The impact of acetylcholinesterase inhibitors on ileus and gut motility following abdominal surgery: a clinical review

Pharmacologic prevention and therapy of postoperative paralytic ileus after gastrointestinal cancer surgery: systematic review and meta-analysis

BACKGROUND

Postoperative paralytic ileus (POI) is a significant concern following gastrointestinal tumor surgery. Effective preventive and therapeutic strategies are crucial but remain elusive. Current evidence from randomized-controlled trials on pharmacological interventions for prevention or treatment of POI are systematically reviewed to guide clinical practice and future research.

MATERIALS AND METHODS

Literature was systematically searched for prospective randomized-controlled trials testing pharmacological interventions for prevention or treatment of POI after gastrointestinal tumor surgery. Meta-analysis was performed using a random effects model to determine risk ratios and mean differences with 95% CI. Risk of bias and evidence quality were assessed.

RESULTS

Results from 55 studies, involving 5078 patients who received experimental interventions, indicate that approaches of opioid-sparing analgesia, peripheral opioid antagonism, reduction of sympathetic hyperreactivity, and early use of laxatives effectively prevent POI. Perioperative oral Alvimopan or intravenous administration of Lidocaine or Dexmedetomidine, while safe regarding cardio-pulmonary complications, demonstrated effectiveness concerning various aspects of postoperative bowel recovery [Lidocaine: -5.97 (-7.20 to -4.74)h, P <0.0001; Dexmedetomidine: -13.00 (-24.87 to -1.14)h, P =0.03 for time to first defecation; Alvimopan: -15.33 (-21.22 to -9.44)h, P <0.0001 for time to GI-2 ] and length of hospitalization [Lidocaine: -0.67 (-1.24 to -0.09)d, P =0.02; Dexmedetomidine: -1.28 (-1.96 to -0.60)d, P =0.0002; Alvimopan: -0.58 (-0.84 to -0.32)d, P <0.0001] across wide ranges of evidence quality. Perioperative nonopioid analgesic use showed efficacy concerning bowel recovery as well as length of hospitalization [-1.29 (-1.95 to -0.62)d, P =0.0001]. Laxatives showed efficacy regarding bowel movements, but not food tolerance and hospitalization. Evidence supporting pharmacological treatment for clinically evident POI is limited. Results from one single study suggest that Neostigmine reduces time to flatus and accelerates bowel movements [-37.06 (-40.26 to -33.87)h, P <0.0001 and -42.97 (-47.60 to -38.35)h, P <0.0001, respectively] with low evidence quality.

CONCLUSION

Current evidence concerning pharmacological prevention and treatment of POI following gastrointestinal tumor surgery is limited. Opioid-sparing concepts, reduction of sympathetic hyperreactivity, and laxatives should be implemented into multimodal perioperative approaches.

Molecular mechanisms of cholinergic neurotransmission in visceral smooth muscles with a focus on receptor-operated TRPC4 channel and impairment of gastrointestinal motility by general anaesthetics and anxiolytics

Acetylcholine is the primary excitatory neurotransmitter in visceral smooth muscles, wherein it binds to and activates two muscarinic receptors subtypes, M2 and M3, thus causing smooth muscle excitation and contraction. The first part of this review focuses on the types of cells involved in cholinergic neurotransmission and on the molecular mechanisms underlying acetylcholine-induced membrane depolarisation, which is the central event of excitation-contraction coupling causing Ca2+ entry via L-type Ca2+ channels and smooth muscle contraction. Studies of the muscarinic cation current in intestinal myocytes (mICAT) revealed its main molecular counterpart, receptor-operated TRPC4 channel, which is activated in synergy by both M2 and M3 receptors. M3 receptors activation is of permissive nature, while activation of M2 receptors via Gi/o proteins that are coupled to them plays a direct role in TRPC4 opening. Our understanding of signalling pathways underlying mICAT generation has vastly expanded in recent years through studies of TRPC4 gating in native cells and its regulation in heterologous cells. Recent studies using muscarinic receptor knockout have established that at low agonist concentration activation of both M2 receptor and the M2/M3 receptor complex elicits smooth muscle contraction, while at high agonist concentration M3 receptor function becomes dominant. Based on this knowledge, in the second part of this review we discuss the cellular and molecular mechanisms underlying the numerous anticholinergic effects on neuroactive drugs, in particular general anaesthetics and anxiolytics, which can significantly impair gastrointestinal motility. This article is part of the Special Issue on "Ukrainian Neuroscience".

Pyridostigmine in chronic intestinal pseudo-obstruction - a systematic review

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) may be a primary or secondary phenomenon and is often multifactorial. Treatment is largely directed at improving colonic motility. The use of cholinesterase inhibitors such as pyridostigmine has been hypothesized to increase acetylcholine in the bowel, improving symptoms and transit times.

METHODS

A systematic review of the use of pyridostigmine in CIPO was conducted using scientific and commercial search engines identifying scientific studies enrolling adult human subjects, published from 2000 to 2022 in the English language.

RESULTS

Four studies were identified including two randomized controlled trials (RCT) and two observational studies. The studies had heterogenous inclusion criteria, dosing regimens and reported outcomes. Two studies were identified as being at high risk of bias. All studies reported improved patient outcomes with use of pyridostigmine, and low rates (4.3%) of mild cholinergic side effects. No major side effects were reported.

CONCLUSION

The use of pyridostigmine in management of CIPO is biologically plausible due to its ability to increase colonic motility, and early studies on its role are uniformly suggestive of benefit with low side-effect profile. Four clinical studies have been conducted to date, with small sample sizes, heterogeneity and high risk of bias. Further high-quality studies are required to enable assessment of pyridostigmine's utility as an effective management strategy in CIPO.

The Postoperative Effect of Sugammadex versus Acetylcholinesterase Inhibitors in Colorectal Surgery: An Updated Meta-Analysis

BACKGROUND

the aim of this meta-analysis was to evaluate the postoperative effects of neuromuscular blockade reversal with sugammadex compared with acetylcholinesterase inhibitors in colorectal surgery.

METHODS

A systematic literature search was performed for studies comparing the postoperative course of patients receiving neuromuscular blockade reversal with either sugammadex or acetylcholinesterase inhibitors (control) after colorectal surgery. Data from eligible studies were extracted, qualitatively assessed, and included in a meta-analysis. Odds ratios and standardized mean differences with 95% confidence intervals (CIs) were calculated.

RESULTS

Five studies with a total of 1969 patients were included (sugammadex n = 1137, control n = 832). Sugammadex reversal resulted in a significantly faster return of defecation or flatus after surgery compared to acetylcholinesterase inhibitors (SMD 13.01, 95% CI 6.55-19.46, p = < 0.0001). There were no significant differences between the two groups in other clinical outcomes such as surgical morbidity and length of hospital stay.

CONCLUSION

The present data support the beneficial impact of sugammadex on gastrointestinal motility after colorectal surgery. However, the effect of sugammadex on the prevention of surgical complications and a prolonged hospital stay is diminishing. Larger randomized controlled trials with standardized study protocols are needed to validate the results presented here.

S-ketamine promotes postoperative recovery of gastrointestinal function and reduces postoperative pain in gynecological abdominal surgery patients: a randomized controlled trial

BACKGROUND

This prospective randomized controlled study was designed to evaluate the effect of S-ketamine with sufentanil given intraoperatively and postoperatively on recovery of gastrointestinal (GI) function and postoperative pain in gynecological patients undergoing open abdomen surgery.

METHODS

One hundred gynecological patients undergoing open abdomen surgery were randomized into an S-ketamine group (group S) or placebo group (0.9% saline; group C). Anesthesia was maintained with S-ketamine, sevoflurane, and remifentanil-propofol target-controlled infusion in group S and with sevoflurane and remifentanil-propofol target-controlled infusion in group C. All patients were connected to patient-controlled intravenous analgesia (PCIA) pump at the end of the surgery with sufentanil, ketorolac tromethamine, and tropisetron in group C and additional S-ketamine in group S. The primary outcome was the time of first postoperative flatus, and the secondary outcome was postoperative pain score of patients. Postoperative sufentanil consumption within the first postoperative 24 h and adverse events such as nausea and vomiting were recorded.

RESULTS

The time of first postoperative flatus in group S was significantly shorter (mean ± SD, 50.3 ± 13.5 h) than that in group C (mean ± SD, 56.5 ± 14.3 h, p = 0.042). The patient's visual analog scale (VAS) pain score 24 h after surgery at rest was significantly lower in group S than in group C (p = 0.032). There were no differences in sufentanil consumption within the first postoperative 24 h, postoperative complications related to PCIA between the two groups.

CONCLUSIONS

S-ketamine accelerated postoperative GI recovery and reduced 24 h postoperative pain in patients undergoing open gynecological surgery.

TRIAL REGISTRATION

ChiCTR2200055180. Registered on 02/01/2022. It is a secondary analysis of the same trial.

Exploring Pharmacological Treatments for Chronic Idiopathic Constipation in Adults: A Look Back to the Future

Despite great progress in pharmaceutical research, the medical treatment of chronic idiopathic constipation is far from ideal. The aim of the present article was to review literature data, focusing on poorly studied or commercially unavailable/unapproved drugs potentially useful for the treatment of chronic idiopathic constipation in adults. An extensive online literature search was conducted using the keywords "chronic constipation", "colon", "constipation", "drugs", "laxatives", and "treatment", in various combinations between January 1960 and December 2022. The literature search showed the presence of some drugs whose efficacy has only recently been demonstrated by modern investigations, and which are likely to be incorporated into future guidelines, of others that are proven effective and potentially effective on constipated patients but limited by small or relatively old studies, or by side effects which could be used in experienced hands, and of others that might be useful but lack a solid scientific background. Looking into the future for patients with chronic constipation might add some more tools to the therapeutic portfolio, especially for certain subgroups of these patients.

Effect of neuromuscular reversal with neostigmine/glycopyrrolate versus sugammadex on postoperative ileus following colorectal surgery

BACKGROUND

Postoperative ileus (POI) is a common complication following colorectal surgery and is mediated in part by the cholinergic anti-inflammatory pathway (CAIP). Neostigmine (acetylcholinesterase inhibitor), co-administered with glycopyrrolate, is frequently given for neuromuscular reversal before tracheal extubation and modulates the CAIP. An alternative reversal agent, sugammadex (selective rocuronium or vecuronium binder), acts independently from the CAIP. The aim of our study was to assess the impact of neuromuscular reversal agents used during anaesthesia on gastrointestinal recovery.

METHODS

Three hundred thirty-five patients undergoing elective colorectal surgery at the Royal Adelaide Hospital between January 2019 and December 2021 were retrospectively included. The primary outcome was GI-2, a validated composite measure of time to diet tolerance and passage of stool. Demographics, 30-day complications and length of stay were collected. Univariate and multivariate analyses were performed.

RESULTS

Two hundred twenty-four (66.9%) patients (129 [57.6%] males and 95 [42.4%] females, median age 64 [19-90] years) received neostigmine/glycopyrrolate and 111 (33.1%) received sugammadex (62 [55.9%] males and 49 [44.1%] females, median age 67 [18-94] years). Sugammadex patients achieved GI-2 sooner after surgery (median 3 (0-10) vs. 3 (0-12) days, p = 0.036), and reduced time to first stool (median 2 (0-10) vs. 3 (0-12) days, p = 0.035). Rates of POI, complications and length of stay were similar. On univariate analysis, POI was associated with smoking history, previous abdominal surgery, colostomy formation, increased opioid use and postoperative hypokalaemia (p < 0.05). POI was associated with increased complications, including anastomotic leak and prolonged hospital stay (p < 0.001). On multivariate analysis, neostigmine, bowel anastomoses and increased postoperative opioid use (p < 0.05) remained predictive of time to GI-2.

CONCLUSIONS

Patients who received sugammadex had a reduced time to achieving first stool and GI-2. Neostigmine use, bowel anastomoses and postoperative opioid use were associated with delayed time to achieving GI-2.