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Cyanosis, Emergency Medicine

Basics

Description

- 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

- Impaired pulmonary function: - Hypoventilation: - Pneumonia - Chronic obstructive pulmonary disease - Pulmonary edema

- 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

- Respiratory: - Upper airway disorders: - Croup - Bacterial tracheitis - Epiglottitis - Retropharyngeal abscess - Foreign body

- Establish timing of onset of cyanosis - Associated symptoms - Pain - Dyspnea - Fatigue - Headache - Changes in mental status

- Lower extremities with upper extremities unaffected - Differential cyanosis - Pseudocoarctation and patent ductus arteriosus - Inferior vena cava syndrome

- Single extremity - Arterial or venous insufficiency

- Arterial blood gas: - Oxygen tension - Measured hemoglobin saturation - Cyanosis in face of normal PO2, think methemoglobinemia - Blood in methemoglobinemia is chocolate color. - Methemoglobin level

- Echo: - Bubble study if septal defect/shunt suspected - Wall motion/valvular abnormalities - Pericardial fluid

- Chromhidrosis - Rare condition characterized by the secretion of colored sweat

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/dLMethemoglobin >1.5 g/dLSulfhemoglobin >0.5 g/dL
  • The absolute amount of deoxygenated hemoglobin is the pigment that creates the bluish tintThe amount of oxyhemoglobin does not affect the bloods colorCyanosis 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 cyanosisCentral cyanosisHypoxemiaAnatomic right to left shuntsAbnormal hemoglobin derivativesPeripheral cyanosisTissue extracts more than normal amounts of O2 from the bloodHypoperfusionVasoconstriction to cold air or waterArterial insufficiencyVenous insufficiencyAcrocyanosis: Painless, symmetrical, cyanosis in distal parts of body, the pathophysiologic cause of which is not known

Etiology

Central cyanosis

  • Impaired pulmonary function:Hypoventilation:PneumoniaChronic obstructive pulmonary diseasePulmonary edemaVentilation/perfusion mismatch:Diffusion problems:Interstitial lung diseaseAnatomic shuntsPulmonary arteriovenous fistula:Hereditary hemorrhagic telangiectasiaHigh-altitude related, with decreased atmospheric pressure at 16,000 ft
  • Cardiac abnormalities with right to left shuntEisenmenger syndromePulmonary hypertensionLongstanding intracardiac shunt (VSD, patent ductus arteriosus, ASD)Reversal of flow through detected when pulmonary artery pressure exceeds threshold
  • Abnormal hemoglobinLow-oxygen affinity hemoglobin mutants:Hb KansasHb Beth IsraelHb St. MandeCongenital methemoglobinemia:Cytochrome b5 reductase deficiencyHemoglobin M diseaseAcquired methemoglobinemia:Aniline dyesChloroquine, primaquineDapsoneLocal anesthetic agents such as lidocaineHigh doses of methylene blueNaphthaleneNitrites, nitroglycerineSulfonamidesFava beansSulfhemoglobin:Generally benignIrreversible alteration of hemoglobinCaused by many medicationsDimethyl sulfoxidePaintPhenacetinPhenazopyridinePhenylenediaminePhenylhydroxylamineSulfanilamideSulfapyridineSulfathiazoleSulfur compounds

Peripheral cyanosis

  • Shock
  • Exposure to cold
  • Arterial insufficiency
  • Venous insufficiency
  • Raynaud phenomenon
  • Acrocyanosis
  • Cardiac:Cyanotic congenital defects:Tetralogy of FallotTransposition of great vesselsTruncus arteriosusPulmonary and tricuspid atresiaEbstein anomalyPseudocoarctationPatent ductus arteriosusTotal anomalous pulmonary venous return
  • Pulmonary stenosis:Any right-to-left shunting
  • Respiratory:Upper airway disorders:CroupBacterial tracheitisEpiglottitisRetropharyngeal abscessForeign bodyLower airway disorders:AsthmaBronchiolitisPneumoniaCystic fibrosisPulmonary edema/CHFPulmonary embolism
  • Neurologic:

Diagnosis

Signs and Symptoms

  • A bluish discoloration of the skin and mucous membranes that blanches with pressure:Chocolate color:Slate gray color:Methemoglobinemia, sulfhemoglobinReddish blue

History

  • Establish timing of onset of cyanosis
  • Associated symptomsPainDyspneaFatigueHeadacheChanges 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 discolorationSymmetrical involving extremities and mucus membranesFace, neck, and upper extremitiesSuperior vena cava syndromeLower extremities with upper extremities unaffectedDifferential cyanosisPseudocoarctation and patent ductus arteriosusInferior vena cava syndromeSingle extremityArterial or venous insufficiencySymmetrical, painful, involving extremitiesSymmetrical, painless, involving extremities and face with hyperhidrosis
  • Clubbing
  • 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 commonConsider methemoglobinemia

Diagnosis Tests & Interpretation

Lab

  • Pulse oximetry:Does not assess ventilationResults inaccurate with:Abnormal hemoglobinsNail polishPigmented skinHypoperfusionUse of vital dyes
  • Arterial blood gas:Oxygen tensionMeasured hemoglobin saturationCyanosis in face of normal PO2, think methemoglobinemiaBlood in methemoglobinemia is chocolate color.Methemoglobin level
  • Complete blood chemistry:
  • 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 bodyExpiratory view if occult pneumothorax suspected
  • Radiograph of neck for upper airway disorders:Foreign bodySteeple sign (croup)Prevertebral swelling (retropharyngeal abscess)Epiglottic swelling
  • EKG:Dysrhythmia, injury, or ischemia
  • Echo:Bubble study if septal defect/shunt suspectedWall motion/valvular abnormalitiesPericardial fluid

Differential Diagnosis

  • Abnormal skin pigmentation (fails to blanch with pressure)AmiodaroneMinocyclineChronic high-dose chlorpromazineArgyria (silver deposits)ArsenicAlkaptonuriaChrysiasis (secondary to parenteral administration of gold salts)Tattoos
  • ChromhidrosisRare 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 μg/min, titrate up by 5 μg/min every 3-5 min until desired effect
  • Prostaglandin E1: 0.05-0.1 μg/kg/min IV; max. 0.4 μg/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)