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A patent, effective airway IS the most important function that any individual must be able to maintain in order to sustain life. If the airway is blocked, or the individual is unable to effectively exchange air through the airway, life WILL cease to exist. It's just a matter of time. It is for just that reason that, when assessing a patient (as when we did in "CPR") we start with the "ABC's,." And, when we start the "ABC's" we start with "A" (Airway.)
Being able to recognize a patient in respiratory distress, respiratory failure, or respiratory arrest are skills that must be learned, and perfected, so that the "recognition" is immediate. If, as stated above, it is just a "matter of time," then a proficient emergency care provider MUST be able to minimize the amount of time necessary to come to the proper diagnosis and initiate the proper treatment when dealing with a patient with airway problems.
Effective Airway Management starts with a thorough understand of the anatomy and physiology of the human airway.
The respiratory system has two major sub-divisions. The upper airway and the lower airway.
The upper airway consists of the mouth and nose, the nasal passageways, the nasopharynx and oropharynx, the pharynx and the epiglottis.
The lower airway consists of the larynx, the trachea, the carina, the bronchi, the bronchioles and the alveoli.
The physiology of the respiratory system is a bit more complicated. There is a detailed explanation of the respiratory system in a section of the page entitled "The Human Body," and this link will take you there. Read through the entire section, there's a link at the bottom of that section that will return you to this location.
Basic techniques for "maintaining an airway" have been discussed in earlier sections, and include hyperextension and the modified jaw thrust. Illustrations of both are here.
As an EMT you will be expected to be able to insert either an oropharyngeal or a nasopharyngeal airway. Both are selected with the 'size' of the patient's anatomy in mind.
Oropharyngeal airways look like 'spoons,' and are designed to lift the tongue away from the posterior aspect of the oropharynx. Nasopharyngeal airways are 'tubes' which are designed to bypass the anatomical obstruction created by the tongue resting against the posterior aspect of the oropharynx. (There are a variety of different types of oro- and naso- airways. Examples will be presented by your instructors.) Consequently, choosing the appropriate size (of either) is of paramount importance, if they are to work correctly. An incorrectly 'sized' airway adjunct will more likely lead to an obstructed airway, than create a patent one.
When choosing an oropharyngeal airway, measure it by placing it along side the patient's face. A correctly sized airway will span the distance between the patient's earlobe and the corner of the patient's mouth.
When choosing a nasopharyngeal airway, it should span the distance between the patient's earlobe and the tip of the patient's nose. Do not 'stretch' the airway in an effort of span this distance, but allow it to assume its natural curvature.
Be as exact as you possibly can with this measurement (size DOES matter.)
When positioning a properly sized oropharyngeal airway, the device is introduced into the patient's mouth in an inverted position, moved toward the back of the throat until the tip of the device contacts the soft pallet, then rotated 180°, catching the back of the tongue, and finally, the flange of the device is placed outside the patient's teeth. When properly sized and inserted, the airway will 'scoop' the back of the tongue and hold it away from the back of the throat, and the flange will 'rest' comfortably on the patient's teeth. A contraindication for the use of an oropharyngeal airway would be an 'intact' gag reflex.
When introducing a properly sized nasopharyngeal airway, start by lubricating it with a water-soluble lubricant. Look at both nares (nostrils,) usually one nare will be larger than the other. Choose the larger of the two as the initial insertion point (local protocol may suggest otherwise.) The tip of the airway is introduced into the nare, close to the septum, with the curvature of the airway matching the natural curvature of the nasopharynx and nasal passageways. Introduce the airway gently, and direct it straight back toward the back of the head, not up (toward the crown of the skull,) as might be expected. The nasal passageways go straight back and the delicate nasal tissues associated with the sinuses (some of which are superior to the nasal passageways) are easily damaged and some unwanted bleeding may occur if they are 'scraped' by the tip of the airway. If any resistance is encountered while inserting the airway, withdraw it, re-lubricate it, and try the other nare. The nasopharyngeal airway is designed to follow the natural curvature of the nasopharynx and when fully inserted the tip is located in the back of the pharynx immediately posterior to the tongue. This type of airway is better tolerated by patients who have an 'intact' gag reflex, however contraindications include any trauma that might risk 'intubating' brain tissue. The flexible nature of the airway, and the presence of adequate water-soluble lubricant, allow the airway to properly 'place' itself. If, however, there is any possibility of basilar skull fracture, the tip of the airway may enter the 'hole' caused by the fracture and end up in brain tissue. Although, ultimately we are concerned with supplying oxygen to the brain, this is not the "preferred route."L
In some areas of the country, EMT's are charged with the responsibility of placing an endotracheal tube into the patient's trachea, in order to assure a 'protected' airway. Our experience has shown that this 'activity' is one that requires considerable additional training, practice, and knowledge of the airway anatomy. Because we believe that the overwhelming majority of EMT's are not charged with such responsibility, we are going to defer the in-depth discussion (of this) to the section on Advanced Life Support. However, many EMT's may be asked to help manage, lift, and/or move a patient that has an endotracheal tube in place. For that reason we believe that all providers should have a basic understanding of what is involved, and what is important to avoid.
The provider placing the endotracheal tube will use an "endoscope" to visualize the opening of the patient's trachea (the landmark being the vocal chords.) A properly sized endotracheal tube will be selected and the distal end of the tube will be visualized as it passes through the vocal cords. A small "balloon" (cuff) just proximal to the distal end of the tube will be inflated using a syringe, and this cuff will serve to 'fill' the trachea, thereby blocking any foreign bodies from entering the lower airway, and allowing for positive ventilation of the lungs. (It will also serve to 'hold' the tube in place, although this "function" is very unreliable and all providers should avoid moving or bumping the tube, or [dare we say it] using the tube as a "handle.") In recent times, the 'industry' has developed different devices for securing the endotracheal tube once placed, in an effort to prevent any movement, but even in the presence of such devices, care should to employed to avoid moving or bumping the tube. The endotracheal tube has numbers printed along its length, and the provider who placed the tube will record the number on the tube that is adjacent to the patient's teeth. If you move or bump the tube, PLEASE advise the provider, that placed the tube, so he/she can re-check its placement by referring to this number. An improperly placed tube will be indicated by a variety of findings. Immediately after placing the tube, the provider will verify that "bilateral breath sounds" are present. If 'belly gurgling' is heard then the tube has been placed in the esophagus, the tube must be properly removed, discarded, the procedure repeated, and THIS TIME, the provider must VISUALIZE the tube passing between the vocal chords. If breath sounds are heard only on the right side, it is possible that the tube has been introduced too far into the trachea and has passed the carina creating a situation called "right mainstem bronchus intubation." In this case the provider will probably withdraw the tube a few centimeters at a time, until bilateral breath sounds are heard. The are a number of additional "tools" used by these providers to assure proper placement of the tube. There are also a variety of other types of tubes (other than 'endotracheal') used to secure a 'protected' airway. A detailed discussion of these will also be deferred to the section on Advanced Life Support.
Having 'established' a patent airway, it still may be necessary to clear the airway in order to provide adequate ventilation to a patient. Suctioning an airway is a process of removing "obstacles" that inhibit that ventilation. For the most part, those "obstacles" will be some type of fluid, although suctioning can also be used to remove solid and semi-solid obstacles.
The "tools" include some type of 'vacuum' device and either a hard or soft suctioning catheter.
Portable suction devices are usually battery powered, although there are an increasing number of hand-powered suctioning devices. Battery powered devices require regular maintenance, including battery charging, and testing the effective suctioning action of the device. When you NEED it, is NOT the time to find out that it's not working.
Suctioning technique is something best taught by actual demonstration. Look to your instructors for guidance. Our only comment here would be, to be mindful that, in addition to 'suctioning' out obstacles, the suctioning action is also 'sucking' out the air (including any oxygen that's in that air.) Look to local protocols for guidance on suctioning time limits, remember those limits, and stick to them. If your patient is already experiencing some degree of hypoxia (as a result of a compromised airway,) 'starving' them of any additional oxygen will only exacerbate the problem.
During you career as an EMT you will invariably be asked, "What is the drug most often used at the scene of any emergency?" Let's start you off right and give you the answer up-front. OXYGEN.
Yes, it is considered a drug. Granted, it has few if any untoward side-effects, unless it is withheld from the patient that needs it, but it is still to be considered a 'drug' with all the respect you would assign to any other drug.
Not ALL patients will respond positively to the administration of oxygen.
Those who rely on a hypoxic drive to initiate respirations will after of period of time, loose the 'urge' to breathe when 'flooded' with oxygen. There is some disagreement among the experts when it comes to just "how long" that 'period of time' is, but you need to know that when administering oxygen to a patient with "Chronic Obstructive Pulmonary Disease (COPD,)" the reaction to the oxygen MAY be something other than what you expect. This is not to suggest that COPD patients should not receive oxygen, just that when a COPD patient is receiving oxygen, the patient needs to be closely monitored.
There is also some concern about administering full-strength oxygen to newborn babies. Again, there is dissention among the experts regarding this 'concern,' and again, if the baby is exhibiting signs of oxygen deprivation, the administration of oxygen is imperative. Our suggestion would be to administer the oxygen using a "blow-by" method, where a mask (or other delivery device) is not used, but the oxygen supply tubing is slowing "waved" back and forth across the baby's face with the oxygen flowing at a few liters per minute.
Other than the aforementioned, we can think of no patient that will react in an inappropriate fashion, to the administration of this drug.
Oxygen is supplied to the medical profession in tanks. Those tanks come is sizes that range from 'small enough' to fit under your arm to 'large enough' to required a truck to move them. There are two sizes with which you will most likely be involved, "D" and "M." The "D" tank is the one that you are most likely to be carrying into the scene. The "M" tank is the one that is most likely 'installed' in your ambulance for providing on-board O2 to your patient.
Regardless of the size of the tank, all oxygen tanks in medical service have a few things in common:
The useful "life" of any tank is dependent on the size of the tank and the flow rate at which the oxygen is consumed. Obviously, larger tanks 'last' longer than smaller ones.
To 'supply' this oxygen to our patient, at a pressure and flow-rate that is tolerable, it must first be 'regulated' down from tank pressure to service pressure and volume. This is accomplished by attaching a yoke/regulator to the smaller (portable) tanks, and a yoke (with a remote regulator) to the larger tanks. It is the yoke that has the "Pin-Index-Safety-System" (PISS) that will prevent an oxygen yoke from being attached to a carbon dioxide tank, or anything other than an oxygen tank.
With a full tank (held securely or securely 'installed' in place) verify first that it is indeed an oxygen tank (green color, proper pin indexing, the word "OXYGEN" if it appears on the tank, and/or the DOT ID Number for oxygen if you are familiar with those numbers.) Then VERY carefully 'crack' open the tank valve and immediately close it. This will serve to blow out the supply port on the valve stem, expelling any foreign material (dust, lint, etc.) that you would otherwise not want 'blown' into the yoke and subsequently into the regulator. Place the yoke over the valve stem, align the pins, and ascertain that the yoke port aligns properly with the valve stem supply port. There should be a hard plastic washer in place between the port on the valve stem and the port of the yoke. Hand tighten the set screw on the yoke to attach the yoke to the valve stem. DO NOT OVER-TIGHTEN, hand-tight and 'snug' is good enough. During this part of the process it is imperative that you DO NOT contaminate the valve stem or the yoke with any foreign substances (especially oily substances, like the oil normally found on your hands) and for that reason it is suggested that you perform all of the foregoing while wearing examination gloves. Never handle any oxygen tank (or any compressed gas tank) by its valve stem. Not only is contamination a concern, but the valve stem is not strong enough to support the tank, and if it breaks off and the tank is pressurized, the resulting "missile" will "launch" itself (fueled by the escaping gas) in a direction, at a rate, and with a sound level, that you NEVER want to experience. Once the yoke is securely in place, CAREFULLY crack open the tank valve just until you hear the flow of gas into the regulator. Allow the 'system' to achieve equilibrium, and when the sound of flowing gas has ceased, continue opening the valve to it full-open limit, THEN close the valve about 1/4 of a turn. This keeps the valve free, and prevents it from becoming 'locked' in the open position. Besides, if you 'find' an already assembled tank/yoke assembly and you are uncertain if it is opened or closed, an attempt to 'open' this tank will result in a valve that only 'opens' 1/4 turn, a clear indication that the valve was already opened.
A word of caution here. When initially 'cracking' the tank (after the attachment of a proper yoke) do so very carefully. Following is an explanation that details "WHY?" Is very involved, but very important.....so if you're thirsty or hungry, or there's anything else that's going to interrupt your reading and understanding the ENTIRE explanation...take care of it now, so that you can concentrate on what is going to be explained..... ......we'll wait. ................. READY?...... .........GOOD!........ .......HERE WE GO.
When pressure is released in an area, the surrounding area is cooled. This is the principle that a refrigerator uses to 'produce' cold. Freon (in liquid form) is allowed to expand in the refrigerated compartment (into a gaseous form) and a 'cold compartment' is the result. At the other end of the 'cycle' is a compressor (which compresses) the evaporated gas back into a fluid (a condition requiring greater pressure) and heat is produced. It follows then, that when pressure is increased in an area, the surrounding area is heated.
The graphic above shows the top view of a "yoke/regulator/flow-meter" assembly attached to the valve stem of an oxygen tank. Assuming that the tank is pressurized to full pressure and that the area shown in red is at atmospheric pressure (considerably less than tank pressure,) and that the flow-meter section is closed, let's determine what will happen as we open the tank valve.
Pressure in the tank is going to fall. In fact, if the yoke assembly were not in place, and the tank were allowed to 'free flow' in an open position for a period of time, the tank would begin to feel cold. The degree of 'coldness' would be dictated by the rate of the flow, and the time that the flow was permitted to continue. "Wide Open" the tank would actually develop frost in a very short period of time. The same is true if pressure is increased, quickly in a confined area, significant heat is produced.
Let's concentrate for a moment on the area shown in red. It's at atmospheric pressure, prior to opening the tank. If we increase the pressure in this area, quickly enough we will actually produce a significant amount of HEAT. So how does that concern YOU?
Well...there are three 'elements' necessary to support fire. Oxygen, fuel, and temperature.
We're dealing with an oxygen tank here. No question one of the three elements of FIRE is readily available. If we just "crank the tank" to the open position (with the yoke assembly in place) there is a very real possibility that we will produce a significant amount of heat in that area (shown in red.) Now...the second of the three elements of FIRE is available. So where's the third? Remember our suggestion above that you handle the equipment with 'gloved hands?' Well, the third of the three elements of FIRE is available from YOUR skin if you decide to handle the equipment with unprotected skin.
Let's return to the world of 'reality' for just a moment. You're between calls, having just completed a 'run.' The "D" tank was exhausted by the previous patient and there's a call 'waiting' for you. You don't have a lot of time, but it imperative that you change the "D" tank. Are you really going to take the time to find a pair of gloves before you change the tank? You're in a hurry. Oh heck, just change the damn thing. You're in a hurry. Get it assembled, open it up, and get it back into the carrier. So you just grab the new tank (probably by the valve stem [it is a very convenient "handle"],) disassemble the 'old' one, reassemble the yoke onto the 'new' one, and "crank the tank" to the open position.
Let us assure you, that this is an event that we would like to see, but only if we were looking at this 'scene' through very powerful binoculars, from a VERY appropriate distance.
By "learning" to open an oxygen tank SLOWLY, you minimize the likelihood that HEAT is going to be produced when the tank is opened. By "learning" to handle oxygen delivery equipment with gloved hands, you minimize the likelihood that FUEL is going to be available in this oxygen-rich environment. IF after "learning" you have to forgo avoiding the availability of one or the other of the two elements (that you CAN control,) you'll have a better understanding of the possible results of your actions. In order to prevent FIRE you only NEED to remove one of the three elements. If you've been trained properly, you will (on a regular basis) avoid two of them. As Instructors, we are NOT in the business of turning out potential "crispy critters."
Now that we have a properly assembled tank and regulator. we need to deliver an appropriate amount of oxygen to our patient.
Just how much oxygen is enough. Can you administer too much?
Well the answer is, unfortunately, not real clear. If you are in doubt about just how much oxygen your patient really needs, give them as much as you possibly can. Generally, patients experiencing mild respiratory distress will respond to the amount of oxygen administer through a nasal cannula. Any patient that is using accessory muscles to breathe, any patient in obvious (or impending) respiratory failure, or any patient in respiratory arrest should receive an oxygen flow rate that provides 90 - 100% oxygen concentration.
The following description of each of the delivery devices will help explain how to achieve the desired amount of oxygen for your patient.
Before we begin the 'description' of the devices there are some things that you should know about air. The air in the room you're in right now, has about 21% oxygen by volume. If you mix (into that air) medical grade oxygen at a rate of about 1 liter of oxygen per minute (additional volume) and that 'volume' of air is immediately inhaled, you increase the concentration of oxygen (delivered to the patient) by about 4%. As a matter of fact, oxygen (mixed with room air) increases the available amount of oxygen by about 4% per liter of oxygen per minute, assuming that the 'mixing' occurs just prior to inhalation. (The volume of air in the room greatly exceeds the volume of oxygen in the tank, and the two volumes left to mix [in the air] would dramatically reduce the volumetric concentration of oxygen.) From this it follows that if 1 liter per minute of oxygen increases the inhaled oxygen percentage to 24% (about 21% plus about 4%,) then 2 liters per minute would increase the percentage of delivered oxygen to about 29% (21 + 8,) 3 liters per minute 33% (21 +12,) and so on.
A nasal cannula is a device that is designed to delivery oxygen at a flow rate from 1 to 6 liters per minute (LPM). Using the scale above, you can see, that this device is designed to provide an oxygen concentration between 24% and 44% oxygen. Medical oxygen, delivered in the field, is rarely humidified, and the drying effect, at rates above 6 liters per minute, of the 'dry' bottled oxygen inhaled through the nose (via a nasal cannula) is not only irritating, but may dry sinus cavities and nasal passageways to the point where cracking can occur, and some bleeding (over the long-haul) may result. Therefore, it is suggested that you limit the flow of oxygen through a nasal cannula to 6 LPM or less.
An oxygen mask is designed to supply oxygen concentrations up to about 90% at flow rates from 10 -15 LPM. At rates under 10 LPM, the mask (especially if it is a 're-breather' mask) may not supply enough volume of oxygen to sufficiently supply the patient's need. Consequently, oxygen masks are usually not used for flow rates under 10 LPM.
A bag-valve-mask (BVM) is a device for "positive pressure ventilation" of the patient. When connected to an oxygen supply, the BVM can supply an oxygen concentration of up to 100%. The normal flow rate for this device is 15 LPM (or 'wide opened' and/or 'flush.')
Also available to field personnel, is the "oxygen-powered, flow-restricted, positive-pressure" ventilation device. It's that neat little mask (with a 'button' on the back of it) that's connected to the regulator on the "D" tank (and may also be attached to the wall of the ambulance, over the 'service counter,' near the head of the stretcher.) The 'button' on the back of the mask is depressed and a controlled flow of positive pressure is delivered to the mask (and ultimately to the patient's onto whom the mask has been placed.) When used correctly, it's a very effective positive pressure ventilation tool. However, our experience has been that most providers do not know how to used this device 'correctly,' and consequently it causes as many problems as it corrects.
The proper use of "positive pressure ventilation" devices is best learned through demonstration and repeated practice. Again, this is not the proper forum to attempt to teach such a skill. Look to your Instructors for guidance.
Other ventilation tools include the CPR mask (with an oxygen supply port) and venturi masks. CPR masks are devices with which you should already be familiar. A venturi mask is a device (not customarily used in the pre-hospital scene) that delivers a very precise percentage of oxygen to a patient whose blood gases are being monitored and adjusted through the delivery of closely screened percentages of oxygen.
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