European Journal of Cardiovascular Medicine

Postoperative nausea and vomiting (PONV) is among the most common adverse events associated with anaesthesia and surgery. Although it is usually self-limiting, PONV can cause marked discomfort, dehydration, electrolyte imbalance, wound stress, delayed oral intake, and prolonged stay in the post-anaesthesia care unit. In selected surgical settings, repeated vomiting can also contribute to wound disruption, bleeding, aspiration, and unplanned hospital admission. The impact of PONV extends beyond physical morbidity because patients consistently identify nausea and vomiting among the postoperative outcomes they most wish to avoid [1,2]. Consequently, prevention and early treatment of PONV are important components of quality perioperative care.

The occurrence of PONV is multifactorial and reflects the interaction of patient susceptibility, the surgical procedure, and anaesthetic exposure. Prospective studies have repeatedly identified female sex, nonsmoking status, previous PONV or motion sickness, younger age, longer surgery, and postoperative opioid administration as relevant risk factors [3-6]. These observations led to development of simplified clinical prediction systems, particularly the Apfel score, which uses four readily identifiable factors: female sex, nonsmoking status, previous PONV or motion sickness, and anticipated postoperative opioid use [5]. Although such scores do not predict individual outcomes with certainty, they provide a practical framework for stratifying baseline risk and selecting the intensity of prophylaxis.

Anaesthetic technique also influences emetic risk. Volatile anaesthetics contribute particularly to early postoperative vomiting, whereas opioid exposure can increase nausea and vomiting through central and gastrointestinal mechanisms [8,9]. Large clinical trials have demonstrated that several preventive interventions, including antiemetic drugs and reduction of emetogenic anaesthetic exposures, independently decrease PONV risk [10]. Evidence-based reviews and consensus recommendations therefore support a multimodal approach that combines baseline-risk reduction, appropriate antiemetic prophylaxis, and rescue treatment when symptoms occur [11-14]. However, the relative importance of individual predictors varies across institutions because surgical case mix, anaesthetic practice, prophylactic prescribing, and postoperative analgesic strategies differ.

Local prospective data are valuable for estimating the burden of PONV and identifying modifiable factors within routine clinical practice. Such information can support risk-based prophylaxis rather than indiscriminate antiemetic administration and can guide opioid-sparing recovery pathways. The present study was therefore undertaken among adult patients undergoing elective surgery under general anaesthesia at a tertiary-care teaching hospital in coastal Andhra Pradesh. The objectives were to determine the incidence and temporal pattern of PONV during the first 24 postoperative hours; assess associations between selected demographic, historical, surgical, and anaesthetic variables and PONV; and identify independent predictors of PONV using multivariable logistic regression.

Study design: This was a prospective observational study conducted to evaluate the incidence and predictors of postoperative nausea and vomiting among adults receiving general anaesthesia for elective surgery. The study was observational; anaesthetic technique, analgesic prescribing, and antiemetic prophylaxis were determined by the treating anaesthesiologist according to routine institutional practice and were not altered for research purposes.

Study setting and period: The study was conducted in the Department of Anaesthesiology at Konaseema Institute of Medical Sciences and Research Foundation, Amalapuram, Andhra Pradesh, India, a tertiary-care teaching institution providing elective surgical services across general surgery, gynaecology, orthopaedics, otorhinolaryngology, and related specialties. Recruitment and follow-up were undertaken from January 2017 to June 2017.

Participants and sampling: Adult patients aged 18 years or older, classified as American Society of Anesthesiologists physical status I or II, and scheduled for elective surgery under general anaesthesia were eligible. Patients undergoing emergency surgery, those with active nausea or vomiting before surgery, patients requiring planned postoperative mechanical ventilation, and individuals unable to communicate postoperative symptoms reliably were excluded. Consecutive eligible patients were approached during the study period until 80 participants were enrolled. Written informed consent was obtained before inclusion.

Data collection: Baseline variables included age, sex, body mass index, ASA physical status, smoking status, and history of previous PONV or motion sickness. Perioperative variables included duration of surgery, use of volatile anaesthetic maintenance, postoperative opioid administration, and prophylactic antiemetic use. These factors were selected because previous prospective studies and risk models identified them as clinically relevant determinants of PONV [3-6,9]. Anaesthetic and recovery-room records were reviewed prospectively by the study team.

PONV assessment and outcomes: Patients were assessed for nausea and vomiting during the first 24 postoperative hours. Nausea was defined as a subjective unpleasant sensation associated with an urge to vomit, and vomiting as forceful expulsion of gastric contents. PONV was considered present when either nausea or vomiting occurred. The timing of the first episode was classified as 0-2 hours, >2-6 hours, or >6-24 hours. Requirement for rescue antiemetic medication was also recorded. The primary outcome was the cumulative 24-hour incidence of PONV. Secondary outcomes included the incidence of nausea and vomiting separately, timing of first PONV, rescue antiemetic use, and identification of associated predictors.

Statistical analysis: Continuous variables were summarized as mean ± standard deviation and categorical variables as frequency and percentage. Associations between categorical predictors and PONV were examined using the chi-square test, with Fisher's exact test when required. Crude odds ratios with 95% confidence intervals were calculated. A parsimonious multivariable logistic regression model assessed prespecified clinically relevant predictors while limiting model complexity for the number of PONV events. Adjusted odds ratios with 95% confidence intervals were reported. A two-sided P value <0.05 was considered statistically significant.

Ethical considerations: Necessary Permissions were obtained before starting the study. Participant confidentiality was maintained throughout the study. 

Participant flow and baseline characteristics

A total of 80 adult patients undergoing elective surgery under general anaesthesia were included in the final analysis. Complete perioperative data and PONV assessments during the first 24 postoperative hours were available for all participants, with no missing outcome data. The mean age of the study population was 44.8 ± 13.1 years, and 48 (60.0%) patients were female. The mean body mass index was 25.7 ± 3.5 kg/m². Forty-seven (58.8%) participants were classified as ASA physical status I and 33 (41.3%) as ASA II. Previous PONV or motion sickness was reported by 18 (22.5%) patients, while 61 (76.3%) were nonsmokers. Volatile anaesthetic maintenance was used in 63 (78.8%) patients, postoperative opioids in 42 (52.5%), and prophylactic antiemetics in 44 (55.0%) (Table 1).

Table 1. Baseline demographic and perioperative characteristics of the study participants (n=80)

Data are presented as mean ± standard deviation or n (%). BMI: body mass index; ASA: American Society of Anesthesiologists; PONV: postoperative nausea and vomiting.

Incidence and pattern of postoperative nausea and vomiting

PONV occurring at any time during the first 24 postoperative hours was documented in 27 of 80 patients, yielding an overall incidence of 33.8%. Postoperative nausea occurred in 25 (31.3%) patients, vomiting in 14 (17.5%), and both symptoms in 12 (15.0%). Rescue antiemetic therapy was required in 19 (23.8%) participants.

Among the 27 patients who developed PONV, 16 (59.3%) experienced their first episode within the initial 2 postoperative hours. Eight (29.6%) developed their first episode between >2 and 6 hours, while three (11.1%) first developed symptoms between >6 and 24 hours. Thus, the majority of PONV began during the early postoperative recovery period (Table 2).

Table 2. Incidence, clinical pattern, and timing of postoperative nausea and vomiting

Factors associated with PONV

PONV was significantly more frequent among females than males (43.8% vs 18.8%; P=0.021). Patients with a previous history of PONV or motion sickness had a higher incidence than those without such a history (61.1% vs 25.8%; P=0.005). Postoperative opioid recipients also had more PONV than patients who did not receive postoperative opioids (45.2% vs 21.1%; P=0.022). Similarly, surgery lasting more than 90 minutes was associated with a higher incidence than procedures of 90 minutes or less (45.7% vs 24.4%; P=0.046).

Nonsmokers had a higher PONV incidence than current smokers (39.3% vs 15.8%), although this difference was not statistically significant (P=0.058). Prophylactic antiemetic administration was associated with a lower incidence of PONV (22.7% vs 47.2%; P=0.021). Volatile anaesthetic maintenance was not significantly associated with PONV (36.5% vs 23.5%; P=0.315) (Table 3).

Table 3. Association of selected perioperative factors with postoperative nausea and vomiting

OR: odds ratio; CI: confidence interval; PONV: postoperative nausea and vomiting. P values were obtained using Pearson chi-square analysis.

Independent predictors of PONV

A parsimonious multivariable logistic regression model was constructed using clinically relevant predictors. Previous PONV or motion sickness remained the strongest independent predictor of postoperative symptoms (adjusted OR [aOR] 4.18; 95% CI: 1.27-13.77; P=0.019). Female sex was independently associated with an approximately threefold increase in the odds of PONV (aOR 2.91; 95% CI: 1.01-8.37; P=0.048), and postoperative opioid administration was also independently associated with increased risk (aOR 3.02; 95% CI: 1.03-8.85; P=0.044). In contrast, prophylactic antiemetic administration was independently associated with lower odds of PONV (aOR 0.34; 95% CI: 0.12-0.97; P=0.044) (Table 4).

Table 4. Multivariable logistic regression analysis of predictors of postoperative nausea and vomiting

Adjusted OR: adjusted odds ratio; CI: confidence interval.

The present prospective observational study found a 24-hour PONV incidence of 33.8% following elective surgery under general anaesthesia. This proportion is clinically important and is consistent with the long-recognized estimate that roughly one-third of unselected surgical patients experience nausea or vomiting after anaesthesia [1,10]. Most first episodes occurred within the initial two postoperative hours, indicating that the early recovery period represented the highest-risk interval in this cohort. The concentration of events soon after emergence is biologically plausible because volatile anaesthetic exposure exerts a particularly strong influence on early postoperative emesis [8].

Female sex was independently associated with PONV, with nearly a threefold adjusted increase in odds. This finding agrees with large prospective studies and pooled analyses in which female sex consistently emerged as one of the strongest patient-related predictors [3-6,12]. Previous PONV or motion sickness was the strongest independent predictor in the present study. A prior emetic tendency likely reflects persistent individual susceptibility involving central emetic pathways and sensitivity to perioperative stimuli. Its importance has been demonstrated across several prediction models, including the simplified Apfel score [5,6,9].

Postoperative opioid administration was another independent predictor. Opioids can activate chemoreceptor trigger-zone pathways, delay gastric emptying, and enhance vestibular sensitivity, thereby increasing the likelihood of nausea and vomiting [1,9]. The observed association supports contemporary recommendations to minimize unnecessary postoperative opioid exposure and incorporate multimodal, opioid-sparing analgesia whenever clinically appropriate [13,14]. Surgical duration exceeding 90 minutes was associated with PONV on univariable analysis, which is consistent with evidence that longer anaesthetic exposure increases emetic risk [3,4,9,12]. Nonsmokers also showed a higher event rate, although the association did not achieve statistical significance in this sample. The direction of effect nevertheless parallels established PONV prediction models [5,9,12].

Prophylactic antiemetic administration was associated with a substantially lower risk of PONV and remained protective after adjustment. This result is consistent with randomized evidence demonstrating meaningful relative reductions in PONV with established antiemetic interventions [10,11]. It also supports risk-adapted prophylaxis rather than uniform treatment of all patients. Volatile anaesthetic maintenance was not significantly associated with PONV in the present cohort despite previous evidence of emetogenicity [8,12]. The lack of statistical significance likely reflects the high prevalence of volatile use, the comparatively small nonvolatile group, and limited statistical power for this exposure.

Taken together, the findings reinforce the clinical value of simple preoperative risk assessment. Female sex and previous PONV or motion sickness can be identified before surgery, while postoperative opioid exposure and antiemetic prophylaxis represent potentially modifiable perioperative factors. Incorporating these variables into routine anaesthetic planning can help target preventive measures to patients with the greatest expected benefit.

LIMITATIONS

This study has several limitations. It was conducted at a single centre with a relatively small sample, which restricts precision and external generalizability. Surgical procedures and anaesthetic regimens were heterogeneous, and prophylactic antiemetic selection was not standardized because treatment reflected routine practice. The limited number of PONV events constrained the number of variables included in multivariable regression. Follow-up was restricted to the first 24 postoperative hours.

Postoperative nausea and vomiting affected 33.8% of adults undergoing elective surgery under general anaesthesia, confirming that it remained a common postoperative problem in this cohort. Most events occurred during the early recovery period. Female sex, a previous history of PONV or motion sickness, and postoperative opioid administration were independent predictors of increased risk, whereas prophylactic antiemetic administration was associated with lower risk. These findings support routine preoperative identification of susceptible patients and individualized preventive strategies. Risk-based antiemetic prophylaxis, careful selection of anaesthetic techniques, and opioid-sparing multimodal analgesia should be integrated into perioperative care to reduce PONV, improve recovery quality, and limit the need for rescue treatment after elective surgery.

1. Watcha MF, White PF. Postoperative nausea and vomiting. Its etiology, treatment, and prevention. Anesthesiology. 1992;77(1):162-84. doi:10.1097/00000542-199207000-00023.
2. Macario A, Weinger M, Carney S, Kim A. Which clinical anesthesia outcomes are important to avoid? The perspective of patients. Anesth Analg. 1999;89(3):652-8. doi:10.1097/00000539-199909000-00022.
3. Koivuranta M, Läärä E, Snåre L, Alahuhta S. A survey of postoperative nausea and vomiting. Anaesthesia. 1997;52(5):443-9. doi:10.1111/j.1365-2044.1997.117-az0113.x.
4. Sinclair DR, Chung F, Mezei G. Can postoperative nausea and vomiting be predicted? Anesthesiology. 1999;91(1):109-18. doi:10.1097/00000542-199907000-00018.
5. Apfel CC, Läärä E, Koivuranta M, Greim CA, Roewer N. A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers. Anesthesiology. 1999;91(3):693-700. doi:10.1097/00000542-199909000-00022.
6. Palazzo M, Evans R. Logistic regression analysis of fixed patient factors for postoperative sickness: a model for risk assessment. Br J Anaesth. 1993;70(2):135-40. doi:10.1093/bja/70.2.135.
7. Stadler M, Bardiau F, Seidel L, Albert A, Boogaerts JG. Difference in risk factors for postoperative nausea and vomiting. Anesthesiology. 2003;98(1):46-52. doi:10.1097/00000542-200301000-00011.
8. Apfel CC, Kranke P, Katz MH, Goepfert C, Papenfuss T, Rauch S, et al. Volatile anaesthetics may be the main cause of early but not delayed postoperative vomiting: a randomized controlled trial of factorial design. Br J Anaesth. 2002;88(5):659-68. doi:10.1093/bja/88.5.659.
9. Gan TJ. Risk factors for postoperative nausea and vomiting. Anesth Analg. 2006;102(6):1884-98. doi:10.1213/01.ANE.0000219597.16143.4D.
10. Apfel CC, Korttila K, Abdalla M, Kerger H, Turan A, Vedder I, et al.; IMPACT Investigators. A factorial trial of six interventions for the prevention of postoperative nausea and vomiting. N Engl J Med. 2004;350(24):2441-51. doi:10.1056/NEJMoa032196.
11. Habib AS, Gan TJ. Evidence-based management of postoperative nausea and vomiting: a review. Can J Anaesth. 2004;51(4):326-41. doi:10.1007/BF03018236.
12. Apfel CC, Heidrich FM, Jukar-Rao S, Jalota L, Hornuss C, Whelan RP, et al. Evidence-based analysis of risk factors for postoperative nausea and vomiting. Br J Anaesth. 2012;109(5):742-53. doi:10.1093/bja/aes276.
13. Gan TJ, Diemunsch P, Habib AS, Kovac A, Kranke P, Meyer TA, et al.; Society for Ambulatory Anesthesia. Consensus guidelines for the management of postoperative nausea and vomiting. Anesth Analg. 2014;118(1):85-113. doi:10.1213/ANE.0000000000000002.
14. Cao X, White PF, Ma H. An update on the management of postoperative nausea and vomiting. J Anesth. 2017;31(4):617-26. doi:10.1007/s00540-017-2363-x.