Rosen & Barkin's 5-Minute Emergency Medicine Consult (186 page)

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
      b
      5 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

• 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
      

• 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
  

• 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
  

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

• 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 PO
    ₂
    , think methemoglobinemia
    
  • Blood in methemoglobinemia is chocolate color.
    
  • Methemoglobin level
    
• Complete blood chemistry:
  
  • Check hemoglobin.
    
• Hyperoxia test for congenital cyanosis of newborn:
  
  • If PO
    ₂
    fails to increase to 100 mm Hg after 100% O
    ₂
    , suspect congenital heart disease.
    

• 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
    

• 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

• Assess and establish patent airway.
  
• Correct any airway obstruction.
  
• Recognize an incorrectly placed airway.
  
• 100% O
  ₂
  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
  

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

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

• 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 E
  ₁
  : 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