Nebulized Epoprostenol (FLOLAN) and Phenylephrine on One Lung Ventilation (OLV)

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