The use of regional anaesthesia in lower abdominal surgeries has increased a lot in last few decades. Spinal anaesthesia is the most practiced amongst all regional techniques, as it is easy to perform and provides a rapid onset with dense surgical block[1]. It is not associated with risk for toxicity to local anaesthetics, but it may result in different complications, particularly post – operative nausea and vomiting, hypotension and bradycardia which may be deleterious to the patients.

Post-operative nausea and vomiting is a distressing and very common complication of spinal anaesthesia with an incidence of upto 80% in a high risk patient and 22-25% in normal patients. It affects the patients in many ways, in terms of physical, metabolic, psychological and economical aspects[2].

There are number of factors which makes the patients prone to develop post-op nausea and vomiting such as female sex, obesity, anxiety, history of motion sickness or previous episodes of post-op nausea and vomiting, psychological factors, gastroparesis, abdominal sugery, use of opioids, pharyngeal stimulation, pain, gastrointestinal distension, hypoxia, vestibular disturbances etc[3].

The frequency of postoperative nausea and vomiting has remained high, and it has a significant detrimental effect on the degree to which patients are satisfied with their entire surgical experience[4-6]. PONV has also received additional attention as a result of the ongoing trend toward ambulatory operations because its occurrence could delay release or result in an unplanned hospital hospitalisation.

Probably, major causes of post-operative nausea and vomiting are pharyngeal stimulation, hypotension, gastrointestinal distension, abdominal manipulation, tissue trauma and inflammation in surgery, pain, use of opioids, hypoxia, vestibular disturbances, and psychological factors[7].

An observational comparative clinical study was conducted. 100 patients of ASA grade І & ІІ of either sex scheduled for elective lower abdominal surgeries under Spinal anaesthesia were divided into 2 groups.

GROUPING: Patients were randomly assigned to receive ondansetron 4 mg (group A) Palonosetron 0.075 mg (group B). Study medications were prepared, presented as identical 2 ml filled syringes and injected 10 minutes before spinal anaesthesia.

INCLUSION CRITERIA

1. Patient giving valid consent
2. Patients of ASA grade I & II
3. Patients of age group 20 to 60 years of either sex.
4. Patients of body weight between 40-80 kg selected after pre

anaesthetic check-up

EXCLUSION CRITERIA

1. Patient refusing to give consent
2. ASA grade III and onwards.
3. Patients under 20 year and above 60 year of age.
4. Known history of sensitivity to study drugs.

TABLE 1: Demographic data in both groups

TABLE 2: COMPARISON OF INTRAOPERATIVE AND POST OPERATIVE MEAN OXYGEN SATURATION IN BOTH GROUPS

The Oxygen Saturation was well maintained at 99% in the both the Group through the time lapse from pre-op till 48 hours postoperatively, with p value >0.05, which is statistically insignificant.

The Nausea severity score of 0 (nil), 1 (Mild), 2 (Moderate) & 3 (Severe) were taken into consideration. It was noted that Nausea from pre OP till 120 min (2 hours) in Ondansetron Group had episodes of 0, 5, 1 & 1 in the category of 0,1,2,3 respectively, while palonosetron Group had episodes of 0, 3, 1 & 1 respectively.

TABLE 3: COMPARISON OF POSTOPERTIVE NAUSEA IN BOTH GROUPS

TABLE 4: COMPARISON OF POSTOPERATIVE RETCHING IN BOTH GROUPS

TABLE 5: COMPARISON OF POST OPERATIVE VOMITTING IN BOTH GROUPS

The different groups received the following  medications - Group A (n=50) : Patients receiving I/V Ondansetron 2ml (4mg) slowly intravenously over 10 seconds 10 mins prior to SAB Group B (n=50) : Patients receiving I/V Palonosetron 1.5ml (0.075mg) diluted up to 2ml with normal saline given slowly intravenously over 10 seconds, 10 minutes prior to SAB[8]. This dose was similar as in studies conducted by S.P. Sharma et al.

The comparison of the mean oxygen saturation with preoperative basal saturation at different time intervals. Studies conducted by Sahoo T et al evaluated the effect of intravenous ondansetron 4mg and demonstrated that it attenuated spinal induced hypotension if given before spinal anesthesia in patients undergoing lower abdominal surgeries[9]. Also study by Owczuk R et al reported that ondansetron 8 mg I/V reduced the fall of SBP and MAP but doesn’t have influence on DBP and HR in comparison with placebo (normal saline).

During the intraoperative period, 2 patients each of ondansetron and palonosetron groups experienced retching respectively, while 48 patients from each group were free from retching, and in post-operative period, 6 patients from ondansetron group and 2 patients from palonosetron group respectively experienced retching which was statistically insignificant[10].

Incidence of vomiting among the two groups. During the intraoperative period, 2 patients from ondansetron group and none of the patients in palonosetron group experienced vomiting, which was statistically insignificant[11-12]. Meanwhile in post-operative duration, 6 patients from ondansetron group experienced vomiting but none of the patients in palonosetron group experienced vomiting, which was statistically significant.

Few studies conducted among two groups have shown domination of palonosetron as antiemetic agent. palonosetron has ranked one in anti-emetic property than other 5HT₃ antagonists like ramosetron and granisetron. Palonosetron was found to have a reduced incidence of nausea, vomiting, and retching than ondansetron and ramosetron in the study by S. H. Kim and colleagues[13-14]. Palonosetron seems to be successful at controlling PONV even when combined with chemotherapy. A study on PONV in palonosetron with dexamethasone and ondansetron with dexamethasone was completed by Sharma A. N. and colleagues. Palonosetron and dexamethasone together were shown to be more successful in their study at controlling the early and late phases of PONV in patients who had undergone laparoscopic hysterectomies

We found that Both ondansetron and palonosetron for prevention of  PONV in patients posted for elective lower abdominal surgeries under Sub Arachnoid Block, with palonosetron being significantly more effective than ondansetron in terms of long-term action when given 10 minutes before spinal anesthesia in patients undergoing lower abdominal surgeries. Efficacy of both the drugs for prevention of intra operative nausea and vomiting is comparable

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