Certified Registered Nurse Anesthetist (CRNA) Practice Exam

What does the Swan-Ganz catheter primarily help measure?

1. Systemic blood pressure

2. Intravascular pressure in the left atrium

3. Oxygen levels in the pulmonary circulation

4. Pulmonary vascular resistance

The correct answer is: Intravascular pressure in the left atrium

The Swan-Ganz catheter, also known as a pulmonary artery catheter, is primarily designed to measure pressures in the heart and pulmonary arteries, specifically offering valuable hemodynamic information. One of its key functions is to assess the pressures in the left atrium indirectly by measuring the pulmonary capillary wedge pressure (PCWP). This measurement provides critical data regarding left atrial pressure and fluid status, which is essential for managing patients with heart failure or other conditions affecting cardiac output and fluid dynamics. While systemic blood pressure can be measured using various methods, the Swan-Ganz catheter's specific utility lies in its ability to provide insights into the pressures of the heart chambers, particularly the left atrium, through the pulmonary vasculature. It does not measure systemic blood pressure directly, nor does it determine oxygen levels in the pulmonary circulation or calculate pulmonary vascular resistance directly, although it can contribute to a broader understanding of these parameters in the context of overall cardiac performance and fluid status.