Efficacy of intraperitoneal bupivacaine in laparoscopic bariatric surgery

A best evidence topic has been constructed using a described protocol. The three-part question addressed was: In [patients undergoing bariatric surgery], is [intraperitoneal local bupivacaine during the operation ] associated with [ lower pain score and decrease in post operative pain medications]? The search has been done and six randomized trial studies are considered to be appropriate to answer this question. The outcome assessed is the value of intraperitoneal bupivacaine in bariatric surgery in terms of effect on the pain score and post operative analgesia. We concluded that intraperitoneal bupivacaine causes improvement in both the pain score and post operative analgesia.


Introduction
This BET was constructed using a framework outlined by the International Journal of Surgery [1]. A BET provides evidence-based answers to the common clinical questions, using a systematic approach of reviewing the literature.

Clinical scenario
You are going to perform a laparoscopic bariatric surgery [eg. laparoscopic gastric bypass, laparoscopic sleeve gastrectomy, laparoscopic sleeve gastrectomy ] in an obese patient. You are anticipating that the patient will have post operative pain after such a procedure, and you understand that pain control is imperative for patient's recovery and length of stay [2]. This is especially important in the obese patients group, where improper pain control in a coexisting co-morbidities might increase the incidence of the post operative complications [2]. You discussed with a colleague whether or not to give an intraperitoneal local anaesthesia during the operation [bupivacaine], and you decided to conduct a systematic review to look for an evidence based answer for this technique.

Three-part question
In [patients undergoing bariatric surgery], is [intraperitoneal local bupivacaine during the operation ] associated with [lower pain score and decrease in post operative pain medications]?

Search strategy
The search was conducted as following: Embase 1974 to 06/ December/2021 and MEDLINE® 1946 to 06/December/2021 using the OVID interface: [intraperitoneal] AND [local anaesthesia OR local anaesthetic OR bupivacaine] AND [bariatric surgery OR bariatric procedure OR weight loss procedure]. The search was limited to the English language and human studies. Studies which are non-randomized and conference abstracts were excluded from this review.

Search outcome
A total of 8020 papers were found using OVID. Out of those 8020, 8010 were excluded because they were irrelevant based on titles and abstracts or duplicates. Ten full-text articles were screened and examined for eligibility. Of those ten, six randomized trials papers were identified to provide the best evidence to answer the question.

Discussion
Obesity is a serious disease worldwide and bariatric procedures are becoming more popular as a tool to improve the quality of life and comorbidities [4,9]. Multiple studies has reported a decrease in the post operative pain and length of hospital stay with intraperitoneal local anaesthesia [4].
Safari et al., 2020 and Omer et al., 2019 [ 3,5] conducted a randomized controlled trial, to assess the efficacy of bupivacaine in the bariatric procedures, using 106 and 100 patients respectively. The two studies included different types of bariatric patients and included a mix of LSG, LRYGB and LMGB [ Table 1]. Safari et al., 2020 installed 0.2% bupivacaine to wash the operated site before closure while Omar et al., 2019 installed 0.25% bupivacaine in the subdiaphragmatic space and patients held in Trendelenburg position for 5 min to enhance the effect of the intraperitoneal bupivacaine. Both [3,5]  showed similar findings with the maximum reduction in the pain score at the recovery followed by 4th hour post operatively, in which the pain score reduction was 1.12 and 0.86 respectively. Although safari et al. [3] noted that the improvement in the pain score lasted for 24 h, Omar et al. [5] noted that the effect of intraperitoneal bupivacaine on the pain score lasted for the first 6 h, with no difference in the pain score at 12 and 24 h. A smaller randomized trials from USA [ 6,7] [ Table 1] showed also positive outcome with the use of intraperitoneal bupivacaine. Alkhamesi et al., 2008 [6] included only patients undergoing LRYGB while Sherwinter et al., 2008 [7] involved only patients having LAGB. Both Alkhamesi et al., 2008 andSherwinter et al., 2008 reported statistically significant reduction in the pain score for the patients who received intraperitoneal bupivacaine, and the improvement in the pain score continued tell 24 h and 48 h respectively [6,7]. Moreover, in the Sherwinter et al. study [7], the improvement in the pain score in the intervention group was almost two fold that of the normal saline group, with the use of continuous infusion of intraperitoneal On-Q pump catheter containing 0.375% bupivacaine. Alkhamesi et al., 2008 [6] used a special device to aerosolize intraperitoneal 0.5% bupivacaine in the whole intraperitoneal cavity.
On the other hand, Symons et al., 2007 [8] and Schipper et al., 2019 [4] reported no difference in the pain score with the application of intraperitoneal bupivacaine compared to intraperitoneal normal saline [  [8] showed that patients who received intraperitoneal bupivacaine had less post operative analgesia requirements compared to the normal saline group.
In summary, four randomized trials showed improvement in the pain score in the bariatric operations [3,[5][6][7], and two of which [3,5] showed additional reduction in the post operative analgesic requirement of the patients. While the other two studies [4,8] didn't show statistically significant reduction in the pain score with the use of intraperitoneal bupivacaine, Symons et al., 2007 [8] reported statistically significant reduction in the post operative analgesia demands in the patients who received intraperitoneal bupivacaine. From the above findings, it is evident that intraperitoneal bupivacaine does help with the pain management in bariatric patients by either reducing the pain score or reducing the post operative analgesics.

Limitations of this review
1. There are different amounts and concentrations of bupivacaine used in the intervention groups in the above six randomized trials. 2. Intraperitoneal bupivacaine was applied using different techniques among the randomized trials in this review. 3. There is heterogenicity among the type of bariatric procedures included in each study, as some studies included one specific type of patients undergoing bariatric procedures [ Table 1] and others included a mix of patients undergoing different bariatric procedures [ Table 1]. 4. There are different post operative analgesia medications regime among the different randomized trials.

Clinical bottom line
There is a good evidence that intraperitoneal bupivacaine causes improvement in the control of postoperative pain after bariatric procedures, in terms of reduction of the pain score and post operative analgesia.

Ethical approval
Not applicable.

Sources of funding
None.

Author contributions
TS: devised the idea of the study, conducted literature search and wrote the paper.
SA: assisted in literature search and collecting the data. MO: assisted in literature search and writing the paper. MSG: assisted in literature search editing and writing the paper.

Guarantor
Tamer Saafan, Sabry Abounozha, Munzir Obaid, Mohamed Said Ghali Trial registry number 1. Name of the registry: Not applicable 2. Unique Identifying number or registration ID: Not applicable 3. Hyperlink to your specific registration (must be publicly accessible and will be checked): Not applicable

Consent
Not applicable.

Declaration of competing interest
None.