Prehospital Practice Volume 3 First edition: From classroom to paramedic practice

By Jeff Kenneally

This is the third volume in a series of easy to read text books intended for paramedics and other responders to prehospital medical and traumatic emergencies.  Each chapter focuses on a different yet common medical or traumatic emergency situation.  

They begin case study based and create a real situation that may be encountere

• Language: English
• Publisher: Prehemt
• Release date: Feb 12, 2017
• ISBN: 9780992552657

Jeff Kenneally

Intensive Care Paramedic of over thirty years experience Clinical effectiveness manager of a major ambulance service Senior University Lecturer Road Accident Rescue team leader and trainer

Book preview

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Volume 3

Pre-Hospital Practice Hypothetically Speaking

Jeff Kenneally

Published in Melbourne by:

PrehEMT Pty Ltd

[e-mail]

www.prehemt.com

First published 2017

National Library of Australia

Cataloguing-in-Publication entry:

Kenneally, Jeff author.

Pre-hospital practice : hypothetically speaking /

Jeff Kenneally.

ISBN 978-0-9925526-5-7

ebook version

Medical emergencies—Australia—Textbooks.

Assistance in emergencies—Australia—Textbooks.

First aid in illness and injury—Australia—Textbooks.

Copyright ©2017 Jeff Kenneally

All rights reserved. Reproduction of any part of this book without the publishers written permission is prohibited.

This material is intended for educational use by pre-hospital medical emergency responders. It should be read in conjunction with traditional relevant educational programs that provide for Australian first aid and emergency medical and trauma response. It does not intend to replace other education or training.

PrehEMT makes every effort to ensure the quality and currency of this information. It intends to provide guidance to applying appropriate pre-hospital emergency care to common medical and traumatic emergencies. It cannot cover every situation specifically as each patient and circumstance can vary from case to case. Before implementing any clinical practice or patient care the appropriate clinical practice guidelines, protocols and work instructions for the relevant organisation should be consulted and deferred to in all situations.

contents

5 Pre-hospital emergencies hypothetically speaking introduction

Hypotheticals

7 The airway again

19 Acute coronary syndrome

37 Carbon monoxide

52 Road accident rescue

68 Oxygen therapy

84 Decompression illness

95 Heat stroke

107 The ECG basics

123 Acute stroke

137 Cardiac arrest

154 The child in respiratory failure

165 The older patient

181 Tracheostomy tubes

191 Continuous positive airway pressure

209 SVT and the valsalva manoeuvre

225 Child trauma

241 Severe headache

259 Abdominal pain

280 Traumatic hypotension

299 Glossary of abbreviations

Pre-hospital emergencies

hypothetically speaking

The role of pre-hospital emergency responder is a lot of things. It is challenging. It is daunting. It is tiring. It is incredibly satisfying. It is unique in many ways. It is a bit first aid, a bit doctor, a bit social worker and almost always jack of all trades. The call outs never stop coming and you never quite get to that point where you have seen it all. University education is common in the modern pre-hospital era but that only prepares you for a lot more learning. When you finally start work, when once you would have been an ambulance driver or officer, you are now more likely to be a paramedic or emergency medical technician. Whatever you get called there is one certainty – you will be a novice in this working world that is like few others. You have precious few diagnostic tools, language barriers, extremes of emotion, the elements against you with uncertainty your constant companion.

There is an expression that says experience is something you get just after you need it. Experience is something every pre-hospital responder needs. You will gain a lot of it over the years of a career. Much of it will come under duress and the hard way through error or your partner putting you right just before something goes wrong. But what if you could learn through sharing the experience of others? You might avoid some of those errors or close call moments. You would certainly be much better prepared for the differing situations as they arise.

These hypotheticals are all based on real call outs, real patients and real situations. These are the cases where experience came just after it was needed the first time. It doesn’t have to be this way for others though. They encompass typical medical and traumatic emergencies as confront pre-hospital responders and look beyond the simple written guidelines and protocols provided. They are not based on the practices of any one organisation and reference to the applicable specific guidelines should be sought before putting these experiences into action.

This is the third volume in this series of hypothetical texts. Readers have included undergraduate students,through to intensive care paramedics. They can be read as an educative story or as scenario bases for training exercises. My philosophy is this. Everything in prehospital can be made simple. Break it down into the most basic elements, grasp the concepts, then build it back up with some medical words and practical context. Link just the right theory with just what they expect you to do in clinical practice. That’s what these books seek to do.

The airway again

hypothetical

The young man you are assessing has caught you off guard. What started out as a patient with what nseemed a chest infection is deteriorating far quicker than you anticipated. More quickly than you can make management decisions to head the problems off.

Initially he had been sitting up in bed with some moderate breathing difficulty troubled by an occasional productive cough. His demeanour had been a little agitated but you hadn’t really given that much attention. Turning to question his partner so as not to trouble the man with questions, you determine that he has been having difficulty for more than twenty four hours. He has stubbornly refused to see a doctor about it believing he will get better on his own.

His underlying health is unremarkable though his partner suggests he does not eat healthily and regularly succumbs to mild infections. She also provides a questioning expression that casts doubt on her belief he is being sufficiently stoic despite being unwell. The man flu accusation is thrown his way. Distracted briefly by this discussion, you turn your attention back to the assessment.

The patient looks very tired now. He was initially sitting upright and appeared alert. You feel that some of the fight to breathe has gone out of him. He has also slumped slightly to one side of the chair and makes no attempt to straighten himself upright again.

With some relief you observe that when you speak to him he looks up at you. Tired he may be but he still has that level of awareness. He doesn’t reply at all to you though. Examining his breathing more closely now you note his respiratory rate is actually forty per minute. He has a laboured and slightly prolonged expiratory phase. His inspiratory effort is noticeably increased betraying increased work of breathing. He has audible coarse crackles throughout all his lung fields. His pulse rate is 120 per minute with blood pressure a concerning 90/40mmHg systolic. His pulse oximetry is most alarming at a declining 88%.

(1) What is your initial assessment and most pressing priority?

The first, but not the only priority problem, is the worsening hypoxia. The patient is tiring and losing the ability to maintain sufficient oxygen within his blood. He is deteriorating from being in severe respiratory distress to even more ominous respiratory failure. Whilst he was fighting hard and using his accessory respiratory muscles he was drawing in a greater amount of air with a larger minute volume. This allowed him to partly overcome the inflammatory barrier blocking gas diffusion from alveoli to pulmonary blood. But as the respiratory muscles tire and the oxygen figure falls away this will not be enough. He is about at that point now.

The first simple step in response to this problem is to increase his oxygenation. There are a number of ways to do this. You could administer supplemental oxygen therapy through a nasal cannula. Generally flow is limited to a maximum of around six litres per minute with these or else they become uncomfortable for the patient. At this maximum flow rate the fraction of inspired oxygen will likely not rise above about 0.4. This does not seem to be a sufficient enough response for this problem.

More recently high flow oxygen has been shown to be effective at increasing oxygenation in patients with acute respiratory failure associated with pulmonary infection without any significant untoward effect¹,². Typically though a wide bore nasal cannula and humidifier is used which is not usually available for prehospital responders.

You could choose a standard oxygen therapy mask instead. These require flow rates from six up to as high as fifteen litres per minute or more. If the flow rate drops below six there is the risk that more exhaled carbon dioxide can accumulate in the mask than can be flushed out and displaced by oxygen. Above that though and the fraction of inspired oxygen can be increased to as much as 0.6. Better than a nasal cannula certainly.

For this patient this may prove sufficient and you open the cover on your oxygen therapy system to select a mask. Just at that moment your partner draws your attention to the oxygen saturation continuing its decline to only 80% now. Anything below around 90% on the oxygen-haemoglobin dissociation curve and deterioration can be rapid and steady so this is obviously bad. Instead you choose to apply a non-rebreather mask with fifteen litres of oxygen flow per minute connected. This can provide as much as 0.9 as a fraction of inspired oxygen. Better again than the other choices.

This isn’t your lucky day though, nor is it the patient’s. The non-rebreather mask doesn’t improve the oxygen saturation. This has declined now to 75% and the patient appears to have slumped even more. His eyes are closed now. He opens them only to sternal pain then closes them again. He is no longer making verbal responses. He does not localise with his arms to the sternal pain but does make bilateral weak withdrawal responses to pain.

(2) This needs a more significant response than provided so far. What will that be?

Importantly, simple delivery of oxygen may not be enough. This man cannot drag enough air into his lungs to place sufficient oxygen into the alveoli and remove carbon dioxide again. With respiratory failure evident now, not only will increased oxygen have to be delivered but some assistance with assisting ventilation will be needed to remove carbon dioxide.

The decrease in consciousness and the need to provide assisted ventilation brings new airway risk. Airway reflexes diminish as consciousness reduces. Given this patient now has a GCS of only E2+V1+M4=7, his diminishing airway reflexes are of concern.

You could roll the patient into a lateral position. This can help initially by allowing the tongue to fall forward away from the glottis. You can adequately ventilate the patient in this position even if it is a little awkward. You might prefer to manage the patient in a supine position but this might need further airway support.

(3) What is the commonest airway problem to be managed in these circumstances? What airway procedures may be required at this point?

All clinical care guidelines begin with words ‘maintain a patent airway’. What does this mean practically though? The airway is simply a pipe to allow air to flow in and out between the mouth or nose at one end and the alveoli at the other. As such a patent airway is one that allows this free air flow movement. Airway and breathing/ventilation go together. Any airway procedure performed should help to improve the patient’s ventilation ability in some way otherwise why do it?

Compromise to airway patency effectively means one thing. The one job of allowing air to flow in and out is reduced. In other words, the airway, and air flow, is obstructed. To manage airway obstructions you first have to work out where the problem is.

(4) What are the next commonest airway obstruction causes to consider here?

Firstly though, before proceeding any further when managing any airway, personal protection is needed. Airborne transmission is a great way to contract and pass on infection. Performing airway procedures causes you to be very close to the patient’s face, one way of exposing you to whatever infective ailment they might have. Don personal protective eyewear, gloves and, importantly, a respiratory rated surgical facemask.

You have decided that your first airway problem is the patient’s tongue. There are a few methods to remove this as a cause of obstruction. Before any of them is employed, an even more basic question must be answered.

(5) What position will you place this patient in?

By raising the back of the bed this small amount, around twenty to thirty degrees, you facilitate venous return from his head and allow the abdominal organs to drop away slightly from the diaphragm. Full ventilation of all lungs fields should be easiest from this position and the time to de-saturate increased⁷,⁵.

The sniffing position, with the auditory meatus of the ear raised until it is in line with the angle of the sternum, provides for both maximum diameter of the airway to be achieved whilst still allowing all airway techniques. The lower cervical spine is angled flexed anteriorly from the shoulders whilst the head is kept in the same plane as the chest by slightly extending back the top of the cervical spine5. This helps maximise the likelihood that the cords will be able to be sighted. You may need to use a lot of padding beneath the patient’s occiput to achieve and hold this position⁴.

With the patient positioned to your satisfaction, you turn now to dealing with the tongue as the first possible source of obstruction. With the patient almost supine like this and head in the sniffing position, you will now need to move the tongue forward and away from the glottis. You immediately turn to two methods.

(6) What two methods are these?

You apply effective jaw thrust to the patient beneath the angle of the jaw, equally on both sides. With that applied, your partner inserts an oropharyngeal airway. The jaw thrust works very well and you note a significant amount of anterior movement of jaw, teeth and presumably tongue. This helps to allow optimal placement of the OPA into the oropharynx. The tongue should be displaced forward like this whenever the OPA, or nasopharyngeal airway for that matter, is inserted. Ideally, the jaw should continue to be kept displaced forward even after the OPA is in position. If not, the OPA alone many not be sufficient to keep the tongue and epiglottis clear of the glottis.

However, on this occasion the OPA is causing a problem. The patient still has just enough residual airway reflexes to weakly cough and gag. You consider for a fleeting moment trying to hold in the OPA but realise that this irritant could likely cause vomiting or perhaps raise intracranial pressure. The latter may not be a particular problem with this man, such as it might be in stroke or head trauma, but the vomiting of course would be undesirable.

Your partner quickly removes the OPA. You are happy to continue with the jaw thrust but would still like a support device to help. Looking into the airway bag you smile at the next best option.

(7) Which is the next best option?

The airway is, for the moment at least, patent. This allows oxygen to be moved in and carbon dioxide out. Oxygenation of the alveoli is critical. Getting carbon dioxide back out is also important but sometimes is more challenging. With asthma for instance or perhaps COPD the carbon dioxide battle might be temporarily lost. In such cases the aim is to at least continue to replenish the oxygen supply.

So to oxygenation. Once oxygen saturation in any patient drops to 90% the oxyhaemoglobin dissociation curve drops sharply⁷. Further patient deterioration can then be very quick for any patient from here. To minimise this risk, oxygen therapy is used to increase the oxygen reservoir available within the alveoli. Oxygenation of the alveoli not only includes increasing the oxygen available to them, it also means displacing any other gas. The roughly 80% nitrogen in normal air is the obvious gas to displace. This approach of oxygenation and denitrogenation is critical before any advanced airway procedure is performed and that reservoir may be called upon.

Performing advanced airway procedures invariably means delays whilst neither assisted ventilation or oxygenation are being provided. To endure this, each patient must have a sufficient reserve of plentiful oxygen in advance to draw upon⁷.

The trick to effective preoxygenation and denitrogenation is to find a system that delivers a maximum amount of oxygen whilst removing afterward all the exhaled nitrogen away from the patient. In reality this is difficult. Use of high concentration non rebreathing oxygen masks with reservoir bags are effective to some extent. However they do not reach absolute maximum in either of these aims leaving an amount of nitrogen that cannot be washed out of the alveoli.

Re-breathing oxygen delivery systems will not remove nitrogen even if they can remove carbon dioxide through chemical scrubbing mechanisms such as soda lime crystals. This makes them less useful in building that alveolar oxygen reservoir. Non re-breathing systems with a high inspiratory fraction of oxygen not only increase oxygen deliver but also allow removal of exhaled nitrogen and discharge out to the atmosphere. Since almost 80% of air is nitrogen, there is a lot trapped within the alveoli at the beginning of treatment that can be replaced with oxygen.

A more effective way to pre-oxygenate a patient before an airway procedure, such as intubation, is to make use of a bag/valve/mask non re-breathing system. There are strict provisos with this though that cannot be underestimated. Firstly, bag/valve/mask systems only deliver air unless supplemented with high flow oxygen and a reservoir bag is attached. Even then, an amount of air nitrogen is still drawn in as the recoil bag fills each time. The highest flow available should be used to supplement. Both the non rebreathing mask and the bag/valve/mask can be effective in pre-oxygenation if they are supported with high flow supplemental oxygen⁸.

The more oxygen there is in the alveoli, the greater the partial pressure there is to cause diffusion into the lungs. More alveolar oxygen extends the duration before hypoxemia begins. A bag/valve/mask system with high flow oxygen attached and a reservoir bag can approach an inspiratory fraction of inspired oxygen of 1.0. The addition of positive expiratory end pressure (PEEP) dramatically increases the ability to keep alveoli inflated, increasing time for gas exchange and decreases the work amount of effort to reinflate them. Where it is available, the addition of a PEEP valve attached to the bag/valve/mask device is desirable⁷. This is what you turn to now.

(8) What other provisos should be anticipated with this?

All pre-hospital responders must practice to develop and maintain the skill of bag/valve/mask ventilation. In some cases it can be done very well with one hand pushing downward on the mask whilst simultaneously using the fingers of the same hand curled under the patient’s chin and jaw to apply jaw thrust. This leaves the other hand free to squeeze the bag as necessary.

At times this might prove difficult to do. There will be occasions when one hand is simply not able to form a seal between the mask and the patient’s face. This can happen, for example, when the patient’s face is gaunt, they have a beard or when dentures have been removed. In such cases the only way to maintain mask seal and apply jaw thrust might be to use both hands, one either side of the mask, simultaneously pushing it down whilst lifting the jaw with the fingers. Two hands of course means you cannot do anything else and need a second operator to squeeze the ventilation bag. The essential aim is to oxygenate the patient. If it needs two operators to do this then so be it. Done poorly the result could be patient deterioration or even death.

The patient we are attending is not being pre-oxygenated ahead of an advanced airway procedure such as intubation yet. However the extremely poor oxygen saturation needs to be addressed somehow and the same method will prove beneficial. You manage to gain a good facial seal yourself and note that the oxygen saturation is improving back toward ninety. With all that infection and inflammation, it may not get much higher.

However the news is not all good as the patient’s conscious state has decreased to a GCS of only three now. His own spontaneous respiratory effort has also dropped to a slow eight breaths per minute with shallow tidal volume. Simple oxygenation will no longer be enough. Assisted ventilation must be added as well. You begin to ventilate the patient at a rate of twelve per minute with a tidal volume of around seven millilitres per kilogram of body weight.

He tolerates this therapy for a few minutes but you find yourself now with two more concerns. Firstly every few breaths you lose the seal and feel precious oxygen blow off under the face mask. The patient has what is proving to be an awkward facial structure to work with. This is frustrating and forces you to restore the facial grip and mask seal each time and wonder how effective your ventilation really is. Secondly, like all prehospital patients, he is unfasted meaning you are quite likely to be blowing some air into his oesophagus and stomach. You simply can’t help that. Given his loss of consciousness, his oesophageal sphincters will have lost their muscle tone allowing for regurgitation of stomach content..

(9) How will you deal with these new challenges?

The patient continues to have a Glasgow coma score of only three. Continuing oxygenation and jaw thrust for the moment, you select the device you want to use. You have chosen to insert a laryngeal mask airway (LMA) into the patient’s airway. With the patient kept in the sniffing position with head and back slightly raised, you decide to quickly inspect the oropharynx first under laryngoscopy. If there is any vomitus in the oropharynx, now would be a good time to remove it. You know that you have suction apparatus ready for use beside you but find that you do not need it on this occasion.

Your laryngoscopic airway inspection lasts only a few seconds before you exchange the laryngoscope in your hand with the LMA. You insert the LMA quickly into the mouth pushing it until it becomes seated in the pharynx against the hypoglottis. There is no need to search around for a syringe to inflate the cuff as this second generation device has a silicone cuff. It seats well and you immediately attach it to the ventilation device. With some relief you find you are able to ventilate effectively through this.

It is important to be mindful that airway procedures can compromise oxygenation and ventilation if they take too long to perform. Pre-oxygenation can allow increased time before this happens but in patients who are already poorly saturated, as this man is, it may be only a few seconds before problems begin to appear. This applies also when suctioning the airway and during the insertion of devices such as an endotracheal tube. Such techniques should only be performed when absolutely essential. All should be performed quickly. It is better to withdraw and re-oxygenate and have a second attempt than to persevere with a protracted first attempt.

Despite initially being effective, oxygen saturation begins to decline again after a slight rise. You note that the chest rise and fall doesn’t seem pronounced as it initially was. The laryngeal mask airway doesn’t seem to be doing the job anymore.

(10) What would be a problem solving response here?

You find yourself unsure why the device isn’t working as effectively as it initially was. You have problem solved and still have a deteriorating patient and a device not meeting the ventilation need. You feel your frustration and anxiety rise with every numerical drop in the pulse oximetry. And those numbers are dropping steadily and quickly.

(11) What is the best response to this situation right now?

No intubation attempt and ideally no surgical airway attempt should be done in a frantic uncontrolled manner trying to correct a desperate deterioration. Unfortunately this wish will occasionally be impossible to fulfil in the case of the surgical airway where the indications are frequently the definition of desperate.

However in this case there is one temporary fall back position. An interim return to assisted ventilation should occur now to try to buy time to reconsider options and prepare for whichever option is next to come. The bag/valve/mask with oxygen reservoir is the usual option whenever there is a problem with oxygenation and ventilation such as this.

Intubation will require the necessary equipment including laryngoscope and an endotracheal tube. Ideally it should have end tidal capnography available to help confirm correct placement. Incorrect placement could prove fatal. It will take an operator reasonably proficient in practice. It will likely require drugs to overwhelm residual airway reflexes that may still be encountered even with GCS of only three. The choice of drug will depend greatly on the presenting problem and presentation.

Further, many attempts will not go as quickly or as streamlined as would be desired. Performing airway procedures means there is no possibility of oxygenating or ventilating during the procedure itself. Where the patient begins with poor oxygen saturation, it will be only a very short time before that deteriorates to a critical point7. An intubation attempt with a hypoxic patient is very risky. If muscle relaxants are administered, there will be a total reliance on bag/valve/mask ventilation if the patient cannot be intubated.

(12) How is pre-oxygenation performed before intubation, particularly such as this?

To help extend the desaturation period further, a nasal cannula with high flow oxygen at 15L/min can be attached throughout. You couldn’t normally run a cannula with this much flow as it can be irritating. However now the conscious state is so poor, this will be okay. It won’t interfere with ventilation techniques and airway procedures. Its presence can help delay desaturation⁷,¹⁰. This is only ‘insurance’ and should not mean the procedure takes any longer.

The other alternative, the surgical airway, is not necessarily a better option. If intubation is thought too great a risk, this may be the safer option. However just like intubation, a rescuer skilled in the technique is needed along with the necessary device for insertion. Again, prior oxygenation is needed only in this case this can continue as the device is inserted.

Ventilating a surgical airway is quite different. A rapid small volume method is often used called jet ventilation. This is usually used where there is an upper obstruction such as angioedema or a foreign body assisting air flow downward into the lungs. Without this obstruction there is less likelihood of air flowing downward.

Whichever option is chosen, the performance of advanced airway procedures is complex, difficult and not without risk. Patient demise is a very possible outcome if not done well. What is far more reliable and easier to perform are the basic methods of head position, pharyngeal methods, supraglottic methods, oxygenation and ventilation. These should always be relied on as the first options and always immediately considered when other methods prove ineffective or inadequate..

Suggested Answers

His obvious main presenting problem is that he is in severe respiratory distress with suspected bilateral chest infection. You might briefly explore the likelihood that it could be acute pulmonary oedema or the result of aspiration but infection seems more likely. Likely the diagnosis will be pneumonia. Arguably his most pressing problem is the progressively worsening hypoxia. As if that isn’t enough, the underlying extension into sepsis, betrayed perhaps by the borderline hypotension, also cannot be ignored.

Firstly, the amount of oxygen being provided is insufficient. More oxygen is necessary. There isn’t much more room to move if the inspired fraction through a non-rebreather mask is already as much as 0.9. However changing to a recoil bag/valve/mask set up with high flow oxygen attached may add that little more. Further, simply supplying oxygen isn’t enough. Delivering oxygen under pressure, such as with continuous positive airway pressure (CPAP), can increase the partial pressure of oxygen in the alveoli. Where the problem is due to failure to ventilate the lungs and move air in and out, the answer isn’t to simply change the inspiratory atmosphere. Instead, assisted ventilation is needed.

The patient may still have some airway reflexes and not require a lot of support. However with a single figure GCS it is likely some airway support will be needed. The tongue is the ever present airway problem for every patient. It is made worse when in the supine position. The tongue is a large muscle designed to do two things. One muscle type allows for fine movement of the tip to aid in speaking and swallowing. The other is not as fine and enables the tongue to move backward. This pushes back onto the cartilaginous epiglottis attached at the tongue base. In turn this covers the glottis to provide protection for the trachea from food entry. With loss of muscle control and airway reflexes with the conscious state decrease, the tongue becomes a genuine airway obstruction when the patient is managed supine. A plan to keep the tongue away from the glottis may be needed to avoid this. Lateral position can allow the tongue to pull forward. There are physical manipulations that can be employed to pull the tongue forward. Finally, a device may be required to be inserted into the airway to physically displace the tongue forward and away from the glottis.

The tongue and epiglottis first and foremost. This has already been discussed. The small muscles of the pharynx can also relax and cause snoring. A foreign body would be next complication. This might be introduced from outside the mouth and nose as an external foreign body. Alternatively it may come from the stomach and make its way back into the pharynx as an internal foreign body. Less commonly the airway obstruction could be a medical problem within the larynx itself including laryngospasm of the vocal cords or oedema from an allergic response, upper airway burns or infective cause such as croup. The next level of airway obstruction can come lower down the airway again and include bronchitis, bronchospasm of the bronchioles and even alveolar destruction such as associated with emphysema. The first point is to identify where and what the obstruction is, then choose the corrective management strategy that might help.

Whilst the patient is fighting and struggling to breathe, almost certainly he will prefer sitting or standing upright in some way. He may choose to lean forward in a tripod position and make greater use of accessory muscles to try to pull the chest open a little more. This position may help with postural drainage of oedema or other fluid that may be in his lungs. The patient leans forward with shoulders slightly pushed outward from the body attempting to increase the movement of the chest during breathing3. This position allows for increased input from the scalene, sternocleidomastoid and pectoralis muscles, referred to as accessory muscles of respiration. However now with the fight going out of him this may not be sufficient. He will be much easier to manage if he is lying down. You could choose to place him laterally. This could work but you want to ensure more adequate oxygenation and ventilation and have in mind to provide further airway support to help. So you position him supine being wary this means there are airway issues to immediately address. But you don’t leave him totally supine. Instead you lift his occiput from the floor into a sniffing position. You further use the top part of the ambulance bed to provide a roughly twenty degree upward tilt of the patient’s upper body.

To move the tongue and epiglottis anteriorly in the mouth you need to grab the tongue and pull it forward. Now you could do that literally with fingers or Magill’s forceps for instance….or you could be more realistic. There are two better methods. Firstly, the tongue is attached around much of its base to the jaw. If the jaw is moved forward, it will drag the attached tongue with it. Jaw thrust, applied by pushing anteriorly under the angle of the jaw, can achieve this. So too will lifting the chin forward. Either method will increase the open airway space between base of the tongue and the epiglottis and the glottis itself. These are manual techniques and this is the point where most airway obstructions will be found7. They are particularly useful as they are both effective with neither requiring any extra equipment. The other useful adjunct is the use of an airway device such as the oropharyngeal airway. This too can displace the tongue forward as long as it is correctly sized and inserted7.

The nasopharyngeal airway (NPA) of course. Able to get around biting trismus, the softer NPA is much less likely to induce a gag response. Provided the nose isn’t too smashed up and insertion is possible, size the correct NPA and insert it into one nostril. Unlike the oropharyngeal airway, this device will very likely need some lubrication to allow free passage. It goes straight in along the roof of the mouth and not upward toward the brain. Occasionally resistance might be felt part way in. Don’t fight this. Gently rotate the device to change the position of the bevel and try again. If it won’t go in don’t force it. Try the other side. In fact, there is no real problem with inserting one into both nostrils at the same time.

There always seems to be a downside to everything. Using the bag/valve/mask does have a few problems to overcome. An important task will be maintaining an effective face mask seal. Without this, air will only leak out and not move down into the lungs. These devices have a one way valve system built into them to ensure that air only flows to the patient from the bag itself. Exhaled air is vented out from the face mask. For this to work though, an effective facial seal is required otherwise it will be easier for air to be drawn back in directly between the face mask and the face. The operator thus must maintain an effective seal throughout to avoid this leak and to ensure that the one way valve is opened each time7. Some patients will not lend themselves well to a good facial seal11,12. Increasing supplemental oxygen therapy and the pre-oxygenation duration may help in some but not all cases12. Facial hair can cause problems. Patients with prominent or sunken cheekbones may prove difficult. If some thoughtful person has removed the false teeth thinking them a potential airway hazard this too can cause problems. You need the teeth to hold the facial structure. If they have been removed, find them and put them back in if you can. The other thing that the operator needs to concurrently be able to do is to be able to pull the jaw forward with the hand that is holding the mask. This allows the continued jaw thrust to be applied.

The tongue is no longer our only problem. It is time to introduce the next level of airway protection to deal with these new problems too. So far there has only been a concentration on tongue shifting devices. What is needed now is something more definitive against this next enemy – gastric regurgitation and aspiration. Unconscious patients don’t really vomit as such. Instead relaxed upper and lower sphincters combined with your inrush of air predispose to silent passive stomach content into the hypopharynx. A supraglottic device is a good option now.

The response will vary with the device used and the presenting problem. It could be that the trachea or even the laryngeal mask itself is becoming occluded with infective material from the lungs. That would make suctioning a useful option. New resistance to being able to ventilate the patient might be noted in such cases. The LMA may have been displaced from its seal on the hypopharynx. This happens easily if the shaft is twisted to the left or right in the mouth. The device in such cases must be realigned midline in the mouth and re-seated back into the oropharynx. If using a device with an air filled cuff, it is important to not put more air into the cuff than the manufacturer advises. Instead of helping, this can serve to push the entire distal tip out of the oesophagus and break the seal required to work.

If one response level doesn’t fix the airway problem, you need to immediately move to the next. Generally the flow is to use a superior option if the one before does not solve the problems. There are two superior options now. The first is for the patient to be intubated. The second is to move directly to a surgical airway such as cricothyroidotomy. Neither will be easily or quickly done but one may turn out to be life saving.

Pre-oxygenation should take at least three minutes11. After this you can be confident that unless there is interfering pulmonary disease, suitable pre-oxygenation should have taken place. It is important to maintain a good facial seal with the mask to ensure no air is able to enter the mask and all exhaled gas is removed. Pulmonary diseases may not allow the oxygen saturation to rise to 100%. It is also important not to allow the patient to breathe room air even once as the nitrogen from the air can fill the alveoli again. Part of the intention is to de-nitrogenate as well as oxygenate. The ideal position for pre-oxygenation is not supine, as already described, particularly if the patient is obese or has pulmonary disease. It is a semi upright position of around twenty to thirty degrees. The head should be in the sniffing position to optimise airway diameter and maximise likelihood of visualisation during the procedure. This is how you have this patient already. In a healthy adult there can be about 450ml of oxygen in the alveoli during inspiration. Pre-oxygenation may be able to increase this to as much as 3000ml. Each minute 250ml of oxygen will be used. If not replaced desaturation will occur. The time taken to be problematic will vary. Healthy adults may take more than eight minutes if no ventilation occurs. Sicker adults can take half this with critical or obese patients less than three minutes.

References

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3. Ki-song Kim, Min-kwang Byun, Won-hwee Lee, Heon-seock Cynn, Oh-yun Kwon, Chung-hwi Yi. Effects of breathing maneuver and sitting posture on muscle activity in inspiratory accessory muscles in patients with chronic obstructive pulmonary disease. Multidisciplinary Respiratory Medicine 2012, 7:9

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5. K. B. Greenland, M. J. Edwards, N. J. Hutton. External auditory meatus–sternal notch relationship in adults in the sniffing position: a magnetic resonance imaging study. Br. J. Anaesth. 2010;104(2):268-269

6. Jasmeet Soar, Jerry P Nolan, Berndt W Bottiger, Gavin D Perkins, Carsten Lott, Pierre Carli, Tommaso Pellis, Claudio Sandroni, Markus B Skrifvars, Gary B Smith, Kjetil Sunde, Charles D Deakin. European Resuscitation Council Guidelines for Resuscitation 2015. Section 3: Adult advanced Life Support. Resuscitation95. 2015;100-147

7. Scott D. Weingart, Richard M. Levitan. Preoxygenation and Prevention of Desaturation During Emergency Airway Management. Annals of Emergency Medicine. March 2012;59(3):165–175.e1

8. Venkateswaran Ramkumar, Goneppanavar Umesh, Frenny Ann Philip. Preoxygenation with 20º head-up tilt provides longer duration of non-hypoxic apnea than conventional preoxygenation in non-obese healthy adults. Journal of Anesthesia. April 2011;25(2):189-194

9. Amelia Robinson, Ari Ercole. Evaluation of the self-inflating bag-valve-mask and non-rebreather mask as preoxygenation devices in volunteers. BMJ Open 2012;2:e001785

10. Satya Krishna Ramachandran, Amy Cosnowski, Amy Shanks, Christopher R. Turner. Apneic oxygenation during prolonged laryngoscopy in obese patients: a randomized, controlled trial of nasal oxygen administration. Journal of Clinical Anesthesia. May 2010;22(3):164–168

11. T. Russell, L. Ng, E. Nathan, E. Debenham. Supplementation of standard pre-oxygenation