Postoperative nausea and vomiting (PONV) are common and distressing complications following laparoscopic surgeries, leading to prolonged recovery times, increased hospital stays, and decreased patient satisfaction1. The incidence of PONV can vary, but it remains a significant challenge, especially given its association with increased healthcare costs and the need for additional medical interventions2. Various pharmacological agents have been introduced to mitigate the risk and severity of PONV, with 5-HT3 receptor antagonists, such as ondansetron and palonosetron, being among the most commonly used treatments3.

Ondansetron, a first-generation 5-HT3 receptor antagonist, has been widely employed for the prevention and treatment of PONV4. However, despite its efficacy, its relatively short half-life and potential side effects can limit its effectiveness, particularly in the context of high-risk surgeries such as laparoscopic procedures5. In contrast, palonosetron, a second-generation 5-HT3 receptor antagonist, offers a longer half-life and a more potent binding affinity to the serotonin receptor, which may provide superior antiemetic effects and a more favorable side effect profile6.

The comparison between these two agents palonosetron and ondansetron—has garnered interest in recent clinical studies, particularly in terms of their ability to prevent PONV and their impact on postoperative recovery7,8. Given that laparoscopic surgeries are increasingly performed due to their minimally invasive nature and associated benefits, understanding the most effective pharmacological strategies to manage PONV is essential for enhancing patient outcomes.

This study aims to assess the comparative efficacy of intravenous palonosetron (75 mcg) versus intravenous ondansetron (4 mg) in preventing PONV in patients undergoing laparoscopic surgeries. By analyzing various outcome measures, including Visual Analog Scale (VAS) scores for nausea and vomiting, severity scores for vomiting, and hemodynamic stability over a 24-hour postoperative period

This study is a randomized controlled trial (RCT) conducted from  July 2023 to February 2024, in the Department of Anaesthesiology, Government General Hospital/Government Medical College, Anantapuramu.The aim of the study was to compare the efficacy of intravenous palonosetron (75 mcg) versus intravenous ondansetron (4 mg) in preventing postoperative nausea and vomiting (PONV) in patients undergoing laparoscopic surgeries.

Participants

A total of 180 patients scheduled for elective laparoscopic surgery were enrolled in the study. Inclusion criteria included adult patients aged 18-65 years, undergoing laparoscopic procedures under general anaesthesia. Exclusion criteria included patients with a history of motion sickness, PONV, allergy to 5-HT3 receptor antagonists, or those with pre-existing conditions affecting nausea and vomiting (e.g., gastrointestinal disorders, pregnancy, or severe liver/kidney disease).

Randomization

Patients were randomly assigned to one of two groups using a computer-generated randomization list:

Group A (Ondansetron group)

4 mg of intravenous ondansetron administered at the time of anaesthesia induction.

Group B (Palonosetron group)

75 mcg of intravenous palonosetron administered at the time of anaesthesia induction.

Intervention

Both drugs were administered as a single dose during the anaesthesia induction, with the drug being administered intravenously.

Outcome Measures

Primary Outcome

The effectiveness of palonosetron and ondansetron in preventing postoperative nausea and vomiting, measured by:

Visual Analog Scale (VAS)

Nausea and vomiting was assessed using a 10-point Visual Analog Scale (VAS), where 0 represents no nausea, vomiting and 10 represents the worst possible nausea and vomiting.

4-point Severity Scores

Severity score was assessed over 24 hr, The severity of nausea and vomiting was recorded using a 4-point scale  ranging from 0 (no nausea/vomiting) to 3 (severe nausea/vomiting).

Secondary Outcomes:

Hemodynamic Stability

Blood pressure and heart rate measurements were taken preoperatively, immediately after surgery, and at 2, 6, 12, and 24 hours postoperatively to assess the fluctuations in hemodynamic parameters.

Side Effects

Any side effects related to the drugs, including headaches, dizziness, or constipation, were recorded during the postoperative period.

Study Procedures

The anaesthesia protocol for laparoscopic surgery followed standard institutional guidelines. General anaesthesia was induced with propofol, fentanyl, and muscle relaxants as per the patient's requirement.

Both drugs (palonosetron and ondansetron) were administered intravenously just before induction of anaesthesia.

Post-surgery, patients were monitored for PONV symptoms using VAS and severity scores at 2, 6, 12, and 24 hours.

Hemodynamic parameters (heart rate and blood pressure) were recorded at specified intervals to assess hemodynamic stability.

Statistical Analysis

Data were analyzed using SPSS software version 22. Descriptive statistics were computed for baseline demographic and clinical variables. The primary outcome (VAS scores and 4-point severity scores) and secondary outcomes (hemodynamic parameters and side effects) were compared between groups using independent t-tests. A p-value of <0.05 was considered statistically significant.

Ethical Considerations

The study was approved by the Institutional Ethics Committee of Government Medical College, Ananthapuramu. Written informed consent was obtained from all patients before enrollment in the study. Patient confidentiality and data privacy were strictly maintained.

A total of 180 patients participated in this study, with 90 assigned to Group A (receiving ondansetron) and 90 to Group B (receiving palonosetron). The demographics, including gender, age, and ASA status, were compared across the two groups.

Gender Distribution

The gender distribution revealed a higher proportion of female participants, with 57.8% (104 patients) compared to 42.2% (76 patients) male participants. This trend reflects a predominantly female cohort, which aligns with the higher incidence of postoperative nausea and vomiting (PONV) observed in women following laparoscopic procedures (Table 1).

Table 1.Gender Distribution

ASA Status

The majority of participants were classified as ASA I (116 patients, 64.4%), indicating normal health status, while 35.6% (64 patients) were classified under ASA II, reflecting mild systemic disease. The distribution of ASA status was similar between both groups, ensuring comparability (Table 2).

Table 2.ASA Status

Age Comparison

The mean age of participants in Group A was 36.81 ± 13.34 years, while Group B had a mean age of 38.50 ± 13.31 years. A t-test comparison revealed no statistically significant difference in age between the two groups (t = -0.850, p > 0.05), confirming that the groups were age-matched (Table 3).

Table 3.Age Comparison

Blood Pressure Measurements

Blood pressure measurements were recorded at three stages: pre-operative, intra-operative, and post-operative.

Pre-operative Systolic and Diastolic Blood Pressure: Group A had significantly higher pre-operative systolic blood pressure (131.74 mmHg) compared to Group B (128.32 mmHg), with a t-value of 3.505 and p < 0.05. Similarly, Group A had higher pre-operative diastolic blood pressure (81.73 mmHg) compared to Group B (79.31 mmHg), with a t-value of 3.289 and p < 0.05 (Table 4).

Intra-operative Blood Pressure: There was no significant difference in intra-operative systolic blood pressure (129.23 mmHg for Group A and 127.46 mmHg for Group B, t = 1.578, p > 0.05). However, Group A exhibited significantly higher intra-operative diastolic blood pressure (83.81 mmHg) compared to Group B (79.80 mmHg), with a t-value of 5.027 and p < 0.05 (Table 4).

Post-operative Blood Pressure: Both systolic and diastolic blood pressures remained significantly higher in Group A post-operatively. The systolic

blood pressure in Group A was 130.46 mmHg, while Group B had 128.27 mmHg (t = 2.247, p < 0.05). The diastolic blood pressure in Group A was 85.08 mmHg, while Group B had 79.84 mmHg (t = 6.296, p < 0.05) (Table 4).

Table 4.Blood Pressure Comparison

Heart Rate Comparison

Heart rate measurements were significantly different between the groups at all three stages:

Pre-operative Heart Rate: Group B had a higher mean pre-operative heart rate (83.34 bpm) compared to Group A (79.60 bpm), with a t-value of 2.237 and p < 0.05 (Table 5).

Intra-operative Heart Rate: Group A demonstrated a significantly higher intra-operative heart rate (91.01 bpm) compared to Group B (82.74 bpm), with a t-value of 5.009 and p < 0.05 (Table 5).

Post-operative Heart Rate: The post-operative heart rate was higher in Group A (84.81 bpm) compared to Group B (79.91 bpm), with a t-value of 3.375 and p < 0.05 (Table 5).

Table 5.Heart Rate Comparison

Visual Analog Scale (VAS) Scores

VAS scores for nausea and vomiting at multiple time points post-surgery were significantly lower in Group B (palonosetron) compared to Group A (ondansetron):

At 2 hours post-surgery (VAS 2), Group B showed a significantly lower mean VAS score (0.72) compared to Group A (1.30), with a t-value of 8.506 and p < 0.05 (Table 6).

At 6 hours post-surgery (VAS 6), Group B had a mean score of 2.98, compared to Group A's mean score of 4.07 (t = 15.902, p < 0.05) (Table 6).

At 12 hours post-surgery (VAS 12), Group B had a mean score of 3.00, while Group A's score was 4.01 (t = 19.752, p < 0.05) (Table 6).

At 24 hours post-surgery (VAS 24), Group B showed a lower mean VAS score (3.18) compared to Group A (4.00), with a t-value of 20.289 and p < 0.05 (Table 6).

Table 6.VAS Scores Comparison

4-Point Severity Score

The 4-point severity score for nausea and vomiting over 1 hour, 2 hours, 6 hours, 12 hours, and 24 hours post-surgery was consistently lower in Group B across all time points:

At 1 hour, Group B had a significantly lower severity score (0.72) compared to Group A (0.96), with a t-value of 3.588 and p < 0.05 (Table 7).

At 2 hours (t = 6.088, p < 0.05), 6 hours (t = 6.725, p < 0.05), 12 hours (t = 6.713, p < 0.05), and 24 hours (t = 13.682, p < 0.05), Group B showed significantly lower scores at each time point (Table 7).

Table 7.4-Point Severity Score Comparison

Postoperative nausea and vomiting (PONV) remain significant challenges in the postoperative care of patients, particularly following laparoscopic surgeries. PONV not only compromises patient comfort and satisfaction but also increases recovery times and hospital stays. As such, effective prevention and management of PONV are essential to improving patient outcomes and enhancing the overall quality of care.

This study aimed to compare the efficacy of intravenous palonosetron and intravenous ondansetron in preventing PONV in patients undergoing laparoscopic procedures. The results of the study support the hypothesis that palonosetron, a second-generation 5HT3 antagonist, is more effective than ondansetron, a first-generation 5HT3 antagonist, in both preventing nausea and vomiting and in stabilizing hemodynamic parameters.

Efficacy in Preventing PONV

The findings of this study show that palonosetron significantly reduced the severity of PONV compared to ondansetron at all measured time

points (2, 6, 12, and 24 hours post-surgery). Specifically, the Visual Analog Scale (VAS) scores for nausea and the 4-point severity scores for nausea and vomiting were consistently lower in the palonosetron group (Group B) than in the ondansetron group (Group A). These results align with previous studies, which have demonstrated that palonosetron has a longer half-life and more potent antiemetic effects than ondansetron, which could explain its superior efficacy in preventing PONV11 (Campos et al9., 2019). The prolonged duration of action of palonosetron is likely responsible for its sustained antiemetic effect, which is crucial in the context of laparoscopic surgeries, where nausea and vomiting often persist for several hours postoperatively (Krishnan et al12., 2024).

Hemodynamic Stability

A notable finding of this study was the better hemodynamic stability observed in the palonosetron group. Patients in Group B demonstrated more stable heart rate and blood pressure, with significantly less fluctuation compared to those in Group A. This finding is particularly important as fluctuations in vital signs can contribute to patient discomfort and may indicate a more severe physiological response to anesthesia or postoperative complications. Previous studies have suggested that palonosetron has a more favorable pharmacokinetic profile, which may contribute to its ability to maintain more stable hemodynamic parameters. The reduced cardiovascular effects associated with palonosetron could lower the risk of potential complications in patients with comorbidities, such as those with preexisting cardiovascular conditions (Yoo et al10., 2020).

Side Effect Profile

Another important consideration is the side effect profile of the two antiemetic agents. In this study, no significant differences in adverse effects were observed between palonosetron and ondansetron, which is consistent with the safety profiles of both drugs. However, previous research has suggested that palonosetron may have a more favorable side effect profile due to its longer duration of action and reduced need for repeated dosing. Both drugs were well-tolerated in this study, but the improved efficacy and hemodynamic stability of palonosetron make it a more attractive option for preventing PONV in laparoscopic surgery patients (Kim et al13., 2013; Laha et al14., 2013).

Limitations and Future Research

Despite these promising results, the study has some limitations. The sample size of 180 patients, while adequate, could be expanded in future studies to provide more robust data. Additionally, the study only included patients undergoing laparoscopic surgery, and the results may not be directly applicable to other types of surgery, such as open surgeries or those involving higher-risk patients. Future studies could examine the efficacy of palonosetron in a broader range of surgical procedures, including those with higher rates of PONV or in patients with specific risk factors, such as older age or a history of motion sickness.

Furthermore, while the study focused on hemodynamic parameters and PONV outcomes, it did not assess other potential benefits of palonosetron, such as its effect on patient satisfaction, recovery time, or length of hospital stay. These factors are crucial for improving overall

patient experience and may provide additional insights into the clinical benefits of palonosetron over ondansetron.

This study provides evidence supporting the use of palonosetron as a more effective and stable option for preventing postoperative nausea and vomiting in patients undergoing laparoscopic surgeries. Palonosetron demonstrated superior efficacy in reducing the severity of PONV and was associated with more stable hemodynamic parameters compared to ondansetron. Given its longer duration of action and more favorable side effect profile, palonosetron should be considered as a preferred choice for antiemetic prophylaxis in laparoscopic surgery patients. Further studies are warranted to confirm these findings and explore the broader implications for different patient populations and surgical types.

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