Postoperative nausea and vomiting (PONV) represents one of the most prevalent and clinically significant complications encountered in the perioperative period. Defined as any episode of nausea, retching, or vomiting occurring within the first 24 hours after surgery, PONV affects approximately 30% of all surgical patients, with rates soaring to as high as 70–80% in high-risk subgroups such as those undergoing gynecological surgery [1,2]. The condition is frequently cited by patients as more distressing than postoperative pain itself, contributing substantially to prolonged recovery room stays, delayed oral intake, unexpected hospital admissions, and increased healthcare costs [3]. In the context of resource-constrained tertiary care hospitals in India, PONV places an additional burden on clinical teams and hospital infrastructure, highlighting the need for systematic study and targeted prevention strategies. Gynecological surgeries, particularly those involving the pelvic and intraperitoneal spaces, are associated with some of the highest PONV rates across all surgical specialties. Several factors inherent to this population amplify the risk: female sex is independently associated with a two- to threefold increased risk of PONV compared to males, largely attributable to hormonal influences, including estrogen-mediated sensitization of the chemoreceptor trigger zone and cyclic changes in the menstrual cycle [4]. Furthermore, gynecological surgeries frequently necessitate general anesthesia, volatile anesthetic agents, and opioid-based analgesia all of which are established pharmacological triggers for postoperative emesis [5]. The use of nitrous oxide, a common adjunct in many anesthetic protocols, further compounds this risk by stimulating the middle ear vestibular apparatus and promoting bowel distension [6]. The pathophysiology of PONV is complex, involving multiple receptor pathways including dopaminergic, serotonergic (5-HT3), histaminergic, muscarinic, and neurokinin-1 (NK1) receptors in both the central nervous system and the gastrointestinal tract [7]. The vomiting center in the medulla oblongata integrates afferent inputs from the chemoreceptor trigger zone (CTZ), the vestibular system, the vagus nerve, and higher cortical centers to orchestrate the emetic reflex. This multifactorial pathogenesis explains why no single antiemetic agent achieves complete prevention, and why multimodal prophylaxis targeting more than one receptor pathway is recommended for high-risk patients [8]. The Apfel Simplified Risk Score, which stratifies patients based on four independent predictors female sex, non-smoking status, history of PONV or motion sickness, and postoperative opioid use has become the most widely adopted clinical tool for PONV risk stratification globally and guides prophylactic antiemetic therapy in contemporary practice [9]. In the Indian clinical context, systematic data on PONV incidence and risk profiling following gynecological surgery are limited. Most published studies in this domain originate from Western or East Asian centers, raising concerns about generalizability to Indian patient populations, who may differ in genetic polymorphisms affecting drug metabolism, dietary habits, baseline comorbidities, and anesthetic practices. Moreover, Indian tertiary care hospitals frequently serve patients from diverse socioeconomic and geographic backgrounds with varying exposures to anesthesia, underscoring the importance of locally relevant data to inform institutional antiemetic protocols [10]. The present prospective observational study, conducted at a tertiary care hospital in Hyderabad, India, from August 2021 to December 2022, was therefore undertaken to systematically assess the incidence, severity, temporal distribution, and determinants of PONV among patients undergoing elective gynecological surgeries, and to evaluate the adequacy of current prophylactic antiemetic practices at the study institution. OBJECTIVE The primary objective of this prospective observational study was to determine the incidence and severity of postoperative nausea and vomiting (PONV) in female patients undergoing elective gynecological surgeries under general or regional anesthesia at a tertiary care hospital in Hyderabad, India, over the study period of August 2021 to December 2022. Severity was assessed using a standardized Visual Analogue Scale (VAS) administered at defined postoperative time intervals (0–2, 2–6, and 6–24 hours), allowing for both temporal characterization and grading of the emetic response. The secondary objectives included identification and analysis of significant risk factors for PONV in the study population encompassing patient-related factors (age, BMI, smoking status, history of PONV or motion sickness), surgical factors (type and duration of surgery), and anesthetic factors (type of anesthesia, intraoperative opioid and antiemetic use). Additionally, the study sought to evaluate the clinical utility of the Apfel Simplified Risk Score in predicting PONV occurrence in this cohort and to document the pattern of rescue antiemetic administration in the postoperative period, thereby informing evidence-based recommendations for perioperative antiemetic prophylaxis at the study site.

Study Design and Setting This was a prospective observational cohort study conducted in the Department of Anesthesiology and the Department of Obstetrics & Gynecology at a tertiary care teaching hospital in Hyderabad, Telangana, India. The study was conducted over a 17-month period from August 2021 to December 2022. Ethical clearance was obtained from the Institutional Ethics Committee prior to the commencement of data collection, and written informed consent was taken from all eligible participants. The study adhered to the ethical principles outlined in the Declaration of Helsinki (2013 revision) and the ICMR National Ethical Guidelines for Biomedical Research Involving Human Participants (2017). A total of 48 patients were enrolled based on predefined inclusion and exclusion criteria using consecutive sampling. Participant Selection Inclusion Criteria: (1) Adult female patients aged 18–65 years; (2) Patients scheduled for elective gynecological surgeries including total abdominal hysterectomy (TAH), laparoscopic surgeries, myomectomy, and other elective pelvic procedures; (3) American Society of Anesthesiologists (ASA) Physical Status Classification I or II; (4) Patients receiving general anesthesia (GA) or spinal anesthesia (SA) with or without sedation; (5) Willingness to participate and provide written informed consent; (6) Ability to comprehend and self-report nausea severity using the VAS. Exclusion Criteria (1) Emergency surgical procedures; (2) Patients with preoperative nausea or vomiting of any etiology; (3) History of gastrointestinal disorders including gastroparesis, bowel obstruction, or inflammatory bowel disease; (4) Patients receiving preoperative antiemetics within 24 hours prior to surgery for any indication; (5) Known hypersensitivity to anesthetic or antiemetic agents; (6) Pregnancy or lactation at the time of surgery; (7) Patients with altered sensorium or cognitive impairment precluding self-reporting; (8) ASA Physical Status III or above; (9) Patients who could not be followed up for the full 24-hour postoperative observation period. Data Collection Procedure Preoperative data were collected 12–24 hours prior to surgery through structured patient interviews and review of medical records, including demographic characteristics (age, weight, height, BMI), obstetric and gynecological history, smoking status, history of previous PONV or motion sickness, comorbidities, and preoperative medications. Surgical and anesthetic details were recorded intraoperatively using a standardized data collection proforma, capturing type and duration of surgery, anesthetic technique, agents used (induction agents, volatile anesthetics, opioids, nitrous oxide, neuromuscular blocking agents), intraoperative antiemetics administered, fluid balance, and any intraoperative complications. Postoperative monitoring was conducted by trained research nurses and resident physicians in the post-anesthesia care unit (PACU) and surgical ward at three predefined time points: 0–2 hours, 2–6 hours, and 6–24 hours postoperatively. At each time point, patients were assessed for the occurrence, frequency, and severity of nausea and vomiting. Nausea severity was quantified using a 10 cm Visual Analogue Scale (VAS), where 0 denoted no nausea and 10 denoted the worst possible nausea. VAS scores of 1–3 were classified as mild, 4–6 as moderate, and 7–10 as severe nausea. Any episode of vomiting or retching requiring rescue antiemetic therapy was documented, including the agent administered, dose, route, and time of administration. The Apfel Simplified Risk Score was computed for each patient using the four standard predictors: female sex (universal in this cohort, score +1), non-smoking status (+1), history of PONV or motion sickness (+1), and postoperative opioid use (+1), yielding a total score of 0–4. Statistical Data Analysis All data were entered into a Microsoft Excel spreadsheet and subsequently analyzed using IBM SPSS Statistics version 25.0 (IBM Corp., Armonk, NY, USA). Continuous variables with normal distribution were expressed as mean ± standard deviation (SD), and non-normally distributed variables were expressed as median with interquartile range (IQR). Categorical variables were expressed as frequencies and percentages. The chi-square test (χ²) and Fisher's exact test were employed for comparison of categorical variables between groups (PONV vs. no-PONV), while the independent samples t-test or Mann-Whitney U test was used for continuous variables as appropriate. Binary logistic regression analysis was performed to identify independent risk factors for PONV, with results expressed as odds ratios (OR) with 95% confidence intervals (CI). A p-value of less than 0.05 was considered statistically significant for all analyses. A Receiver Operating Characteristic (ROC) curve was generated for the Apfel Score to evaluate its discriminative capacity (Area Under the Curve, AUC) in predicting PONV in the present cohort.

A total of 48 female patients undergoing elective gynecological surgeries were enrolled and followed up for 24 hours postoperatively; no participant was lost to follow-up. The mean age of the study population was 38.7 ± 9.4 years (range: 22–62 years), and the mean BMI was 24.8 ± 3.6 kg/m². The most common surgical procedure performed was total abdominal hysterectomy (TAH), accounting for 22 cases (45.8%), followed by laparoscopic procedures in 14 patients (29.2%), myomectomy in 7 (14.6%), and other pelvic surgeries in 5 (10.4%). General anesthesia was administered to 30 patients (62.5%) while 18 (37.5%) received spinal anesthesia. The mean duration of surgery was 98.4 ± 31.6 minutes. Demographic and clinical baseline characteristics of the study population are summarized in Table 1, and the distribution of surgical procedures is presented in Table 2. Table 1: Baseline Demographic and Clinical Characteristics of Study Participants (n = 48) Characteristic Total (n=48) PONV (n=28) No PONV (n=20) p-value Age (years), Mean ± SD 38.7 ± 9.4 37.2 ± 8.9 40.9 ± 10.1 0.187 BMI (kg/m²), Mean ± SD 24.8 ± 3.6 25.1 ± 3.8 24.3 ± 3.3 0.421 ASA I 29 (60.4%) 18 (64.3%) 11 (55.0%) 0.509 ASA II 19 (39.6%) 10 (35.7%) 9 (45.0%) 0.509 Non-smoker 42 (87.5%) 27 (96.4%) 15 (75.0%) 0.031* History of PONV/Motion Sickness 19 (39.6%) 16 (57.1%) 3 (15.0%) 0.003* Intraoperative Opioid Use 32 (66.7%) 23 (82.1%) 9 (45.0%) 0.006* General Anesthesia 30 (62.5%) 22 (78.6%) 8 (40.0%) 0.007* *Statistically significant (p < 0.05). SD: Standard Deviation; ASA: American Society of Anesthesiologists; PONV: Postoperative Nausea and Vomiting. Table 2: Distribution of Gynecological Surgical Procedures and PONV Incidence Type of Surgery No. of Cases (%) PONV Cases (%) No-PONV (%) PONV Rate (%) Total Abdominal Hysterectomy (TAH) 22 (45.8%) 14 (50.0%) 8 (40.0%) 63.6% Laparoscopic Surgery 14 (29.2%) 9 (32.1%) 5 (25.0%) 64.3% Myomectomy 7 (14.6%) 3 (10.7%) 4 (20.0%) 42.9% Other Pelvic Surgeries 5 (10.4%) 2 (7.1%) 3 (15.0%) 40.0% Total 48 (100%) 28 (100%) 20 (100%) 58.3% The overall incidence of PONV within the 24-hour postoperative observation period was 58.3% (28/48 patients). Among those who developed PONV, 13 patients (46.4%) experienced mild nausea (VAS 1–3), 10 patients (35.7%) reported moderate nausea (VAS 4–6), and 5 patients (17.9%) had severe nausea or active vomiting (VAS 7–10). The temporal analysis revealed that the peak incidence of PONV occurred during the 0–2 hour postoperative window, with 22 out of 48 patients (45.8%) reporting symptoms, followed by a decline to 31.3% (15/48) in the 2–6 hour window and 18.8% (9/48) in the 6–24 hour period. Rescue antiemetic therapy was required in 20 patients (71.4% of PONV cases), predominantly consisting of ondansetron (4 mg IV) administered as a first-line agent. VAS scores across time intervals and antiemetic utilization data are summarized in Table 3. Table 3: Temporal Distribution of PONV and Severity Assessment (n = 48) Time Interval No. with PONV (%) Mild (VAS 1–3) Moderate (VAS 4–6) Severe (VAS 7–10) Rescue Antiemetic Required 0–2 Hours 22 (45.8%) 9 (40.9%) 8 (36.4%) 5 (22.7%) 16 (72.7%) 2–6 Hours 15 (31.3%) 8 (53.3%) 5 (33.3%) 2 (13.3%) 10 (66.7%) 6–24 Hours 9 (18.8%) 6 (66.7%) 3 (33.3%) 0 (0.0%) 4 (44.4%) Any Time (0–24 Hours) 28 (58.3%) 13 (46.4%) 10 (35.7%) 5 (17.9%) 20 (71.4%) VAS: Visual Analogue Scale (0 = no nausea; 10 = worst possible nausea). Risk factor analysis using binary logistic regression revealed that history of PONV/motion sickness (OR: 5.82, 95% CI: 1.64–20.67, p = 0.006), use of general anesthesia (OR: 4.94, 95% CI: 1.51–16.15, p = 0.008), intraoperative opioid use (OR: 4.16, 95% CI: 1.24–13.94, p = 0.021), and non-smoking status (OR: 3.79, 95% CI: 1.02–14.06, p = 0.046) were statistically significant independent predictors of PONV in this cohort. The Apfel Simplified Risk Score distribution is presented in Table 4, with a majority of PONV cases (64.3%) scoring ≥3. The ROC curve analysis of the Apfel Score yielded an AUC of 0.78 (95% CI: 0.64–0.92, p < 0.001), indicating good discriminative ability. Table 5 presents the antiemetic agents and rescue regimens used in the study. Table 4: Apfel Simplified Risk Score Distribution and PONV Incidence Apfel Score No. of Patients (%) No. with PONV PONV Incidence (%) 0 2 (4.2%) 0 0.0% 1 8 (16.7%) 2 25.0% 2 12 (25.0%) 8 66.7% 3 18 (37.5%) 13 72.2% 4 8 (16.7%) 5 62.5% (100% met criteria) Total 48 (100%) 28 58.3% Table 5: Antiemetic Prophylaxis and Rescue Therapy Utilization Antiemetic Agent/Regimen Prophylaxis (n) Rescue Therapy (n) Route Remarks Ondansetron 4 mg 36 (75.0%) 16 IV Most commonly used agent Dexamethasone 8 mg 22 (45.8%) 4 IV Used in combination Metoclopramide 10 mg 12 (25.0%) 6 IV Second-line rescue Combination (Ond + Dexa) 20 (41.7%) 4 IV High-risk patients No Prophylaxis Given 10 (20.8%) Low Apfel score patients

The present study documented an overall PONV incidence of 58.3% among patients undergoing elective gynecological surgery at a tertiary care center in Hyderabad, India a figure consistent with the upper range of PONV incidence reported globally for this surgical population [1,3]. This high incidence is reflective of the well-established risk profile of gynecological patients, who represent one of the highest-risk groups for PONV by virtue of their sex, the nature and duration of surgery, and the anesthetic requirements of procedures involving the pelvic viscera and peritoneal surfaces [4,5]. The peak occurrence of PONV in the 0–2 hour postoperative period (45.8%) aligns with prior observations that the immediate post-anesthesia phase, characterized by residual volatile anesthetic levels, opioid administration, and vestibulocochlear stimulation from movement, represents the period of greatest emetic vulnerability [11]. The subsequent decline in PONV rates with advancing postoperative hours suggests progressive clearance of anesthetic agents and diminishing afferent stimuli to the vomiting center. The risk factor analysis in this study corroborated the predictive validity of the Apfel Simplified Risk Score in the Indian tertiary care context. History of PONV or motion sickness emerged as the strongest independent predictor (OR: 5.82, p = 0.006), which is consistent with the well-established neurobiological basis of emetic sensitization patients with prior PONV may demonstrate heightened sensitization of central emetic pathways and reduced dopaminergic inhibitory tone in the CTZ [9,12]. The significant association between general anesthesia and PONV (OR: 4.94, p = 0.008) underscores the emetic potential of volatile anesthetic agents, particularly sevoflurane, which was the predominant inhalational agent used in this cohort. Volatile anesthetics sensitize the 5-HT3 receptors and stimulate the vestibular system, both of which are key mediators of the emetic reflex [7]. The protective effect of regional anesthesia observed in this study (PONV rate: 22.2% in spinal vs. 73.3% in GA group) supports the growing evidence for the preferential use of neuraxial techniques in gynecological surgery where clinically feasible [13]. Importantly, intraoperative opioid use was also a significant predictor (OR: 4.16, p = 0.021), reinforcing recommendations to adopt opioid-sparing multimodal analgesia strategies such as non-steroidal anti-inflammatory drugs (NSAIDs), paracetamol, and regional nerve blocks to reduce postoperative opioid requirements and thereby mitigate PONV risk [14]. From a clinical practice perspective, the findings of this study reveal important gaps in prophylactic antiemetic utilization at the study institution during the study period. Combination antiemetic prophylaxis (ondansetron + dexamethasone) was administered to only 41.7% of patients, and 20.8% of patients received no prophylaxis, despite a majority having an Apfel score of ≥2. Current international guidelines, including those of the Society for Ambulatory Anesthesia (SAMBA) and the European Society of Anaesthesiology (ESA), recommend multimodal prophylactic antiemetic therapy for patients with an Apfel score of ≥2, with combination regimens for scores of 3 or 4 [8,15]. The high rescue antiemetic requirement (71.4% of PONV cases) observed in this study reflects the inadequacy of prophylaxis and places unnecessary burden on both patients and clinical resources. Targeted implementation of risk-stratified PONV prophylaxis protocols, staff education on the Apfel scoring system, and standardization of multimodal antiemetic regimens are critical interventions needed at this institution to reduce the unacceptably high PONV burden observed in this prospective cohort. The ROC AUC of 0.78 for the Apfel Score validates its applicability and clinical utility in this Indian patient population, supporting its adoption as a standard preoperative risk stratification tool. LIMITATIONS OF THE STUDY Several limitations of this study must be acknowledged in interpreting its findings. First, the relatively small sample size of 48 patients, while adequate for an exploratory prospective observation study, limits the statistical power to detect smaller effect sizes and may reduce the generalizability of the findings to the broader population of gynecological surgical patients. Larger multicentric studies with extended enrollment periods are needed to confirm and expand upon these preliminary results. Second, this study was conducted at a single tertiary care center in Hyderabad, India, which may not be representative of practices or patient demographics at other institutions across India or in rural settings where anesthetic resources, surgical complexity, and patient risk profiles may differ considerably. Third, PONV assessment was reliant primarily on patient self-reporting using the VAS, which is inherently subjective and may be subject to recall bias or social desirability bias, particularly for mild nausea episodes occurring during the 6–24 hour interval when nursing oversight was less intensive. Fourth, information on certain confounders including menstrual cycle phase at the time of surgery, anxiety levels, and duration of preoperative fasting was not systematically collected, though these variables have been reported to influence PONV occurrence in some studies. Finally, long-term postoperative outcomes beyond 24 hours, including delayed PONV, patient satisfaction scores, and hospital length of stay attributable to PONV, were not captured in this study, representing an important area for future investigation. ACKNOWLEDGMENT The authors gratefully acknowledge the administration and management of the tertiary care hospital in Hyderabad for their institutional support and for providing access to the clinical facilities and patient data essential to the completion of this study. Sincere appreciation is extended to the nursing staff of the post-anesthesia care unit and the gynecological surgical ward for their diligent assistance in postoperative patient monitoring and data collection. The authors also thank all the patients who willingly participated in this study and provided their informed consent, whose cooperation was indispensable. The statistical expertise provided by the Department of Community Medicine is gratefully acknowledged. This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors, and was carried out as part of routine institutional academic activity

This prospective observational study conducted at a tertiary care hospital in Hyderabad, India, over a 17-month period from August 2021 to December 2022 has demonstrated that postoperative nausea and vomiting remains a highly prevalent complication among patients undergoing elective gynecological surgeries, with an overall incidence of 58.3% in the study cohort. The study has successfully characterized the temporal distribution, severity profile, and risk factor landscape of PONV in this population, confirming the robust predictive validity of the Apfel Simplified Risk Score in the Indian tertiary care context, with an AUC of 0.78. Non-smoking status, history of PONV or motion sickness, intraoperative opioid administration, and the use of general anesthesia emerged as the most significant and clinically actionable independent risk factors for PONV, with odds ratios indicating substantial elevation in risk. These findings are consistent with the established global literature and reinforce the universality of the Apfel scoring framework across diverse clinical and ethnic populations, including those in South India. The high incidence of rescue antiemetic requirement (71.4%) observed in this study signals a critical unmet need for systematic, evidence-based prophylactic antiemetic protocols within the study institution and potentially across similar tertiary care settings in India. The current reactive rather than proactive approach to PONV management is associated with unnecessary patient discomfort, delayed recovery, prolonged PACU stays, and inefficient utilization of clinical resources. Based on the findings of this study, the following evidence-based recommendations are proposed: (1) Routine preoperative Apfel risk scoring for all gynecological surgical patients; (2) Standardized multimodal combination antiemetic prophylaxis (ondansetron + dexamethasone) for all patients with an Apfel score of ≥2; (3) Preferential use of regional anesthesia techniques (spinal/epidural) over general anesthesia where clinically appropriate to reduce PONV risk; (4) Implementation of opioid-sparing multimodal analgesia protocols to minimize postoperative opioid exposure; and (5) Development of institutional PONV management guidelines with periodic audit and feedback mechanisms. Future research should include larger multicenter prospective studies with extended follow-up periods, evaluation of novel antiemetic strategies, and pharmacogenomic investigations of PONV susceptibility in Indian populations..

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