A right-to-left shunt produces which clinical finding?

A right-to-left shunt produces which clinical finding?

• A. Tachycardia
• B. Cyanosis
• C. Pulmonary edema
• D. Hypertension

Answer: (B)

Right-to-left shunting causes deoxygenated blood to bypass the lungs and enter the systemic arterial circulation. This lowers the oxygen content of arterial blood, so tissues receive hypoxemic blood. The result is central cyanosis—the bluish discoloration of the lips, tongue, and mucous membranes—especially when oxygen saturation drops significantly. Tachycardia can accompany hypoxemia as a compensatory response, but it’s not specific to shunting. Pulmonary edema and hypertension are more related to other conditions or left-sided pressures, not the direct consequence of a right-to-left shunt. So cyanosis is the hallmark finding.

Right-to-left shunting causes deoxygenated blood to bypass the lungs and enter the systemic arterial circulation. This lowers the oxygen content of arterial blood, so tissues receive hypoxemic blood. The result is central cyanosis—the bluish discoloration of the lips, tongue, and mucous membranes—especially when oxygen saturation drops significantly. Tachycardia can accompany hypoxemia as a compensatory response, but it’s not specific to shunting. Pulmonary edema and hypertension are more related to other conditions or left-sided pressures, not the direct consequence of a right-to-left shunt. So cyanosis is the hallmark finding.