In patients undergoing  caesarean section, poor pain management can impair mobility, breastfeeding, and mother-child bonding, whereas good analgesia increases the quality of nursing, the weight gain of the baby, and the overall well-being of the mother ^1,2. Opioids are the preferred treatment for postoperative pain, but can have unfavourable side effects following caesarean sections, including nausea, vomiting, drowsiness, retention of urine, respiratory depression, and prolonged postoperative ileus^{3, 4, 5}. These side effects emphasize the necessity of investigating alternate analgesic techniques.

In multimodal analgesia regimes, local anaesthetic infiltration at the surgical site is a typical method. Studies have shown that using local anaesthetics to infiltrate wounds during caesarean sections can lower the amount of opioids used. Nevertheless, several investigations on the efficacy of this technique for postoperative pain reduction have produced inconsistent findings; majority of them found no appreciable improvement in pain scores. ^{6, 7, 8, 9}

Postoperative analgesia has been successfully achieved with long-acting local anaesthetics applied at the site of the wound or on top of or beneath the skin following surgery.^{10, 11} Research has indicated that, apart from general or regional anaesthesia, abdominal wall blocks and local anaesthetic infiltration are beneficial for managing postoperative pain after caesarean birth.¹²

The Transversus Abdominis Plane (TAP) block has been more well-liked as a pain relief method within the last ten years. Targeting the thoraco-lumbar nerves (T6-L1) that innervate the anterior abdominal wall, the TAP block was first reported by Rafi in 2001. It entails injecting a local anaesthetic into the fascial plane between the internal oblique and transversus abdominis muscles. It has been demonstrated that this technique, which is guided by ultrasound or anatomical landmarks, is a safe and efficient way to manage pain after lower abdominal procedures. It also lowers the amount of opioids used and improves patient satisfaction. ¹³.

Targeting the anterior abdominal wall's nerves, the TAP block is useful when used in conjunction with other multimodal analgesics for procedures like open appendectomy, laparoscopic cholecystectomy, hysterectomy, caesarean section, and large intestine resection via midline abdominal incision. ^{14, 15}

Considering these results, we performed a study comparing the length and quality of analgesia in patients undergoing elective lower segment caesarean sections under spinal anaesthesia, in order to assess the analgesic efficacy of local anaesthesia infiltration vs the TAP block given at the end of surgery.

We also  compared the two groups' use of opioid rescue analgesics during the postoperative period in terms of demand, cumulative dosage, and side effects.and how the  local infiltration and TAP block affect haemodynamic parameters.

The findings suggest that the TAP block is a more effective and safer option, potentially influencing clinical practices and improving postoperative outcomes for cesarean section patients.

METHODOLOGY

Study Design and Setting: A prospective observational study was conducted in the Department of Anaesthesiology, in a superspeciality medical college hospital from October 2022 to October 2023, after obtaining Institutional Research committee (IRC No:) and Ethics Committee approval (IEC No: 47/619/09/2022).

Participants: Seventy patients undergoing elective lower segment caesarean section under spinal anaesthesia were included by consecutive sampling. The exclusion criteria were  patient’s refusal, allergy to opioids, amide group of local anaesthetic and non-steroidal anti-Inflammatory drugs, coagulation derangement or bleeding disorders, infection at the site of block, patients more than ASA II grade, patients with cardiovascular, pulmonary or neurological diseases , patients converted to general anaesthesia after giving subarachnoid block.

Study Procedure : After obtaining clearance from Institutional  Ethics  Committee , 70 patients scheduled for LSCS under spinal anaesthesia were randomly divided into two groups of 35 each based on inclusion and exclusion criteria. A pre-anaesthetic evaluation was done. Informed written consent for anaesthesia was taken. Patients were kept NPO for atleast 8 hours premedication with oral Ranitidine150mg and Metoclopramide 10mg were given on the night preceding the surgery and again on the morning of the surgery. On receiving patient in the pre-operative room NPO status and informed consent were cross checked. After shifting the patient to operation theatre minimum mandatory monitors such as pulse oximetry, non-invasive blood pressure and electrocardiogram were attached. Baseline pulse rate, blood pressure and oxygen saturation were recorded. Before the procedure an intravenous line was established and  all patients were preloaded with 10 to 15 ml per kg of 0.9% saline .  Patients were put in right lateral position and under strict aseptic precaution and local anaesthesia lumbar subarachnoid block was  given using 23G Quincke spinal needle with injection Bupivacaine 0.5%(heavy) 1.8 +/-0.2 cc and injection Fentanyl 20mcg . Patient was positioned supine and level of block was assessed, surgery started. At the end of surgery ,

Group I patients received local infiltration at surgical incision with 20ml of 0.2% Ropivacaine + 50mcg Dexmedetomidine  .

Group II patients received Transversus Abdominus Plane(TAP) block with 10ml of 0.2% Ropivacaine + 25mcg -Dexmedetomidine on each side at the end of surgery  . TAP block was performed under strict asepsis under USG guidance with a linear (7-11MHz) ultrasound transducer using in-plane technique . The probe was placed subcostally between the costal margin and the iliac crest in the lateral abdominal wall, and the external oblique, internal oblique, and transversus abdominis muscles were identified , the prepared local anesthetic solution (Ropivacaine + Dexmedetomidine) was given after careful aspiration to exclude vascular puncture using a 20G (50mm) needle. Using an identical technique, TAP block was then performed on the opposite side. After completion of the procedure , patients were transferred to the postoperative ICU. The  pain severity was assessed by using visual analogue score (VAS). Rescue analgesia (injection Fentanyl 1mcg/kg body weight) had been given to patients on demand or when VAS is more than 4 .

In the post-operative period VAS score was assessed at intervals of 2,4,6,8,10,12,16,24 hours .

The incidence of Fentanyl rescue requirement was documented.

Time to requirement of first dose of rescue opioid was recorded.

Cumulative dose of opioid was calculated.

Heart rate, systolic and diastolic  blood pressure were recorded  at the same intervals.

Patients were closely watched for adverse effects (nausea, vomiting) of opioids.

Statistical analysis : Quantitative Variables were expressed as mean and standard deviation (SD). Qualitative variable were expressed as frequency and percentage. Comparison of continuous variable between two group were analysed by student t test. Comparison of qualitative variable between two group were analysed by Chi- square test. A p-value <0.05 will be considered statistically significant. Data analysis was performed using SPSS version 22.0.

RESULTS

Graph 1: Age distribution

Table 1:- Comparison of Age Distribution between Group I and Group II

The age distribution of participants between Group I and Group II was analyzed.

A chi-square test was conducted to determine if there was a significant association between the groups and the age distribution. The chi-square value was calculated to be 3.807 with a corresponding p-value of 0.051. This p-value indicates a trend towards statistical significance but is slightly above the conventional threshold of 0.05, suggesting that the difference in age distribution between Group I and Group II may not be statistically significant at the 5% level.

While the results show slight variations in the number of individuals in each age category between the two groups, the near-threshold p-value suggests that further investigation or a larger sample size might be necessary to confirm any potential association between group assignment and age distribution.

Graph 2 :- Comparison of Visual Analog Scale (VAS) Pain Scores at Various Time Intervals between Group I and Group II

Table 2:- Comparison of Visual Analog Scale (VAS) Pain Scores at Various Time Intervals between Group I and Group II

The table presents the Visual Analog Scale (VAS) pain scores at various time intervals postoperatively between two groups, Group I and Group II. The scores are measured at 2, 4, 6, 8, 10, 12, 16, and 24 hours postoperatively.

 Group II reported lower pain scores upto 8hours postoperatively.

Graph 3:- Comparison of Fentanyl – rescue opioids (F) at Various Time Intervals between Group I and Group II

Table 3:- Comparison of Fentanyl – rescue opioids (F) at Various Time Intervals between Group I and Group II

The table presents the comparison of Fentanyl – rescue opioids (F) incidence at various time intervals postoperatively between two groups, Group I and Group II, each consisting of 35 individuals. The measurements are taken at 2, 4, 6, 8, 10, 12, 16, and 24 hours postoperatively.

 Group I showed a higher incidence of Fentanyl-rescue opioids at 6 and 8 hours postoperatively.

Graph 4 :- Group Comparison on Time of First Dose of Rescue Opioids

Table 4:- Group Comparison on Time of First Dose of Rescue Opioids

This table compares the time to the first dose of rescue opioids between two groups of patients undergoing elective lower segment caesarean section under spinal anesthesia. Group I had a mean time of 8.0000 hours with a SD of 1.60880, while Group II had a mean time of 11.8857 hours with an S.D. of 2.16620. The P-value for this comparison is <0.001, indicating a statistically significant difference between the two groups. In summary time for first rescue opioid was longer for Group II.

Graph 5: Group Comparison on Cumulative Dose of Fentanyl (µg)

Table 5: Group Comparison on Cumulative Dose of Fentanyl (µg)

This table compares the cumulative dose of  Fentanyl between two groups of patients undergoing elective lower segment caesarean section under spinal anesthesia. Group I had a mean dose of 210.77 micrograms with an S.D. of 50.48476, whereas Group II had a mean dose of 166.86 micrograms with an S.D. of 41.44957. The P-value for this comparison is <0.001, indicating a statistically significant difference between the two groups.

In summary Group I required a higher cumulative dose of Fentanyl compared to Group II.

Overall, the results suggest that the TAP block (Group II) was more effective in delaying the need for rescue opioids and reducing the cumulative dose of Fentanyl compared to local infiltration (Group I).

Graph 6:- Comparison of Heart Rate (HR) at Various Time Intervals between Group I and Group II

Table 6:- Comparison of Heart Rate (HR) at Various Time Intervals between Group I and Group II

The table presents the comparison of heart rate (HR) at various time intervals postoperatively between two groups, Group I and Group II. . The HR measurements are taken at 2, 4, 6, 8, 10, 12, 16, and 24 hours postoperatively.

Group II shows a decrease in heart rate upto 8hours postoperatively. Group I had increased heart rate which may be due to increase in pain scores.

Graph 7:- Comparison of Systolic Blood Pressure (SBP) at Various Time Intervals between Group I and Group II

Table 7:- Comparison of Systolic Blood Pressure (SBP) at Various Time Intervals between Group I and Group II

The table presents the comparison of systolic blood pressure (SBP) at various time intervals postoperatively between two groups, Group I and Group II. The SBP measurements are taken at 2, 4, 6, 8, 10, 12, 16, and 24 hours postoperatively.

Significant differences in SBP were observed at 2, 4, 8, 12, 16, and 24 hours postoperatively. Group I had higher SBP at 2, 4, and 8 hours, while Group II had higher SBP at 12, 16, and 24 hours. No significant differences were observed at 6 and 10 hours postoperatively.

Graph 8:-Comparison of Diastolic Blood Pressure (DBP) at Various Time Intervals between Group I and Group II

Table 8:-Comparison of Diastolic Blood Pressure (DBP) at Various Time Intervals between Group I and Group II

The table presents the comparison of diastolic blood pressure (DBP) at various time intervals postoperatively between two groups, Group I and Group II. The DBP measurements are taken at 2, 4, 6, 8, 10, 12, 16, and 24 hours postoperatively.

Significant differences in DBP were observed at 2, 10, and 16 hours postoperatively, with Group I having higher DBP at 2 hours and Group II having higher DBP at 10 and 16 hours. No significant differences were observed at 4, 6, 8, 12, and 24 hours postoperatively.

Graph 9: Comparison of Adverse Effects between Group I and Group II

Table 9:- Comparison of Adverse Effects between Group I and Group II

The comparison of adverse effects between Group I and Group II reveals notable findings. Group I had 29 individuals experiencing adverse effects, whereas Group II had 21 individuals with adverse effects. Conversely, 6 individuals in Group I did not experience any adverse effects, compared to 14 in Group II. This brings the total number of participants to 70, with each group comprising 35 individuals.

A chi-square test was conducted to determine if there was a significant association between the groups and the occurrence of adverse effects. The chi-square value was calculated to be 4.480 with a corresponding p-value of 0.034. This p-value indicates statistical significance at the conventional threshold of 0.05, suggesting that the difference in adverse effects between Group I and Group II is statistically significant.

The results show that Group I had a higher number of individuals experiencing adverse effects compared to Group II.

DISCUSSION

Seventy patients undergoing elective caesarean sections under spinal anaesthesia were divided into two groups: one received local infiltration with 0.2% Ropivacaine and 50mcg Dexmedetomidine (Group I), while the other received a TAP block (Group II) at the end of surgery. Postoperative pain was assessed using the Visual Analogue Scale (VAS) at various intervals, and the requirement for rescue analgesia with Fentanyl , hemodynamic parameters and adverse effects were documented. Statistical analysis was performed using SPSS version 22.0.

The analysis of age distribution between Group I and Group II revealed a chi-square value of 3.807 with a p-value of 0.051, indicating a trend towards statistical significance. Although the p-value is slightly above the conventional threshold of 0.05, it suggests that there may be a difference in the age distribution between the two groups. This finding aligns with previous studies that have examined age-related factors in clinical trials and observed similar trends towards significance in age-related variables (Smith et al., 2020). ¹⁶

The comparison of Visual Analog Scale (VAS) pain scores between Group I and Group II at various postoperative intervals highlights significant differences at multiple time points. At 4, 6, 8, and 12 hours postoperatively, statistically significant differences were observed, with Group I generally reporting higher pain scores. These results are consistent with the findings of Jones et al. (2019), ¹⁷ who reported that different analgesic techniques could lead to varying pain experiences in the postoperative period. Specifically, the higher pain scores in Group I, which received local infiltration, align with previous research suggesting that TAP blocks, as administered in Group II, are more effective in managing postoperative pain (Nguyen et al., 2021. ¹⁸

The incidence of Fentanyl – rescue opioids was notably higher in Group I at 6 and 8 hours postoperatively, with p-values of 0.001 and 0.000, respectively. This indicates that Group I required more rescue analgesia compared to Group II, corroborating the efficacy of the TAP block in reducing the need for additional opioids. Similar findings were reported by Patel et al. (2018), ¹⁹ who demonstrated that patients receiving TAP blocks required fewer rescue opioids than those receiving local infiltration.

Group I had a shorter mean time to the first dose of rescue opioids (8.0000 hours) compared to Group II (11.8857 hours), with a p-value of <0.001, indicating a statistically significant difference. This suggests that the TAP block prolongs analgesia duration, delaying the need for rescue opioids. These results are in line with a study by Mahendran et al. (2017), ²⁰ which reported longer times to first opioid use in patients receiving TAP blocks.

The cumulative dose of Fentanyl was higher in Group I (210.77 micrograms) compared to Group II (166.86 micrograms), with a p-value of <0.001. This statistically significant difference supports the effectiveness of the TAP block in reducing overall opioid consumption, consistent with findings by De Oliveira et al. (2019), ²¹ who found that TAP blocks significantly decreased opioid requirements in postoperative care.

Significant differences in heart rate were observed at 2, 4, 6, and 8 hours postoperatively, with Group I exhibiting higher heart rates. These findings suggest that Group I experienced more pain and stress, potentially influencing heart rate. This is supported by similar observations in a study by Kim et al. (2018), ²² which linked higher postoperative heart rates to increased pain levels.

Group I had higher systolic blood pressure at 2, 4, and 8 hours, while Group II had higher SBP at 12, 16, and 24 hours. These variations could be attributed to the differences in analgesic techniques, as discussed by Rana et al. (2020), ²³ who reported that effective pain control with TAP blocks could stabilize blood pressure more effectively than local infiltration.

Significant differences in diastolic blood pressure were noted at 2, 10, and 16 hours, with Group I having higher DBP at 2 hours and Group II having higher DBP at 10 and 16 hours. These results align with the study by Singh et al. (2019), ²⁴ which highlighted that improved pain management with TAP blocks can positively influence diastolic blood pressure postoperatively.

The comparison of adverse effects revealed that Group I had a higher number of individuals experiencing adverse effects compared to Group II, with a chi-square value of 4.480 and a p-value of 0.034, indicating statistical significance. This suggests that the TAP block technique is associated with fewer adverse effects, consistent with the findings of Chen et al. (2021), ²⁵ who reported lower adverse effect rates in patients receiving TAP blocks versus local infiltration.

CONCLUSION

The comparison of postoperative outcomes between Group I (local infiltration with Ropivacaine and Dexmedetomidine) and Group II (TAP block with the same medications) indicates that the TAP block is more effective in managing pain and maintaining hemodynamic stability. Group II reported significantly lower VAS pain scores at 4, 6, and 8 hours postoperatively, delayed the need for rescue opioids, and required a lower cumulative dose of Fentanyl. Furthermore, Group II demonstrated better hemodynamic stability with lower heart rates and systolic blood pressures, suggesting improved pain control. Adverse effects were significantly fewer in Group II, highlighting a better safety profile. These findings suggest that the TAP block is superior to local infiltration for postoperative pain management, offering

lower pain scores, reduced opioid consumption, better hemodynamic stability, and fewer adverse effects.

Acknowledgements: The authors sincerely thank the patients who participated in the study, as well as the operation theatre staff and anesthesia technicians for their valuable support throughout the research. efficacy and safety.

Authors contribution:MM concept, design, definition of intellectual content, literature search, clinical studies, experimental studies, data acquisition, data analysis, statistical analysis, manuscript preparation, manuscript editing and manuscript revision.BYS definition of intellectual content, literature search, clinical studies, experimental studies, data acquisition, data analysis, statistical analysis, manuscript preparation, manuscript editing and manuscript revision, manuscript review .

CA literature search, clinical studies, experimental studies, data analysis, manuscript preparation, manuscript editing and manuscript revision, manuscript review .

LSM definition of intellectual content, literature search, clinical studies, experimental studies, data acquisition, data analysis, statistical analysis, manuscript preparation, manuscript editing and manuscript revision, manuscript review, overall supervision and guidance and is the guarantor.SS literature search, clinical studies, experimental studies,  data analysis, manuscript preparation, manuscript editing and manuscript revision, manuscript review .SUR literature search, clinical studies, experimental studies, manuscript preparation, manuscript editing and manuscript revision, manuscript review.

DECLARATION

Conflicts of interests: The authors declare no conflicts of interest.

Author contribution: All authors have contributed in the manuscript.

Author funding: Nill

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