Emergency Medicine
Preface
The idea when we started was to collect the core Emergency Medicine
information and present it in an abbreviated, succinct manner, useful to
housestaff and medical students. As we progressed it became obvious that
the very breadth of the specialty prevented any one person from accomplishing
this task. It also became obvious that our specialty had advanced past the
point where succinctness was possible. We peeled, boiled and pared, and
came up with this. We hope you find it useful.
Acknowledgments
To Carrie S. Korn, R.N., for her help in keeping track of all that paper.
CHAPTER 1
CHAPTER 1
Emergency Medicine, edited by Sean Henderson. ⓒ2006 Landes Bioscience.
Emergency Resuscitation
Stuart P. Swadron, Peter C. Benson and William K. Mallon
What Is Resuscitation?
Resuscitation, a word derived from the Latin word meaning “to set in motion”, is
the term most commonly used to describe the emergent treatment of the most severely
ill and injured patients. To the emergency physician, the term encompasses
not only attempts to reanimate those patients in cardiopulmonary arrest, but the
treatment of virtually any diseases in the extremes of presentation. Resuscitation is
an active process that is intervention-oriented and often invasive. The emergency
physician (EP) confronted with a resuscitation must multitask and “set into motion”
a team of health care workers which includes nurses, technologists and consultants.
Resuscitation and the Downward Spiral of Disease
Most disease processes move through stages of severity, beginning with an asymptomatic
phase and progressing toward their end-stage. Generally speaking, disturbances
in one physiologic function lead to disturbances in others and, through a
sort of pathologic “multiplier effect”, diseases gain momentum as they progress.
Diseases that have reached their end-stage often have such momentum that they
require intensive and rapid intervention if there is to be any hope of reversing the
underlying pathology. Although patients may present to the emergency department
at any stage in the continuum, it is those patients at the bottom of the spiral, those
with decompensated and end-stage disease, that will require resuscitation.
In general, attempts are made to tailor the treatment of a particular patient to the
tempo of their disease. The treatment of these processes should ideally occur at a
similar pace, because abrupt changes may cause additional risk to the patient. Nonetheless,
the momentum of end-stage disease will often force the emergency physician
to use drastic and potent therapy, and such therapy is usually not without adverse
consequences. The effect of the unwanted effects of therapy, together with the powerful
and synergistic downward forces of multiply deranged physiologic functions,
make resuscitation among the most challenging tasks of the emergency physician.
Shock: The Final Common Pathway
The final common pathway of most severe disease states is that of shock. Simply
defined, shock is the failure of the circulation to provide adequate tissue perfusion.
Although shock may not be present in all patients requiring emergent resuscitation,
if untreated or treated inadequately, most will eventually deteriorate into a shock
state. Once an illness progresses to a shock state, further deterioration involves a
complex interaction between the underlying disease, host factors and the pathophysiology
of the shock state itself.
Because of its central role in severe decompensated disease, a working knowledge
of the classification and approach to shock is essential. When the diagnosis is known,
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treatment is directed at both the underlying cause as well as the shock state itself. For
those patients in whom the diagnosis is unknown, general resuscitative measures
and treatment of shock proceeds alongside the diagnostic evaluation. Table 1.1 outlines
the major classes of shock and gives examples of individual etiologies of each
class. Many patients have compound presentations when more than one root cause
is present.
The Recognition of Occult Shock
Many of the traditional clinical indicators of shock, such as blood pressure (BP)
and heart rate (HR), lack the sensitivity to identify all patients in shock. In fact,
more sophisticated indices, such as pooled venous oxygen saturation measured
through a central catheter, can demonstrate a mismatch between the delivery of
oxygen to the tissues and its consumption in some patients with normal or elevated
BPs. Moreover, evidence suggests that using such indices to guide therapy in septic
shock (not simply the BP) results in better outcomes. Thus, the early identification
of shock before the traditional vital signs are grossly deranged (in its so-called “occult”
form) is essential to management and disposition.
In the ED, shock is still most often recognized by the presence of persistent hypotension
(e.g., systolic BP of <90 mm Hg in an adult) Nonetheless, there are many
other clinical indicators that when considered together can alert the clinician to the
presence of early shock, leading to appropriately vigorous resuscitation. Table 1.2
gives a list of clinical parameters that can assist in making the diagnosis of early or
“occult” shock.
Table 1.1. Classification and causes of shock
Cardiogenic (inadequate pump function)
Cardiac rupture
Congestive heart failure
Dysrhythmia
Intracardiac shunt (e.g., septal defect)
Ischemia/infarction
Myocardial contusion
Myocarditis
Valvular dysfunction
Distributive (misdistrubution of the circulating volume)
Adrenal crisis
Anaphylaxis
Capillary leak syndromes
Neurogenic
Sepsis
Toxicologic
Obstructive (extracardiac obstruction to circulation)
Air embolism
Cardiac tamponade
Massive pulmonary embolus
Tension pneumothorax
Hypovolemic (Inadequate circulating volume)
Adrenal crisis
Hemorrhage
Severe dehydration
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Diagnosis and Treatment in the Critically Ill Patient
In the classical medical model, the physician performs a history and physical
examination before proceeding to diagnostic tests and then treatment. But the ED
patient often requires treatment emergently and often in the absence of a diagnosis.
This paradigm is taken to its extreme in the setting of resuscitation. There is clearly
no time for history-taking or detailed physical examination in a patient who is pulseless
and apneic. Treatment of this patient, regardless of the underlying diagnosis, must
be immediate and maximal at the onset of the patient encounter (in this case by
securing an airway, providing rescue breathing and performing chest compressions).
Because there are final common pathways for most disease processes, (e.g., the
loss of spontaneous circulation and profound coma), the approach to any resuscitation
always begins with general supportive measures that may not be specific to the
underlying disease process. As more data is gathered, both by assessing the patient’s
response to therapy and obtaining incremental data from the ongoing history, examination
and bedside laboratory testing, the resuscitation becomes more specific,
focusing therapy to the most likely pathologies. Such upward reversal of disease
momentum mirrors its downward spiral—powerful, broad therapies are used to
reverse the intense downward momentum of end-stage disease, followed by more
specific and focused therapy as the curve of disease momentum becomes less steep.
Overview of a Resuscitation
In resuscitation, multiple interventions, both diagnostic and therapeutic, occur
simultaneously. These interventions are artificially separated out for the purposes of
analysis and education, beginning with the primary survey, the so-called ABCDEs,
a rapid evaluation and management of cardiopulmonary and cerebral function. The
primary survey focuses the clinician on the critical early interventions. After the
primary survey, a “resuscitation” phase is begun, which focuses on the acquisition of
Table 1.2. Clinical parameters in the diagnosis of shock
Parameter Comment
Heart rate Tachycardia (HR >100 in non-pregnant adults) is present in most
patients with shock; however, its presence may be masked by multiple
factors including spinal cord injury, medications, intra-abdominal
catastrophe, older age and cardiac conduction abnormalities.
Blood pressure Hypotension (arbitrarily systolic BP <90) is a late finding in shock. In
early shock, it may actually be transiently elevated. Measurements, in
particular with standard BP cuff, become less accurate in shock
states. A narrow pulse pressure may be present in hypovolemic
shock. A wide pulse pressure may be seen in distributive shock.
Shock index Heart rate/systolic blood pressure. An index of >0.9 is a more sensitive
indicator of shock than either blood pressure or heart rate alone.
Pulsus paradoxus A wide variation of blood pressure with respiration (>10 mm Hg) may
indicate obstructive shock (e.g., cardiac tamponade)
Respirations Either high (>24/min) or low (<12/min) rates may suggest a shock
state, as may very shallow or deep breathing
Skin signs Cool and clammy skin is often an indicator of a shock state although
certain distributive shock states may have warm and dry skin
(neurogenic and early septic shock). Delayed capillary refill (>2
seconds) is another sign of shock.
Urine output Most often reduced (<30 ml/h) in shock states.
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additional data and the continuation of emergent interventions initiated in the primary
survey. The secondary survey which follows is a head to toe examination that
may reveal abnormalities not yet noted and that may alter further therapy. Finally,
the resuscitation enters the definitive care stage, which may continue for the course
of several days, as the patient moves from the ED to the operating room, intensive
care unit and/or other inpatient treatment areas. Table 1.3 gives the organizational
framework of a resuscitation.
Preparation
The few minutes immediately prior to a major resuscitation may be precious.
Any advanced notification that a critically ill patient is en route to hospital may be
used to assemble the resuscitation team and to ready necessary equipment. This
time is not to be taken for granted; if not utilized correctly, it may directly contribute
to poor outcomes and inefficient resuscitation. Table 1.4 outlines critical steps
that should occur before a patient(s) even arrives.
Table 1.3. Overview of a resuscitation
Preparation
Primary survey
Airway
Breathing
Circulation
Disability
Exposure
Resuscitation phase
Continuation of interventions and monitoring begun in primary survey
History
Bedside diagnostic investigations Blood tests
Electrocardiography
Diagnostic imaging
Advanced monitoring Central venous pressure monitoring
Pulmonary catheter monitoring
Intraarterial catheter monitoring
Cardiotocodynamometry (in pregnancy)
Non-invasive monitoring (biothoracic impedence)
Nasogastric and urinary catheter placement
Secondary survey
Head-to-toe examination (inspection, percussion, palpation and auscultation)
Definitive care phase
Diagnostic specific therapy
Consultations
Preparations for patient disposition Transfer
Operating room
Specialized intensive care unit
Family conference
Resource utilization Respiratory therapist
Social services
Religious support services
Organ procurement agencies
Law enforcement and forensic services
Sexual assault and domestic violence
Emergency Resuscitation 5
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Table 1.4. Preparation for a resuscitation
Prehospital data analysis
Number of patients
Age and gender of patients (possibility of obstretrical, pediatric and/or neonatal
resuscitation)
Description of illness/injury
C-spine precautions in place
Level of consciousness
Airway status
Vital signs
Estimated time of arrival
Need for decontamination (hazardous materials), sterile field (burns)
Need for law enforcement, security personnel (possible compromise of patient, staff safety)
Team assembly
Physicians Team leader
Airway management
Procedural support
Consultant staff -surgical
-interventional cardiology
-gastroenterology
-neonatal/pediatric
-obstetrical
Nursing Charting and timing
Monitor placement
Venous access and emergency lab specimens
Catheter placement (Foley, NG tubes) and other procedures
Resuscitation medications and fluids ready and available
Circulating
Family and visitor management
Respiratory therapist Assistance with airway management
Ventilator and non-invasive ventilation techniques
Radiation technologist Perform and develop STAT portable X-rays
CT scan running and available
Laboratory personnel Blood bank readiness
STAT laboratory testing
Clerical staff Provide emergent identification and prepare hospital ID
Equipment
Airway management Functioning suction with catheter attached
Flowing oxygen
Airway adjuncts including -an array of sizes of oral airways
-bag-valve-mask setup
-ET tubes with stylets placed and
balloons tested
-laryngoscopes with bulbs tested
-rescue airway adjuncts ready
-medications for rapid sequence
intubation ready
Other procedural Dress and gloves for universal precaution maintenance
Blood warming and rapid transfusion equipment
Ready procedure trays for -central venous access
-thoracostomy and thoracotomy
-surgical airway management
(cricothyroidotomy)
Warmed fluids/blankets, non-invasive warming equipment
Adequate tubing for blood/blood product administration
Emergency ultrasound at bedside
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The Primary Survey
During the primary survey, the critical therapeutic efforts of resuscitation are
initiated. At the same time, the signs of the various shock states are unmasked and
clues to the underlying diagnosis may be elicited. Although a definitive diagnosis is
often not made initially, it is almost always possible to direct resuscitative efforts
toward a particular class of shock.
When problems are encountered in the primary survey, they should be addressed
immediately. Each element may be managed with either temporizing or definitive
maneuvers. For example the airway may be temporarily managed with the chin-lift and
bag-valve-mask ventilation, or definitely managed with endotracheal intubation.
A—Airway
When approaching the airway, the clinician ensures that cervical spine precautions
are in place if trauma is a possibility and determines whether the airway is
patent, protected and positioned adequately. The clinician:
Observes for level of consciousness, drooling and secretions, foreign bodies, facial burns,
carbon in sputum
Palpates for any facial or neck deformities and checks for a gag reflex, and
Listens for hoarseness or stridor.
Findings Diagnostic Implication
Drooling, stridor Upper airway obstruction
Decreased level of consciousness Unprotected airway
Diminished gag
Facial burns Unstable airway (potential obstruction)
Facial instability
Airway management in the primary survey may be as simple as positioning of the
airway using the chin lift or jaw thrust maneuvers (used when cervical spine instability
is a concern). It may also involve the placement of nasopharyngeal or oral
airway devices and the application of supplemental oxygen. In cases of obstruction,
foreign bodies may need to be dislodged using basic life support maneuvers or manually
with suctioning and Magill forceps. Definitive airway intervention, such as oral
endotracheal intubation (with or without rapid sequence technique), nasotracheal
intubation or a surgical airway (e.g., cricothyroidotomy) may be required.
B—Breathing
To assess the adequacy of the breathing apparatus, the clinician:
• Observes for signs of tracheal deviation, jugular venous distention (JVD), Kussmaul’s
sign (increased JVD with inspiration), respiratory distress (such as indrawing, splinting
and use of accessory musculature) and trauma (contusions, flail segments, open wounds)
• Palpates for bony crepitus, subcutaneous air or tenderness
• Auscultates to assess air entry, symmetry, adventitial sounds (crackles, wheezes and
rubs), and
• Percusses, if necessary, for hyperresonance or dullness on each side.
Findings Diagnostic Implication
JVD, unilaterally absent Obstructive shock
breath sounds (tension pneumothorax)
JVD, clear lung fields Obstructive shock
(cardiac tamponade, massive pulmonary embolism)
Cardiogenic shock
(right ventricular myocardial infarction)
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JVD, diffuse crackles Cardiogenic shock
(cardiogenic pulmonary edema)
JVD, diffuse or localized Status asthmaticus, COPD exacerbation, aspiration
wheezes syndrome
Kussmaul (“air hunger”) Metabolic acidosis
breathing
Chaotic, irregular breathing Central nervous system insult
Abdominal breathing, failure High spinal cord injury
of chest expansion
Possible interventions during the breathing segment of the primary survey include
bag-valve mask ventilation, the administration of naloxone for narcotic induced
apnea, placement of thoracostomy needles and tubes and the application of
positive pressure ventilation, by either non-invasive or invasive means.
C—Circulation
To assess the circulation, the clinician:
• Palpates the pulse for rate, regularity, contour and strength. Pulses should be checked
in all four extremities, and if absent, central pulses (femoral and carotid) are palpated.
Also, palpates the skin for temperature, moisture and the briskness of capillary refill in
the extremities.
• Observes for signs of obvious hemorrhage such as visible exsanguination, a distending
abdomen, an unstable pelvis or long bone deformities.
• Measures the blood pressure, notes pulse pressure, and if necessary, compares BP among
the extremities.
• Auscultates the precordium for the clarity of heart tones, listening for any extra sounds,
murmurs, rubs or Hammon’s crunch (pneumomediastinum)
Findings Diagnostic Implication
Sinus tachycardia, hypotension, Obstructive shock
JVD cool, pale extremities (cardiac tamponade, tension pneumothorax,
massive pulmonary embolism)
Cardiogenic shock
(right ventricular myocardial infarction)
Sinus tachycardia, hypotension Hypovolemic shock
cool, pale extremities
Hypotension, relative bradycardia Distributive shock
warm, pink extremities (neurogenic shock from spinal cord injury)
Tachycardia, hypotension, Cardiogenic shock
gallop rhythm (S3, S4) (left ventricular failure)
Tachycardia, hypotension, Cardiogenic shock
loud systolic murmur (acute mitral regurgitation or ventricular
septal defect)
Central cyanosis Hypoxia
Methemoglobinemia
Interventions during the circulation segment of the primary survey include
placing the patient on a cardiac and pulse oximetry monitor and the establishment
of vascular access. They may also include the administration of fluids and
blood products, electrical and pharmacological therapy for dysrhythmias,
pericardiocentesis and, in some cases, such as penetrating trauma, emergency
thoracotomy.
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D—Disability
Disability represents the neurological assessment in the primary survey. If at all
possible, it is desirable to obtain a cursory assessment prior to use of paralyzing
agents. The clinician:
• Assesses the level of consciousness, using the Glasgow Coma Scale.
Eye Opening Motor Verbal
1 None No movement No sounds
2 To pain Decerebrate postutre Moans
3 To command Decorticate posture Words
4 Spontaneous Withdrawal from pain Confused
5 Localize to pain Oriented
6 To command
Minimum Score = 3 (severe coma); Maximum Score = 15
• Observes the pupils for size, symmetry and reactivity to light, and observes all four
extremities for their gross movement
• Palpates rectal tone by digital examination
Findings Diagnostic Implication
Coma, unilateral dilated pupil, Cerebral herniation
hemiparesis
Pinpoint pupils Opiate, cholinergic or clonidine overdose
Pontine lesion
Dilated, reactive pupils Sympathomimetic overdose
Dilated, unreactive pupils Anoxia
Anticholinergic overdose
Deviation of eyes to one side Ipsilateral cortical lesion
Contralateral brainstem lesion
Decreased rectal tone Spinal cord injury
Other neurological insults, seizures, toxins
Rigid extremities Neuroleptic malignant syndrome
Serotonin syndrome
Tetanus, strychnine poisioning
Interventions in the disability segment of the primary survey are often limited to
airway, breathing and circulation, as these all affect neurological function. Once
these are addressed, attention can be directed toward interventions such as cranial
CT, the administration of mannitol and hyperventilation for suspected acute brain
herniation, and surgical decompression. Pharmacologic therapy is directed at causes
of altered levels of consciousness, such as the administration of glucose for hypoglycemia,
naloxone for suspected opiate overdose and thiamine for Wernicke-Korsakoff
syndrome.
E—Exposure
Often described as “strip, flip, touch and smell”, exposure means not only completely
undressing the patient, but also looking for other important clues. The clinician
should:
• Expose the entire surface area of the patient
• Inspect and palpate the back for abnormalities, using cervical spine precautions to roll
the patient if there is a possibility of trauma. Also, inspect the skin for rashes, other
obvious lesions and signs of trauma
• Note any particular odors about the patient, and
• Measure a rectal temperature
Emergency Resuscitation 9
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Findings Possibile Diagnostic Significance
Hyperthermia/Hypothermia Hypovolemic (severe dehydration)
Distributive shock (e.g., septic)
Cardiogenic shock
Unsuspected wounds Hypovolemic shock
(especially in axilla, back, (hemorrhagic shock from occult trauma)
neck, perineum)
Odors:
Fetid urine Distributive shock (urosepsis)
Bitter almonds Cyanide toxicity
Garlic Organophosphate or arsenic toxicity
Fruity Ketoacidosis, isopropyl alcohol toxicity
Alcohol Complications of alcohol abuse
(trauma, multiorgan toxicity)
Track marks of IV drug use Distributive shock (sepsis)
Cardiogenic shock (valvular disease)
Opiate overdose
Non-cardiogenic pulmonary edema
Dialysis shunt (AV fistula) Cardiogenic shock (volume overload)
Obstructive shock (pericardial tamponade)
Hyperkalemia
Uremic encephalopathy
Cullen’s or Gray-Turner signs Hypovolemic shock
(periumbilical or flank (retroperitoneal hemorrhage from ruptured aortic
ecchymosis) aneurysm, ectopic pregnancy, hemorrhagic
pancreatitis and other abdominal catastrophes)
Diffuse purpuric rash Distributive shock (meningococcal sepsis)
Diffuse maculopapular rash Distributive shock (toxic shock syndrome)
Unilateral lower extremity edema Obstructive shock (massive pulmonary embolism)
The most important intervention in the exposure segment of the primary survey
is often the measurement of rectal temperature and the maintenance of euthermia.
This may be as simple as placing a warm blanket on the patient or as involved as
invasive rewarming procedures in the unstable hypothermic patient. In some resuscitations,
hypothermia may be maintained or deliberately induced. Hyperthermic
patients may simply receive acetaminophen, or, in the case of severely elevated temperatures
(>105˚ F), aggressive mechanical cooling measures may be necessary. Sterile
dressings should be applied to patients with burns.
Resuscitation Phase
History
Historical information should be elicited from either prehospital personnel, family
members as well as patients themselves. Historical elements may point to a particular
class of shock or underlying process. Some findings, however, such as altered
mental status and chest pain, may be simply a result of inadequate tissue perfusion
and not the key to determining the cause. Identification of a class of shock present
will help guide the initial resuscitation. For example, a history of bleeding, vomiting,
diarrhea or trauma will immediately alert the clinician to the possibility of
hypovolemic shock and the need for rapid volume administration. A history of heart
disease, especially with the symptoms of paroxysmal nocturnal dyspnea or orthopnea,
are highly suggestive of a cardiogenic shock state. A history of infection, fever
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or the use of a new medication may suggest distributive shock. Table 1.5 reviews
critical historical elements and clues that may lead to life-saving interventions in the
resuscitation of the critically ill patient.
Bedside Diagnostic Investigations
The nature of emergency resuscitation precludes the type of methodical diagnostic
workup that is possible in less critically ill patients. Each diagnostic tool must be
evaluated for its ability to change the course of the resuscitation. Near immediate
results are essential, and tests should not interfere with life-saving interventions.
Table 1.6 outlines diagnostic investigations that are useful during the initial phases
of resuscitation.
Secondary Survey
As the severity patient’s condition on presentation increases, so does the relative
importance of the physical examination. Thus, both primary and secondary surveys
in resuscitation are primarily directed at physical findings. There is a significant
Table 1.5. Important clues on history
Critical historical elements
Bystander resuscitation Rescue breathing
Chest compressions
Automated external defibrillation
Medical alert/identification bracelets
Medications brought in by paramedics
Old medical records/electrocardiograms
Organ donor identification/drivers license
Paramedic and bystander observations
Patient’s clothing/belongings for medications/devices/recreational drug paraphernalia
Presence of possible toxins on scene
Response to prehospital interventions Oxygen
Fluid challenge
Electrical therapy
Medications
Positioning
Vital sign trends and neurological status changes in prehospital phase
Historical clues in shock states:
History Possible Class Of Shock
Preceding chest pain, Cardiogenic
shortness of breath Obstructive
Orthopnea Cardiogenic
Any new medication Distributive (anaphylactic)
Vomiting and diarrhea Hypovolemic
Hemorrhage Hypovolemic
Rash Distributive (anaphylactic, septic)
Intravenous drug use Distributive (septic)
Cardiogenic
Indwelling devices (catheters, lines) Distributive (septic)
Chronic debility/neurologic disease Distributive (septic)
Hypovolemic
Trauma Hypovolemic (hemorrhage)
Diagnostic investigations
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Table 1.6. Diagnostic investigations in resuscitation
Continuous monitoring
Pulse oximetry Pulse oximetry is considered “a fifth vital sign”. It is tremendously
helpful when it can be recorded accurately; however, in severe
shock states diminished pulses and cool extremities may make it
impossible to obtain. Pulse oximetry probes can be placed on
the earlobes as well as the extremities. Falsely reassuring
readings may occur with abnormal hemoglobins, such as with
CO toxicity or methemoglobinemia.
Neurological status Mental status has also been referred to as a vital sign. A progressive
alteration in mental status has a broad differential diagnosis,
but within the context of an individual resuscitation its significance
is often clear. In shock states, it may represent worsening
cerebral perfusion or hypoxia and the need for more aggressive
resuscitative efforts. In patients with intracranial pathology, it may
represent brain herniation and the need for lowering intracranial
pressure, especially when combined with localizing signs. When
toxic, metabolic and endocrinologic derangements are present,
worsening electrolyte abnormalities or hypoglycemia may be
present and a multitude of interventions, ranging from simple
dextrose administration to hemodialysis may be necessary.
Pain scales Signs of pain, both verbal and non-verbal, should not be ignored.
These may indicate the need to search for an occult injury such
as a fracture or penetrating trauma that may change the direction
of the resuscitation. Pain can also be used as a guide to the
success of resuscitation, as is the case when chest pain and
dyspnea resolve with adequate treatment of myocardial ischemia
or pulmonary edema.
Continuous cardiac Continuous telemetry is essential in any resuscitation to monitor
monitor for life-threatening dysrhythmias and responses to treatment.
Electrocardiography
12-lead EKG The 12-lead EKG is enormously helpful in resuscitation. It has
utility in both cardiac and non-cardiac emergencies. EKG
findings may be either the cause or result of the underlying
condition requiring resuscitation. Attention is directed at signs of
myocardial infarction and ischemia, electrolyte derangements
and clues to other life threatening pathologies such as decreased
voltage in cardiac tamponade or signs of acute right-sided heart
strain in pulmonary embolus. Certain drug toxicities have
characteristic EKG findings as well.
Additional EKG leads Right-sided precordial leads (RV3 and RV4) may be critical in
identifying the cause of cardiogenic shock as right ventricular
MI. Posterior leads (V8 and V9) may unmask the presence of
posterior MI.
Bedside laboratory tests
Blood glucose Critically low blood glucose results from many different lifethreatening
processes and must be addressed immediately. The
finding of high blood glucose is similarly important and may
help tailor early resuscitative efforts. Blood glucose should be
measured in all patients with altered mental status and, when
abnormal, frequent rechecks are indicated.
continued on next page
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Table 1.6. Continued
Hemoglobin or Both of these tests express hemoglobin concentration and, as
hematocrit such, can appear misleadingly high in acute hemorrhage before
volume resuscitation has occurred. These tests are subject to
error, and repeat and serial values should be obtained when they
are utilized to guide resuscitation.
Pregnancy test A positive serum or urine pregnancy test may lead to a diagnosis
of the underlying pathology in a critically ill female. In addition,
this finding may affect decisions made during resuscitation with
respect to monitoring, emergent procedures, the selection of
medications and imaging studies and disposition.
Blood type and This is an essential test that must be performed to facilitate
crossmatch treatment with blood and blood products in a multitude of
resuscitations, both traumatic and non-traumatic. The infusion of
fresh frozen plasma and platelets also requires crossmatching.
Bedisde electrolytes The availability of blood electrolyte analysis at the bedside is
increasing and very helpful. Knowledge of the electrolytes in the
first few minutes may enable critical interventions to be started
early. In some cases, such therapies should be started even
before electrolytes are available (e.g., giving emergent treatment
for hyperkalemia in the presence of a typical EKG and history)
Arterial blood gases Although an assessment for hypoxia and hypercarbia should be
made clinically, arterial blood gases have a special role when
pulse oximetry is not possible or unreliable, to assess for certain
toxins such as carbon monoxide and methemoglobin, and to
assist with mechanical ventilation management. The pH and
base excess values obtained from blood gases (including venous
gases) may also be used as an adjunct to gauge the severity of
shock states and response to resuscitative efforts.
Pooled venous Requires the placement of central venous line with a special
oxygen levels probe. May be used to gauge the severity and response to
resuscitation.
Other bedside assays Although there are many potential pitfalls in their application
and interpretation, bedside assays may be extremely helpful. In
some cases, elevated cardiac markers may confirm suspicion of
an MI. A variety of toxicological tests are now available, and, in
the appropriate circumstances, bedside screening assays for
various bioterrorism agents.
Diagnostic imaging
Chest film An early portable chest X-ray is of paramount importance. It
may, by itself, identify the type of shock state present (e.g., the
finding of cardiomegaly and pulmonary edema in cardiogenic
shock, tension pneumothorax in obstructive shock, hemothorax
or pleural effusion in hypovolemic shock). It may also be helpful
in pulmonary embolism—less for the presence of rare signs such
as Hampton’s Hump and Westermark’s sign than for the absence
of significant findings pointing to alternative diagnoses such as
pulmonary edema and pneumonia. A widened or abnormal
mediastinum may represent aortic rupture or dissection.
Cervical spine films The presence of cervical spine trauma may help explain the
findings of shock, neurological deficits and ventilatory failure.
continued on next page
Emergency Resuscitation 13
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overlap in the examination during the primary and secondary surveys, but the secondary
survey tends to reveal those features which would be missed unless specifically
looked for. In the context of an individual resuscitation, some of these findings
may be very important or even critical.
Simply stated, the secondary survey is a complete, compulsive physical examination.
Once resuscitative measures are underway, every critically ill patient should
have such an examination. Several examples of secondary survey findings that may
alter acute management are given below:
Table 1.6. Continued
Pelvis This is an important film that may identify a source of hemorrhage
and occult trauma.
Lateral soft tissue neck This film may identify mechanical airway obstruction, a source
of septic shock or foreign bodies.
Abdominal films Although rarely helpful in resuscitation, a single abdominal film
may show a pattern of calcification of the aorta in the case of a
ruptured aortic aneurysm and the presence of radiopaque toxic
ingestions such as iron, phenothiazines and enteric release
tablets.
Ultrasonography Bedside ultrasound is ideal for use in resuscitation because of its
availability, repeatability and speed.
Bedside echocardiography can be used to reveal the presence of
various shock states by identifying cardiac tamponade, global
hypokinesis or right ventricular outflow obstruction. In the future,
it may be utilized by emergency physicians to evaluate valvular
lesions and dyskinesis. It can also assist with the distinction
between pulseless electrical activity and cardiac standstill
(electromechanical dissociation). This may help to determine
when resuscitation efforts should be terminated.
Abdominal ultrasound may quickly identify free-fluid (most
importantly, hemorrhage) in the peritoneal cavity. Hemothorax,
as well as pleural effusions, may also be identified during the
focused assessment with sonography for trauma (FAST)
examination.
The aorta may be quickly imaged to assess for abdominal aortic
aneurysm.
Pelvic ultrasonography in the female patient with intraperitoneal
hemorrhage may further delineate the source of shock. The
absence of an intrauterine gestation in a pregnant female may
represent ectopic pregnancy, whereas its presence may indicate
a bleeding cyst, heterotopic ectopic pregnancy or occult trauma.
Ultrasonography also has a role in assisting with emergency
procedures, such as line placement and pericardiocentesis.
Cranial CT Of all CT studies, cranial CT, because of its speed and lack of
need for contrast, may be performed even in the unstable
patient. It may identify the need for emergent surgical decompression,
measures to lower intracranial pressure or the search
for other causes of altered mental status, all which may change
the course of a resuscitation.
14 Emergency Medicine
1
Findings Possible Diagnostic Significance
Impaired visual acuity Occult trauma
Arterial thromboembolism
(cerebrovascular accident, aortic dissection)
Hemotympanum Occult head trauma
Nuchal rigidity, meningeal signs Meningitis
Subarachnoid hemorrhage
Thyroidectomy scar Myxedema coma
Right ventricular heave Obstructive shock
(acute right heart strain, massive pulmonary
embolism)
Absent bowel sounds Distributive or hypovolemic shock (peritonitis)
Occult spinal cord injury
Retained vaginal foreign body Distributive shock (toxic shock syndrome)
Dysmetria, ataxia limb movements Cerebellar lesion
Unilateral upgoing plantar response Cerebrovascular accident
Non-convulsive status epilepticus
Definitive Care Phase
Definitive care phase of the resuscitated patient may begin in the ED and continue
in various inpatient settings (the operating room, intensive care unit, cardiac
catheterization or interventional radiology suite, etc.). Transfer to another facility
for specialized care may be necessary.
The importance of the family of the critically ill patient should not be forgotten.
Many patients requiring extensive resuscitation in the ED may have been previously
well. In the case of patients with chronic, controlled disease, family members may
be quite shaken by the sudden decompensation in their loved one’s condition. It is
the responsibility of the EP and other members of the primary resuscitation team
(nursing staff, social services) to make themselves available to the family as soon as it
is possible. Early communication with family and friends serves several purposes: to
obtain additional relevant history, to explain the current condition and resuscitative
efforts that are taking place, to clarify any advance directives or previously expressed
wishes of the patient, and to express the concern and support of the resuscitative
team. Although controversy exists as to whether family members should be permitted
to view resuscitative efforts, there is little doubt that interacting with family
members in these situations is a skill that requires training, practice and flexibility.
Other individuals that may become involved as indirect members of the resuscitation
team include religious or spiritual counselors, organ procurement specialists,
law enforcement, forensic specialists, sexual assault and domestic violence personnel.
It is the responsibility of the EP to understand the reporting requirements for
victims of violence, abuse, neglect and organ procurement in their respective practice
jurisdictions.
Ethical and Legal Aspects of Resuscitation
Many ethical issues are magnified and intensified during a resuscitation. How
aggressive should resuscitation efforts be when there is a low likelihood of survival?
How should resources in the ED be distributed between critically ill patients with
poor prognoses and less severely ill patients? Under what circumstances is a patient
that is still communicating in a position to refuse resuscitative efforts when they are
Emergency Resuscitation 15
1
emergently needed? What process should be followed to obtain consent for organ
donation?
There are, however, certain legal realities that the EP and other members of the
resuscitation team need to be compliant with. Moreover, laws and guidelines that
apply to medical emergencies differ from jurisdiction to jurisdiction. These include
laws relating to Do Not Resuscitate (DNR) orders, advance directives, living wills,
consent or refusal of treatment and mandatory reporting laws to police, coroner and
various social agencies.
In general, resuscitative efforts should not be initiated when obvious signs of
death are apparent, such as dependent lividity, rigor mortis or trauma inconsistent
with life. Although statutes regarding DNR directives vary, the fundamental right of
an individual to make decisions about their medical care, including end-of-life care,
should be honored by medical personnel. This right was recognized in the United
States by the Patient Self-Determination Act of 1991. Similar legislation exists in
other countries.
The decision of when to cease resuscitative efforts once they have begun is often
more difficult. Survival after prolonged loss of spontaneous circulation and, perhaps
more importantly, survival with neurological function that would be acceptable to
the patient, becomes less likely as time elapses, with the rare exception of miraculous
survival such as sometimes occurs with victims of accidental hypothermia. Ultimately,
a judgment must be made by the responsible physician, weighing the likelihood
of benefit against the disadvantages of continuing aggressive resuscitative efforts.
CHAPTER 2
Emergency Medicine, edited by Sean Henderson. ©2006 Landes Bioscience.
Cardiovascular Disorders
Jason Greenspan, Shahram Tabib and Stuart P. Swadron
Part A: Hypertension and Hypertensive
Emergencies
Hypertension is one of the most common conditions affecting patients in developed
countries. As the population ages and the emergency department continues to
serve populations without access to appropriate primary care, issues regarding hypertension
will become more important. Emergency Physicians must be comfortable
in evaluating and treating patients with conditions associated with an acute rise
in blood pressure, conditions secondary to long-standing hypertension, as well as
with the complications of medications used to control hypertension.
Definitions
• Essential Hypertension is a persistently elevated blood pressure measured on two separate
occasions. The Joint National Committee on Prevention, Detection, Evaluation,
and Treatment of High Blood Pressure has classified hypertension based on the degree
of elevation (Table 2A.1).
• Hypertensive Urgency is the presence of an elevated BP without signs or symptoms of
end organ damage. Blood pressure should be reduced gradually over 24-48 h in hypertensive
urgencies.
• Hypertensive Emergency is the presence of an elevated BP with evidence of end-organ
damage. Table 2A.2 lists conditions regarded as true hypertensive emergencies. These
conditions necessitate the careful reduction of blood pressure in minutes to hours.
Epidemiology/Pathophysiology
• The majority of hypertensive emergencies occur in previously hypertensive patients.
In these patients, the ability of the body to autoregulate blood pressure is adjusted to
accommodate for the chronic elevation of blood pressure. A hypertensive emergency
occurs with an acute elevation in blood pressure over baseline.
• While the actual blood pressure is important in the evaluation and diagnosis of these
conditions, it is the presence of end-organ damage and not the actual blood pressure
measurement that indicates the need for emergent lowering of blood pressure.
• The rate of elevation of the blood pressure may be more important in the pathogenesis
of end-organ damage than the actual blood pressure.
Diagnosis and Evaluation
History and Physical Examination
• The evaluation of the hypertensive patient involves a careful history focused on evaluating
the presence of symptoms suggestive of end-organ damage, the risk of developing
subsequent end-organ damage if untreated, and any past treatment for hypertension
or associated conditions.
Cardiovascular Disorders 17
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• Patients should also be questioned regarding foods, medicines, or the use of medications
or illicit drugs which may contribute to blood pressure elevation.
• Physical exam begins with the proper measurement of blood pressure in multiple extremities
with a proper sized blood pressure cuff.
• Examination should include a complete neurologic evaluation including fundoscopy
to rule out retinal hemorrhages or papilledema, cardiovascular exam including evaluation
of new murmurs, an S3 or S4, pulses in multiple extremities, pulmonary exam
listening for findings indicative of pulmonary edema, and an abdominal exam to evaluate
for bruits or aneurysms.
Laboratory and Studies
• The laboratory examination in severely hypertensive patients is geared towards the
evaluation of any presenting emergent condition.
• Baseline studies should include a CBC to evaluate for the microangiopathic hemolytic
anemia associated with malignant hypertension, evaluation of electrolytes and renal
function, evaluation of cardiac specific enzymes, and urinalysis to evaluate for proteinuria
and/or hematuria.
• An EKG and CXR should be obtained to evaluate cardiovascular emergencies.
• Other studies including CT scans, abdominal ultrasound, or aortography are done as
needed.
Specific Hypertensive Emergencies
Certain disease processes are discussed in greater detail in other sections of this
handbook. However, treatment with respect to blood pressure control is discussed
here.