In the last ten years patient safety during routine surgical interventions has increased; however as there is an increase in the number of specialized surgical interventions and high risk patients like elderly and emergency patients, the incidence of perioperative cardiac arrest has not reduced but remains fixed. The incidence of perioperative cardiac arrest varies from 4.3-34.6 for each 10,000 procedures. However as in a lot of other countries exact data are lacking also for Turkey. With this study the investigators want to start collecting data about intraoperative cardiac arrest in Turkey, starting at their institution The aim is to evaluate the incidence and outcome in the study. Secondary aim is to assess the causes of cardiac arrest in the operating room.

Patient information will be collected on a form entitled "Data collection form" including all medications and interventions during cardiopulmonary resuscitation and routine daily used anesthesia registration form.

Inclusion Criteria:

• All patients who develop cardiac arrest in the operating room

Exclusion Criteria:

• Absence of informed consent
• Patients arriving into the operating room with ongoing CPR

This study will include all patients who develop cardiac arrest in the operating room (including preoperative waiting area and postoperative recovery unit) Dokuz Eylul University Hospital.