Cukurova University

METHODOLOGY This descriptive, cross-sectional study was conducted at Department of Surgical Oncology of a tertiary care hospital between June 2020 and August 2020. The study centre has a 1,200-bed capacity and the surgical oncology clinic has a 30-bed capacity. A total of 57 women who were scheduled for elective mastectomy for breast cancer were included. Inclusion criteria were as follows: women aged ≥18 years, hospitalization 6 hours prior to surgery, American Society of Anesthesiologists (ASA) Class I-III, having no chronic pain or alcohol and/or substance abuse, having no cognitive impairment, no need for mechanical ventilation, having a confirmed diagnosis of breast cancer, and being scheduled for mastectomy. Prior to study, all patients were informed about the nature of the study and a written informed consent was obtained. The study protocol was approved by the institutional Non-Interventional Clinical Research Ethics Committee (No: 15.05.2020/99). The study was conducted in accordance with the principles of the Declaration of Helsinki.

Preoperative and postoperative data within 48 hours were collected via face-to-face interviews. The Patient Assessment Form, which was developed in accordance with the previous studies in the literature, was used to collect data including age and body mass index (BMI) pre- and postoperatively. For the postoperative evaluation, the four-item, simplified Apfel Risk Scoring System was used. It is a valid tool which assesses PONV and/or motion sickness, non-smoking status, and postoperative use of opioids. Accordingly, 0-1 indicate low, 2 indicate moderate, and ≥3-4 indicate high risk for PONV [12]. In our study, PONV was evaluated using the Patient Assessment Form at 0, 2, 4, 8, 24, and 48 hours as "Yes/No" scoring.

Statistical analysis was performed using the SPSS version 22.0 software (IBM Corp., Armonk, NY, USA). Descriptive data were expressed in mean ± standard deviation (SD), median (min-max) or number and frequency, where applicable. The chi-square test was used to evaluate relationship between categorical variables. The Mann-Whitney U test (Z table values) was performed to compare two independent groups which did not meet the normal distribution. The continuity correction and Fisher exact test were used to examine the relationship between two quantitative variables. The independent samples t-test (t table values) was used to compare two independent groups which met the normal distribution. A p value of <0.05 was considered statistically significant.