This study demonstrates that the incidence of PONV within 24 h of recovery after laparoscopic sleeve gastrectomy (LSG) is 40.4% (46 cases). Women, inhalation anesthesia, and a surgery duration of ≥ 120 min were identified as independent risk factors for PONV. Additionally, the use of a combination of two or more antiemetic drugs was found to be a protective factor against PONV.

Apfel et al. [11] conducted a meta-analysis of 22 studies on risk factors for PONV. The results indicated that patients’ individual risk factors ranked as follows in terms of their contribution: being female (OR = 2.57, 95% CI 2.32–2.84), having a history of PONV (OR = 2.09, 95% CI 1.90–2.29), being a non-smoker (OR = 1.82, 95% CI 1.68–1.98), having a history of motion sickness (OR = 1.77, 95% CI 1.55–2.04), and experiencing a 10-year increase in age (OR = 0.88, 95% CI 0.84–0.92). This study found that women are at a higher risk of PONV after LSG, which is consistent with the research findings of Apfel et al. [11]. This is primarily attributed to the disparity in hormone levels between men and women, particularly the elevated levels of serum sex hormones, progesterone, and estrogen in female patients. Hormonal fluctuations post-surgery are substantial, leading to symptoms such as nausea, vomiting, and irritability in some female patients [14].

However, unlike the findings of Apfel et al. [11], this study discovered that a smoking history was not a risk factor for PONV after LSG. This discrepancy may be due to the small proportion of smokers in this study, which prevented the impact of tobacco on reducing the occurrence of PONV from being reflected. Nonetheless, it should be noted that nicotine, polycyclic aromatic hydrocarbons, and other substances in tobacco can diminish nerve receptor function, induce an increase in Cytochrome P450 Isozyme expression, and enhance the body’s tolerance to surgery and narcotics, thereby reducing the likelihood of PONV [15].

Furthermore, all patients included in this study were middle-aged and young, and the age difference between the PONV group and the non-PONV group was similar. Consequently, no correlation between age and PONV was observed in this study.

The results of this study showed a significant increase in the incidence of PONV in patients with a surgery time ≥ 120 min, which is consistent with the results of Apfel et al. [11]. The reason may be related to the use of drugs during the operation. As the operation time extends, the amount of sedatives, analgesics, and muscle relaxants used during the operation will increase accordingly. The accumulation of drugs in the body stimulates the mucosa of the digestive tract, causing the intestinal Chromaffin cells to release neurotransmitters that stimulate the Vagus nerve and visceral nerve afferent fibers in the intestinal wall. This transmission of stimulus signals to the vomiting center or initiation of the vomiting reflex occurs through the chemoreceptor trigger area.

Additionally, relevant studies [4] have shown that for every 30-minute increase in surgical duration, the incidence of PONV increases by 60%. This increase may be attributed to the prolonged use of large amounts of potential emetic drugs. Therefore, reducing the patient’s surgical time through skilled surgical procedures can help mitigate the occurrence of PONV in patients.

The research results indicate that the incidence of PONV is lower in patients receiving total intravenous anesthesia compared to those undergoing inhalation anesthesia, which aligns with the findings of Scheiermann P’s study. The reason for this difference may be attributed to the stimulating effect of inhaled anesthetics on the vomiting center of the cerebral cortex; however, the specific mechanism remains unknown [16]. Furthermore, studies have demonstrated that patients under sevoflurane anesthesia exhibit higher levels of motilin, which is closely associated with nausea and vomiting. It is possible that sevoflurane increases the occurrence of nausea and vomiting by modulating motilin production. On the other hand, propofol possesses certain antiemetic properties, possibly by mediating γ-aminobutyric acid receptors, leading to a decrease in serotonin (5-HT) concentration and inhibiting the chemical receptor vagus nucleus, thereby producing an antiemetic effect [17].

The incidence of PONV in patients undergoing laparoscopic sleeve gastrectomy (LSG) in this study was lower (40.4%) compared to previous studies (58.6%) [4]. This difference can be attributed to the multi-channel prevention of PONV in our hospital, which involves the combined use of antiemetic drugs with different mechanisms (with two or more drugs accounting for 66.7%) [18]. Apart from dexamethasone, our hospital also combines a 5-HT3 receptor antagonist (azasetron) and/or butyrophenone drugs (droperidol) simultaneously when using more than two types of anti-vomiting medications to achieve a favorable clinical effect of prevention. This finding aligns with the conclusions of Zaina Naeem et al. [19] and confirms that the combination of multiple drugs, as recommended for high-risk PONV patients, is equally effective for patients undergoing LSG.

Furthermore, some studies [20] have suggested that high-risk patients should consider supplementing with a third, and possibly a fourth, type of antiemetic drug with different mechanisms. Whether the routine application of three or more antiemetic drugs to bariatric surgery patients can yield more effective results requires further investigation. Additionally, the potential side effects of combined medications should also be taken into consideration. Overall, adverse events associated with antiemetics are relatively rare, and the quality of evidence regarding these events is low. However, when patients experience adverse drug reactions, they should not be ignored. Common side effects may include headache, dizziness, restlessness, sedation, constipation, dry mouth, blurred vision, prolonged QT interval, allergic reactions, extrapyramidal reactions, and other symptoms.

The prediction model established in this study is only applicable to predicting PONV in patients with LSG for more than 1 h, and not applicable to other types of bariatric surgery. The reason is that a survey conducted by P. Ziemann Gimmel et al. revealed that the incidence of PONV varies across different surgical procedures in bariatric surgery [4]. The reported incidences of PONV for each surgical procedure were as follows: SG—58.6%, laparoscopic Roux-en-Y gastric bypass (LRYGB)—19.4%, gastric banding (GB)—0%, revision LRYGB—23.1%, and Conversion—0%. The variation in the incidence of PONV mentioned above may be attributed to the divergent alterations in gastric pressure and compliance induced by distinct surgical techniques [21, 22]. The fundus of the stomach is excised in LSG, resulting in a reduction in the distensibility and compliance of the remaining stomach post-surgery, leading to a significant elevation in gastric pressure after surgery and an increased susceptibility to PONV.

Additionally, it is worth investigating the potential impact of changes in ghrelin levels on PONV. Ghrelin has been shown to possess antiemetic properties and its mechanism of action is associated with alleviating gastric paresis [23]. However, it should be noted that ghrelin primarily originates from X/A-like cells located in the gastric fundus mucosa. Previous studies have demonstrated a decrease in ghrelin levels among patients following LSG [24]. However, the clinical confirmation of whether alterations in ghrelin levels impact the incidence of PONV remains pending.

Due to the characteristics of retrospective studies, this study has several limitations. Firstly, there are fewer patients included in this study, which may have a certain impact on the stability of the logistic regression analysis results and introduce bias in the modeling outcomes. Secondly, the lack of a history of motion sickness/nausea and vomiting and the specific dosage of postoperative opioids may affect the accuracy of the prediction model, and since the operation time of the included cases was more than 1 h, the model is not suitable for rapid LSG. Lastly, this study was conducted at a single center, and the generalizability of the findings requires further validation with multi-center data.

In conclusion, there have been few studies on the prediction model of the PONV nomogram after LSG. This study conducted logistic regression analysis based on single-factor analysis and obtained four independent influencing factors of PONV, which include gender, anesthesia mode, operation time, and anti-vomiting drug combination treatment. Furthermore, a prediction model for the PONV nomogram was established. We believe that this model can provide personalized assessment and clinical suggestions for the development of PONV after LSG. However, it is important to note that since this is a retrospective study, this conclusion still needs to be supported by a multicenter and large-scale randomized controlled trial.