After the first graft is sewn into the aorta during cardiopulmonary bypass, which explanation best accounts for a rise in arterial pressure with a concomitant low pulmonary artery pressure?

After the first graft is sewn into the aorta during cardiopulmonary bypass, which explanation best accounts for a rise in arterial pressure with a concomitant low pulmonary artery pressure?

• A. Malposition of the aortic cannula
• B. Malposition of the venous cannula
• C. Faulty ventricular venting
• D. Pulmonary artery catheter migration

Answer: (D)

A sudden rise in arterial pressure with a low reading from the pulmonary artery catheter points to a displacement of the Swan-Ganz catheter. When perfusion is being re-established after grafting, the systemic arterial line can show high pressure as expected, but if the PA catheter tip has moved out of the pulmonary artery and into the high-pressure systemic circuit (for example, into the aorta or through the catheter path into the arterial side), the PA port no longer measures true pulmonary artery pressures and may read abnormally low. This catheter migration creates the discordant two-pressure pattern. Other scenarios, like a malpositioned aortic cannula or venous cannula, primarily affect flow and perfusion rather than producing a specific combination of high arterial pressure with low PA pressure. Faulty ventricular venting changes drainage and filling, not the separate readings of arterial versus PA pressures. So the observed pressure pattern is best explained by the pulmonary artery catheter migrating out of its intended position, giving a high systemic arterial reading while the PA pressure remains falsely low. If this occurs, confirm catheter location and reposition as needed to restore accurate hemodynamic monitoring.

A sudden rise in arterial pressure with a low reading from the pulmonary artery catheter points to a displacement of the Swan-Ganz catheter. When perfusion is being re-established after grafting, the systemic arterial line can show high pressure as expected, but if the PA catheter tip has moved out of the pulmonary artery and into the high-pressure systemic circuit (for example, into the aorta or through the catheter path into the arterial side), the PA port no longer measures true pulmonary artery pressures and may read abnormally low. This catheter migration creates the discordant two-pressure pattern.

Other scenarios, like a malpositioned aortic cannula or venous cannula, primarily affect flow and perfusion rather than producing a specific combination of high arterial pressure with low PA pressure. Faulty ventricular venting changes drainage and filling, not the separate readings of arterial versus PA pressures. So the observed pressure pattern is best explained by the pulmonary artery catheter migrating out of its intended position, giving a high systemic arterial reading while the PA pressure remains falsely low. If this occurs, confirm catheter location and reposition as needed to restore accurate hemodynamic monitoring.