Effects of Desflurane and Propofol During Lung Volume Reduction Surgery

The anesthetic technique for lung volume reduction surgery consists of a thoracic epidural in combination with a general anesthetic. The thoracic epidural is routine for this operation and allows administration of local anesthetics and painkillers in the epidural space which results in profound pain relief in the area of surgery. The epidural is routinely used for pain control during the surgery and after the surgery when the patient is awake. The general anesthetic used may be a volatile agent (gas for example Desflurane), which is administered through the anesthesia machine, or an intravenous anesthetic agent, which is administered into a vein through an intravenous line as a continuous infusion (example Propofol). The use of an anesthetic agent and an epidural often causes a decrease in blood pressure which is treated with medication. The investigators are comparing the two anesthetic techniques regarding their effect on blood pressure and the amount of medication needed to treat it.