Extracorporeal membrane oxygenation (ECMO) is the device which increases the supply of oxygen to the body tissues in vitro and to assist in heart and lung function. Venoarterial (VA) ECMO is used in patients with cardiogenic shock, cardiac arrest, ventricular arrhythmia and is able to secure a time to self-recovery by reducing the excessive stimulation applied to the heart. However, in ECMO patients, pharmacokinetics of drugs are changing such as increased volume of distribution (Vd) or decreased clearance (CL). For this reason, it is hard to provide the best treatment in ECMO patients. The study is to evaluate whether the PK of drugs is influenced by VA ECMO and to recommend the optimal dosing strategies for proposed drugs in adult patients receiving VA ECMO.

Inclusion Criteria:

• patient who are ≥ 19 years old and receiving VA ECMO in Severance Hospital, Yonsei University Health System.
• patient who are receiving one of these drugs: teicoplanin or levofloxacin or piperacillin/tazobactam or meropenem or vancomycin or remifentanil or cefepime or cefpirome or sufentanil or midazolam or clopidogrel or ticagrelor or prasugrel
• patients who are agreed to participate in this study

Exclusion Criteria:

• patients who are pregnant
• patients who are receiving drugs that could affect study drug's concentration due to drug-drug interaction.

Patients over the age of 19 who are receiving teicoplanin or levofloxacin or piperacillin/tazobactam or remifentanil or sufentanil or clopidogrel or ticagrelor while using VA ECMO in Severance Hospital, Yonsei University Health System.