This study, it is aimed to determine the effect of Apfel risk score and fasting times on postoperative nausea and vomiting (PONV).

PONV are common causes of delayed discharge. PONV; nausea and/or vomiting in the first 24 hours after surgery. The incidence of PONV after elective surgeries varies between 30-80% depending on anesthesia, type of surgery, and risk factors of the patient. PONV is not only an uncomfortable complication for the patient but is associated with significant patient dissatisfaction. It also includes dehydration, electrolyte imbalance, acid-base imbalance, pulmonary aspiration, pneumothorax, hypoxia, esophageal rupture, increased intracranial pressure, wound problems, bleeding, delayed oral intake, prolonged hospitalization, fatigue, anxiety, unexpected hospital readmission, increased medical costs. Therefore, the prevention and management of nausea and/or vomiting in the perioperative period in surgical patients is very important.

In the preoperative period, patients' risk of nausea and/or vomiting should be evaluated with standard measurement tools. The most commonly used is the Apfel risk score, including four risk factors. These; female gender, history of PONV and/or motion sickness, non-smoking, and postoperative opioid use. In the presence of 0, 1, 2, 3, and 4 risk factors, the incidence of PONV is approximately 10%, 20%, 40%, 60%, and 80%, respectively. It has been observed that the use of risk scoring for PONV significantly reduces the rate of nausea and vomiting in the postoperative period. The risk of PONV varies depending on the patient, the type of anesthesia and the surgery. Female gender, young age, non-smoking, history of PONV or motion sickness are important risk factors for PONV. Type of anesthesia, duration of administration, use of volatile anesthetics and nitrous oxide, and use of opioids in the perioperative period are among other risk factors. It has been reported that PONV is seen more frequently after laparoscopic, bariatric, gynecological surgery, and cholecystectomy.

In order to prevent the development of nausea-vomiting and aspiration pneumonia during and after the operation, patients should be fasted for a certain period of time before the operation. Fasting periods in the preoperative period should not be long enough to cause adverse outcomes in patients. It has been reported in the literature that long preoperative fasting periods do not prevent some complications, but on the contrary increase them. Therefore, it is emphasized that it is unnecessary to starve patients for a long time in the preoperative period. In the study of Hausel et al., it was reported that patients who were fasted for 12-24 hours before surgery had more nausea and vomiting in the postoperative period than patients who were fasted for a short time and were given oral carbohydrate-containing fluids. According to the results of different studies conducted in this area, it has been reported that reducing the preoperative fasting period eliminates the patient's feeling of thirst before the operation, reduces nausea and vomiting, alleviates anxiety, increases patient comfort, accelerates recovery, and significantly shortens the length of hospital stay. It is stated that a short pre-operative fasting period reduces the loss of nitrogen in the urine and prevents loss of muscle strength, reduces the feeling of anxiety and thirst before the operation, and increases patient comfort by reducing nausea and vomiting in the early postoperative period. It has been reported that there are limited clinical studies to explain the relationship between perioperative fasting time and PONV in terms of the level of evidence. In this respect, it is important to determine the relationship between risk factors preoperative fasting times, and PONV.

Inclusion Criteria:

• Being over 18 years old
• To have applied for elective surgery,
• Being hospitalized 6 hours before the operation,
• American Society of Anesthesiologists (ASA) score I-III
• Not having a vision-hearing problem
• Not having chronic pain,
• No alcohol and/or substance addiction,

Exclusion Criteria:

• Performing emergency surgical intervention,
• Need for intensive care after surgery

The population of the study will be composed of patients who applied for elective surgery to Çukurova University Medical Faculty Balcalı Training and Research Hospital General Surgery Clinic and Tarsus State Hospital General Surgery Clinic between the dates of the study. The sample, on the other hand, will consist of a total of 250 patients who comply with the selection criteria, agree to participate in the study, and are determined by power analysis.

The sample of the study was carried out using an unknown population model. The data obtained from the study of Weibel et al. (2020) were used for the effect size to be used in the calculation of the sample number (Weibel et al., 2020).

Results regarding the relationship between APFEL risk score fasting times and PONV will be shared. However, personal information will not be shared.