Laparoscopic cholecystectomy is now regarded as the gold standard surgical management of the symptomatic gallstone disease and other benign gall bladder disorders. Laparoscopic surgery has many advantages compared to open cholecystectomy, such as less post-operative pain, shorter hospital stay, earlier mobilization, faster recovery and better cosmetic results¹. Postoperative pain is a major clinical problem after the laparoscopic cholecystectomy, although this procedure is performed in a minimally invasive manner. Surgical pain can be caused by several mechanisms, such as pain from trocar insertion, stretching of the peritoneum caused by the pneumoperitoneum, irritation of the diaphragm with surgery, and visceral manipulation during surgery². Failure to provide adequate postoperative pain management may prolong recovery, lengthen hospital stay, effect patient satisfaction and contribute to higher health care costs³.

Then postoperative pain management becomes a critical part of “perioperative care”. Traditionally, opioids have been the mainstay of postoperative analgesia; however, their use is frequently associated with adverse effects such as nausea, vomiting, respiratory depression, urinary retention, sedation, and delayed gastrointestinal recovery⁴. These complications have led to the pursuit of safer and more effective strategies for analgesia that reduce the use of opioids and yet provide effective pain relief. In modern surgical practice, multimodal analgesia has become a preferred method that involves using a combination of analgesics and their mechanisms of action to achieve optimal pain control and minimize adverse effects of opioids⁵.

Pre-emptive analgesia is one of the important concepts in multimodal analgesia. Pre-emptive analgesia involves using an analgesic procedure prior to the occurrence of surgical injury to prevent development of central sensitization and postoperative pain (POP) intensity⁶. Nociceptors in the periphery become excited during surgery, leading to an increase in excitability of central nervous system neurons. This is called central sensitization and can increase the perception of pain after surgery and increase the need for analgesia⁷. Pre-emptive analgesic techniques may reduce the transmission of nociceptive information and enhance the post-operative response⁸ by giving analgesic prior to the onset of a painful stimulus.

There are several agents being studied for pre-emptive analgesia, of which paracetamol is the one that has attracted a great amount of interest due to its efficacy, safety, availability, and the fact that it has little side effects. In the world, Paracetamol (acetaminophen) is one of the most frequently used non-opioid analgesics and antipyretics.⁹. Paracetamol's analgesic activity mechanism is not completely understood, but it is thought that it acts by inhibiting cyclooxygenase enzymes in the central nervous system, modulating serotonergic pathways, and possibly acting on cannabinoid receptors in the central nervous system that regulate pain.¹⁰ Paracetamol also does not significantly alter the function of platelets, gastric mucosa or renal blood flow, as is the case with the nonsteroidal anti-inflammatory drugs (NSAIDs), and hence is a safer choice in many surgical patients.¹¹

An IV formulation of Paracetamol has increased its use in perioperative medicine. Compared with oral formulations, intravenous administration offers immediate onset of action, a predictable plasma concentration, and 100% bioavailability.¹² Thus, IV paracetamol has gained increasing prominence in the perioperative analgesia regimes of many surgical specialties. Intravenous paracetamol has been shown to be effective for reducing postoperative pain scores and be able to decrease the amount of opioids required when combined with multimodal analgesia.¹³ These benefits could be vital to a better recovery, fewer opioid side effects, and greater satisfaction.

Laparoscopic cholecystectomy may have the most severe pain for the first 24 hours after surgery. Intravenous Paracetamol as an early pre-emptive analgesic can be an effective way of controlling pain early and may help to minimise rescue analgesics during this important post-operative period. Studies have shown that paracetamol given preoperatively intravenously, leads to reduced pain scores, reduced need for rescue analgesics and reduced opioid requirements.¹⁴ The size of these benefits, however, has been reported differently in studies, and variations in patient population, delivery time, and analgesic treatments have been responsible for inconsistent results.

Despite the availability of numerous effective pain management techniques, proper postoperative pain management is difficult in developing countries such as Pakistan because of the lack of resources, differences in practice and worries about side effects associated with opioids. Intravenous Paracetamol is an option which is relatively safe, easily administered and cheap. It could enhance patients' recovery and reduce the need for opioid analgesics in perioperative pain management. However, there is limited evidence about its effectiveness as a pre-emptive analgesic in laparoscopic cholecystectomy in the local context. The generation of context-specific data is relevant to evidence based clinical practice and to optimize post-operative pain management strategies in the local healthcare context.¹⁵

Hence, the present study was aimed at assessing the effectiveness of pre-emptive intravenous paracetamol prior to surgery in patients with laparoscopic cholecystectomy. The study was conducted to assess the difference in post-operative pain intensity, time to first rescue analgesic and total analgesic consumption for patients who received IV pre-operative paracetamol and those who received standard care. Intravenous Paracetamol was administered preoperatively in an attempt to improve the postoperative pain control, reduce the need for postoperative analgesics and improve recovery after a laparoscopic cholecystectomy. The results of this study could be a part of the accumulating evidence of multimodal analytic therapy and may also be helpful to develop effective, safe and economical analytic management for surgical patients.

This randomized controlled trial was conducted in the Department of General Surgery of a tertiary care teaching hospital after obtaining approval from the Institutional Ethical Review Committee (ERC). Written informed consent was obtained from all participants before enrollment. The study was carried out over a period of six months from April 2022 to October 2022. The study population comprised patients undergoing elective laparoscopic cholecystectomy for symptomatic cholelithiasis under general anesthesia. The sample size was calculated using the WHO sample size calculator by considering a 95% confidence level, 80% study power, and a level of significance of 5%. Based on previously published studies reporting differences in postoperative pain scores between intervention and control groups, a minimum sample size of 60 patients (30 in each group) was required to detect a statistically significant difference. To compensate for possible dropouts, all eligible patients presenting during the study period were considered for inclusion. Patients aged 18–65 years of either gender with American Society of Anesthesiologists (ASA) physical status I or II and scheduled for elective laparoscopic cholecystectomy were included in the study. Patients with known hypersensitivity to paracetamol, chronic pain disorders, hepatic or renal impairment, history of opioid dependence, pregnancy or lactation, conversion to open cholecystectomy, or those receiving analgesic medications within 24 hours prior to surgery were excluded from the study. A total of 60 patients fulfilling the eligibility criteria were enrolled through consecutive sampling and randomly allocated into two equal groups using a computer-generated randomization sequence. Patients in Group A received intravenous paracetamol 1 g diluted in 100 mL solution approximately 30 minutes before induction of anesthesia, whereas patients in Group B received 100 mL of normal saline as placebo. Both the patients and the postoperative assessors were blinded to group allocation. Standardized general anesthesia was administered to all participants according to departmental protocols. After completion of surgery, postoperative pain was assessed using the Visual Analog Scale (VAS), where 0 represented no pain and 10 represented the worst imaginable pain. Pain scores were recorded at 1, 4, 8, 12, and 24 hours after surgery. Rescue analgesia in the form of intravenous tramadol was administered when the VAS score was ≥4 or when requested by the patient. The time to first rescue analgesia and total postoperative analgesic consumption during the first 24 hours were documented. Patients were also monitored for adverse events including nausea, vomiting, dizziness, allergic reactions, and any drug-related complications. All collected data were entered and analyzed using Statistical Package for Social Sciences (SPSS) version 26. Quantitative variables such as age, body mass index, VAS pain scores, time to first rescue analgesia, and total analgesic consumption were expressed as mean ± standard deviation. Qualitative variables such as gender and occurrence of adverse effects were presented as frequencies and percentages. Independent sample t-test was used to compare continuous variables between the two groups, while Chi-square test or Fisher’s exact test was applied for categorical variables. A p-value of ≤0.05 was considered statistically significant.

ThisA total of 60 patients undergoing elective laparoscopic cholecystectomy were included in the study and randomly allocated into two groups. Thirty patients were allocated to Group A (1 g IV Paracetamol, preoperatively) and 30 to Group B (Placebo). Baseline demographic and clinical parameters were similar between the two groups without any difference found to be statistically significant.

Table 1: Baseline Characteristics of Study Participants

No statistically significant differences were observed between the two groups at baseline.

Table 2: Comparison of Postoperative Pain Scores (VAS)

Patients receiving intravenous paracetamol demonstrated significantly lower postoperative pain scores at all assessment intervals compared with the placebo group.

Table 3: Comparison of Rescue Analgesia Requirements

The mean time to first rescue analgesia was significantly longer in the paracetamol group. Furthermore, fewer patients required rescue analgesics in Group A compared with Group B.

Table 4: Total Postoperative Analgesic Consumption During First 24 Hours

Total postoperative analgesic consumption during the first 24 hours was significantly lower among patients receiving preoperative intravenous paracetamol.

Table 5: Comparison of Adverse Effects

The difference in incidence of PONV was not statistically significant between the two groups, although there was a lower incidence in the paracetamol group. There were no serious adverse reactions or drug related complications noted in either group.

Intravenous Paracetamol (IVP) significantly decreased the postoperative pain intensity, the time to first rescue analgesic requirement and overall consumption of rescue analgesics in patients undergoing LC in the present study. The results confirm that intravenous Paracetamol is an effective pre-emptive analgesic in Perioperative pain management.

The The management of postoperative pain is a critical part of perioperative care, assisting in patient recovery, minimization of complications, and increased patient satisfaction after surgery. While laparoscopic surgery is minimally invasive, the patient is often moderately painful for the first 24 hours after surgery. This present study aimed to assess pre-emptive intravenous paracetamol for the postoperative use in patients undergoing laparoscopic cholecystectomy. The results showed that patients who were administered intravenous paracetamol reported significantly less pain, took longer to require the first dose of rescue analgesia and used less total postoperative analgesic than those who were administered a placebo. The findings are in line with the emerging evidence for the use of IV Paracetamol in multimodal analgesia in laparoscopy.

There were no differences between the groups in baseline demographic data including age, gender distribution, BMI or ASA status, suggesting that the differences in the postoperative results observed were not likely to be confounded by these demographic factors. This baseline comparability has been previously demonstrated in other RCTs that have compared pre-emptive analgesic strategies in laparoscopic cholecystectomy.^16,17

The most important results of this study were that patients receiving intravenous paracetamol had fewer pain scores after surgery. There were significantly lower VAS scores at 1, 4, 8, 12 and 24 hours after surgery in the intervention group. The results of this study were similar to those of Sinatra et al. who found significantly better postoperative analgesia in patients receiving intravenous acetaminophen than in those receiving a placebo after receiving surgical procedures.¹⁸ The results indicated that they were able to find that paracetamol could be used for pain relief intravenously, and that they could monitor the central mechanism by which this was accomplished, without many of the side effects of opioid administration.

Likewise, Macario et al analyzed several RCTs and found that the IV administration of paracetamol effectively reduced postoperative pain intensity, and increased patient comfort during the immediate postoperative period¹⁹. The findings of the present study corroborate these observations and indicate that pre-operatively administered may improve analgesic effects via a pre-emptive pathway.

The rationale behind the notion of pre-emptive analgesia is that surgical trauma can lead to central sensitization. Surgical tissue injury stimulates nociceptive pathways, leading to increased central nervous system (CNS) neuronal excitability.Surgical tissue damage activates nociceptive pathways, leading to increased excitability of neurons within the central nervous system (CNS). This process leads to the development of hyperalgesia and greater sensitivity to pain after surgery. The use of analgesic agents prior to the surgical injury could dampen these physiological changes, thereby minimizing the degree of the ensuing pain²⁰. The significantly reduced pain scores noticed within this study confirmed the hypothesis that intravenous paracetamol has beneficial pre-emption analgesic effect prior to induction of anaesthetic.

The other significant result was that of the patients who got intravenous Paracetamol, they made their first request for rescue analgesia at a significantly longer time. The patients in the intervention group had to take rescue analgesia after 7.8 hours, while the placebo group had to after 4.6 hours. The results are similar to those of Cakan et al. who noted a longer analgesic effect and postponed the need for rescue analgesics in patients who received intravenous paracetamol prior to laparoscopic surgery.²¹ It is important clinically to postpone the delayed use of supplemental analgesia as this will create greater comfort for the patient and may reduce the nursing workload at the immediate post operation period.

Another clinically relevant finding of this study was the decrease in overall consumption of postoperative analgesics. Patients who were treated with Paracetamol intravenously had significantly lower doses of Tramadol taken in the first 24 hours after surgery than the controls. This opioid sparing effect is well reported in the literature. Remy et al. conducted a systematic review and found that Paracetamol use resulted in a significant reduction in opioid consumption after surgery without compromising analgesia.²² Hyllested et al. found that paracetamol plays an important role in multimodal analgesia and reduces opioid use after surgery.²³

There are significant clinical implications of opioid reduction. While useful, opioid analgesics have a host of side effects such as nausea, vomiting, respiratory depression, sedation, ileus, urinary retention and recovery delay. Thus, strategies that decrease the need for opioids and still provide effective analgesia are especially beneficial. In the current study, the reduction in postoperative nausea and vomiting seen with the use of intravenous Paracetamol may be related to the opioid-sparing effect that was demonstrated, though these differences were not statistically significant.

In the present study, the incidence of adverse effects was low in both group, and there were no serious adverse effects or allergic reaction. This is in line with earlier studies which have shown that the use of intravenous paracetamol is safe. Intravenous paracetamol has been shown to be well tolerated by patients with few side effects and was well accepted by patients in the postoperative period.²⁴ Moreover, Paracetamol does not produce significant gastrointestinal, renal or haematological side effects, further substantifying its use as part of pain management regimes associated with surgery.

The results of the present study are also similar to recommendations made by Enhanced Recovery After Surgery (ERAS) groups that recommend multimodal and opioid sparing anesthesia regimens to promote rapid recovery after surgery. Recent ERAS guidelines recommend the standard use of non-opioid analgesics (paracetamol), which are known to be effective and safe as part of a perioperative care pathway.²⁵ The marked decrease in pain scores and number of analgesics used in this study is in line with these recommendations.

Intravenous paracetamol has several practical benefits in resource-limited health care settings. Easy to administer, predictable pharmacokinetics, rapid onset, and does not need any special monitoring. IV paracetamol may be a cost-effective approach to enhance postoperative pain management in developing countries where more advanced pain management techniques are not available. Findings of this study then are important in clinical practice in other environments of similar healthcare systems.

Although good results have been noted, there are some limitations to consider in interpreting the results. The study was carried out in one institution and included a fairly small number of students. In addition, only short-term postoperative outcomes were evaluated. Long-term pain outcomes and patient satisfaction scores were not assessed. In spite of this, the present study offers good local data to support the use of Paracetamol for pre-emptive analgesia in Laparoscopic Cholecystectomy.

The findings of the present study are consistent with the international literature, which has confirmed that intravenous paracetamol is an effective, safe and well tolerated part of multimodal analgesia. The better-than-double reduction in postoperative pain intensity, the lower need to use rescue analgesia and the reduced opioid consumption was seen in this study and further supports the value of pre-emptive use of this agent. The results of this study suggest that perioperative use of intravenous Paracetamol should be routinely considered in the pain management plan for patients undergoing laparoscopic cholecystectomy and probably other minimally invasive surgical interventions.²⁶

The present study showed that intravenous paracetamol prior to laparoscopic cholecystectomy is an effective pre-emptive analgesia technique. Preoperative IV Paracetamol group had significantly lower postoperative pain scores, longer time to rescue analgesia and less total postoperative consumption of rescue analgesics than placebo group. No serious adverse effects were observed with the intervention and it was well tolerated. These results suggest that IV Paracetamol could be used as an effective part of multimodal analgesia and effective in improving postoperative recovery. It might also further lower the risk of opioid-related complications without compromising effective pain management because of its opioid-sparing effect. From the findings of this study, it is suggested that preoperative intravenous Paracetamol use could be a safe, effective and economically viable option of analgesics for patients undergoing laparoscopic cholecystectomy.

Study Limitations

There are some limitations in the present study which should be taken into consideration while interpreting the results. First, the study was done at one tertiary care hospital thus limiting the generalizability of the findings to other health care facilities and patients' populations. Second, the small sample size may not be representative of all patients with further laparoscopies for cholecystectomy. Thirdly, the effect of intravenous paracetamol given preoperatively with regards to pain management and recovery was only measured in the first 24 hours after the surgery; the long-term effects could not be determined. In addition, the study did not include patient satisfaction and quality-of-recovery scores, which could have contributed to an understanding of the intervention's overall effectiveness. Lastly, the results of this study are limited to patients undergoing laparoscopic cholecystectomy, and may not be directly applicable to other surgical procedures with different pain characteristics and postoperative analgesic needs.

Recommendations

From the present study, it can be concluded that intravenous paracetamol can be used as a useful complementary agent in multimodal analgesia strategies for those patients undergoing laparoscopic cholecystectomy. It could help to optimise postoperative pain management and decrease opioid analgesics usage. Larger multicenter randomized controlled studies are needed to confirm these results in a variety of patient and health care settings.

Moreover, long-term postoperative results, quality of recovery, functional status and patient satisfaction should be evaluated to have a wide-ranging assessment of the intervention. Analyses of other pre-emptive analgesic strategies, using other drugs and methods in other patients, may also aid in determining the best pain management strategy prior to surgery. Furthermore, the use of intravenous Paracetamol as part of Enhanced Recovery After Surgery (ERAS) protocols should be investigated to assess its role on the optimization of the postoperative patient recovery and reduction of opioid-related complications.

Authors’ Contributions

Dr. Afifa Aamir Khan conceived the study, led clinical data collection, and drafted the manuscript. Dr. Rifat Latif supervised the randomized trial, developed the randomization sequence, and managed corresponding author duties. Naveed Ahmed and Dr. Hamza Ashfaq administered anesthesia protocols, prepared the preoperative solutions, and monitored post-operative parameters. Dr. Ulas Khan oversaw the surgical procedures and patient enrollment within the Department of General Surgery. Prof. Nargis Danish performed the statistical analysis in SPSS and contributed to the literature review. All authors read and approved the final manuscript.

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