Tag Archive | "oxygenation in children"

Treat Anaphylactic Incidents Before it’s Too Late

Tags: , , , , , , , , , ,


A bee sting is an example of an allergen that can trigger an anaphylactic reaction.
Photo Kathy Keatley Garvey

Learning Objectives:
>> Identify the different types of anaphylaxis.
>> Learn the pathophysiology and the leading causes of anaphylactic reactions.
>> List methods of treatment for anaphylactic incidents.

Key Terms
Allergen: An environmental substance that can produce a hypersensitive allergic reaction in the body but may not be intrinsically harmful.

Anaphylactic reaction: An acute allergic responses triggered by IgE-mediated antigen-stimulated mast cell activation resulting in histamine release.

Anaphylactic shock: A severe and sometimes fatal systemic allergic reaction to a sensitizing substance, such as a drug, vaccine, specific food, serum, insect venom or chemical.

Anaphylaxis: An exaggerated, life-threatening hypersensitivity reaction to a previously encountered antigen.

Basophil: A granulocytic white blood cell that represent 1% or less of the total white blood cell count. The relative number of basophils increases in severe allergic reactions.

Bronchodilation: A widening of the lumen of the bronchi, allowing increased airflow to and from the lungs.

Mast cells: A constituent of connective tissue containing large basophilic granules that contain heparin, serotonin, bradykinin and histamine.

Paramedics responding to a school cafeteria for a respiratory distress call encounter a 7-year-old male patient with a known allergy to peanuts, who lapsed into acute respiratory distress after he had nibbled on a snack bar that contained peanuts.

His chief complaint to the school nurse was tightening in the throat, which quickly progressed to a chief complaint of shortness of breath. He was only able to speak three or four word phrases, and his respiratory rate climbed to 44 by the time the EMS crew arrived on scene.

The young patient soon became unresponsive, apneic and grossly cyanotic. Paramedics introduced bag-valve-mask (BVM) rescue breathing. Because the patient’s allergy history was known, he was also quickly administered epinephrine via the intramuscular (IM) route while peripheral IV access was obtained. Because of his shock state, it was difficult to gain peripheral vein access, so an EZ-IO needle was placed via the intraosseous (IO) route in his left proximal tibia. Diphenhydramine was then given via IO, and BVM assistance was continued.

His initial oxygen saturation measured 33%. After approximately one minute of BVM oxygenation, oxygen saturation improved to 80%. Nebulized albuterol and ipratroprium bromide were then introduced to the BVM circuit and delivered to the patient. Paramedics consulted with a base hospital physician, and an order for epinephrine via IO was given. Shortly after the IO epi was administered, the patient’s oxygen saturation increased to 92%, and transport was initiated.

Anaphylaxis refers to a rapidly developing allergic reaction that can affect a number of the body’s systems at once. Severe anaphylactic reactions can be fatal and happen within minutes. Anaphylactic reactions can happen so suddenly and become severe so rapidly that there have been examples of hospital inpatient deaths.

Many patients can suffer minor allergy symptoms; however, some can react in a more rapid and accelerated manner that can result in severe shock and, often, death. Substances injected into, or ingested by, an individual gain access into the bloodstream and can trigger anaphylaxis. A reaction involving the skin, lungs, nose, throat and gastrointestinal tract can then result.

Severe cases of anaphylaxis can occur within seconds or minutes of exposure and be fatal if untreated or not treated fast enough. Most anaphylactic reactions are less severe and can be ended with prompt medical attention or EMS and ALS interventions.

Pathophysiology
Approximately 1,500 deaths are reported annually from anaphylaxis. Causes for anaphylaxis can be divided into four major subtypes: food, drugs, latex reaction and insect stings. Largely depending on the substance, the chance of anaphylaxis after exposure to a substance has been from less than 1% to up to 10%.

The physiology of anaphylaxis and its leading causes can be divided into two major groups. The first group is commonly related to the production of Immunoglobulin E (IgE). The body produces IgE when it’s exposed to an allergen. The production of IgE causes the body to become sensitized to the allergen. Further exposures to the allergen by a sensitized individual may result in anaphylaxis. The severity of the anaphylactic reaction is difficult to predict. This group is referred to as IgE-mediated anaphylaxis.

IgE-mediated anaphylaxis results when basophils and mast cells in tissue and blood become coated with IgE. Basophils and mast cells release substances, known as mediators (largely histamines), which can cause allergic reactions. Subsequent reexposure to allergens can cause an explosive release of these mediators and IgE, resulting in an anaphylactic reaction.

Common IgE-mediated causes include medications, such as penicillin, cephlosporins and anesthetics. Insect stings, including fire ants, wasps, honey bees and hornets, are common causes. Other common causes are foods, such as peanuts, shellfish, eggs, milk and wheat. Vaccines, hormones, latex and animal proteins round out other common causes of IgE-mediated anaphylaxis.

The second group, called non-IgE-mediated anaphylaxis, or anaphylactoid reactions, are similar to IgE-mediated reactions, except they don’t require an IgE-immune reaction.

These types of reactions are thought to result in the commonly unexpected anaphylactic reactions that require 9-1-1 services because of the sudden development of anaphylactic shock. In these cases, no previous sensitivity is required, and the signs and symptoms are no different from IgE-mediated anaphylaxis. It’s difficult to distinguish the difference between the two groups. They are usually most easily differentiated by the attainment of the patient’s history. However, treatment is no different for either group. Common non-IgE-mediated causes of anaphylaxis include non-steroidal anti-inflammatories, narcotics, muscle relaxants and gamma gobulin, X-ray dyes, preservatives, sulfites, and physical exercise.

These reactions occur during intense, prolonged and strenuous exercise and often after eating prior to exertion. In some cases, the cause can be idiopathic. Up to 25% of non-IgE mediated anaphylactic reactions can be idiopathic. Often, IgE-mediated anaphylaxis can be confused with non-IgE-mediated anaphylaxis because the victim most likely was unwittingly sensitized to previous exposures, (i.e., they had previously been bitten or stung by an insect or eaten food with hidden allergens).

Because anaphylaxis affects almost all human systems, reactions of this type are almost always categorized as severe. The severity of the reaction will vary from person to person. The more rapidly the signs and symptoms of anaphylaxis develop, the more likely a severe reaction will result. Subsequent reactions to the same trigger often result in similar reactions; however, this doesn’t necessarily incline the person to a non-IgE-mediated reaction.

Signs & Symptoms
An underlying history of asthma or any type of allergic disease, such as eczema, rhinitis or multiple environmental allergies, doesn’t increase the risk of IgE-medicated anaphylaxis, but it does increase the risk of non-IgE-mediated anaphylaxis and can be more difficult to treat. The risks of anaphylaxis may decrease over time, but a person who’s known to be at risk should always be prepared for the worst. Many patients usually have refillable prescriptions from their doctors for such products as EpiPen Auto-Injectors and usually have oral diphenhydramine nearby.

The symptoms of anaphylaxis can occur within seconds of exposure or can take an hour or more. The earliest symptoms are often related to changes in the skin, including hives and itching—especially in the groin and armpits. Flushing of the skin, often with a patchy appearance, coupled with a complaint of warmth is common. These symptoms are often accompanied by a feeling of impending doom, rapid and often irregular pulses, and increased anxiety. Continued symptoms include swelling of the throat and tongue, resulting in hoarseness, as well as difficulty breathing and swallowing. Sneezing, wheezing and runny nose all increase difficulty breathing. Vomiting, diarrhea and abdominal cramping may also develop.

In more severe cases—about 25% of all anaphylactic reactions—the mediators flood the bloodstream and cause gross capillary vasodilatation and a subsequent drop in blood pressure, lightheadedness and loss of consciousness, resulting in anaphylactic shock. The speed and severity of the reaction indicate the treatment needed to mitigate the anaphylaxis. The effects of the treatment often lead to the three following outcomes:

>> Signs and symptoms are sometimes mild enough and recognized early enough, and they often fade when self-treated;
>> Signs and symptoms don’t subsequently recur from this type of exposure; and
>> Treatment is rendered, and improvement of the signs and symptoms is seen; however, symptoms may recur in four to 12 hours. This late phase reaction requires further treatment and close observation, and it can occur in about 10% of the cases. About 20% of anaphylactic reactions are severe enough and persistent enough to require intense EMS treatment and hospitalization. Let’s take a look at a few more cases.

Case Presentation No. 2
While visiting a remotely located zoological garden, a 23-year-old man was stung by an insect, presumed to be some type of bee or wasp. Although the insect wasn’t seen, the man found the stinger and removed it quickly after being stung. The man rapidly developed hives, experienced difficulty breathing and complained of his throat feeling tight and swollen. Nearby zookeepers summoned onsite first-aid personnel, who administered oxygen and called 9-1-1.

On arrival, paramedics find the patient supine on a park bench being cared for by park first-aid personnel. They tell the crew that the patient has had no previous history of allergic reactions, and no knowledge of having been stung by a bee before. The patient is observed by the crew to be flushed (red faced) and lethargic. Audible and auscultated wheezing is heard.

The patient’s initial blood pressure taken by the first-aid crew was 100/60. Paramedics recheck the blood pressure and find it to now be 80/40. His pulses are thready with a rate of 130 bpm corresponding with an ECG rhythm of sinus tachycardia, and his oxygen saturation is measured at 70%.

The paramedic crew quickly administers 0.3 mg of epinephrine 1:1,000 IM while they prepare for IV access. The patient becomes unresponsive, and his blood pressure is no longer obtainable. The ECG rhythm remains sinus tachycardia at a rate of 150 bpm. No pulses can be now felt. IO vascular access is quickly obtained, and the paramedic’s base hospital physician quickly orders epinephrine 1:10,000 (0.1 mg) via IO. Chest compressions and BVM ventilations are initiated.

The patient is placed on a spine board, and advanced airway equipment is readied. After two minutes of chest compressions and ventilations, pulses can now be felt at the carotid artery. An ECG shows a sinus tachycardia with a heart rate of 130 bpm and blood pressure of 100/64. The patient remains unresponsive; however, respiratory effort is spontaneous and wheezing is clearing, with oxygen saturation at 88%. While the crew prepares for transport, the patient regains consciousness but remains disoriented.

Treatment
Treatment for anaphylactic reactions includes oxygenation, airway support, and medications, such as nebulized albuterol or ipratroprium. Additional medications, including epinephrine, diphenhydramine, dopamine and dosed fluid boluses, may also be required. CPR is often necessary. Maintenance of a patient’s oxygenation levels and airway support are of primary concern. Maintaining oxygen levels is often the key to successful resuscitation efforts, although it may present one of the largest challenges.

All patients suffering from anaphylaxis should be placed on supplemental oxygen as soon as possible, and maintenance of oxygen saturation should be monitored. Development of severe wheezing, increased bronchial secretions, and swollen or inflamed respiratory anatomy, increases the need for supplemental oxygenation. Management of the airway with advanced airway devices may initially present a challenge. Basic management may be required until the actions of delivered medications have a chance to reduce the airway obstacles.

The focus of the resuscitative efforts for anaphylactic reactions should be largely directed at mitigating the anaphylactic process. It’s important to provide inline nebulized medications, including albuterol and ipratroprium, via a device that will ensure proper delivery, such as handheld oxygen-powered nebulizer devices, nebulizer mask configurations or devices placed within the BVM circuit.

Careful consideration should be given to the use of fluid boluses or aggressive fluid infusions to treat the hypotensive effects of anaphylaxis. The presence of clear lungs may be an indication to use fluid to help increase volume and preload to aid in the resuscitation of hypotension and also dilute the histamine boluses within the bloodstream. Normal saline solution is ordinarily preferred; however, it’s important to be wary of fluid shifts because they may have medical implications. Selecting an alternative fluid may be more helpful. Epinephrine, a sympathomimetic with both alpha and beta effects, has actions that include bronchodilation (beta-2) and vasoconstriction (alpha). Actions on the heart include increased heart rate (beta-1, chronotropic), contractility (inotropic), atrial-ventricular conduction and automaticity (dromotropic).

Onset of actions usually occurs when administered via IV or when IM is one to two minutes with duration of action of five to 10 minutes. IM route action occurs in about five to 10 minutes, with a duration of action of one to four hours. Dosages for IM routes are usually 0.3 mg of a 1:1,000 concentration and 0.1mg of 1:10,000 concentration for IV or IM routes. These dosages are common for anaphylactic reactions.

Many people with a known history of allergic or anaphylactic reactions carry an EpiPen Auto-Injector. Most EpiPens deliver a 0.3 mg dosage of epinephrine via the IM route when the device is pressed against the injection site. Devices often carried by children deliver an IM dosage of 0.15 mg of epinephrine. First responders should consider the dosage administered and an estimation of the time when it was injected when assessing patients with anaphylactic reactions.

Another primary prehospital medication that’s helpful with resuscitation of anaphylactic reactions is diphenhydramine hydrachloride. A common brand name, Benadryl, is a potent antihistamine. The action of diphenhydramine results when it binds to histamine receptor sites, blocking the effects of histamines.

Notable onset of action is 15–30 minutes and can last from six to 12 hours. Preferable routes during an anaphylactic emergency include IM, IV and IO. It should be noted that the subcutaneous route has been abandoned in the prehospital setting for the delivery of injectable medications for anaphylactic reactions where capillary stability in the dermis during an anaphylactic reaction is often compromised and uptake of medications is delayed. Corticosteroidal and steroidal medications are also used in the prehospital setting; however, these medications aren’t considered resuscitative. Onset of action for these medications is considered outside the resuscitative window; however, it’s believed to reduce the chances of recurrence or late phase reactions.

Use of these medications for anaphylactic reactions is typically considered during a post resuscitative, planned therapeutic regimen to aid in recovery and prevention of anaphylactic reactions. Corticosteroid, often referred to as the “sooner the better” therapy deployed in the prehospital setting, has seen positive outcomes for patients who have suffered an anaphylactic reaction. However, it’s not clearly known whether the administration of the drug in the prehospital setting is more beneficial than delivery of the drug after emergency department (ED) admission.

Albuterol (Proventil and Ventolin) is a potent sympathomimetic bronchodilator (beta-2 specific). Albuterol works by relaxing bronchial smooth muscles by stimulating beta-2 adrenergic receptors, producing bronchodilation, relieving bronchospasm and decreasing airway resistance. Onset of action occurs in about five minutes, peaks in about an hour and lasts up to five hours. Initial dosage (usually in combination with ipratroprium) is 6 mL (0.083%) via nebulizer.

Ipratroprium bromide (Atrovent) is an anticholinergic bronchodilator. It works as an antagonist on the actions of acetylcholine. It prevents the interaction of acetylcholine with muscarinic receptors in bronchial smooth muscle, causing bronchodilation. The effects also cause drying of respiratory tract secretions with an onset of action within 15–30 minutes, peaking in one to two hours and lasting about four to five hours. Adult dosage (usually in combination with albuterol) is 2.5 mL (0.02%) via nebulizer. Dopamine hydrocholoride (Intropin) is a sympathomimetic vasopressor with both alpha and beta properties. In low and medium dosages, it selectively dilates blood vessels supplying the brain, kidneys, heart and gastrointestinal tract. At medium to high doses, it can increase cardiac output by improving contractility and stroke volume, with a resulting increase in blood pressure.

At high dosages it causes vasoconstriction and an increase in heart rate. Onset of action occurs in less than five minutes and duration is approximately 10 minutes after drug administration has stopped. First responders should quickly assess patients suffering from anaphylactic reactions and institute appropriate interventions as the needs are identified. Information about the history of the situation is extremely helpful in these situations, so seek out anyone who witnessed the event or who was able to discuss the problem with the patient before the patient became incapacitated.

Often, as in the first case presentation, the patient has a known allergy and felt the risk of exposure was less than they actually experienced. In this case, the wrapper from the snack food was retained, and first responders were able to quickly identify the allergen. Treatment focused on the mitigation of the anaphylactic reaction with emergency interventions for the symptoms that required them.

Timing is important, especially when there are delays from the time of exposure to the time 9-1-1 is summoned and first responders encounter the patient with anaphylaxis. Many people, not knowing they have been exposed or being exposed with no previous history of problems, dismiss the initial signs and symptoms. Unfortunately, the signs and symptoms progress so rapidly that help may be out of reach for a period of time, which could be detrimental to their chances of survival.

Case Presentation No. 3
A 53-year-old female with previous exposures to bee stings with no reactions was meeting friends for a horseback ride. She stopped to clear a small tree that had fallen across her path. As she moved toward the obstruction, she was stung by a wasp near her left temple. She quickly brushed the wasp away and cleared the tree from the trail.

While she was returning to her horse, she remarked to her friends that she felt dizzy. She dismissed the feeling, took three more steps toward her horse and collapsed. Her friends realized she lapsed into an unconscious state and was not breathing well, so they placed her in a supine position in the bed of a pickup truck and called 9-1-1 to request an EMS unit meet them at the nearest rendezvous location. The responding EMS crew was BLS and there were no nearby first responder services. Because of the remote location, 20 minutes elapsed from the time of the exposure to the arrival of the BLS ambulance.

On arrival, the EMS crew finds the female without a pulse and not breathing. CPR is initiated and an immediate transport to the nearest hospital, approximately 30 minutes away, is initiated. An ALS ambulance is dispatched to intercept the BLS ambulance near the halfway point to the destination hospital. Cardiac arrest algorithms are followed for asystole by the ALS crew during transport. The patient was delivered to the hospital approximately 50 minutes after the sting, where a return of spontaneous circulation was achieved.

The patient in this case had an expired prescription for an EpiPen Auto-Injector. The patient’s friends had no knowledge of the patient’s previous exposures or risk factors. The situation was further compounded by the lack of available ALS services and the remote location. People with known exposures or allergies are usually counseled for preparedness, uses of medications and availability of special kits to carry with them. They’re also usually counseled about best practices to avoid exposures, including sharing information with others to help decrease the risks
of exposures.

Patient No. 1 was admitted to the hospital for observation and completely recovered. He was discharged home 24 hours later with his parents and with appropriate education and direction including carrying use of an Epi Pen. Patient No. 2 was admitted to the hospital for observation and recovery of anoxic brain syndrome. He was released after three days of care without any significant or noticeable effects and direction to have an Epi Pen available at all times. Patient No. 3 was admitted to the Medical Intensive Care Unit and subsequently succumbed after absence of brain function was discovered and life support terminated by her family. The family has since made Epi Pen products available in and around their ranch and vehicles.

Conclusion
EMS should educate the public that it’s always better to contact them when an exposure is identified rather than allow the signs and symptoms to progress untreated. Everyone should take precautions should the unexpected anaphylactic reaction occur.

Rick Rod, RN, CEN, NREMT-P, is currently the Paramedic Field Training Coordinator and Clinical Educator for City of San Diego EMS – Rural/Metro of San Diego and San Diego Fire-Rescue Department

References
1. Tintinalli J, ed. Tintinalli’s Emergency Medicine: A comprehensive study guide 4th edition. McGraw-Hill: New York, (209–211), 2011.
2. Neumar R, Otto C, Link M, et al. Part 8: Adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010;11(122):S729–S767.
3. San Diego County Paramedic Association: Protocol and Medication Guide. 2011–2012 ed. SDCPA: La Mesa, Calif.

Post to Twitter

The Young Airway

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , ,


Case presentation
A 12-year-old male is accidentally shot in the face by a friend with a 410 shotgun at a distance of about 5 yards. His friend assists him in walking about a half mile out of the woods and summons 9-1-1. The location is rural, with a 20-minute response time and a 30-minute travel time to a hospital. Air transport is not possible due to fog and rain.

When you arrive on scene, the patient is alert, talking and anxious. He’s experiencing increasing difficulty swallowing. His initial vital signs include a pulse of 120, a blood pressure of 160/90, a respiratory rate of 24, and an oxygen saturation of 97% on room air. There’s no stridor, and his voice is normal. A non-rebreather mask is applied, and his oxygen saturation increases to 100%.

His face is peppered with buckshot entry wounds on the left side, and there’s a moderate degree of edema. The eyes are spared. There’s no neurological deficit. He can open his mouth, and there’s no swelling apparent inside the mouth or deviation of any anatomical structures.

Your neck exam reveals full and painless range of C-spine motion. There’s mild to moderate swelling of the left side of the neck. Examination of the chest reveals no obvious subcutaneous air, and the remainder of the physical examination is normal.

You start an 18-gauge IV with lactated Ringers in an antecubal area, and your crew packages the patient for transport to the hospital.

But what about his airway, which is likely to become obstructed? Should it be managed in the field? If his vitals deteriorate, how will you proceed?

Assessment of the pediatric respiratory system
Experience often lends providers a “sixth sense” about adult patient assessment. However, because pediatric care makes up just 10-20% of our prehospital patient population, many otherwise competent and experienced EMTs and paramedics often fear the assessment and care of critically ill or injured pediatric patients. (1) For this reason, we should rely on well-established and easily reproduced assessment tools for our pediatric cases.

The Pediatric Assessment Triangle (PAT) is a widely published and recognized tool to facilitate assessment of pediatric patients. The PAT relies on three key components — appearance, work of breathing and circulation — to quickly assess and triage patients into treatment categories of “sick” and “not sick.” (2)

Appearance:How does the patient look? Is there acknowledgement of your presence? This first assessment is the most important aspect of the PAT.

A general impression of appearance quickly reflects adequacy of ventilation, oxygenation, brain perfusion and central nervous system (CNS) function. (1) This initial assessment enables you to quickly prioritize your airway-management plan.

Loud, boisterous crying is the best sound any prehospital provider can ever hear going into an unknown pediatric emergency. Conversely, a flaccid, unresponsive child with a fixed gaze should be considered seriously ill, requiring immediate action to ensure adequate ventilation and oxygenation.

TICLS — which stands for tone, interactiveness, consolability, look/gaze, and speech/cry — is a useful mnemonic for assessing the pediatric patient for oxygenation failure and CNS dysfunction. This tool expands the first leg of the PAT and reminds you to examine all aspects of the patient’s appearance.

Utilizing the PAT appearance and TICLS assessment tools allows you to better detect subtle abnormalities than the more conventional AVPU (alert, voice, pain, unresponsive) scale.(1)

Work of breathing: Unlike the adult patient, a child’s work of breathing is often a better assessment of oxygenation and ventilation status than breath sounds and respiratory rate. Work of breathing reflects the patient’s attempt to overcome abnormalities in respiratory function and the patient’s ability to exchange gas.(2)

This doesn’t mean breath sounds should not be auscultated in the pediatric patient; however, an evaluation of the work of breathing in pediatric patients will alert providers of imminent respiratory arrest before auscultation will.

During this leg of your assessment, the first step can often be accomplished without using a stethoscope. Abnormal, audible airway sounds can quickly alert providers to upper airway status. Snoring, difficulty swallowing secretions and a muffled voice (aka, “hot-potato” voice, as though the patient is rolling hot potato with their tongue) or hoarse voice are subtle indicators of upper airway obstruction.

Stridor (a high-pitched, audible sound on inspiration) is a particularly sinister finding in pediatric patients with acute airway disorders and heralds total obstruction that’s often insurmountable by bag-mask ventilation. Croup, bacterial infections, foreign bodies, edema or bleeding can all result in upper-airway obstructions, which are clearly audible on work of breathing assessment.(2)

Grunting, like the pursed-lip expiration in adults with chronic obstructive pulmonary disease, provides a degree of positive pressure to be maintained throughout the expiratory phase and may be thought of as “auto-PEEP” (positive end-expiratory pressure). This maneuver enables you to stent open small airways and alveoli facilitating gas exchange.(2)

Pediatric patients who have an acute respiratory disorder and exhibit grunting are usually already moderately or severely hypoxic, reflecting poor gas exchange. Conditions most often associated with grunting in children include pneumonia and pulmonary edema.(1) Additional signs of increased work of breathing include displaying the sniffing position while breathing; the tripod position; retraction of the sternal notch, supraclavicular areas and intercostals spaces (a sign seen more in children than adults due to the pliability of their tissues); head bobbing; and nasal flaring.

The sniffing position is when the patient spontaneously flexes their neck slightly forward and extends their head up and back in order to open a partially obstructed upper airway. The tripod position is when the patient has an erect torso and their arms planted firmly on a horizontal surface to maximize the mechanical advantage of the accessory muscles of respiration in the neck and chest. Head bobbing is typically in response to the child’s use of accessory muscles and the attempt to produce maximal negative intrathoracic pressure for inspiration.

The Silverman-Anderson Index is an assessment scoring system that evaluates five parameters of work of breathing and assigns a numerical score for each parameter (see Table 1, below). Each category is scored as “0” for normal, “1” for moderate impairment or “2” for severe impairment. Parameters assessed are retractions of the upper chest, lower chest and xiphoid; nasal flaring; and expiratory grunt.(3) Normally functioning children should have a cumulative score of 0, whereas critically ill and severely depressed children will have scores closer to 10.

The last physical assessment tool used to evaluate work of breathing should be auscultation of the lower airways with a stethoscope. Because a child’s chest is so small, stethoscope placement differs slightly from auscultation of an adult’s chest. The transmission of sounds from areas distant from the stethoscope can be a problem when assessing breath sounds in small children. For this reason, place the stethoscope bell near the armpit to maximize transmitted breath sounds.(4)

Wheezing, the movement of air through partially blocked smaller airways, is the most common lower airway sound heard in children with respiratory compromise. Initially, wheezing is heard only on exhalation and upon auscultation with a stethoscope. But as the degree of obstruction increases, it may be heard in both inspiration and expiration, and may even be audible to the naked ear.

Once a patient becomes extremely fatigued, airflow velocity begins to fatigue and wheezing may attenuate and disappear, a pre-arrest finding. Therefore, it’s necessary to treat wheezing aggressively in the early stages before the increased work of breathing leads to fatigue and respiratory arrest.(1)

Circulation:
The goal is to determine the adequacy of cardiac output.(1) Key findings in the distressed child are related to signs of poor oxygenation, such as peripheral or central cyanosis. Bluish tinting to the skin and/or mucous membranes reflects significant hypoxemia. Corrective action regarding airway management and optimal oxygenation must be made a priority.

Beyond the PAT
EMS providers must also consider respiratory effort and rate when assessing the pediatric airway (see Table 2). Tachypnea is often the first manifestation of respiratory distress in children.(4) Irrespective of cause, rapidly breathing children will eventually tire and respiratory arrest will ensue.

Slow respiratory rates in acutely ill children, often associated with a disorder of mentation or decreased level of consciousness, is a particularly ominous sign.(4) Be alarmed if an acutely ill child has a slowing respiratory rate. Do not assume slowing rates equal improvement.

Lastly, diagnostic equipment can be very helpful in assessing the child’s respiratory system (including the upper airway). In children, pulse oximetry readings above 94% saturation are generally considered acceptable. A reading below 90% during administration of 100% oxygen is an indication for immediate intervention with assisted ventilations.

However, crews must be cautious not to discount or disregard symptoms or signs of respiratory distress in a child simply because the pulse oximetry reading is above 94%. This is because children in respiratory distress or failure can maintain acceptable oxygen saturation levels by increasing work of breathing and respiratory rate until the point of respiratory arrest, particularly if supplementary oxygen is being administered. Thus, pulse oximetry should always be used in conjunction with work of breathing assessment.

Anatomical & physiological factors
The fundamental priorities of prehospital pediatric airway management are: optimizing oxygenation, ventilation and airway protection. Decisions regarding airway management must be made rapidly, and the course of action selected should be designed to minimize error.

The anatomical development of the child in general, and the lungs in particular, along with associated changes in the maturing physiology, must be taken into consideration in pediatric airway management. Another factor frequently underemphasized is that, excluding congenital anomalies, children are remarkably consistent from one to another.

In pediatric patients from one to two years of age, the principal difference between the adult and pediatric airway is size.(5) For patients younger than one, the relative proportions of some structures vary from the adult proportions. In fact, most descriptions of the “pediatric” airway in the purest sense focus on this latter age group.

The age group from two to eight years represents a transition to the adult airway and, in fact, more closely resembles the adult airway than the infant’s. Besides size, the most obvious difference between the adult and pediatric airway is its position in the neck. The pediatric airway is described as “anterior,” when in reality it’s more superior, the glottic opening lying higher, at approximately the level of C-2 or C-3, as opposed to C-6 in the adult. This position places the glottic opening at the base of the proportionally larger and predominantly intra-oral tongue. Because the airway may become “hidden” up high behind the tongue on laryngoscopy, this position is often referred to as “anterior.”

All airways are anterior in the sense that they’re palpable externally, but the pediatric airway is also more superior. The relatively larger intra-oral tongue exacerbates this position.

The epiglottis is also proportionally larger in the child than the adult. The ligamentous connection between the base of the tongue and the epiglottis isn’t as strong as it is in the adult, making elevation of the proportionally larger epiglottis by manipulation of the vallecular space with a curved blade more difficult. For this reason, and because the large tongue is more difficult to remove from the field of vision with the curved blade, a straight blade is preferred for the first year or two of life when these changes are most pronounced. A straight blade can be inserted past the epiglottis to lift it up out of the field of vision.

The narrowest portion of the child’s airway is at the level of the cricoid ring, as compared with the adult, in which the narrowest portion is at the level of the vocal cords. The significance of this anatomical variation is that, in the adult patient, endotracheal tube size is less critical, because a low-pressure cuff can be inflated to ensure adequate fit.

In the child, the size is more critical because an uncuffed tube is used and therefore the largest possible tube is inserted to ensure the largest internal diameter possible. A smaller tube reduces ventilatory ability, and a tube that is too large can cause pressure ischemia and necrosis of the tracheal mucosa with resultant subglottic stenosis. At approximately eight years of age, this variation normalizes and cuffed tubes are appropriate.

Two anatomic variations preclude blind naso-tracheal intubation in the child younger than eight to 10 years of age. The first is the presence of adenoidal tissue, which is frequently hypertrophied. This tissue can easily be injured, resulting in copious bleeding. Second, the angle of approach that a nasally introduced endotracheal tube must take to find its way into the glottis is much more acute in a child than an adult, so the success rate of the procedure is unsatisfactory.

The optimal position for alignment of the tracheal, pharyngeal and oral axis for bag-valve mask ventilation (BVM) or intubation is the sniffing position. In the adult, optimal axis alignment is accomplished by flexion of the neck on the chest (usually accomplished by placing a towel or other support beneath the occiput) and hyperextension of the head at the atlanto-occipital joint.

In most children, it’s unnecessary to provide support to flex the neck because of their proportionally large occiput. Slight extension of the head at the atlanto-occipital joint (not hyperextension, which can actually cause obstruction) is all that’s necessary.

To achieve the sniffing position in small infants, it’s sometimes necessary to balance the disproportionate occipital size by placing a support under the shoulders. The older child and adolescent are positioned similar to the adult.

In all ages, once positioned, if an imaginary horizontal line can be drawn traversing the external auditory canal and passing anterior to the shoulders, correct positioning has been obtained (see Figure 1).

Proper BVM technique is particularly important in pediatric patients, whose crisis is often driven by a primary respiratory problem. They are more frequently hypoxemic than their adult counterparts and are subject to more rapid oxyhemoglobin desaturation, so BVM (Sellick’s is maintained during BVM to prevent one from inflating the stomach and enhancing the risk of regurgitation and aspiration) is frequently required during the pre-oxygenation and paralysis phases of rapid sequence intubation (RSI) to achieve and maintain adequate O2 saturation.

As in adults, oral and nasopharyngeal airways are important adjuncts to BVM.

Because of the miniscule size of the cricothyroid membrane in the child, surgical cricothyrotomy is contraindicated. Needle cricothyrotomy is the procedure of choice for small children.

A combination of physiological factors decrease the ability to pre-oxygenate the pediatric patient as efficiently as the adult patient. The first and most important isthat the pediatric patient metabolizes oxygen twice as quickly as the adult (6 mL/kg versus 3 mL/kg).

Because of the lack of elastic lung recoil of the pediatric patient’s chest, the child also possesses a proportionally smaller FRC — the lung volume measured when all forces in the chest are in equilibrium. This latter effect is especially exacerbated in the supine position.

Under similar pre-oxygenating conditions, the child sustains a significantly shorter period of oxygen saturation above 90% than the adult. The clinical implication is that a child may desaturate during the RSI procedure, and the provider must anticipate this and be prepared to initiate BVM ventilation with cricoid pressure.

Pediatric ventilation requires smaller tidal volumes, higher rates and size-specific equipment. The pediatric airway is particularly amenable to positive pressure ventilation, even in the presence of upper airway obstruction.

In pediatric airway management, identification and use of size-appropriate equipment is crucial. For this reason, standardized age and size-appropriate systems, such as the Broselow-Luten Color Coded systems, are recommended.

Advanced airway management
Because inadequate oxygenation and ventilation have been identified as primary contributors to preventable mortality, it would seem intuitive that successful endotracheal intubation (ETI) would mitigate these deaths. Thus, ETI has become the gold standard in prehospital airway management.

However, considerable controversy exists as to whether pediatric patients requiring ETI should have it performed in the field or deferred until hospital arrival. Studies have shown higher rates of complication and failure in children than in adults, and one prospective, pseudo-randomized trial showed no demonstrable advantage in survival outcome following ETI compared with a group managed via BVM.(6-10)

Despite controversy, the indications for ETI of adults and children in an emergency remain: failure to maintain adequate oxygenation, failure to maintain adequate ventilation (CO2 removal), failure to protect the airway, the need for neuromuscular blockade or the anticipated clinical course.(5) So even though there may not be a compelling reason to intubate the trachea at a given point in your care of a patient, prehospital providers must continually evaluate the risk of an insidiously progressive condition advancing to the point when intubation would become more hazardous or physically impossible.

The best example in prehospital care relates to the transport environment, such as in the opening case. GroundEMS providers should consider whether future patient positioning in a helicopter will severely limit access to the head and neck, and thus the airway.

Once the decision to intubate is made, you must decide how to proceed. First responders and basic rescuers are typically limited to basic upper-airway adjuncts and BVM ventilation. Intermediate rescuers may employ supraglottic devices, such as the Laryngeal Mask Airway (LMA), the Combitube and the King LT Airway, to facilitate bag ventilation and provide some element of airway protection. For these personnel, the decision is typically a simple one: Will the victim tolerate insertion of the device?

ALS providers capable of endotracheal intubation who do not use neuromuscular blocking agents have limited options available to them beyond BVM ventilation and direct laryngoscopy intubation.

Once the child is intubated, the endotracheal tube (ETT) must be secured at the mouth, and since head and neck movement translates into ETT movement, a cervical collar or other device should be employed.

In infants, small movements are capable of dislocating the ETT into the esophagus, emphasizing the importance of head and neck immobilization. Securing the ETT at the mouth is traditionally done by taping the tube to the cheek or by using commercial devices.

Drug dosage & selection
A significant problem in the management of pediatric emergencies is the timely and accurate delivery of medications. The use of color-coded resuscitation aids for drug dosing and estimating ETT size in children precludes many of these problems, including having to estimate weight and remember and calculate drug doses.

One particular drug worthy of special mention when used with children is succinylcholine. Because the drug is rapidly distributed into extracellular water, and children have a relatively larger volume of extracellular fluid than adults, the recommended dose of succinylcholine is higher in children.(5)

In 1993, the FDA, in conjunction with pharmaceutical companies, revised the package labeling of succinylcholine after reports arose of hyperkalemic cardiac arrests due to the drug’s administration to patients with previously undiagnosed neuromuscular disease. However, the initial advisory warnings continue to recommend succinylcholine for emergency or full-stomach intubation in children.

Case wrap-up
Because the 12-year-old patient’s respiratory status was kept stable, the patient’s airway did not require further field management.

On arrival at the emergency department (ED), the patient was unable to swallow secretions, had a muffled voice, was complaining of occasional air hunger and refused to lie flat. The attending emergency physician (a family practitioner) was unwilling to intubate the patient without anesthesia or surgery back-up available at the hospital. The weather had cleared, so air evacuation was requested.

When the air medical transport team arrived 20 minutes later, the patient’s condition was unchanged. The flight crew elected to progressively sedate the young patient and proceeded with a sedation-assisted direct-vision intubation prior to transport. He was sedated and paralyzed for the duration of the transport and arrived at the Level 1 trauma center in stable condition. He was weaned and extubated on the sixth hospital day, and the remainder of his recovery was uneventful.

Summary
Respiratory assessment and airway management in the pediatric patient present many challenges, including differences in equipment sizes and drug dosing, anatomical variation that continuously evolves as development proceeds from infancy to adolescence, and the stress of resuscitating a critically ill child.

During the emotional mix of a pediatric resuscitation, it’s easy to get sidetracked by co-existing confounding issues. Therefore, the importance of methodically working your way through airway evaluation and management cannot be overstressed. Assessment is the key to gathering critical evidence of a pediatric patient’s respiratory status or warning of impending respiratory arrest.

Michael F. Murphy, MD, FRCPC (EM), FRCPC (ANES), is certified as a specialist by the Royal College of Physicians and Surgeons of Canada in both emergency medicine and anesthesiology. He’s the professor and chair of anesthesia and professor of emergency medicine at Dalhousie University, and the clinical chief of anesthesia at the Capital District Health Authority in Halifax, Nova Scotia. He’s also a founding faculty member of “The Difficult Airway Course: Emergency” and “The Difficult Airway Course: EMS.” Contact him at murphymf1@gmail.com.

Michael Keller, BS
, NREMT-P, is a curriculum faculty member with Gaston College, Department for EMS Education in Dallas, N.C., a member of Lincoln County (N.C.) EMS and a national faculty member for “The Difficult Airway Course: EMS.”

Robert Luten, MD, is professor of pediatrics and emergency medicine at the University of Florida, Shands Jacksonville, and former president of the Society for Pediatric Emergency Medicine. He’s the author and principal instructor of the pediatric section of the National Emergency Airway Management course.

Colby J. Rowe, EMT-P, FP-C, CIC, is a paramedic supervisor, flight paramedic, and the continuing education and training coordinator at Stony Brook University Medical Center EMS on Long Island, N.Y. He’s also a national faculty member of “The Difficult Airway Course: EMS” and an adjunct faculty in the Emergency and Disaster Management concentration at Stony Brook University.

Mary Beth Skarote, NREMT-P, is an emergency response and recovery coordinator for Wake Forest University Baptist Medical Center, Winston-Salem, N.C.; a paramedic with Davidson County (N.C.) EMS; president for North Carolina Association of Paramedics; and one of the original faculty for “The Difficult Airway Course: EMS.”

References
1.AmericanAcademy of Pediatrics: Pediatric Education for Prehospital Professionals. Jones & Bartlett:Boston, Mass., 2000. pp. 2-35.

2. Caroline N: Emergency Care in the Streets. Jones & Bartlett:Boston,Mass., 2008. p. 41.

3. Institute for Continuing Education. www.ceu.org/cecourses/981117/ch11b.htm

4. Bledsoe B, Porter R, Cherry R: Paramedic Care: Principles & Practice. Pearson Prentice Hall:Upper Saddle River,N.J., 2006. p. 59.

5. Walls RM, Murphy MF, Luten RC (eds): Manual of Emergency Airway Management. Harvard Medical School: Boston, Mass., 2004. pp. 212Ï281.

6. Aijian P, Tsai A, Knopp R, et al: “Endotracheal intubation of pediatric patients by paramedics.” Annals of Emergency Medicine. 18(5):489-494, 1989.

7. Vilke GM, Steen PJ, Smith AM, et al: “Out-of-hospital pediatric intubation by paramedics: The San Diego experience.” Journal of Emergency Medicine. 22(1):71Ï74, 2002.

8. Brownstein D, Shugerman R, Cummings P, et al: “Prehospital endotracheal intubation of children by paramedics.” Annals of Emergency Medicine. 28(1):34Ï39, 1996.

9. Gausche M, Lewis RJ, Stratton SJ, et al: “Effect of out-of-hospital pediatric endotracheal intubation on survival and neurological outcome: A controlled clinical trial.” JAMA. 283(6):783-790, 2000.

Post to Twitter


EMS Airway Clinic is a new site offering best practices in airway management and education for EMS professionals and educators, featuring:
  • • Regular articles by Charlie Eisele, Flight Paramedic, retired First Sergeant with the Maryland State Police Aviation Command, and co-founder of the Advanced Airway Course at EMS Today
  • • Case studies, how-to videos and podcasts
  • • The "Airway Funnies" from popular EMS cartoonist Steve Berry
  • • The latest news, features and educational content on prehospital airway management
  • Learn more about EMS Airway Clinic

    Like Us on Facebook

    Featured Airway Products

    Providing emergency patient care on the ground or in the air is complex and challenging. That's why the tools used by paramedics and EMTs must be adaptable in a constantly changing clinical situation — quickly operational, rugged and easy to use. Learn more about EMS airway management.

    GlideScope Ranger

    The GlideScope Ranger video laryngoscope delivers consistently clear airway views enabling faster intubations in EMS settings. Available in reusable or single-use configurations.

    See more products …

    GlideScope Cobalt AVL

    GlideScope Cobalt AVL

    The GlideScope Cobalt AVL video laryngoscope offers airway views in DVD-clarity, along with real-time recording. On its own or when combined with the GlideScope Direct intubation trainer, the Cobalt AVL is an ideal tool to facilitate instruction of laryngoscopy.

    See more products …

    GlideScope AVL Reusable

    GlideScope Cobalt AVL

    The GlideScope AVL Reusable video laryngoscope offers airway views in DVD-clarity, along with real-time recording. On its own or when combined with the GlideScope Direct intubation trainer, the AVL is an ideal tool to facilitate instruction of laryngoscopy.

    See more products …

    Featuring Recent Posts WordPress Widget development by YD