This is a pilot study of a new use of Epoprostenol via inhalation (Epoprostenol is approved for intravenous use). The purpose of this study is to administered inhaled Epoprostenol and intravenous Phenylephrine to improve arterial oxygen tension during one-lung anesthesia either with volatile anesthesia (Sevoflurane) or with intravenous anesthesia (Propofol).

Inclusion Criteria:

• Patients undergoing esophagectomy via video assisted thoracoscopy surgery or open thoracotomy.
• Patients greater than eighteen years old that have the capacity to provide consent.
• Patients who weigh 89kg or less.
• Patients with a preoperative platelet count > 100,000mm3

Exclusion Criteria:

• Contraindication or allergy to any of the study drugs e.g. epoprostenol, phenylephrine, sevoflurane or propofol.
• Spirometry: Force expiratory Volume (FEV1) less than 80% predicted for age. Patients with spirometry indicative of obstructive lung disease are less likely to develop hypoxemia during OLV compared to patients with normal spirometry . These patients are likely to have a smaller treatment effect if any.
• A history of a bleeding diathesis.
• Use of a platelet inhibitor within the last seven days e.g. Aspirin, clopidogrel