Respiratory and Thoracic Anesthesia Flashcards

During mediastinoscopy, the surgeon reports loss of the right radial pulse. The most likely cause is:

Answer: Compression of the innominate (brachiocephalic) artery by the mediastinoscope

The mediastinoscope can compress the innominate artery against the trachea, reducing right-sided perfusion; pulse oximetry on the right hand detects this before serious sequelae occur.

Which statement about the use of PEEP during one-lung ventilation is TRUE?

Answer: PEEP on the ventilated lung reduces shunt by recruiting collapsed alveoli

Judicious PEEP (5 cmH2O) to the ventilated dependent lung recruits atelectatic alveoli and improves V/Q matching, though excessive PEEP can increase PVR and worsen hypoxemia.

A fiberoptic bronchoscope confirms the right upper lobe bronchial orifice is blocked by the bronchial cuff of a right-sided double-lumen tube. The correct initial action is:

Answer: Deflate the bronchial cuff and withdraw the tube 1-2 cm

The right upper lobe bronchus originates close to the carina; partial withdrawal with cuff deflation allows the RUL orifice to align with the tube's ventilation slot.

Hypoxic pulmonary vasoconstriction is blunted by all of the following EXCEPT:

Answer: Acidosis

Acidosis actually potentiates HPV rather than inhibiting it; vasodilators, hypothermia, and volatile agents at high concentrations are all recognized HPV inhibitors.

Postoperative analgesia after VATS resection is MOST commonly managed with:

Answer: Paravertebral block

Paravertebral blocks provide unilateral segmental analgesia comparable to thoracic epidural analgesia with fewer side effects (hypotension, urinary retention) and are preferred for VATS procedures.

In a patient with a bronchopleural fistula requiring general anesthesia, the safest initial airway management strategy is:

Answer: Awake fiberoptic intubation with a double-lumen tube before induction

Awake intubation with a DLT isolates the fistula side before positive pressure is applied, preventing massive air leak and tension pneumothorax under anesthesia.

The oxyhemoglobin dissociation curve is shifted to the RIGHT by which combination of factors particularly relevant during thoracic surgery?

Answer: Acidosis, hyperthermia, increased 2,3-DPG

Acidosis, increased temperature, and elevated 2,3-DPG all reduce hemoglobin's oxygen affinity (Bohr effect), facilitating oxygen unloading to tissues during periods of increased demand.