This study will examine the pharmacokinetics of the various, routinely given antibiotics, sedatives, and opioids in patients undergoing venous-venous extra-corporal oxygenation (ECMO). Little is known about the distribution and effectiveness of antibiotics in this particular patient population.

Patients with severe hypoxia that is refractory to traditional therapies are occasionally placed on venous-venous extracorporal membrane oxygenation (vv ECMO) to provide a bridge during the time when lungs alone cannot provide necessary support. This procedure is gaining prominence but it is largely unknown how medications, especially antibiotics, given to the patient on ECMO is distributed throughout the body as compared to patients without ECMO. Since the serum level of medication determines the biological activity of the drug, it is important to know if there is a difference in drug distribution between ECMO and non-ECMO patients. The investigator already collected well-established data on several antibiotics on non-ECMO as a part of FDA labeling. The study will help to determine if the concentration of currently prescribed are sufficient enough to reach their intended concentration in the study.

Inclusion Criteria:

• Patient with respiratory failure undergoing ECMO.

Exclusion Criteria:

• Lack of consent
• Age less than 18 years old
• Hematocrit lower than 7

All patients undergoing ECMO will be invited to participate. In order to determine pharmacokinetics of the drugs, the investgators need at least 10-15 subjects in order to create a pharmacological model. Since the site plan to study 3 antibiotics, propofol and hydromorphone, the investigators calculated the initial sample size at 50