Cyanosis, Emergency Medicine

Basics

Description

Abnormal bluish discoloration of the skin or mucous membranes

Caused by abnormal elevations of deoxygenated hemoglobin or hemoglobin derivatives in the capillaries:
- Deoxygenated hemoglobin >5 g/dL
- Methemoglobin >1.5 g/dL
- Sulfhemoglobin >0.5 g/dL
The absolute amount of deoxygenated hemoglobin is the pigment that creates the bluish tint
- The amount of oxyhemoglobin does not affect the bloods color
- Cyanosis is more common in patients with polycythemia and less common in patients with anemia.
Cyanosis varies based on skin thickness or pigment
Accumulation of deoxygenated hemoglobin may be systemic producing central cyanosis or localized producing peripheral cyanosis
- Central cyanosis
  - Hypoxemia
  - Anatomic right to left shunts
  - Abnormal hemoglobin derivatives
- Peripheral cyanosis
  - Tissue extracts more than normal amounts of O2 from the blood
  - Hypoperfusion
  - Vasoconstriction to cold air or water
  - Arterial insufficiency
  - Venous insufficiency
  - Acrocyanosis: Painless, symmetrical, cyanosis in distal parts of body, the pathophysiologic cause of which is not known

Etiology

Central cyanosis

Impaired pulmonary function:
- Hypoventilation:
  - Pneumonia
  - Chronic obstructive pulmonary disease
  - Pulmonary edema
- Ventilation/perfusion mismatch:
  - Asthma
  - Pulmonary embolus
- Diffusion problems:
  - Interstitial lung disease
  - Anatomic shunts
- Pulmonary arteriovenous fistula:
  - Hereditary hemorrhagic telangiectasia
- High-altitude related, with decreased atmospheric pressure at 16,000 ft
Cardiac abnormalities with right to left shunt
- Eisenmenger syndrome
  - Pulmonary hypertension
  - Longstanding intracardiac shunt (VSD, patent ductus arteriosus, ASD)
  - Reversal of flow through detected when pulmonary artery pressure exceeds threshold
Abnormal hemoglobin
- Low-oxygen affinity hemoglobin mutants:
  - Hb Kansas
  - Hb Beth Israel
  - Hb St. Mande
- Congenital methemoglobinemia:
  - Cytochrome b5 reductase deficiency
  - Hemoglobin M disease
- Acquired methemoglobinemia:
  - Aniline dyes
  - Chloroquine, primaquine
  - Dapsone
  - Local anesthetic agents such as lidocaine
  - High doses of methylene blue
  - Naphthalene
  - Nitrites, nitroglycerine
  - Sulfonamides
  - Fava beans
- Sulfhemoglobin:
  - Generally benign
  - Irreversible alteration of hemoglobin
  - Caused by many medications
  - Dimethyl sulfoxide
  - Paint
  - Phenacetin
  - Phenazopyridine
  - Phenylenediamine
  - Phenylhydroxylamine
  - Sulfanilamide
  - Sulfapyridine
  - Sulfathiazole
  - Sulfur compounds

Peripheral cyanosis

Shock
Exposure to cold
Arterial insufficiency
Venous insufficiency
Raynaud phenomenon
Acrocyanosis

Cardiac:
- Cyanotic congenital defects:
  - Tetralogy of Fallot
  - Transposition of great vessels
  - Truncus arteriosus
  - Pulmonary and tricuspid atresia
  - Ebstein anomaly
  - Pseudocoarctation
  - Patent ductus arteriosus
- Total anomalous pulmonary venous return
Pulmonary stenosis:
- Any right-to-left shunting
Respiratory:
- Upper airway disorders:
  - Croup
  - Bacterial tracheitis
  - Epiglottitis
  - Retropharyngeal abscess
  - Foreign body
- Lower airway disorders:
  - Asthma
  - Bronchiolitis
  - Pneumonia
  - Cystic fibrosis
  - Pulmonary edema/CHF
  - Pulmonary embolism
Neurologic:
- Breath holding

Diagnosis

Signs and Symptoms

A bluish discoloration of the skin and mucous membranes that blanches with pressure:
- Chocolate color:
  - Methemoglobinemia
- Slate gray color:
  - Methemoglobinemia, sulfhemoglobin
- Reddish blue
  - Venous stasis

History

Establish timing of onset of cyanosis
Associated symptoms
- Pain
- Dyspnea
- Fatigue
- Headache
- Changes in mental status
Medication list
Occupational exposure or use of chemicals or drugs

Physical Exam

General appearance and vital signs for shock and respiratory distress
Does the discoloration blanch with pressure?
- Distinguishes cyanosis from abnormal skin pigmentation
Location of discoloration
- Symmetrical involving extremities and mucus membranes
  - Central cyanosis
- Face, neck, and upper extremities
  - Superior vena cava syndrome
- Lower extremities with upper extremities unaffected
  - Differential cyanosis
  - Pseudocoarctation and patent ductus arteriosus
  - Inferior vena cava syndrome
- Single extremity
  - Arterial or venous insufficiency
- Symmetrical, painful, involving extremities
  - Raynaud phenomenon
- Symmetrical, painless, involving extremities and face with hyperhidrosis
  - Acrocyanosis
Clubbing
- Chronic hypoxemia
Pulmonary exam
Cardiac exam
Extremities for edema, pulses, and temperature

Essential Workup

Assess airway and ventilation as 1st priority:
- Stabilize airway and provide adequate ventilation.
Investigate hypoxemia causes:
- Cardiac and respiratory most common
- Consider methemoglobinemia

Diagnosis Tests & Interpretation

Lab

Pulse oximetry:
- Does not assess ventilation
- Results inaccurate with:
  - Abnormal hemoglobins
  - Nail polish
  - Pigmented skin
  - Hypoperfusion
  - Use of vital dyes
Arterial blood gas:
- Oxygen tension
- Measured hemoglobin saturation
- Cyanosis in face of normal PO2, think methemoglobinemia
- Blood in methemoglobinemia is chocolate color.
- Methemoglobin level
Complete blood chemistry:
- Check hemoglobin.
Hyperoxia test for congenital cyanosis of newborn:
- If PO2 fails to increase to 100 mm Hg after 100% O2, suspect congenital heart disease.

Imaging

CXR to investigate respiratory or cardiac pathology:
- Inspiratory/expiratory views if foreign body
- Expiratory view if occult pneumothorax suspected
Radiograph of neck for upper airway disorders:
- Foreign body
- Steeple sign (croup)
- Prevertebral swelling (retropharyngeal abscess)
- Epiglottic swelling
EKG:
- Dysrhythmia, injury, or ischemia
Echo:
- Bubble study if septal defect/shunt suspected
- Wall motion/valvular abnormalities
- Pericardial fluid

Differential Diagnosis

Abnormal skin pigmentation (fails to blanch with pressure)
- Amiodarone
- Minocycline
- Chronic high-dose chlorpromazine
- Argyria (silver deposits)
- Arsenic
- Alkaptonuria
- Chrysiasis (secondary to parenteral administration of gold salts)
- Tattoos
Chromhidrosis
- Rare condition characterized by the secretion of colored sweat

Treatment

Pre-Hospital

Assess and establish patent airway.
Correct any airway obstruction.
Recognize an incorrectly placed airway.
100% O2 using a nonrebreathing device
Ensure adequate ventilation.
Recognize need to establish definitive airway.
Protect cervical spine if trauma suspected.
IV line, monitor, pulse oximetry
Albuterol nebulizer for bronchospasm
Racemic epinephrine nebulizer for severe croup
Management of pulmonary edema per protocol

Initial Stabilization/Therapy

Oxygen supplied through a 100% nonrebreathing device
Immediately assess and address airway issues.

Treatment General Measures

Recognize and manage cardiopulmonary disorders.
Methylene blue for methemoglobinemia exceeding 30%:
- Do not use if patient has G6PD deficiency.

Medication

Albuterol nebulized: 0.03 mL/kg (5 mg/mL)
Dexamethasone: (For croup) 0.75-9 mg/d in div. doses q6-12h
Furosemide: 0.5 mg/kg IV over 1-2 min. May double the dose after 1 hr if unsatisfactory response.
Magnesium: 2 g IV over 10 min (40 mg/kg IV over 20 min)
Methylene blue: 1-2 mg/kg IV of 1% solution over 5 min
Methylprednisolone: 1-2 mg/kg IV q6h
Morphine: 2-4 mg IV (0.05-0.1 mg/kg IV q2h PRN)
Nitroglycerine: USE NON-PVC tubing. 5 Î¼g/min, titrate up by 5 Î¼g/min every 3-5 min until desired effect
Prostaglandin E1: 0.05-0.1 Î¼g/kg/min IV; max. 0.4 Î¼g/kg/min
Racemic epinephrine nebulized: 0.25-0.75 mL of 2.25% solution diluted in 2 mL NS

Follow-Up

Disposition

Admission Criteria

Most affected patients should be admitted to the hospital.
ICU admission is required for any instability or cyanosis.

Discharge Criteria
Reversible causes of hypoxia:

Reactive airway disease responsive to β-agonists
Pulmonary edema in patient with known CHF but no suspicion of myocardial injury and diuresis

Pearls and Pitfalls

First assume hypoxemia and immediately assess airway and breathing
Chocolate-colored blood or unchanging oxygen saturation despite aggressive administration of oxygen: Think methemoglobinemia.

Additional Reading

BheemReddy S, Messineo F, Roychoudhury D. Methemoglobinemia following transesophageal echocardiograph: A case report and review. Echocardiography. 2006;23(4):319-321.
Kurklinsky AK, Miller VM, Rooke TW. Acrocyanosis: The flying Dutchman. Vasc Med. 2011;16(4):288-301.
McMullen SM, Patrick W. Cyanosis. Am J Med. 2013;126(3):210-212.
LeBlond R, Brown D, DeGowin R. DeGowins Diagnostic Examination. 9th ed. McGraw Hill Companies; 2009.
Stack A. Cyanosis. Synopsis of Pediatric Emergency Medicine. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2002:64-67.

Codes

ICD9

770.83 Cyanotic attacks of newborn
782.5 Cyanosis

ICD10

P28.2 Cyanotic attacks of newborn
R23.0 Cyanosis

SNOMED

3415004 Cyanosis (finding)
119419001 Cyanosis of skin (finding)
95442007 Peripheral cyanosis (disorder)
95617006 Neonatal cyanosis (disorder)

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