Cyanosis

Published on 21/03/2015 by admin

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Last modified 21/03/2015

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Chapter 12 CYANOSIS

Theodore X. O’Connell

General Discussion

Cyanosis is a blue to dusky hue which may be seen in the newborn. Bruising or ecchymosis may look like cyanosis and is differentiated by applying pressure over the skin, which will blanch with cyanosis but not with ecchymosis. Central cyanosis involves the entire body, including the mucous membranes and tongue. Peripheral cyanosis, or acrocyanosis, is limited to the extremities.

Arterial blood oxygen content is normal in peripheral cyanosis, whereas arterial blood oxygen content is decreased in central cyanosis. Although peripheral cyanosis may be seen with exposure to the cold, it may also be the presenting sign of serious conditions such as sepsis, hypoglycemia, or hypoplastic left-sided heart syndrome. Therefore, peripheral cyanosis should not be ignored unless other conditions have been ruled out.

In addition to central and peripheral cyanosis, cyanosis has several other patterns. In differential cyanosis, the upper part of the body remains pink while the lower part of the body remains cyanotic. This pattern is seen in conditions in which there is right-to-left shunt from the pulmonary artery to the descending aorta through a patent ductus arteriosus (PDA). In reverse differential cyanosis, the upper part of the body remains cyanotic, whereas the lower part remains pink. Reverse differential cyanosis may occur in transposition of the great vessels with pulmonary hypertension and shunt through a PDA and total anomalous pulmonary venous return above the diaphragm with shunt through a PDA. Harlequin condition is a unique phenomenon in which one quadrant or one half of the body may become cyanotic while the rest of the body remains pink. This condition is thought to result from vasomotor instability.

During the assessment of cyanosis in the newborn, it is important to identify the cause of cyanosis on a physiologic basis. The two most common causes of cyanosis are cardiac and pulmonary conditions. Cyanosis also may result from abnormalities in the oxygen carrying states of the hemoglobin, metabolic causes, central nervous system (CNS) conditions, and sepsis. Other causes are outlined below.

Because most causes for cyanosis are attributable to cardiopulmonary problems, it is important to differentiate between cardiac and pulmonary causes. The hyperoxia test, described below, can help differentiate between cardiac and noncardiac causes. Respiratory disease is more likely in newborns who are tachypneic and using accessory muscles of respiration.

Cyanotic congenital heart defects that are not detected in the newborn nursery will present during the first 2 to 3 weeks of life when the ductus arteriosus closes. Echocardiogram is indicated in these patients.

Causes of Cyanosis

Cardiac Causes

Pulmonary Causes

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