During precaval blood collection from swine on the right side, which structure should be avoided?

During precaval blood collection from swine on the right side, which structure should be avoided?

• A. Left phrenic nerve
• B. Right phrenic nerve
• C. Vagus nerve
• D. Aorta

Answer: (A)

During a precaval (cranial vena cava) blood collection from swine approached from the right side, the left phrenic nerve lies close to the expected needle path as it traverses the mediastinal area toward the diaphragm. The left phrenic nerve supplies the left side of the diaphragm, so injuring it could cause diaphragmatic dysfunction on that side. Therefore, avoiding the left phrenic nerve helps prevent diaphragmatic paralysis while accessing the cranial vena cava. The vagus nerve, the aorta, and the right phrenic nerve are less likely to be encountered along a correct right-sided puncture trajectory, or can be avoided with careful technique.

During a precaval (cranial vena cava) blood collection from swine approached from the right side, the left phrenic nerve lies close to the expected needle path as it traverses the mediastinal area toward the diaphragm. The left phrenic nerve supplies the left side of the diaphragm, so injuring it could cause diaphragmatic dysfunction on that side. Therefore, avoiding the left phrenic nerve helps prevent diaphragmatic paralysis while accessing the cranial vena cava. The vagus nerve, the aorta, and the right phrenic nerve are less likely to be encountered along a correct right-sided puncture trajectory, or can be avoided with careful technique.