BCA Thoracic & Vascular Anesthesia Flashcards

During one-lung ventilation (OLV), the MOST common cause of hypoxemia is:

Answer: Hypoxic pulmonary vasoconstriction failure in the non-ventilated lung

Impaired hypoxic pulmonary vasoconstriction (HPV) in the non-ventilated (collapsed) lung allows continued blood flow without gas exchange, creating a large intrapulmonary shunt.

A double-lumen endotracheal tube (DLT) is placed for left lung surgery. Correct positioning is confirmed by:

Answer: Clinical auscultation and fiberoptic bronchoscopy

Fiberoptic bronchoscopy combined with clinical auscultation is the gold standard for confirming correct DLT position and ensuring adequate lung isolation.

During thoracic aortic cross-clamping, the MOST critical consequence of prolonged clamp time is:

Answer: Spinal cord ischemia leading to paraplegia

Aortic cross-clamping interrupts blood flow to the anterior spinal artery (artery of Adamkiewicz), causing ischemic myelopathy and potential permanent paraplegia.

Cerebrospinal fluid (CSF) drainage during thoracic aortic aneurysm repair is used to:

Answer: Increase spinal cord perfusion pressure by lowering CSF pressure

Draining CSF reduces intrathecal pressure, thereby increasing spinal cord perfusion pressure (SCPP = MAP − CSF pressure) and protecting the spinal cord from ischemia.

Which volatile anesthetic MOST inhibits hypoxic pulmonary vasoconstriction (HPV)?

Answer: All volatiles inhibit HPV equally at equipotent doses

At equipotent doses (1 MAC), all currently used volatile anesthetics produce similar degrees of HPV inhibition; the clinical significance at typical doses is modest.

A patient undergoes pneumonectomy. Postoperative fluid management should be conservative primarily because of the risk of:

Answer: Pulmonary edema in the remaining single lung

After pneumonectomy, all cardiac output passes through a single lung; aggressive fluid administration rapidly overwhelms its vascular capacity, causing post-pneumonectomy pulmonary edema.