Emergency Medicine 1


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

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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

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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

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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.