e. the saturations are dropping or there is a lack of end-tidal carbon dioxide then there should be a call for help to allow a 2-person (or 4-hand) technique and/or change of operator and request for the difficult airway trolley. If this does not improve the situation and the saturations are now <90% the situation should be considered as an impossible MV scenario. If impossible MV develops, consideration should be given to waking the patient up, however this is not always a feasible option. If a neuromuscular blocking drug has been administered it may be appropriate to attempt intubation at this point or, in the case of rocuronium, to consider reversal with sugammadex. If unable to intubate then 2 attempts at insertion of a SAD would be appropriate if not already attempted. If a neuromuscular blocker has not been given then insertion of a SAD is an alternative. With a SAD in situ, consideration should be given to using it as a conduit to facilitate intubation. If the oxygen saturations are still dropping this is now a Can’t Intubate Can’t Ventilate (CICV) scenario and requires rescue techniques in the form of either a cannula cricothyroidotomy or surgical cricothyroidotomy. Figure 5 outlines the steps described above. Chrimes and Fritz describe the Vortex approach as a method to organise the management of this complex and evolving situation.13 This looks at achieving oxygenation via a facemask, SAD or endotracheal tube with a maximum of 3 attempts at each. Importantly, they can occur in any order after each has been optimised, and if oxygenation fails with these non-surgical airway techniques, then the next step is an emergency surgical airway. It would be reasonable to suggest that at least one attempt should be made by the most experienced available clinician. This will have been a stressful situation for the whole team and it will be of benefit to have a team debrief to discuss the events, outcome and raise any concerns for future training. Simulator training is becoming more and more frequent in training in anaesthesia and this type of scenario should be considered. Accurate documentation of the difficulties (airway adjunct, two-person technique, administration of neuromuscular blocking drugs), together with an explanation of what occurred to the patient, should follow such events.


Figure 5: Flowchart for management of unexpected difficult MV


Complications of difficult mask ventilation Difficult MV can cause numerous complications with the main concern being failure to oxygenate the patient causing death, hypoxic brain injury or myocardial ischaemia. Other complications include injuries to the eyes, nose and mouth. Eye injuries can occur due to direct trauma from the mask or fingers; dry gases leaking from the mask can themselves cause harm. Nasal airway adjuncts can cause false passages and bleeding which may further compromise the airway. Patients may develop pressure injury due to excessive use of force with the mask against the nose. The mouth and oropharynx contain many structures that may be injured during difficult MV; these include teeth, lips, soft palate, uvula and nerves. Lack of lubrication and excessive use of force for insertion of airway adjuncts can increase the risk of this type of trauma. With increasing difficulty in mask ventilation there is a tendency to increase the inflation pressure via the adjustable pressure-limiting (APL) valve on the anaesthetic machine. This can lead to a vicious cycle: if the airway is not patent, air will be directed into the stomach increasing intra-gastric pressure. This in turn leads to raised diaphragms and a decrease in lung compliance, which leads to more difficult MV. To avoid causing gastric inflation the APL valve should be kept to the minimum requirement and below 20cmH2O. This is specifically addressed in the paediatric guidelines which suggest the insertion of a nasogastric tube if gastric distension is present.12 Furthermore, if the airway is patent and being over-ventilated with high pressures, the increased intra-thoracic pressure can compromise venous return and lead to hypotension and decreased coronary perfusion. Difficult mask ventilation and difficult intubation This represents the worst-case scenario for most anaesthetists and has led to guidelines being developed for how to manage the CICV scenario. The risk factors for difficult intubation and difficult mask ventilation do have some overlap, for obvious reasons. The incidence of this difficult combination was found by Kheterpal et al. to be approximately 0.4%, with difficulty defined as grade 3 or 4 MV and a grade 3 or 4 view at laryngoscopy.14 This likely represents an underestimation given that anticipated difficult airways may have received an awake fibreoptic intubation. Other study by Kheterpal et al. looking at impossible MV found that 19 of the 77 (25%) impossible-to-ventilate patients (out of 50,000 cases) were also difficult to intubate; importantly, 15 of these patients were successfully intubated using various asleep techniques, only 3 were woken up (2 for awake fibreoptic intubation, 1 for awake surgical tracheostomy), and only one required an emergency surgical airway.7 ANSWERS TO QUESTIONS

1. a. True. A beard can cause difficulty in achieving an adequate seal when attempting MV and if concerned, the patient should be advised to shave it off. b. True. A history of snoring can indicate upper airway closure when relaxed and may be due to enlarged soft tissues. c. True. A BMI of 26kg/m2 or more is associated difficult MV. d. False. No association with alcohol has been shown. e. False. Male gender is associated with increased risk of difficult MV.

2. a. True. Hypoxia is an obvious complication from difficult MV and may lead to myocardial ischaemia and hypoxic brain injury. b. False. There is no association between difficult MV and brachial plexus injury. c. True. There is a strong association with high inflation pressures in difficult MV and aspiration risk. d. True. This occurs from direct pressure from the mask or from the drying effect of the gases used. e. False. No association has been shown.

3. a. False. Deepening anaesthesia in an adequately paralysed patient will confer no benefit. b. True. This depends on the situation and how timely the patient can regain spontaneous breathing and airway patency before critical hypoxia develops. If the time frame permits, then rapid reversal of neuromuscular blockade (i.e. sugammadex), benzodiazepine and opioid may be considered. However, if the likelihood of the patient regaining spontaneous airway patency is low (e.g. no readily available reversal agents), then the priority will be to obtain an airway and oxygenate the patient. c. True. An attempt at laryngoscopy would be appropriate, as it would allow oxygenation and ventilation if successful. d. True. An attempt at inserting a SAD is also appropriate as it may improve oxygenation and allow you to awaken the patient. This can also be used after a failed attempt at intubation. e. False. A surgical airway would be the final step after attempting SAD insertion or intubation.


References 1. American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of

the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 2013; 118:251-270.

2. Langeron O, Masso E, Huraux C, Guggiari M, Bianchi A, Coriat P, Riou B. Prediction of difficult mask ventilation. Anesthesiology

2000;92:1229-36.

3. Yildiz TS, Solak M, Toker K. The incidence and risk factors of difficult mask ventilation. J Anesth 2005;19:7-11.

4. Kheterpal S, Han R, Tremper KK, Shanks A, Tait AR, O’Reilly M, Ludwig TA. Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology 2006;105:885–91.

5. El-Orbany M, Woehlck H. Difficult mask ventilation. Anesth Analg 2009;109:1870-1880.

6. Han R, Tremper KK, Kheterpal S, O’Reilly M. Grading scale for mask ventilation. Anesthesiology 2004;101:267.

7. Kheterpal S, Marin L, Shanks AM, Tremper KK. Prediction and outcomes of impossible mask ventilation: a review of 50,000

anaesthetics. Anesthesiology 2009;110:891-7.

8. Bennett JA, Abrams JT, Van Riper DF, Horrow JC. Difficult or impossible ventilation after sufentanil-induced anesthesia is caused primarily by vocal cord closure. Anesthesiology 1997; 87:1070-4

9. Royal College of Anaesthetists, Difficult Airway Society. 4th national audit project of major complications of airway management in

the United Kingdom. Available online from: http://www.rcoa.ac.uk/system/files/CSQ-NAP4-Full.pdf

10. Cattano D, Katsiampoura A, Corso RM, Killoran PV, Cai C, Hagberg CA. Predictive factors for difficult mask ventilation in the obese surgical population. F1000Res 2014;3:239.

11. Patel A, Nouraei S. Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE): a physiological method of increasing

apnoea time in patients with difficult airways. Anaesthesia 2015;70:323-329.

12. Difficult Airway Society, Association of Paediatric Anaesthetists. Difficult mask ventilation – during routine induction of anaesthesia in a child aged 1 to 8 years. Available online from: http://www.apagbi.org.uk/sites/default/files/images/APA1-DiffMaskVent-FINAL.pdf

13. Chrimes N, Fritz P. The vortex approach: Management of the unanticipated difficult airway. Available online from:

http://www.vortexapproach.com (accessed 20/09/15)

14. Kheterpal S, Healy D, Aziz MF, Shanks AM, Freundlich RE, Linton F, et al; Multicenter Perioperative Outcomes Group (MPOG) Perioperative Clinical Research Committee. Incidence, predictors, and outcome of difficult mask ventilation combined with difficult laryngoscopy: a report from the multicenter perioperative outcomes group. Anesthesiology 2013;119:1360-1369.

Further reading • Adnet F. Difficult mask ventilation: an underestimated aspect of the problem of the difficult airway? Anesthesiology

2000;92:1217-8.

• Ramachandran S, Kheterpal S. Difficult mask ventilation: does it matter? Anaesthesia 2011;66(Suppl 2):40-44.

This work is licensed under the Creative Commons Attribution-NonCommercial 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/3.0/

Boone County Fire Protection DistrictEMS Education

Airway & Breathing Course


G a n d P G r a t e d

m a t e r i a l


BLS Airway Unit

Sniffing Position Lesson

Jaw Thrust / Mask Seal Lesson

OPA / NPA Lesson

Bag-Mask Ventilation Lesson


Jaw Thrust / Mask Seal


E-C Technique

Its in all the books!

Its not the most effective for the field.

All the standards talk about how the BVM is a TWO PERSON TOOL so why would you just use one hand for the airway?


Two Thumbs Down


Two Thumbs Down

Jaw Thrust

Mask Seal

Someone else can squeeze the bag!

Video link

http://emcrit.org/podcasts/bvm-ventilation/



m a t e r i a l


BLS Airway Unit



OPA / NPA Lesson



OPA / NPA


OPA

Adjunct to jaw thrust—not a replacement.

Great for those without a gag reflex!

Won’t work if there is a gag reflex.

If you try it and they gag—then they vomit—now things are worse.

Pinch their nailbed with the OPA to test.


NPA

Adjunct to jaw thrust—not a replacement.

Great for those WITH a gag reflex!

IF you can get into their nose.

If you guess wrong and its too long…withdraw it just a bit.

Nosebleed is not uncommon.


When in Doubt…

Nobody said you can’t use both OPA and NPA.

Caution—if you use two NPA then you probably can’t use IN route for meds.


Just Because…

OPA’s and NPA’s together may not be something that you see many field paramedics doing…

…but maybe they ought to.

If it works, your patient needs you to use it even if you partner thinks you are weird.



m a t e r i a l


BLS Airway Unit



OPA / NPA Lesson



Sniffing Position


Ear-To-Sternal Notch

The line between the external auditory meatus (“ear hole”) to the sternal notch should be parallel to the plane of the patient’s face.


Sniffing Position


RampingUse towel(s) or blanket(s) or modules from your EMS Pack or whatever…


Ear-To-Sternal Notch

Just because you don’t see many field paramedics using this technique…doesn’t mean its not helpful and well worth the effort.

Not everything that they use in the OR is worthless in the field!



m a t e r i a l


BLS Airway Unit



OPA / NPA Lesson



Bag Mask Ventilation


Negative Pressure

We are negative pressure breathing animals…its how we were designed.

Air goes where we want it.

Pressure in the chest is how we need it.

Negative pressure breathing is positive for perfusion.


Positive Pressure

Positive Pressure Ventilation causes NEGATIVE perfusion effects.

Air goes where it wants to—stomach is the easiest pathway.

Sometimes we must ventilate—so we must ventilate correctly.


Rate

SLOW is good.

One breath NO MORE OFTEN THAN every SIX seconds.


Pressure

LOW is good.

Smooth squeeze—especially before intubated.


Volume

ONE hand, HALF the Bag.

200 pound patient needs 700cc tidal volume from the 1500cc bag.


Just Because…

…you have always done it wrong or

…you see some “senior” medics do it

Does NOT make it the best thing for your patient.

New evidence and standards support what we are teaching.

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ator

will

mov

e fo

rwar

d in

to th

e pa

tient

val

ve

rem

indi

ng th

e re

scue

r to

redu

ce th

e fo

rce

bein

g ap

plie

d to

the

bag.

THE

USE

OF

MA

NU

AL

OVE

RR

IDE

CO

NTR

OL

Cur

rent

res

earc

h in

dica

tes

that

, for

all

patie

nt c

ondi

tions

, th

e M

anua

l Ove

rrid

e co

ntro

l sho

uld

NO

T B

E U

SED

and

th

e “S

MA

RT

VALV

E” s

houl

d be

left

in th

e “E

NA

BLE

D”

posi

tion.

Thi

s re

com

men

datio

n m

aint

ains

ope

ratio

n of

th

e SM

AR

T B

AG®

M

O

in

stric

t co

mpl

ianc

e w

ith

the

curr

ent

Gui

delin

es

for

CP

R

and

EC

C

as

publ

ishe

d by

the

Am

eric

an H

eart

Ass

ocia

tion

and

the

Eur

opea

n R

esus

cita

tion

Cou

ncil.

Sho

uld

the

oper

ator

dec

ide

to u

se t

he m

anua

l ov

errid

e co

ntro

l, it

is im

porta

nt n

ot s

witc

h in

to t

he d

isab

led

mod

e w

hile

squ

eezi

ng th

e ba

g. U

sing

the

SMA

RT

BA

G®

MO

in

the

“SM

AR

T VA

LVE”

“EN

AB

LED

” m

ode

may

res

ult

in

“Inad

verte

nt h

yper

vent

ilatio

n” w

ith a

ll its

ass

ocia

ted

risks

.

Ref

eren

ces:

1. A

.H.A

G

uide

lines

fo

r C

ardi

opul

mon

ary

Res

usci

tatio

n an

d E

mer

genc

y C

ardi

ac

C

are

– 20

052.

Elli

ng

R,

Pol

itis

J.

An

eval

uatio

n of

em

erge

ncy

med

ical

te

chni

cian

s’

abili

ty

to

use

man

ual v

entil

atio

n de

vice

s.

A

nn E

mer

g M

ed. 1

983;

12:7

65-7

683.

Hes

s D

, B

aran

C

. V

entil

ator

y vo

lum

es

us

ing

mou

th

to

mou

th,

mou

th

to

mas

k

and

bag-

valv

e-m

ask

tech

niqu

es

A

m J

Em

erg

Med

198

5;3:

292-

296.

4. J

esud

ian

MC

, H

arris

on

RR

, K

eena

n R

L,

M

aull

Kl. B

ag-v

alve

-mas

k ve

ntila

tion:

two

resc

uers

are

bet

ter t

han

one:

pre

limin

ary

repo

rt. C

rit C

are

Med

. 198

5;13

:122

-123

5. W

heat

ley

S,

Thom

as

AN

, Ta

ylor

R

J,

Br

own

T. A

com

paris

on o

f thr

ee m

etho

ds

of

ba

g va

lve

mas

k ve

ntila

tion.

Res

usci

tatio

n 19

97 J

an;3

3(3)

:201

-10

6. F

uers

t R

S,

Ban

ner

MJ,

M

elke

r R

J.

Insp

irato

ry ti

me

influ

ence

s th

e

dis

tribu

tion

of v

entil

atio

n to

the

lung

s an

d

sto

mac

h:

Im

plic

atio

ns fo

r C.P

.R. P

rese

nted

at

th

e S

ocie

ty

for

Aca

dem

ic

Em

erge

ncy

Med

icin

e A

nnua

l Mee

ting,

May

199

2.7.

Auf

derh

eide

T. e

t al:H

yper

vent

ilatio

n-

In

duce

d H

ypot

ensi

on D

urin

g

Car

diop

ulm

onar

y R

esus

cita

tion.

Circ

ulat

ion

Apr

il 27

, 200

4 8.

Bra

in T

raum

a Fo

unda

tion.

Gui

delin

es fo

r

the

Man

agem

ent o

f Sev

ere

Hea

d In

jury

-

1995

9. P

itts

and

Kel

lerm

an. E

dito

rial i

n th

e

Lanc

et J

uly

24th

200

5

RES

PON

DIN

G T

O Y

OU

R P

ATI

ENT

If th

e pa

tient

’s a

irway

is le

ss c

ompl

iant

or

mor

e re

stric

tive

(as

in p

atie

nts

with

CO

PD

or

asth

ma)

, hi

gher

airw

ay

pres

sure

s w

ill b

e re

quire

d to

pro

vide

ade

quat

e ve

ntila

tion.

In r

espo

ndin

g to

thi

s in

crea

sed

pres

sure

req

uire

men

t in

th

e pa

tient

’s a

irway

, the

SM

AR

T B

AG®

MO

allo

ws

the

user

to

incr

ease

the

pres

sure

requ

ired

to o

verc

ome

the

resis

tanc

e/co

mpl

ianc

e pr

oble

m a

nd p

rovi

de a

dequ

ate

ven

tilatio

ns.

Rem

embe

r th

at t

he S

MA

RT

BAG

® M

O w

ill o

nly

allo

w

you

to a

pply

hig

her

flow

rate

s ge

nera

ting

high

er a

irway

pr

essu

res

whe

n th

e pa

tient

’s a

irway

con

ditio

n re

quire

s th

em.

You

w

ill

“feel

” th

is

chan

ge

in

com

plia

nce

and

resi

stan

ce a

s th

e SM

AR

T B

AG

® M

O a

llow

s th

e hi

gher

flo

wra

tes

to b

e ge

nera

ted.

NO

TE: I

n th

e un

prot

ecte

d ai

rway

, as

with

any

res

usci

tatio

n de

vice

, th

e ris

k of

gas

tric

insu

fflat

ion

will

incr

ease

if th

e de

liver

ed fl

owra

te in

crea

ses

the

airw

ay

pres

sure

gen

erat

ed a

bove

the

LES

ope

ning

pre

ssur

e .

PRO

VID

ING

CO

NTR

OLL

EDVE

NTI

LATI

ON

By “

self

adju

stin

g” t

o bo

th t

he

patie

nt a

nd t

he r

escu

er,

the

SMA

RT

BA

G®

MO

opt

imiz

es

the

vent

ilatio

ns, c

ontro

lling

the

insp

irato

ry t

ime

and

keep

ing

the

deliv

ered

flo

wra

te

and

subs

eque

nt a

irway

pre

ssur

e to

the

min

imum

req

uire

d fo

r ad

equa

te v

entila

tion

to o

ccur

. Th

is

resu

lts

in a

sig

nific

ant

redu

ctio

n in

th

e ris

k of

ga

stric

in

suffl

atio

n an

d it’

s as

soci

ated

com

plic

atio

ns.

USIN

G T

HE S

MAR

T BA

G® M

O

Usi

ng th

e SM

AR

T B

AG

® M

O

is

EASY

! Ju

st

let

SMA

RT

BA

G®

M

O

com

pres

s un

der

your

ge

ntle

, sl

ow,

hand

sq

ueez

e. A

one

or t

wo-

hand

ed

sque

eze

can

be u

sed.

The

Insp

irato

ry t

ime

shou

ld b

e 1

seco

nd i

n ac

cord

ance

w

ith th

e cu

rren

t int

erna

tiona

l res

usci

tatio

n gu

ide

lines

.

TRA

ININ

G A

ND

SK

ILL

RET

ENTI

ON

Man

y re

fere

nces

exi

st a

s to

the

abili

ty o

f res

cuer

s to

ad

equa

tely

per

form

pra

ctic

al s

kills

. In

addi

tion,

the

rete

ntio

n of

thos

e sk

ills

and

the

abili

ty to

ade

quat

ely

perfo

rm th

em,

over

time,

dec

reas

es w

ithou

t fre

quen

t re

-trai

ning

and

edu

ca-

tion.

By

impa

rtin

g a

degr

ee o

f co

ntro

l fo

r th

e re

scue

r th

e SM

ART

BAG

® M

O h

elps

to

train

the

res

cuer

to

prov

ide

slow

con

sist

ent

vent

ilatio

ns. I

n ad

ditio

n, th

e SM

AR

T B

AG®

MO

cont

inua

lly re

-trai

ns th

e re

scue

r eve

ry ti

me

they

use

the

devi

ce b

y im

parti

ng th

at s

ame

degr

ee o

f con

trol d

urin

g re

sus-

cita

tion.

SMAR

T Va

lve

“Dis

able

d,” S

MAR

T BA

G® M

O re

spon

ds li

ke a

st

anda

rd B

VM.

SMA

RT

VALV

E En

able

dSM

AR

T VA

LVE

Dis

able

d

NO

TES:

[1]

Beca

use

of th

e un

ique

nat

ure

of th

e SM

AR

T B

AG

®

MO

, new

use

rs w

ill re

quire

min

imal

orie

ntat

ion

in th

e

use

of th

e de

vice

.

[2]

The

resu

scita

tor i

s no

t int

ende

d fo

r use

dur

ing

spon

tane

ous

brea

thin

g. D

ue to

the

natu

re o

f the

se

devi

ces,

they

may

onl

y pr

ovid

e a

rest

ricte

d flo

w o

f air

to

the

patie

nt a

nd li

ttle

or n

o su

pple

men

tal o

xyge

n.

Boone County Fire District EMS Education-EMT Course...

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Transcript of Boone County Fire District EMS Education-EMT Course...