The goal of this observational study is to determine the incidence of postoperative nausea and vomiting (PONV) and identify its risk factors in adult patients recovering in the post-anaesthesia care unit (PACU) after elective surgery at RSUPN Dr. Cipto Mangunkusumo, Jakarta, Indonesia. The main questions it aims to answer are:

• What is the incidence of PONV among adult patients during their PACU stay?
• Which patient-, anaesthesia-, and surgery-related factors are independently associated with the occurrence of PONV?

Participants who undergo elective surgery under any anaesthetic technique (general anaesthesia, spinal, epidural, or sedation) will be observed for nausea and vomiting from PACU admission until discharge. Researchers will also record the following variables for each participant:

• Patient factors: age, sex, smoking history, and history of motion sickness or prior PONV
• Anaesthesia factors: type of anaesthesia, intraoperative opioid use, and PONV prophylaxis use
• Surgical factors: type of surgery and surgical duration

Inclusion Criteria:

• Adult patients aged 18 years or older
• Scheduled to undergo elective surgery under any type of anaesthesia (general anaesthesia, spinal, epidural, or sedation)
• ASA (American Society of Anesthesiologists) physical status classification I-IV
• Fully conscious with a Glasgow Coma Scale (GCS) score of 15

Exclusion Criteria:

• Presence of nausea or vomiting before anaesthesia induction
• Use of Monitored Anaesthesia Care (MAC) technique
• Preoperative use of opioids or other emetogenic medications
• Patient or legal guardian refuses informed consent

Adult patients (≥18 years) undergoing elective surgery under anaesthesia at the Central Surgical Installation (Instalasi Bedah Pusat) of RSUPN Dr. Cipto Mangunkusumo, Jakarta, Indonesia.

Individual participant data will not be shared publicly in order to protect the privacy and confidentiality of study participants, in accordance with the ethics approval conditions set by KEPK FKUI-RSCM.