Effects of Oxygen on Lung Tissue During Anesthesia

Inclusion Criteria: * American Society of Anesthesiologists (ASA) Class I-III. * Patient is undergoing elective surgery requiring mechanical ventilation * Patient is an adult, 18 - 80 years old. * Subject has voluntarily signed and dated the informed consent document approved by the Institutional Review Board (IRB). Exclusion Criteria: * Surgical procedures boarded for less than 2 hours * Current Smoker * All Cardiac, Thoracic and/or Vascular surgeries involving the chest * Patient unable to cooperate. * Chronic airway diseases * Asthma * Medical contraindication to anesthetic technique (allergy, cardiac condition, neurologic condition, localized infection, bleeding disorder). * Subjects who are pregnant.