Download Individual Chief Complaint Protocols

Ritu Sahni
“WHAT’S THE CALL?”
This question is on the minds of most EMS responders as they exit their quarters. Our introduction to the
patient is typically the “chief complaint,” which is
relayed to the responding crew by dispatch. This is
universal in the EMS world, whether it is a 9-1-1 ambulance call, a critical care air ambulance response, or
a search-and-rescue call. This information can bring
two outcomes: The field provider can be well prepared
for the upcoming call, or the field provider can be led
astray. This section focuses on a systematic review of
patient care based on a chief complaint.
Each chapter highlights the evaluation, differentiation, and management of individual chief complaints. A key point, however, is also a discussion
of the pitfalls accompanying each chief complaint.
C
SE C TION
Individual
Chief Complaint
Protocols
Pitfalls can occur when a particular sign or symptom that pointed to a more critical situation is missed
or when the chief complaint is not easily related to
the actual problem. In many cases, the authors outline these pitfalls so that errors of both commission
and omission can be avoided. In addition, this section contains a special chapter authored by Andrew
Travers and Ron Stewart that tackles the problem of
the “undifferentiated patient.” Although the initial
concept revolves around dispatch information that
makes categorization difficult, it leads to a thoughtful
discussion of prehospital decision making.
Although most EMS agencies have protocols that
may be based on presenting complaint (e.g., chest
pain) or presenting condition (e.g., cardiac arrest), the
topics reviewed in these chapters can be the basis for
protocols based on either.
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CH APTER
Allergies/Stings
21
Debra Perina
Leslie F. Smith
INTRODUCTION
Patient concern for potential allergic reactions is a
common complaint resulting in calls for EMS response. Allergic reactions can be triggered by a myriad
of different agents, such as foods, medications, topical
agents, and environmental exposures including arthropod stings. Severity can vary from discomfort to life
threatening if left untreated. This chapter will focus on
allergic reactions from bites or stings. EMS medical
directors must be familiar with recognition of allergic
reactions and anaphylaxis, prehospital response capabilities, and treatments in the prehospital environment.
PHYSIOLOGY OF ALLERGIC
REACTIONS
Allergic reactions can vary from very mild, with only
symptoms of pruritus or rash, to full-blown anaphylaxis along the continuum of disease. Anaphylaxis is
a potentially life-threatening hypersensitivity reaction that carries a significant risk of vascular collapse
and/or respiratory compromise. Allergic reactions are
hypersensitivity reactions resulting from the exposure
to an allergen.1 There are four types of hypersensitivity reactions (Table 21.1). Type I accounts for most
cases of anaphylaxis. Type III is most commonly seen
in reactions to blood transfusions and with immunoglobulin therapy.
Reactions typically present with urticaria that can
progress to angioedema (facial or tongue swelling)
followed by respiratory distress, dizziness, syncope,
and shock. Angioedema is very concerning because it
can progress rapidly to life-threatening airway compromise. Angioedema can be medication induced
or genetic. One of the more common causes is
angiotensin-converting enzyme (ACE) inhibitors.
Often the patient has been taking this medication
for some time before such a reaction occurs, which
can be confusing to some who assume that a reaction
would have occurred sooner if the patient was going
to exhibit one. Hereditary angioedema is an autosomal dominant genetic disorder caused by a defect in
the complement pathway that results in either a low
C1 esterase level or a high level of dysfunctional C1
esterase. Patient symptoms can include pruritus, urticaria, wheezing, facial and tongue swelling, dizziness,
hypotension, syncope, and gastrointestinal distress.2
CAUSATIVE AGENTS
Almost anything can be a potential allergen. Common
agents include medications, foods and food additives,
latex, arthropod bites and stings, mold, radiographic
contrast media, and certain marine envenomations
¹(see Chapter 17, Animal Bites; Table 21.2). Some
insect bites or stings, such as those of millipedes, caterpillars, and centipedes, most often cause only pain
and local skin reactions such as blistering.3,4 Certain
species of caterpillars have venom-filled hair and
spines that can cause systemic reactions, including
anaphylaxis, within 2 hours of the sting.3 Some offenders, such as the Gila monster, can remain attached
to the patient. Bites from kissing bugs are painless
and usually occur during sleep. Most often this results
in localized swelling at the bite site but can progress
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TABLE 21.1
Types of Hypersensitivity Reactions
Type I
Type II
Immediate
Cytotoxic
Type III
Type IV
Immune Complex
Delayed
Mediator
Anaphylaxis Cause
IgE or IgG4
Complement cascade
IgG or IgM
IgG or IgM
T-cell
Most common
Yes
Yes
No
IgE, immunoglobulin E; IgG, immunoglobulin G; IgM, immunoglobulin M.
to systemic reactions.5 There are also occasional rare
reports of anaphylaxis from the bites of horse flies,
deer flies, rats, and mice.
Hymenoptera account for the majority of severe
allergic responses and anaphylaxis episodes related to
insect bites. There are three families of Hymenoptera:
bees (honeybees and bumblebees), vespids (yellow jackets, hornets, and wasps), and stinging ants
(fire ants). Since fire ants are in the Hymenoptera
family, the venom in fire ant bites is identical to that of
bees and hornets so that patients allergic to beestings
will also display an allergic reaction to a fire ant bite.6
Africanized honeybees (“killer bees”) are an aggressive
hybrid of the honeybee and have the same venom, but
they sting repeatedly, thus increasing the risk of a severe reaction.7 About 1% of children and 3% of adults
have reportedly had severe systemic allergic reactions
to Hymenoptera venom.8 Anaphylaxis can occur even
with the first episode. Insect stings are the only allergen for which specific immunotherapy currently exists.
This is most likely due to the prevalence and severity of
such responses in humans.9
ASSESSMENT AND GENERAL
APPROACH
The first step in EMS response to calls regarding allergic reactions and/or bites and stings is ensuring that
the scene is safe. Provider and patient safety should be
paramount because no rescue or treatment can occur if
providers fall victim to the same process that is affecting the patient. Next, EMS providers should determine
how the patient was stung or what activity was occurring before the allergic reaction. This will help the
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provider determine if there is any special treatment
needed and if there is the potential for development
of a severe reaction or anaphylaxis. EMS personnel
should take all proper equipment, including life support, emergency drugs, and monitoring equipment with
them when initially approaching the patient. Failure to
do so may delay necessary treatment and result in further physiologic decompensation of the patient. Patient
assessment should rapidly be done to ensure a patent
airway. The patient should be queried for shortness of
breath or dysphagia, and the provider should note if
the patient’s voice is hoarse. The EMS provider should
listen to breath sounds, assessing for stridor or wheezing. Facial, tongue, or orbital swelling should be noted.
A full set of vital signs should be taken. The patient
should be evacuated from the scene as soon as feasible to prevent further contact with the allergen. If the
patient is in extremis and airway control is necessary,
consideration should be given to requesting additional
responders. Continued patient assessment should center on ensuring a patent airway and continuously monitoring vital signs. All patients with significant allergic
reactions or potential for deterioration during transport
should have at least one large-bore IV line started with
normal saline. The patient should be transported expediently to the closest most appropriate facility depending on availability of local resources and other factors
such as distance, weather, and terrain.
Prehospital Treatment
EMS medical directors should ensure that personnel
provide appropriate prehospital care to patients suffering an allergic reaction or anaphylaxis. If the patient
has been stung or bitten, providers should be wary to
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TABLE 21.2
Common Causes of Allergic Reactions
Medications
Antibiotics
Penicillin, vancomycin, trimethoprimsulfamethoxazole
ACE inhibitors
Aspirin
Nonsteroidal anti-inflammatory drugs
Radiographic iodine based dyes
Human/Animal Proteins
Vaccines
Transfusions
Foods
Peanuts/nuts
Eggs
Wheat
Shellfish, soybeans wheat
Additives
Red dye
Sulfites
Animals
Stings/Insects
Hornets/wasps
Fire ants
Scorpion
Caterpillars
Kissing bugs
Centipedes
Millipede
Arachnids
Ticks
Vertebrates
Lizards
Gila monster
Marine bites
Sea nettle
Man-of-war
Jellyfish
Mammals
Rats/mice
Gerbils
Hamsters
Other
Mold
Latex
ensure they also are not affected. The patient should
be removed from the area, and if necessary, decontaminated. BLS evaluation should be the first priority to ensure a patent airway, adequate oxygenation,
and intact circulation. If the patient is in respiratory
distress or wheezing, 100% oxygen should be given
to the patient with a non-rebreather mask. A largebore IV with normal saline should be started and a
fluid bolus of at least 500 ml given. If the patient was
stung, any wounds should be inspected for retained
stingers. If discovered, removal should be accomplished by scraping across the sting with a rigid thin
object, such as an identification badge, to dislodge
the stinger. Forceps or other squeezing devices should
not be used because they may inadvertently disrupt
the venom sac and release more venom into the
patient. Local wound care with cool compresses
and gauze covering should be applied. If there is the
possibility of injected venom, the patient should be
kept still and the affected extremity should be kept
below the level of the heart to keep the venom from
spreading.10,11
If there is only a local isolated reaction, patient
comfort and pain relief is all that is necessary. However, if the patient has a systemic allergic response,
there is need for additional medications. Several medications are useful in this setting, and their use will
depend on the severity of the patient’s symptoms, vital
signs, and past medical history. Before administering
any medication, the provider should ensure that the patient has no medication allergies. The provider should
also determine if the patient has taken any of his or
her own medication (e.g., epinephrine autoinjector,
oral diphenhydramine, or other oral antihistamine) before EMS arrival that may be masking the severity of
the reaction or affect any of the medications EMS will
administer. If the patient has his or her own autoinjector, EMS personnel of all training levels may assist
with administration. Research has demonstrated that
epinephrine autoinjectors can be used safely by EMTs
in the treatment of anaphylaxis in the field.12
Antihistamines are by far the most commonly
used class of medication. Antihistamines block the action of histamine at H1 receptors, but do not decrease
histamine release. Diphenhydramine is the most common medication in this class and can be given orally,
intravenously, intraosseously, or intramuscularly in
a typical dose of 25 to 50 mg for adults. Research
is suggestive that H2 blockers have a synergistic
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action when used in conjunction with diphenhydramine, blocking both cellular histamine receptors.13
Both famotidine and ranitidine are useful H2 blockers,
but cimetidine is not recommended due to its multiple drug interactions. Adult doses are IV famotidine
20 mg or IV ranitidine 50 mg. Corticosteroids, either
orally or intravenously, may also be useful to prevent return of symptoms once other medications are
metabolized. Peak onset of action of corticosteroids
is 2 to 4 hours. Nebulized beta-agonists, such as albuterol, can be used for patients with persistent bronchospasm. Nebulized ipratropium bromide may also
be used. Although both the multidose inhaler and the
nasal spray formulations of ipratropium contain an
ingredient (soy lecithin, used to keep the medication
in suspension) that may cause an allergic reaction in
patients with known peanut allergies, the nebulized
formulation typically used by EMS and emergency
departments lacks this ingredient.2 All of the aforementioned drugs may also be used in children, but
as with any pediatric medication, dosages must be
calculated based on the child’s weight (Table 21.3).
Epinephrine is the first-line medication in a patient with anaphylaxis. However, it should be used
with caution in patients over 50, those with known
coronary artery disease, or in cases with lifethreatening tachydysrhythmias because cardiac ischemia and myocardial infarction may be precipitated and
have been reported.14 Two different concentrations of
TABLE 21.3
Pediatric Allergic Reaction Treatment
Drug Dosages
Drug
Weight-Based Dose
Epinephrine
0.01 mg/kg of 1:1000 IM
1 ml of 1:10,000 mixed
with 10 ml NS
Diphenhydramine
Methylprednisolone
Famotidine
Ranitidine
0.5 ml of 1:1000 in
2.5 ml NS nebulized
1 mg/kg IM/IV/IO/PO
to max of 50 mg
1–2 mg/kg
0.5 mg/kg to max
of 20 mg IV/IO
2–4 mg/kg to max
of 50 mg IV/IO
IM, intramuscularly; IO, intraosseously; NS, normal saline; PO,
by mouth.
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epinephrine may be used, and the provider must exercise great caution to use the proper dosage and formulation when administering it. In adults, epinephrine
0.3 ml of 1:1000 solution can be given subcutaneously
or intramuscularly if the patient is not on the verge of
cardiovascular collapse. If the patient is hemodynamically unstable, epinephrine 1 ml of 1:10,000 mixed
with 10 ml of normal saline can be given slowly by IV
or intraosseous push over 5 to 10 minutes. Epinephrine
may also be nebulized by placing 0.5 ml of 1:1000 solution in 2.5 ml of normal saline. Epinephrine should
be given via the intramuscular route whenever feasible. It has been demonstrated that this route produces
higher peak plasma concentrations in less time than
injection subcutaneously in the deltoid.15 Intramuscular injection in the thigh results in particularly fast
absorption and is thought to be due to the increased
vascularity of the vastus lateralis muscle.5 If the
patient is hypotensive, aggressive fluid resuscitation
with 1 to 2 L of normal saline is indicated in addition
to the aforementioned medications. Patients will become intermittently hypotensive and require multiple
fluid boluses and additional medications en route, so
frequent monitoring of vital signs is imperative.
Localized angioedema is treated as an allergic reaction with antihistamines, steroids, and epinephrine
in severe cases. However, little actual benefit or significant improvement has been shown with these medications. The mainstay of treatment is supportive, with
early consideration for intubation. If the decision to intubate is made, great concern and preparation should
be taken because the edema can extend to the glottic
and subglottic regions. This may not be externally visible, and the only clue the provider may have is that
the patient’s voice is hoarse or different than normal. If
subglottic and/or glottic edema is present, intubation
may be fraught with difficulty, and the provider should
be prepared for a difficult airway including emergency
rescue techniques, such as cricothyrotomy, especially
if rapid-sequence intubation (RSI) is also being employed.16 As with medication-induced angioedema,
hereditary angioedema is generally not responsive to
antihistamines, steroids, and epinephrine.5
SPECIAL CONSIDERATIONS
Several points may be helpful to remember when responding to allergic reaction calls in the prehospital
environment. In general, stinging insects, especially
Hymenoptera, can cause systemic allergic reactions
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and anaphylaxis, but these reactions are rare with
biting insects.17 There is a greater chance of a systemic
reaction with multiple stings. One should remember
that the clinical presentation may be quite varied and
the history vague. Care should be taken to frequently
reassess the patient and document pertinent findings,
which may be the first clue that an allergic reaction is
present if the patient does not relate an exposure or
inciting event. Symptoms can be exacerbated by fear,
exercise, alcohol intake, heat exposure, or underlying
cardiovascular disease. The provider should be careful
not to become complacent or attribute clinical signs
and symptoms solely to these conditions because allergic reactions can progress insidiously. Anaphylaxis
to stings can occur years after the first exposure, even
without intervening stings.
If the patient experiencing a severe allergic reaction
or anaphylaxis routinely takes beta-blocker medications, the action of epinephrine may be blunted. Glucagon may be given in 1-mg increments by any parenteral
route to overcome the effects of beta blockade. Cutaneous symptoms are the most common clinical response
in both adults and children. Hypotension is uncommon
in children, but it has been reported in up to 60% of
adults.18
Patients will sometimes complain of chest pain
or shortness of breath before development of a more
generalized severe allergic reaction. EMS providers
should have a high index of suspicion on calls with
these complaints to ensure that there was no contact
with an allergen that may have caused these symptoms. For instance, radiocontrast media are frequently given in free-standing imaging centers. Consider
the possibility of allergic reactions and anaphylaxis
when responding to calls of shortness of breath or
chest pain in these facilities.19 Anaphylaxis should be
one of the etiologies considered when responding to
cardiac arrests in outside areas, such as golf courses,
because the patient may have been stung before the
cardiac arrest.
Although bites from a Gila monster are infrequent,
if it is still attached to the patient, the provider should
remove it by either prying its jaws apart with a stick or
metal object, holding a flame under the lizard’s chin, or
submerging it in cold water.20 Care should be taken to
avoid additional bites to the patient or the providers.
To determine the most appropriate destination facility for allergic reaction patients, it helps to consider the
etiology of the reaction and the availability of certain
subspecialties, such as otolaryngology, anesthesia, critical care, toxicology, and so on, which may be necessary
to definitively treat the reaction. Transportation time
should also be considered. If the patient is unstable or is
likely to become unstable during an extended transport
time to an appropriate facility, aeromedical evacuation
should be strongly considered. Direct medical oversight
can assist with these decisions.
SUMMARY
Allergic reactions and anaphylaxis are frequently
seen in the prehospital environment. EMS providers
should be alert to the potential for rapid progression
of allergic reactions and be prepared to support the
patient hemodynamically and provide appropriate
airway management. All patients should be provided
with oxygen, IV fluid administration, and continuous
monitoring during transport. Providers should be familiar with the common medications and the dosages
used to treat allergic reactions. Rapid transport to an
appropriate hospital should occur as soon as feasible.
C L I NI C A L VI G N E T T E S
Case 1
An 88-year-old female calls 9-1-1 after accidentally
taking her husband’s penicillin. She has a history
of coronary artery disease and a severe penicillin allergy. When EMS personnel arrive, they find
an anxious elderly female. The patient is assessed and an IV line obtained. En route to the
hospital she complains of itching, and hives are noted. She does not have any respiratory complaints
and lungs are clear to auscultation. Epinephrine
and diphenhydramine injections are prepared. Diphenhydramine is administered intravenously, and
epinephrine is held ready as a precaution. After getting the IV injection, she complains of severe chest
pain and palpitations.
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What is the most likely cause of the patient’s
symptoms?
a. anxiety
b. inadvertent epinephrine administration
c. progression of the anaphylaxis reaction
d. reaction to diphenhydramine
The answer is b. As stated in the chapter, epinephrine must be used with care in the population
at risk for coronary artery disease because it can,
theoretically, produce ischemia.
Case 2
A previously healthy 30-year-old male is working
in the yard when he feels a sharp sting. A few minutes later, he has intense itching and notices red
wheals spreading across his arm. He has a history
of allergies to bees and calls 9-1-1. EMS personnel arrive to find him complaining of difficulty
catching his breath.
After making sure that the scene is safe and
applying oxygen, what should rescuers consider
next?
a. albuterol aerosol
b. diphenhydramine intramuscularly
c. epinephrine intramuscularly
d. epinephrine subcutaneously
e. prednisone by mouth
The answer is c. In a patient who is obviously
anaphylactic, epinephrine should be the frontline treatment. In addition, it is best given to the
“borderline” patient early before he or she becomes
floridly anaphylactic.
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