Alvimopan for the management of postoperative ileus after bowel resection: characterization of clinical benefit by pooled responder analysis

Enhanced recovery programs following adhesive small bowel obstruction surgery are feasible and reduce the rate of postoperative ileus: a preliminary study

PURPOSE

The recovery of gastrointestinal function and postoperative ileus are the leading goals for clinicians following surgery for adhesive small bowel obstruction. While enhanced recovery programs may improve recovery, their feasibility in emergency surgery has not yet been proven. We sought to assess the incidence of postoperative ileus in patients following surgery for ASBO and the feasibility of enhanced recovery programs, including their benefits in the recovery of gastrointestinal functions and reducing the length of hospitalization.

METHODS

This prospective study includes the first 50 patients surgically treated for ASBO between June 2021 and November 2022. Their surgery was performed either as an emergency procedure or after a short course of medical treatment. The main aim was to compare the observed rate of postoperative ileus with a theoretical rate, set at 40%. The study protocol was registered in clinicaltrials.gov under the number NCT04929275.

RESULTS

Among the 50 patients included in this study, it reported postoperative ileus in 16%, which is significantly lower than the hypothetical rate of 40% (p = 0.0004). The median compliance with enhanced recovery programs was 75% (95%CI: 70.1-79.9). The lowest item observed was the TAP block (26%) and the highest observed items were preoperative counselling and compliance with analgesic protocols (100%). The overall morbidity was 26.5%, but severe morbidity (Dindo-Clavien > 3) was observed in only 3 patients (6%). Severe morbidity was not related with the ERP.

CONCLUSION

Enhanced recovery programs are feasible and safe in adhesive small bowel obstruction surgery patients and could improve the recovery of gastrointestinal functions.

CLINICAL TRIAL REGISTRY

NCT04929275. WHAT DOES THE STUDY CONTRIBUTE TO THE FIELD?: Perioperative management of adhesive small bowel obstruction (ASBO) surgery needs to be improved in order to reduce morbidity. Enhanced recovery programs (ERP) are both feasible and safe following urgent surgery for ASBO. ERPs may improve the recovery of gastrointestinal (GI) functions.

Clinical practice guidelines for enhanced recovery after colon and rectal surgery from the American Society of Colon and Rectal Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons

The American Society of Colon and Rectal Surgeons (ASCRS) and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) are dedicated to ensuring high-quality innovative patient care for surgical patients by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus as well as minimally invasive surgery. The ASCRS and SAGES society members involved in the creation of these guidelines were chosen because they have demonstrated expertise in the specialty of colon and rectal surgery and enhanced recovery. This consensus document was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus and develop clinical practice guidelines based on the best available evidence. While not proscriptive, these guidelines provide information on which decisions can be made and do not dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, healthcare workers, and patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. These guidelines should not be deemed inclusive of all proper methods of care nor exclusive of methods of care reasonably directed toward obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all the circumstances presented by the individual patient. This clinical practice guideline represents a collaborative effort between the American Society of Colon and Rectal Surgeons (ASCRS) and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) and was approved by both societies.

Pre-habilitation before colorectal cancer surgery could improve postoperative gastrointestinal function recovery: a case-matched study

PURPOSE

While its effect is controverted, multimodal pre-habilitation could be used to improve the postoperative course following colorectal cancer surgery. However, by increasing lean body mass, pre-habilitation could reduce the time needed to recover gastrointestinal (GI) functions. The aim was to assess the impact of pre-habilitation before colorectal cancer surgery on postoperative GI motility recovery.

METHODS

This is a matched retrospective study based on a prospective database including patients undergoing colorectal surgery without pre-habilitation (NPH) (2016-2018) and with pre-habilitation (PH group) (2018-2019). The main outcome measure was the time to GI-3 recovery (tolerance to solid food and flatus and/or stools).

RESULTS

One hundred thirteen patients were included, 37 underwent pre-habilitation (32.7%). The patient's age, the surgical procedure, the surgical access, the rate of synchronous metastasis, the rate of preoperative chemoradiotherapy, and the rate of stoma were more important in the PH group. Conversely, the rate of patients with an ASA score of > 2 was higher in the NPH group. By matching patients according to age, gender and surgical procedure, 84 patients were compared (61 in the NPH group and 23 in the PH group). The mean of GI-3 recovery was significantly lower in the PH group. The other endpoints were not significantly different but time to GI function recovery and medical morbidity tended to be higher in the NPH group. Compliance with the enhanced recovery program was significantly higher in the PH group.

CONCLUSION

Pre-habilitation before colorectal cancer surgery reduced time to GI function recovery and may increase compliance with the enhanced recovery program.

Activation of p38 mitogen-activated protein kinase pathway by lipopolysaccharide aggravates postoperative ileus in colorectal cancer patients

BACKGROUND AND AIM

Patients undergoing abdominal surgery can develop postoperative ileus (POI). Inflammation of the intestinal muscularis following intestinal manipulation may be caused by displaced bacteria or lipopolysaccharide (LPS). The aim of this study was to investigate the relationship between gut microbiota, LPS, and POI in colorectal cancer (CRC) patients and explore underlying mechanisms of LPS-triggered POI.

METHODS

Sixty CRC patients undergoing colorectal resection were included. Bacterial communities from fecal samples were characterized by 16S rRNA gene sequencing, and fecal LPS levels were determined by Limulus amebocyte lysate assay. Mice were used to mechanistically investigate the causal relationship between microbiota, LPS, and POI.

RESULTS

We discovered that CRC patients who developed prolonged POI (PPOI) had a unique pro-inflammatory gut microbial composition during the perioperative period. The highest proportions of Gram-negative bacteria at the genus level were Escherichia-Shigella and Bacteroides; the abundance of Escherichia-Shigella was higher throughout the perioperative period. Fecal LPS levels were significantly higher in patients with PPOI. In mice treated with an antibiotic cocktail, intestinal muscularis inflammation and intestinal dysfunction were significantly improved. Inflammation and dysfunction were significantly reduced in mice treated with polymyxin B, but were worsened by treatment with LPS. Moreover, LPS upregulated p38 phosphorylation in mice, and treatment with an inhibitor of p38 (SB203580) significantly alleviated intestinal inflammation and dysmotility.

CONCLUSION

Lipopolysaccharide increases intestinal muscularis inflammation via activation of p38 signaling, which aggravates POI. Removing bacterial sources of LPS during the perioperative period is promising for the prophylactic treatment of PPOI.

Alvimopan retains efficacy in patients undergoing colorectal surgery within an established ERAS program

BACKGROUND

Post-operative ileus and delayed return of gastrointestinal function are complications seen frequently in patients undergoing colorectal surgery. Many enhanced recovery after surgery protocols include alvimopan to inhibit the effects of opiates in the gastrointestinal tract and lidocaine to augment analgesics. Limited data exist regarding alvimopan's efficacy in opiate-sparing regimens.

METHODS

This single-center, retrospective cohort analysis was conducted in a randomly selected population of adult patients undergoing colorectal resection between February 2018 and October 2019. Patients meeting inclusion criteria were divided into four groups dependent upon whether or not they received alvimopan (A or a) and/or lidocaine (L or l). The primary endpoint in this study was median time to first bowel movement or discharge, whichever came first. Our secondary endpoint was length of stay.

RESULTS

Of the 430 patients evaluated, a total of 192 patients were included in the final evaluation in the following groups: AL (n = 93), Al (n = 34), aL (n = 44), and al (n = 21). A significant difference was found among the groups for the primary outcome of median time to bowel movement or discharge (p = 0.001). Three subsequent pair-wise comparisons resulted in a significant difference in the primary outcome: group AL 39.4 h vs. group aL 54.0 h (p = 0.003), group AL 39.4 h vs. group al 55.4 h (p = 0.001), and group Al 44.9 h vs. group al 55.4 h (p = 0.01). Length of stay was significantly reduced by 1.8 days in groups AL and Al compared to group aL (p < 0.001).

CONCLUSION

Treatment with alvimopan resulted in a significant improvement in time to GI recovery and decreased length of stay in an established ERAS program. While lidocaine's reduction in opiates was minimal, the group receiving both alvimopan and lidocaine had the greatest reduction in time to GI recovery and length of stay.

Comparison of treatment to improve gastrointestinal functions after colorectal surgery within enhanced recovery programmes: a systematic review and meta-analysis

Despite a significant improvement with enhanced recovery programmes (ERP), gastro-intestinal (GI) functions that are impaired after colorectal resection and postoperative ileus (POI) remain a significant issue. In the literature, there is little evidence of the distinction between the treatment assessed within or outside ERP. The purpose was to evaluate the efficiency of treatments to reduce POI and improve GI function recovery within ERP. A search was performed in PubMed and Scopus on 20 September 2019. The studies were included if they compared the effect of the administration of a treatment aiming to treat or prevent POI or improve the early functional outcomes of colorectal surgery within an ERP. The main outcome measures were the occurrence of postoperative ileus, time to first flatus and time to first bowel movement. Treatments that were assessed at least three times were included in a meta-analysis. Among the analysed studies, 28 met the eligibility criteria. Six of them focused on chewing-gum and were only randomized controlled trials (RCT) and 8 of them focused on Alvimopan but none of them were RCT. The other measures were assessed in less than 3 studies over RCTs (n = 11) or retrospective studies (n = 2). In the meta-analysis, chewing gum had no significant effect on the endpoints and Alvimopan allowed a significant reduction of the occurrence of POI. Chewing-gum was not effective on GI function recovery in ERP but Alvimopan and the other measures were not sufficiently studies to draw conclusion. Randomised controlled trials are needed.Systematic review registration number CRD42020167339.

Fast-track Pathway for Minimally Invasive Colorectal Surgery with and without Alvimopan (Entereg)™: Which is More Cost-effective?

Multimodal fast-track (FT) pathways for both open and laparoscopic colorectal surgery have been shown to improve gastrointestinal recovery, shorten length of stay, and decrease morbidity. The aim of our study was to determine if using alvimopan (Entereg)™ in the setting of a FT minimally invasive colorectal pathway is beneficial and cost-effective. All minimally invasive colorectal surgeries performed by one surgeon using a multimodal FT pathway with and without alvimopan were reviewed. Ninety total patients were identified, 64 patients treated without and 26 with alvimopan. Main outcomes included postoperative day tolerating a soft diet, return of gastrointestinal function, length of stay, 30-day readmission rate, and patient care, anesthesia, pharmacy, and combined cost. Tolerance of a soft diet, return of gastrointestinal function, and length of stay were all shorter and showed significance in the alvimopan group (mean 2.1 vs 2.8 days, mean 1.5 vs 2.4 days, and mean 3.5 vs 4.5 days, respectively) ( P = 0.0197, P = 0.0029, and 0.0158, respectively). Patient care and combined hospital costs were both increased in the nonalvimopan group; however, combined hospital costs was not significant ( P = 0.0216 and P = 0.0875, respectively). The 30-day readmission rate of 6.3 per cent was also not significant in this group ( P = 0.0941). Patients undergoing minimally invasive colorectal surgery treated with a multimodal FT pathway tolerated a soft diet sooner, had earlier return of bowel function, a shorter length of stay, and lower patient care and combined costs when alvimopan was used.

Systematic scoping review of enhanced recovery protocol recommendations targeting return of gastrointestinal function after colorectal surgery

BACKGROUND

Post-operative ileus (POI) and delayed return of gastrointestinal (GI) function are common complications after colorectal surgery. There is a lack of uniformity in enhanced recovery protocols (ERPs) with regards to interventions used to target these complications. This systematic review aims to categorize and summarize management recommendations available from published ERPs.

METHODS

A systematic search of Ovid MEDLINE, Embase, Cochrane Library and PubMed databases was performed from January 1990 to May 2018. All studies publishing enhanced recovery or fast-track or multimodal pathway protocols for colorectal surgery in their full-text were included. Data on interventions aimed at reducing the duration of POI were extracted, as well as references quoted to support specific interventions.

RESULTS

Of 481 manuscripts screened, 37 published ERPs were identified from 37 studies (18 cohort, seven historical-control, five guidelines, four randomized controlled trials, one randomized controlled trial protocol, one case series and one narrative review). The most commonly recommended interventions were magnesium-based laxatives (18 of 37, 48.6%), chewing gum (13 of 37, 35.1%), Alvimopan (6 of 37, 16.2%), lactulose (4 of 37, 10.8%), neostigmine (2 of 37, 5.4%) and bisacodyl (2 of 37, 5.4%). Geographical trends were noted for the various interventions, but high-quality evidence was only referenced to support the use of Alvimopan.

CONCLUSION

ERP recommendations specific to interventions targeting POI and return of GI function are varied. While laxatives are the most commonly recommended intervention, there is only weak evidence reported to support this practice.

Evaluation of Healthcare Use and Clinical Outcomes of Alvimopan in Patients Undergoing Bowel Resection: A Propensity Score-Matched Analysis

BACKGROUND

Postoperative ileus is a significant complication after bowel resection surgeries. Alvimopan is the only US Food and Drug Administration-approved therapy for accelerating the return of bowel function after large- and small-bowel resection.

OBJECTIVE

The purpose of this study was to estimate the healthcare use and in-hospital morbidities associated with on-label use of alvimopan in patients undergoing bowel resection surgeries.

DESIGN

A retrospective observational propensity-matched cohort study was conducted using a large hospital administrative database.

SETTING

The study included inpatient postsurgical patients.

PATIENTS

Patients aged ≥18 years undergoing a primary large or small segmental bowel resection with discharge dates between January 2010 and December 2014 were included.

INTERVENTIONS

Patients receiving 2 to 15 doses of alvimopan were defined as the treatment cohort, and those without any alvimopan use were included as control subjects.

MAIN OUTCOME MEASURES

The primary outcome was postoperative length of stay. Secondary outcomes included postoperative in-hospital morbidities, inpatient mortality, intensive care unit length of stay, discharge disposition, and 30-day readmission.

RESULTS

Each propensity-score matched cohort included 18,559 patients. The mean (±SD) postoperative length of stay was 4.62 ± 2.45 days in alvimopan-treated patients compared with 5.24 ± 3.35 days in control subjects (p < 0.001). Alvimopan-treated patients had lower rates of postoperative GI complication (12.15% vs 16.50%; p < 0.001). The rates of urinary tract infections; other postoperative infections; and cardiovascular, pulmonary, thromboembolic, and cerebrovascular events were also lower compared with the control subjects.

LIMITATIONS

The study was limited by its inability to generalize to the US population, because the database included a convenience sample of hospital discharges. The identification of patients undergoing bowel resection and their clinical conditions relied on the accuracy and completeness of International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis and procedure coding. There may be a confounding effect by the use of enhanced recovery pathways associated with the use of alvimopan.

CONCLUSIONS

The use of alvimopan was associated with a reduction of 0.62 days in postsurgery length of stay and lower rates of postoperative GI complications, infections, and other in-hospital morbidities. See Video Abstract at http://links.lww.com/DCR/A703.

Effect of alvimopan on gastrointestinal recovery and length of hospital stay after retroperitoneal lymph node dissection for testicular cancer

Objective

Alvimopan use has reduced the length of hospital stay in patients undergoing major abdominal surgeries and radical cystectomy. Retroperitoneal lymph node dissection for testicular cancer may be associated with delayed gastrointestinal recovery prolonging hospital length of stay. We evaluate whether alvimopan is associated with enhanced gastrointestinal recovery and shorter hospital length of stay in men undergoing retroperitoneal lymph node dissection for testicular cancer.

Materials and methods

From 2010 to 2016, 29 patients underwent open, transperitoneal bilateral template retroperitoneal lymph node dissection. Data for patients who received alvimopan were prospectively collected and compared to a historical cohort of patients who did not receive alvimopan. Primary outcome measures were length of stay and recovery of gastrointestinal function. Descriptive statistics were reported. Time-to-event outcomes were evaluated using cumulative incidence curves and log rank test. Factors associated with length of stay were analyzed for correlation using multiple linear regression.

Results

Of 29 men undergoing retroperitoneal lymph node dissection, eight received alvimopan and 21 did not. The two cohorts were well matched, with no significant differences. In the alvimopan cohort compared with those who did not receive alvimopan median time to return of flatus was 2 versus 4 days (p=0.0002), and median time to first bowel movement was 2.5 versus 5 days (p=0.046), respectively. Median length of stay in the alvimopan cohort was 4 days versus 6 days in those who did not receive alvimopan (p=0.074). In adjusted analyses, receipt of alvimopan did not influence length of stay.

Conclusion

Alvimopan may facilitate gastrointestinal recovery after retroperitoneal lymph node dissection for testicular cancer. Whether this translates into reduced length of stay needs to be determined by randomized controlled trials using larger cohorts.

Level of evidence

3b.

Alvimopan in the setting of colorectal resection with an ostomy: To use or not to use?

BACKGROUND

Postoperative ileus (POI) is a major cause of morbidity, increased length of stay (LOS) and hospital cost after colorectal surgery. Alvimopan is a µ-opioid antagonist used to accelerate upper and lower gastrointestinal function after bowel resection. We hypothesized that alvimopan would reduce LOS in patients undergoing colorectal resection with stoma, a situation that has not been evaluated.

METHODS

A retrospective review (2010-2015) identified 58 patients who underwent colorectal resection for benign or malignant disease with stoma creation and received alvimopan. They were case-matched to 58 non-alvimopan patients based on age, BMI, baseline comorbidities, stoma type created and surgical approach. We compared overall LOS, incidence of POI and other postoperative complications.

RESULTS

There were equal numbers of laparoscopic (N = 18) and open resections (N = 40) in the alvimopan group and non-alvimopan group. There were also equal numbers of patients with an ileostomy (N = 37) or colostomy (N = 21) in each group. Overall, 41 patients underwent resection for malignant disease in the alvimopan group compared to 37 in the non-alvimopan group. There was a significant reduction in median LOS overall (alvimopan 5 (4-7) versus control 6 (4.75-9.25) days, P = 0.03). While the 6-day median LOS was similar for patients undergoing ileostomy creation (P = 0.25), alvimopan patients had a 3-day decreased median LOS that approached statistical significance (P = 0.06). The overall 30-day complication rate was higher in the control group (41.4 vs. 51.7%, P = 0.26), but the readmission rate within 30 days was higher in the alvimopan group (19 vs. 13.8%, P = 0.45). Neither of these differences reached statistically significance.

CONCLUSION

The use of alvimopan in patients undergoing colorectal resection with stoma is associated with a significantly shorter LOS, but the increased readmission rate warrants further study. Based on these data, alvimopan should be evaluated in a controlled setting for patients undergoing colorectal resection with colostomy creation.

Is there value in alvimopan in minimally invasive colorectal surgery?

BACKGROUND

Alvimopan's goal is to minimize postoperative ileus and optimize outcomes; however, evidence in laparoscopic surgery is lacking. Our goal was to evaluate the benefit of alvimopan in laparoscopic colorectal surgery with an enhanced recovery pathway (ERP).

METHODS

Laparoscopic colorectal cases were stratified into alvimopan and control cohorts, then case-matched for comparability. All followed an identical ERP. The main outcomes were length of stay, complications, readmissions, and costs in the alvimopan and control groups.

RESULTS

About 321 patients were analyzed in each cohort. Operative times were comparable (P = .08). Postoperatively, complication rates were similar (P = .29), with no difference in ileus (P = 1.00). The length of stay (3.69 vs 3.49 days; P = .16), readmission (2.8% vs 3.7%; P = .66) and reoperation rates (2.2% vs 1.6%; P = .77) were comparable for alvimopan and controls, respectively. Total costs were similar ($14,932.47 alvimopan vs $14,846.56 controls; P = .90), but the additional costs in the alvimopan group could translate to savings of $27,577 in the cohort.

CONCLUSIONS

Alvimopan added no benefit in patient outcomes in laparoscopic colorectal surgery with an ERP. These results could drive a change in current practice. Controlled studies are warranted to define the cost and/or benefit in clinical practice.

Delayed gastrointestinal recovery after abdominal operation - role of alvimopan

Postoperative Ileus (POI), which occurs after surgical manipulation of the bowel during abdominal operations, is associated with prolonged hospital stay, increasing medical costs, and delayed advancement of enteral diet, which contributes to a significant economic burden on the healthcare system. The use of accelerated care pathways has shown to positively impact gut function, but inevitable postoperative opioid use contributes to POI. Alvimopan is a peripherally acting μ-opioid receptor antagonist designed to mitigate antimotility effects of opioids. In our review, we examined ten trials on alvimopan’s use after abdominal operations. Several of the earlier studies on patients undergoing bowel resection showed correlations between the study group and GI recovery as defined by passage of flatus, first bowel movement, and time to readiness for discharge. Data in patients undergoing total abdominal hysterectomy showed similarly decreased GI recovery time. Additionally, data within the past few years shows alvimopan is associated with more rapid GI recovery time in patients undergoing radical cystectomy. Based on our review, use of alvimopan remains a safe and potentially cost-effective means of reducing POI in patients following open GI surgery, radical cystectomy, and total abdominal hysterectomy, and should be employed following these abdominal operations.

Clinical features and management of equine post operative ileus: Survey of diplomates of the European Colleges of Equine Internal Medicine (ECEIM) and Veterinary Surgeons (ECVS)

REASONS FOR PERFORMING STUDY

There is a need for an improved understanding of equine post operative ileus (POI), in terms of both clinical definition and optimal management. Although the pharmacological strategies that are used to treat POI continue to evolve, little is known about the supplementary strategies used to prevent and manage this condition.

OBJECTIVES

To report the current strategies used to diagnose, prevent and manage POI following emergency abdominal surgeries.

STUDY DESIGN

Cross-sectional survey.

METHODS

An electronic survey invitation was sent by email to 306 European college diplomates (European Colleges of Equine Internal Medicine, ECEIM n = 120, and Veterinary Surgeons, ECVS n = 186).

RESULTS

The response rate was 33% (100 of 306). The median reported estimated incidence of POI was 10-20%. The presence of reflux on nasogastric intubation was the main criterion used to define POI. Lesions involving the small intestine were thought to be the leading risk factors for developing POI. Anti-inflammatory drugs, antimicrobial drugs and i.v. fluids were the primary preventative strategies when managing cases at high risk for POI. Flunixin meglumine and lidocaine were the drugs most commonly used to treat horses with POI. Supplementary preventative and treatment strategies for POI included control of endotoxaemia, fluid therapy, early ambulation and judicious timing of post operative feeding.

CONCLUSIONS

Appreciation of the potential risk factors associated with the development of POI appeared to have an impact on the choice of management strategies that are implemented. The majority of ECEIM and ECVS Diplomates in the survey used flunixin meglumine and lidocaine, often in combination, to treat horses with POI, which is likely to reflect the contributory role of inflammation in its pathophysiology. Various supplementary strategies were used to prevent and manage POI risk factors intraoperatively and post operatively.

A systematic review of outcome reporting in colorectal cancer surgery

AIM

Evaluation of surgery for colorectal cancer (CRC) is necessary to inform clinical decision-making and healthcare policy. The standards of outcome reporting after CRC surgery have not previously been considered.

METHOD

Systematic literature searches identified randomized and nonrandomized prospective studies reporting clinical outcomes of CRC surgery. Outcomes were listed verbatim, categorized into broad groups (outcome domains) and examined for a definition (an appropriate textual explanation or a supporting citation). Outcome reporting was considered inconsistent if results of the outcome specified in the methods were not reported. Outcome reporting was compared between randomized and nonrandomized studies.

RESULTS

Of 5644 abstracts, 194 articles (34 randomized and 160 nonrandomized studies) were included reporting 766 different clinical outcomes, categorized into seven domains. A mean of 14 ± 8 individual outcomes were reported per study. 'Anastomotic leak', 'overall survival' and 'wound infection' were the three most frequently reported outcomes in 72, 60 and 44 (37.1%, 30.9% and 22.7%) studies, respectively, and no single outcome was reported in every publication. Outcome definitions were significantly more often provided in randomized studies than in nonrandomized studies (19.0% vs 14.9%, P = 0.015). One-hundred and twenty-seven (65.5%) papers reported results of all outcomes specified in the methods (randomized studies, n = 21, 61.5%; nonrandomized studies, n = 106, 66.2%; P = 0.617).

CONCLUSION

Outcome reporting in CRC surgery lacks consistency and method. Improved standards of outcome measurement are recommended to permit data synthesis and transparent cross-study comparisons.

Facilitating return of bowel function after colorectal surgery: alvimopan and gum chewing

Postoperative ileus is common after colorectal surgery, and has a huge impact on hospital LOS. With the impeding cost crisis in the United States, safely reducing length of stay is essential. Chewing gum and pharmacological treatment with alvimopan are safe, simple tools to reduce postoperative ileus and its associated costs. Future research will determine if integrating these tools with laparoscopic procedures and enhanced recovery pathways is a best practice in colorectal surgery.

Identification of clinical outcome measures for recovery of gastrointestinal motility in postoperative ileus

OBJECTIVE

To identify clinical hallmarks associated with recovery of gastrointestinal transit.

BACKGROUND

Impaired gastrointestinal transit or postoperative ileus largely determines clinical recovery after abdominal surgery. However, validated clinical hallmarks of gastrointestinal recovery to evaluate new treatments and readiness for discharge from the hospital are lacking.

METHODS

Gastric emptying and colonic transit were scintigraphically assessed from postoperative day 1 to 3 in 84 patients requiring elective colonic surgery and were compared with clinical parameters. The clinical hallmark that best reflected recovery of gastrointestinal transit was validated using data from a multicenter trial of 320 segmental colectomy patients.

RESULTS

Seven of 84 patients developed a major complication with paralytic ileus characterized by total inhibition of gastrointestinal motility and were excluded from further analysis. In the remaining patients, recovery of colonic transit (defined as geometric center of radioactivity ≥2 on day 3), but not gastric emptying, was significantly correlated with clinical recovery (ρ = -0.59, P < 0.001). Conversely, the combined outcome measure of tolerance of solid food and having had defecation (SF + D) (area under the curve = 0.9, SE = 0.04, 95% CI = 0.79-0.95, P < 0.001), but not time to first flatus, best indicated recovery of gastrointestinal transit with a positive predictive value of 93% (95% CI = 78-99). Also in the main clinical trial, multiple regression analysis revealed that SF + D best predicted the duration of hospital stay.

CONCLUSIONS

Our data indicate that the time to SF + D best reflects recovery of gastrointestinal transit and therefore should be considered as primary outcome measure in future clinical trials on postoperative ileus.(Netherlands National Trial Register, number NTR1884 and NTR222).

Physiology, signaling, and pharmacology of opioid receptors and their ligands in the gastrointestinal tract: current concepts and future perspectives

Opioid receptors are widely distributed in the human body and are crucially involved in numerous physiological processes. These include pain signaling in the central and the peripheral nervous system, reproduction, growth, respiration, and immunological response. Opioid receptors additionally play a major role in the gastrointestinal (GI) tract in physiological and pathophysiological conditions. This review discusses the physiology and pharmacology of the opioid system in the GI tract. We additionally focus on GI disorders and malfunctions, where pathophysiology involves the endogenous opioid system, such as opioid-induced bowel dysfunction, opioid-induced constipation or abdominal pain. Based on recent reports in the field of pharmacology and medicinal chemistry, we will also discuss the opportunities of targeting the opioid system, suggesting future treatment options for functional disorders and inflammatory states of the GI tract.

The safety of prescribing opioids in pediatrics

INTRODUCTION

Pain management has become a widely discussed topic throughout all medical subspecialties. Although pediatric pain management has evolved significantly in its recent history, there is continued interest in the adequacy of pain treatment, both in the acute inpatient setting as well as the postoperative and chronic pain management setting. Although health care providers are becoming more aggressive concerning prompt and effective treatment of acute and chronic pain, safety data and adverse effects of narcotic analgesics may be overlooked.

AREAS COVERED

The authors review the current paradigm of acute pain management with an emphasis on oral narcotic medications, and the safety data available concerning prescribing these medications.

EXPERT OPINION

Further, the authors present their opinions concerning current and future practices regarding the prescribing practice of opiate analgesics, as well as a step-wise approach for acute oral pain management.

Methylnaltrexone for the treatment of opioid-induced constipation

Opioids are the drugs of choice for treating moderate-to-severe pain, especially for patients in the end stage of cancer or other advanced illnesses, and also in critical care or for the treatment of chronic pain. Side effects such as nausea, pruritus, dizziness and constipation have to be controlled in order to use these drugs to their full potential. Opioid-induced bowel syndrome and constipation caused by activation of μ-receptors in the gut can have such distressing effects that some patients prefer to forego adequate pain control. Methylnaltrexone is a μ-opioid receptor antagonist that, unlike naltrexone or naloxone, does not pass the blood-brain barrier, and therefore does not impair the centrally mediated analgesic effect of opioids. It is licensed for the treatment of opioid-induced constipation in palliative care in more than 50 countries. This article presents practically relevant pharmacological data, basic research results and evidence from clinical research about methylnaltrexone, and outlines potential future therapeutic options for this promising drug.

New therapeutic strategies for postoperative ileus

Patients undergoing an abdominal surgical procedure develop a transient episode of impaired gastrointestinal motility or postoperative ileus. Importantly, postoperative ileus is a major determinant of recovery after intestinal surgery and leads to increased morbidity and prolonged hospitalization, which is a great economic burden to health-care systems. Although a variety of strategies reduce postoperative ileus, including multimodal postoperative rehabilitation (fast-track care) and minimally invasive surgery, none of these methods have been completely successful in shortening the duration of postoperative ileus. The aetiology of postoperative ileus is multifactorial, but insights into the pathogenesis of postoperative ileus have identified intestinal inflammation, triggered by surgical handling, as the main mechanism. The importance of this inflammatory response in postoperative ileus is underscored by the beneficial effect of pharmacological interventions that block the influx of leukocytes. New insights into the pathophysiology of postoperative ileus and the involvement of the innate and the adaptive (T-helper type 1 cell-mediated immune response) immune system offer interesting and important new approaches to prevent postoperative ileus. In this Review, we discuss the latest insights into the mechanisms behind postoperative ileus and highlight new strategies to intervene in the postoperative inflammatory cascade.

A meta-analysis of the effectiveness of the opioid receptor antagonist alvimopan in reducing hospital length of stay and time to GI recovery in patients enrolled in a standardized accelerated recovery program after abdominal surgery

BACKGROUND

Despite accelerated recovery programs and the widespread uptake of laparoscopic surgery, postoperative ileus remains a significant factor affecting length of stay after abdominal surgery. Alvimopan, an opioid-receptor antagonist, may reduce the incidence of postoperative ileus and expedite hospital discharge.

OBJECTIVE

The aim of this study was to perform a meta-analysis to determine the role of alvimopan in accelerating GI recovery and hospital discharge after laparoscopic and open abdominal surgery performed within an accelerated recovery program.

DATA SOURCES AND STUDY SELECTION

Cochrane (1999-2010), Embase (1980-2010), MEDLINE (1980-2010), and International Pharmaceutical Abstracts (1970-2010) were searched for relevant double-blinded, randomized controlled trials.

INTERVENTIONS

Twelve milligrams of alvimopan and placebo were given to patients enrolled in an accelerated recovery program after abdominal surgery.

MAIN OUTCOME MEASURES

The primary outcomes measured were the length of stay as defined by the writing of the hospital discharge order and GI-3 and GI-2 GI tract recovery.

RESULTS

: Three trials were included that reported on a pooled modified intention-to-treat population of 1388 patients; 685 (49%) patients received alvimopan. On meta-analysis, alvimopan reduced time to the hospital discharge order (HR 1.37 (1.21, 1.62), p < 0.0001), GI-3 recovery (HR 1.42 (1.25, 1.62), p < 0.001), and GI-2 recovery (HR 1.49 (1.32, 1.68), p < 0.0001).

LIMITATIONS

The search criteria identified only a small number of trials of alvimopan after abdominal surgery with no randomized trials of alvimopan after laparoscopic surgery. In addition, the use of length of hospital stay as the primary outcome measure may be inappropriate, because it is open to many confounding factors. Finally, adverse events, in particular, adverse cardiovascular events, were not considered.

CONCLUSIONS

Alvimopan 12 mg can further reduce time to GI recovery and hospital discharge in patients undergoing abdominal surgery within an accelerated recovery program. Investigation into the effect of alvimopan following laparoscopic surgery and additional cost-benefit analyses are required to further define the role of this intervention.

Pharmacology of peripheral opioid receptors

PURPOSE OF REVIEW

Since the detection of morphine by the pharmacologist Friedrich Sertürner in 1806, opioids have been used as potent centrally acting analgesics. In addition to the central site of action, peripheral endogenous opioid analgesic systems have been extensively studied, especially in the past two decades. This review is not only mentioned to give a brief summary in this well investigated field of peripheral opioid receptors, but also to highlight the role of peripheral opioid receptors in other physiological and pathophysiological conditions.

RECENT FINDINGS

A number of studies, which initially focused on nociception, also revealed an important role of the peripheral opioid receptor system in opioid-induced bowel dysfunction and pruritus, as well as in wound healing, cardioprotection, and the analgesic effects of celecoxib.

SUMMARY

Efforts continue to develop opioid analgesics unable to cross the blood-brain barrier, which act only peripherally in low doses, thus providing adequate analgesia without central and systemic side-effects.The awareness of the influence of peripheral opioid receptors beyond nociception may also have therapeutic ramifications on the other fields mentioned above. For example, the treatment of opioid-induced bowel dysfunction by methylnaltrexone is one of the major findings in the previous years.