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GENERAL CONSIDERATIONS
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Neonatal and pediatric cyanosis is a common complaint seen in the emergency department. The incidence of pediatric cyanosis declines with age; however, the severity of the underlying cause can become more ominous. Accordingly, it is important to categorize and understand various etiologies of cyanosis as they relate to age and presentation in order to stratify risk and severity. This chapter will differentiate peripheral cyanosis from central cyanosis and the benign and pathologic causes and treatment of each.
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Cyanosis is visually perceived as blue or purple discoloration in body tissues resulting from abnormalities of hemoglobin and oxygen saturation in the capillary beds within those tissues. Primarily, desaturated hemoglobin gives the characteristic appearance of cyanosis. Any factor that decreases the overall oxygen saturation of hemoglobin in the arterial blood (loading) or increases the oxygen consumption from hemoglobin in peripheral tissues (unloading) can cause cyanosis. Accordingly, hypoxia or other causes of decreased oxygen exchange at the pulmonary capillary level will cause systemic or central cyanosis.
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Central cyanosis becomes visible to the human eye when desaturated hemoglobin reaches 5 g/dL, which roughly corresponds to an oxygen saturation of approximately 85%. The saturation of hemoglobin and oxygen saturations causing peripheral cyanosis are more variable. A number of factors other than central causes contribute to peripheral cyanosis, ranging from normal physiologic events to life-threatening causes. Most factors relate to changes in arterial flow such as vasomotor tone, perfusion, and temperature changes.
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Although uncommon in the emergency department, the most common type of cyanosis is commonly called acrocyanosis, or cyanosis of the hands, feet, and perioral area. The nonscientific term refers to peripheral cyanosis most common in newborns during the first minutes of life. Neonates are born with a high degree of intrinsic peripheral vascular resistance and vasomotor instability. Normally, with rewarming, suctioning, and oxygenation, acrocyanosis remains confined to the periphery and lasts several minutes only. Cyanosis is included in the APGAR scoring system for newborns (Figures 11–1 and 11–2). In some infants, acrocyanosis may persist longer or become central cyanosis which may become pathologic.
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Well infants may present to the emergency department with peripheral cyanosis. Parents may be concerned about peripheral cyanosis associated with bath time, feedings and sometimes, tantrums. In infants, vasomotor changes associated with temperature, feeding, and agitation or crying can produce transient peripheral cyanosis. Central cyanosis is not typically seen in these patients and should prompt ...