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CHAPTER 14 Cyanosis
Madonna Fernández-Frackelton
PERSPECTIVE
Epidemiology
Cyanosis is a blue or purple appearance of the skin or mucous
membranes. This clinical finding is caused by inadequately oxygenated blood perfusing peripheral tissues or the presence of
abnormal hemoglobin forms unable to bind oxygen or to supply
adequate oxygen to end organs and tissues. Cyanosis is a relatively
rare presenting chief complaint in the emergency department
(ED) and is most commonly noted in patients with a hypoperfused state or known cardiopulmonary disease, including congenital heart disease. Although carbon monoxide poisoning and
cyanide toxicity result in inadequate hemoglobin oxygenation and
tissue hypoxia, these entities typically do not manifest with the
clinical finding of cyanosis and are discussed in other chapters.
Pathophysiology
Cyanosis is evident on physical examination when the absolute
amount of desaturated (unoxygenated) hemoglobin in the circulating capillary blood is elevated to approximately 5 g/dL.1,2 It is
not a percent of desaturated total hemoglobin mass or a decreased
amount of oxyhemoglobin. For this reason, patients with a relatively low hemoglobin level exhibit cyanosis at a much lower
partial pressure of oxygen (Pao2) and arterial oxygen saturation
(Sao2) than those with normal hemoglobin levels. Cyanosis is an
insensitive indicator of tissue oxygenation.3 Its presence suggests
hypoxia, buts its absence does not exclude it.
Abnormal hemoglobin forms contribute significantly to cyanotic disease. Under normal conditions, red blood cells (RBCs)
contain hemoglobin with iron in the reduced ferrous state (Fe2+).
The iron molecule may be oxidized to the ferric state (Fe3+) to
produce methemoglobin. This reaction impairs the ability of
hemoglobin to transport oxygen to and carbon dioxide from the
tissues. The oxygen dissociation curve is shifted to the left, resulting
in tissue hypoxia and lactic acid production (Fig. 14-1). Methemoglobin normally accounts for less than 1% of total hemoglobin.4 Cyanosis results when greater than 10 to 25% of the total
hemoglobin is methemoglobin (approximately 1.5 g/dL), which
has a dark purple-brown or chocolate brown color even when
exposed to room air. Methemoglobin is reduced to ferrous hemoglobin primarily by nicotinamide adenine dinucleotide (NADH)
cytochrome-b5 reductase, an enzyme system present within RBCs.
A secondary system dependent on nicotinamide adenine dinucleotide phosphate (NADPH)-reductase uses glutathione production
and glucose-6-phosphate dehydrogenase (G6PD) to reduce methemoglobin to hemoglobin. This secondary pathway normally
plays a minor role but is accelerated by methylene blue.4
Primary methemoglobinemia is the result of a congenital
error in enzyme metabolism, with either diminished levels
of NADH reductase or an abnormally functioning enzyme.
Patients may have cyanosis in a stable compensated state. Acquired
methemoglobinemia occurs when methemoglobin production
(hemoglobin oxidation) is accelerated beyond the capacity of
NADH reductase activity. This usually occurs as a drug reaction.
(See Box 14-1 for common causes.) Newborns are at risk for
methemoglobinemia because their NADH reductase activity is
relatively low.5
DIAGNOSTIC APPROACH
Differential considerations for patients with cyanosis are listed in
Box 14-2.
Pivotal Findings
Symptoms
The onset, duration, and time of day of symptoms and any previous episodes should be noted. Precipitating factors may include
exposure to cold air or water, high altitude, or exercise in patients
with a history of cardiopulmonary disease. Additional history
should include known congenital heart disease or cardiopulmonary disease, hypercoagulable states, and any family history of
cyanotic disease or hematologic illness. A history of home or occupational exposures to fumes or chemicals should be obtained,
including aniline, azo dyes (phenazopyridine [Pyridium]), phenacetin, and nitrates.6 A drug history should be reviewed, including
use of prescription and over-the-counter medications, health food
supplements, and herbal or alternative preparations.7 The potential of pseudocyanosis resulting from exposure to dyes, heavy
metals, or topically absorbed pigments should be explored.8
In infants, congenital heart disease is suggested by difficulty
feeding, sweating, lethargy, poor weight gain, or respiratory distress. Episodic cyanotic events, or “tet spells,” may be seen in
children with tetralogy of Fallot (ventricular septal defect, overriding aorta, pulmonic stenosis or atresia, and right ventricular
hypertrophy with outlet obstruction). These patients have cyanosis, tachypnea, and anxiety owing to decreased pulmonary blood
flow with shunting of unoxygenated blood into the peripheral
circulation.9,10
Signs
There is significant interobserver variability in detecting cyanosis
on physical examination. Room lighting and temperature may
affect examination of the skin and mucous membranes. A patient’s
129
130 PART I ◆ Fundamental Clinical Concepts / Section Two • Cardinal Presentations
Less
↑ pH
↓ 2,3-BPG O2
delivered
↓ T°
Percent saturation of hemoglobin
100
Oxyhemoglobin
Hereditary
Hemoglobin M
NADH methemoglobin reductase deficiency (homozygote and
heterozygote)
G6PD deficiency
75
↓ pH
More
↑ 2,3-BPG O2
↑ T°
delivered
50
P50
25
Deoxyhemoglobin
0
0
25
50
BOX 14-1 Common Causes of Methemoglobinemia
75
100
Tissue PO2 (mm Hg)
Figure 14-1. Hemoglobin-oxygen dissociation curve.
Deoxyhemoglobin does not bind oxygen efficiently. Methemoglobin has a high affinity for oxygen molecules and does not readily release
oxygen to the peripheral tissues. This shifts the normal oxygen
dissociation curve to the left, resulting in hypoxia and lactic acid
production. Typically, when acid is produced in the tissues, the
dissociation curve shifts back to the right, facilitating oxygen release;
however, the high affinity of methemoglobin prevents this normal
process. 2,3-BPG, 2,3-bisphosphoglycerate; PO2, partial pressure
of oxygen; P-50, oxygen half saturation pressure of hemoglobin;
T°, temperature. (Redrawn from Benz EJ Jr: Hemoglobinopathies.
In Harrison’s online.)
natural skin tone, thickness, and pigmentation also may alter
findings.3
Central cyanosis is often secondary to the shunting of venous
unsaturated hemoglobin into the arterial circulation or the presence of abnormal hemoglobin. A bluish discoloration of the skin
and mucous membranes is best seen on perioral skin, oral mucosa,
or conjunctivae.
Peripheral cyanosis is secondary to vasoconstriction and slow
flow of normally oxygenated hemoglobin in arterial blood, allowing for greater oxygen extraction by the tissues. Peripheral cyanosis affects capillary beds and typically is seen in the extremities
and nail beds. Differential cyanosis may occur in either the upper
or lower (or the right or the left) half of the body, with the
remainder appearing well oxygenated. This form of cyanosis is
usually seen in patients with cyanotic heart disease with multiple
anomalies.
Vital signs should be obtained from all patients. Temperature is
typically normal. Blood pressure and heart rate vary unpredictably. Upper airway obstruction and other signs of respiratory
insufficiency should be sought. Intermittent apnea in infants suggests central nervous system immaturity or a central lesion. Infants
with cyanosis, increased respiratory depth, periodic apnea episodes, or diaphoresis with feeding may have congenital heart
disease.9,10 Tachypnea (>60 breaths/min) in a newborn may indicate a pulmonary disorder, congenital heart disease, infection,
metabolic disorder, or gastrointestinal or central nervous system
pathology.11
General appearance and mental status should be evaluated. The
head, eyes, ears, nose, and throat examination may reveal central
cyanosis. Funduscopic examination may detect dilated tortuous
Acquired
Medications
Amyl nitrite
Antineoplastics (cyclophosphamide, ifosfamide, flutamide)
Dapsone
Local anesthetics (benzocaine, lidocaine, prilocaine)
Nitroglycerin
Nitroprusside
Phenacetin
Phenazopyridine (Pyridium)
Quinones (chloroquine, primaquine)
Sulfonamides (sulfanilamide, sulfathiazide, sulfapyridine,
sulfamethoxazole)
Chemical Agents
Aniline dye derivatives (shoe dyes, marking inks)
Butyl nitrite
Chlorobenzene
Fires (heat-induced denaturation)
Food adulterated with nitrites
Food high in nitrates
Isobutyl nitrite
Naphthalene (mothballs)
Nitrophenol
Nitrous gases (seen in arc welders)
Paraquat
Silver nitrate
Trinitrotoluene
Well water (nitrates)
Pediatric
Reduced NADH methemoglobin reductase activity in infants
(<4 mo)
Seen in association with low birth weight, prematurity,
dehydration, acidosis, diarrhea, and hyperchloremia
Adapted from Goldfrank LR: Toxicologic Emergencies, 9th ed. New York:
McGraw-Hill; 2010.
G6PD, glucose-6-phosphate dehydrogenase; NADH, reduced nicotinamide
adenine dinucleotide.
veins and papilledema in patients with cyanotic congenital heart
disease.12 Jugular venous distention may be seen on the neck
examination in patients with pulmonary edema.
The chest examination may reveal crackles, wheezing, or inadequate ventilation. Heart sounds should be assessed for tachycardia, abnormal rhythm, or gallops, and the presence and quality of
murmurs, especially in newborns. Central pulse strength should
be noted. The abdomen should be examined for the presence of
hepatosplenomegaly, a pulsatile mass, or abdominal bruit.
Extremity examination includes evaluation of nail beds for
peripheral cyanosis, strength and symmetry of distal pulses, and
capillary refill. Evidence of chronic vascular disease, such as hair
loss and temperature difference, should be noted. Clubbing of the
nails may occur because of increased soft tissue and expansion of
the capillary beds (Fig. 14-2). Clubbing may be idiopathic or
hereditary but is usually the result of chronic hypoxemic states,
such as cyanotic heart disease, infective endocarditis, pulmonary
disease (chronic obstructive pulmonary disease, cystic fibrosis),
and some gastrointestinal disorders (cirrhosis, Crohn’s disease,
and regional enteritis). Thrombotic events should also be considered with findings of skin and nail bed hemorrhages or end-organ
damage (eye, kidney).
Chapter 14 / Cyanosis 131
BOX 14-2
Differential Diagnosis of Cyanosis
I. Peripheral cyanosis
A. Low cardiac output states
1. Shock
2. Left ventricular failure
3. Hypovolemia
B. Environmental exposure (cold)
1. Air or water
C. Arterial occlusion
1. Thrombosis
2. Embolism
3. Vasospasm (Raynaud’s phenomenon)
4. Peripheral vascular disease
D. Venous obstruction
E. Redistribution of blood flow from extremities
II. Central cyanosis
A. Decreased arterial oxygen saturation
1. High altitude (>8000 ft)
2. Impaired pulmonary function
a. Hypoventilation
b. Impaired oxygen diffusion
c. Ventilation-perfusion mismatching
(1) Pulmonary embolism
(2) Acute respiratory distress syndrome
(3) Pulmonary hypertension
d. Respiratory compromise
(1) Upper airway obstruction
(2) Pneumonia
(3) Diaphragmatic hernia
(4) Tension pneumothorax
(5) Polycythemia
B. Anatomic shunts
1. Pulmonary arteriovenous fistulae and intrapulmonary
shunts
2. Cerebral, hepatic, peripheral arteriovenous fistulae
3. Cyanotic congenital heart disease
a. Endocardial cushion defects
b. Ventricular septal defects
c. Coarctation of aorta
d. Tetralogy of Fallot
e. Total anomalous pulmonary venous drainage
f. Hypoplastic left ventricle
g. Pulmonary vein stenosis
h. Tricuspid atresia and anomalies
i. Premature closure of foramen ovale
j. Dextrocardia
k. Pulmonary stenosis of atrial septal defect
l. Patent ductus arteriosus with reversed shunt
C. Abnormal hemoglobin
1. Methemoglobinemia
a. Hereditary
b. Acquired
2. Sulfhemoglobinemia
3. Mutant hemoglobin with low oxygen affinity (e.g., hemoglobin Kansas)
Figure 14-2. Symmetrical clubbing. Equal cyanosis and clubbing of
hands and feet resulting from transposition of great vessels and a
ventricular septal defect without patent ductus arteriosus.
The peripheral blood classically appears chocolate brown
in color. Normally a small drop of blood placed on a white
sheet or filter paper will turn bright red in color when exposed
to 100% oxygen. No change in color is highly suggestive of
methemoglobinemia.4
Interpretation of pulse oximetry is problematic in the setting of
cyanosis (see Chapter 5). Assessment of distal perfusion usually
determines if poor circulation is a cause of low pulse oximetry.
Pulse oximetry measures light absorbance of tissue at 660 nm
(red, reduced hemoglobin) and 940 nm (infrared, oxyhemoglobin). The ratio of these two readings is the basis of the pulse
oximetry calculation. Methemoglobin absorbs well at both wavelengths, resulting in a saturation approximation of 85%, regardless
of the actual Pao2 and Sao2.15,16
Arterial blood gas testing assesses Sao2, often sampled when the
patient is breathing room air (see Fig. 14-1). CO-oximetry measurements should be specifically ordered if carbon monoxide
exposure or methemoglobinemia is suspected. Sulfhemoglobin is
reported as methemoglobin on CO-oximetry, so if sulfhemoglobinemia is possible, measured oxygen saturation should be specifically requested. Newer devices designed to measure methemoglobin
levels noninvasively (pulse CO-oximetry) may be useful but have
decreasing accuracy at lower Sao2 levels (<95%) and higher methemoglobin levels (>14%).17,18
Imaging
A neurologic examination should be performed focusing on
mental status, symmetry of motor and sensory function, and any
gross deficit.
Laboratory and Ancillary Testing
The complete blood count should be checked to assess for erythrocytosis, polycythemia, or anemia.13 Peripheral smear assesses
RBC morphology and fragments, as well as white blood cell differential count. A D-dimer level may be obtained if pulmonary
embolism (PE) is suspected. A normal D-dimer is useful in ruling
out PE in patients with a low pretest probability for the disease.14
A chest radiograph should be ordered to evaluate lung fields for
consolidation, infiltrates, and increased vasculature or pulmonary
edema. The cardiac silhouette and mediastinum may suggest congenital heart disease. In patients thought to have PE, an elevated
D-dimer level may indicate the need for lower extremity venous
Doppler ultrasound, computerized tomography pulmonary
angiogram, or rarely ventilation-perfusion scanning.
Electrocardiogram and Echocardiogram
An electrocardiogram should be performed on all patients with
cyanosis to assess for arrhythmias and acute ischemic changes.
Right-axis deviation or right ventricular hypertrophy may be seen
132 PART I ◆ Fundamental Clinical Concepts / Section Two • Cardinal Presentations
with significant cardiopulmonary disease (e.g., cor pulmonale,
acute pulmonary hypertension). An echocardiogram may be
helpful in detecting septal defects in infants or valvular disease in
infants and adults.
DIFFERENTIAL ALGORITHMS
Figures 14-3 and 14-4 outline an approach to the differential diagnosis and treatment for peripheral and central cyanosis, respectively. During the initial assessment, as the distribution of cyanosis
is noted, the clinician should initiate oxygen therapy and follow
steps to determine the cause of cyanosis. Clinical improvement
with oxygen suggests diffusion impairment. Patients who do not
respond to high-concentration oxygen are more likely to have
ventilation-perfusion ratio abnormalities, such as shunting from
a consolidated pulmonary lobule or congenital heart disease
with right-to-left shunting. Cardiac size and silhouette on a chest
radiograph may provide a clue to the presence of congenital
cardiac disease. If heart size is normal, impaired pulmonary
function, pulmonary embolus, or other noncardiac causes should
be considered. If no improvement occurs with 100% oxygen
therapy, the patient’s respiratory status should be reassessed, and
tension pneumothorax or upper airway obstruction considered.
Pulmonary embolus should be considered and a computed
tomography pulmonary angiogram performed. If a patient
exhibits no respiratory distress and remains resistant to oxygen
therapy, cardiac shunting or abnormal hemoglobin forms should
be considered and treated accordingly. Superior vena cava (SVC)
syndrome should be suspected in patients with central cyanosis
with facial, neck, and upper extremity swelling with venous distention and plethora.19
Critical Diagnoses
Acute cardiovascular and respiratory compromise is considered
in a patient with cyanosis and symptoms or signs of shock. The
differential diagnosis for these critical presentations includes
acute heart failure, acute coronary syndrome, and hypovolemic
or cardiogenic shock. In addition, consider acute respiratory
insufficiency or failure, massive PE, an exacerbation or decompensation in a patient with known congenital heart disease, or the first
presentation of pediatric congenital heart disease.
Emergent Diagnoses
Methemoglobinemia is an infrequent cause of cyanosis but should
be considered in patients without a history or physical findings
suggestive of cardiovascular or pulmonary disease.
Sulfhemoglobinemia is a rare cause of cyanosis most commonly
occurring after exposure to hydrogen sulfide from organic sources,
ABCs
Check O2 saturation
Administer oxygen
Improvement
with O2
No
improvement
with O2
Consider
low cardiac
output states
Consider
vascular occlusion
Hypovolemia
Sepsis
Cardiogenic
shock
Administer
IV fluids
Administer
IV fluids and
antibiotics;
vasopressors
as indicated
Inotropes,
chronotropes,
and
vasopressors
as needed
Consider
causes of
hypovolemia
and treat
accordingly
Look for
source of
infection
Consider
causes of
cardiogenic
shock and
echocardiogram
to direct
treatment
Warm
extremity
Improvement
Consider
vasospasm
from
environmental
exposure
Consult
rheumatology
and consider
calcium channel
blockers or
beta-blockers
No
improvement
Peripheral
vascular
disease
likely
Arterial
embolism or
thrombosis
suspected
Measure ABIs
and consult
vascular
surgery
Figure 14-3. An algorithmic approach to peripheral cyanosis. ABCs, airway, breathing, circulation; ABI, ankle brachial index; IV, intravenous.
Chapter 14 / Cyanosis 133
ABCs
Check O2 saturation
and ABG
Administer oxygen
No improvement
with O2 or PaO2
≤100 mm Hg or
SaO2 ≤70
Improvement
with O2 or PaO2
≥100 mm Hg
CXR
CXR and consider
co-oximetry, MetHg,
CO, CN levels,
Abnormal
cardiac
silhouette
Normal
cardiac
silhouette:
Consider
pulmonary
causes
Infiltrate
No
infiltrate
CHF
Inotropes,
chronotropes,
and
vasopressors
as needed
Antibiotics
and
respiratory
support as
needed
Consider PE,
hypoventilation,
polycythemia,
AV fistulae,
decreased
pulmonary
function
ECG
and
Echo
Consider
causes of
cardiogenic
shock
V/Q or
CTPA2
Negative
for PE
Digoxin
Diuresis
Consult
cardiology and
admit to ICU1
Positive
for PE
Hct
>65
Hct
<65
Phlebotomy,
IV fluids,
hematology
consult
IV fluids,
admit for
further
evaluation
ECG, Echo,
cardiac
enzymes
Respiratory
distress
No respiratory
distress
Consider
pneumothorax,
tension
pneumothorax,
PE, upper airway
obstruction,
bronchospasm
Consider:
• Chronic MetHg
• G6PD deficiency
• SulfHg
• Chronic cyanotic
heart disease
Admit or consult
as needed
Pneumothorax
Tube or needle
thoracostomy
Bronchospasm
Beta-agonists,
steroids, intubate
prn
Airway
obstruction
• Open airway
• Intubate
• Surgical
airway prn
• No infiltrate or
pneumothorax
on CXR
• Effusion may
be present
• Bronchospasm
may be present
MetHg >30% or >15%
with symptoms: Admit
• Treat with methylene
blue and O2
• No improvement with
methylene blue
→ SulfHg
CO elevation: Admit
O2 or hyperbaric O2 and
consider other causes.
CN elevation:
Admit Cyanokit
(hydroxocobalamin)
Consider other causes
LMWH or
heparin as
indicated
and admit
to ICU
Figure 14-4. An algorithmic approach to central cyanosis. ABCs, airway, breathing, circulation; ABG, arterial blood gas; AV, arteriovenous;
CHF, congestive heart failure; CN, cyanide; CO, carbon monoxide; CTPA, computed tomography pulmonary angiography; CXR, chest radiograph;
ECG, electrocardiogram; Echo, echocardiogram; G6PD, glucose-6-phosphate dehydrogenase; Hct, hematocrit; ICU, intensive care unit;
IV, intravenous; LMWH, low-molecular-weight heparin; MetHgb, methemoglobin; O2, molecular oxygen; PaO2, partial pressure of arterial oxygen;
ventilation-perfusion scan.
PE, pulmonary embolus; prn, as needed; RA, room air; SaO2, arterial oxygen saturation; SulfHg, sulfhemoglobin; V/Q,
1
Patients with chronic cyanotic heart disease may not require ICU care or even hospital admission. Disposition should be discussed with patient’s
cardiologist.
2 V/Q may be performed when CTPA is unavailable or contraindicated.
134 PART I ◆ Fundamental Clinical Concepts / Section Two • Cardinal Presentations
medications that are sulfonamide derivatives, or gastrointestinal
sources (bacterial overgrowth).20 Strong consideration should be
given to sulfhemoglobin toxicity in patients with cyanotic findings
and methemoglobin on CO-oximetry but who do not improve
with methylene blue treatment.
Polycythemia is defined as an elevated RBC mass from one
of three causes. Polycythemia vera is a disorder of bone marrow
stem cells with increased RBC mass, cyanosis, and splenomegaly.
Patients may demonstrate hyperviscosity syndrome. Secondary
polycythemia occurs with either an appropriate or inappropriate
increase of erythropoietin, a physiologic response to chronic
hypoxemia (<92% oxygen saturation), cyanotic congenital heart
disease, cigarette smoking, or high altitude exposures. Relative
polycythemia is an increased RBC mass, often resulting from
dehydration or reduced plasma volume.
Finally, vascular disease, such as Raynaud’s phenomenon, may
cause a cyanotic appearance. Raynaud’s phenomenon occurs in
15% of the population and has a female predominance. Patients
have an abnormal response to excessive cold or emotional stress
and report vasoconstriction, profound cold sensitivity, and recurrent events of sharply demarcated pallor or cyanosis of the digits.
Most commonly the cutaneous arterial capillary beds of the
fingers and toes are affected,21 but tongue, ear, and other distal
areas may also be affected.
EMPIRICAL MANAGEMENT
Administration of high-flow oxygen is the first therapy for
patients with cyanosis. Any clinical improvement, or lack thereof,
should be noted. Thereafter, consideration of abnormal hemoglobin and toxin-induced cyanosis is crucial because the administration of appropriate antidotes and systemic therapies may decrease
morbidity.
Intravenous fluid resuscitation should be initiated in patients
with hypovolemia. Treatment of congestive heart failure, arrhythmias, or poor cardiac output should occur as clinical conditions
indicate. Cardiology consultation is recommended in patients
thought to have congenital or ischemic heart disease. Although
several specific treatments are discussed here, the cause of the
cyanosis may be elusive, and hospitalization is required in all but
chronic stable cases.
Specific Strategies
Methemoglobinemia and Sulfhemoglobinemia
If cutaneous exposure to an inciting agent (i.e., aniline dyes)
occurred, complete decontamination with soap and water is recommended. The staff should use appropriate protective equipment. Urgent treatment with oxygen and methylene blue (1-2 mg/
kg intravenously [IV] over 5 minutes) is indicated for patients
with symptomatic hypoxia (dysrhythmias, angina, respiratory
distress, seizures, or coma) or methemoglobin levels greater
than 30%. Sulfhemoglobinemia is suggested when the laboratory
reports an elevated methemoglobin level and the patient does not
respond to methylene blue. Treatment of sulfhemoglobinemia is
supportive in addition to removing the causative agent.
Other Causes of Cyanosis
Acute therapy for patients with symptomatic hyperviscosity
syndrome and secondary polycythemia includes phlebotomy
and volume expansion with isotonic crystalloid. The goal of
therapy is a normal hematocrit (45%).22 Long-term therapy is
focused on the underlying cause, and patients require referral to
a hematologist.
Patients with SVC syndrome require further evaluation for
mediastinal mass or vascular abnormality. Conservative management with oxygen and elevation of the head of the bed often
provide significant symptomatic relief. Vascular stenting may be
necessary, and radiation or chemotherapy may be indicated in
cases caused by malignancy.19
Raynaud’s phenomenon is treated by warming the affected
digits and extremities. Systemic vasodilating agents (e.g., calcium
channel blockers [nifedipine] or nitrates, endothelin antagonists,
statins, phosphodiesterase inhibitors, and botulinum toxin) may
be useful in the acute setting.21 If there is no improvement of
peripheral cyanosis with warming and administration of 100%
oxygen, arterial insufficiency or occlusion may be present. In
cases of critical limb ischemia, intravenous heparin should be
considered in consultation with a vascular surgeon. Embolic
sources, such as endocarditis and abdominal aortic aneurysms,
should be considered. Vascular bypass, intra-arterial thrombolysis,
or stenting may be indicated.
Carbon monoxide and cyanide poisoning do not typically cause
cyanosis and are covered elsewhere.
PATIENT DISPOSITION
Admission
All patients with a first episode of cyanosis or an uncertain cause
require hospital admission. Cardiology consultation and referral
are recommended for children with a first episode of congestive
heart failure and newly diagnosed or suggested congenital heart
disease. Surgical consultation and intervention are indicated for
acute arterial occlusion from embolic or thrombotic sources. Multiple consultations may be appropriate in patients with SVC syndrome, including a vascular surgeon, interventional radiologist,
oncologist, and radiation oncologist.
Discharge
Patients with peripheral cyanosis from vasospasm, those with
asymptomatic methemoglobinemia less than 15%, and stable
patients with primary pulmonary disease may be treated as outpatients after several hours of monitoring in the ED. Follow-up
should occur within 24 hours unless the patient has a previous
diagnosis of chronic cyanosis. Instructions should clearly state
that if the cyanosis worsens, or if dyspnea, altered mentation, or
chest pain occurs after discharge, the patient should return immediately to the ED.
The references for this chapter can be found online by
accessing the accompanying Expert Consult website.
Chapter 14 / Cyanosis 134.e1
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