The management of postoperative ileus

Postoperative ileus-Establishing a porcine model

BACKGROUND

Postoperative ileus (POI), characterized by absent gastrointestinal motility, is a frequent complication following major abdominal surgery, with no current effective treatment possibilities. For further research in the treatment of this condition, we aimed to establish a porcine model of POI.

METHODS

A total of 12 Landrace pigs, weighing 60 kg, were included. Five animals were used as pilots to establish the surgical procedure, five animals received the same reproducible surgical procedure developed in the pilot experiments, while two animals were used as control. The primary endpoint was number of days to first stool. Intestinal motility was monitored using the SmartPill system.

KEY RESULTS

Four of the five pigs who underwent the final surgical procedure passed first stool on the third postoperative day (POD), and one passed first stool on the fifth POD. SmartPill data showed retention of the capsule in the stomach in four of five pigs with usable traces.

CONCLUSION AND INFERENCES

An experimental porcine model of POI was established, forming the basis for future studies in POI.

Electroacupuncture versus sham electroacupuncture in the treatment of postoperative ileus after laparoscopic surgery for colorectal cancer: study protocol for a multicentre, randomised, sham-controlled trial

INTRODUCTION

Postoperative ileus (POI) is an inevitable complication of almost all abdominal surgeries, which results in prolonged hospitalisation and increased healthcare costs. Various treatment strategies have been developed for POI but with limited success. Electroacupuncture (EA) might be a potential therapy for POI. However, evidence from rigorous trials that evaluated the effectiveness of EA for POI is limited. Thus, the aim of this study was to examine whether EA can safely reduce the time to the first defecation after laparoscopic surgery in patients with POI.

METHODS AND ANALYSIS

This multicentre randomised sham-controlled trial will be conducted in four hospitals in China. A total of 248 eligible participants with colorectal cancer who will undergo laparoscopic surgery will be randomly allocated to an EA group and a sham EA group in a 1:1 ratio. Treatment will be performed starting on postoperative day 1 and continued for four consecutive days, once per day. If the participant is discharged within 4 days after surgery, the treatment will cease on the day of discharge. The primary outcome will be the time to first defecation. The secondary outcome measures will include time to first flatus, tolerability of semiliquid and solid food, length of postoperative hospital stay, postoperative nausea and vomiting, abdominal distension, postoperative pain, postoperative analgesic, time to first ambulation, blinding assessment, credibility and expectancy and readmission rate.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Ethics Committee of Beijing University of Chinese Medicine (number 2020BZHYLL0116) and the institutional review board of each hospital. The results will be disseminated through peer-reviewed publications. This study protocol (V.3.0, 6 March 2020) involves human participants and was approved by the ethics committees of Beijing University of Chinese Medicine (number 2020BZHYLL0116), Beijing Friendship Hospital Affiliated to Capital Medical University (number 2020-P2-069-01), Beijing Chao-Yang Hospital Affiliated to Capital Medical University (number 2020-3-11-2), National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (number 20/163-2359), and the Affiliated Hospital of Qingdao University (number QYFYKYLL711311920). The participants gave informed consent to participate in the study before taking part.

TRIAL REGISTRATION NUMBER

ChiCTR2000038444.

Prevention and Management of Postoperative Ileus: A Review of Current Practice

Postoperative ileus (POI) has long been a challenging clinical problem for both patients and healthcare physicians alike. Although a standardized definition does not exist, it generally includes symptoms of intolerance to diet, lack of passing stool, abdominal distension, or flatus. Not only does prolonged POI increase patient discomfort and morbidity, but it is possibly the single most important factor that results in prolongation of the length of hospital stay with a significant deleterious effect on healthcare costs in surgical patients. Determining the exact pathogenesis of POI is difficult to achieve; however, it can be conceptually divided into patient-related and operative factors, which can further be broadly classified as neurogenic, inflammatory, hormonal, and pharmacological mechanisms.

Different strategies have been introduced aimed at improving the quality of perioperative care by reducing perioperative morbidity and length of stay, which include Enhanced Recovery After Surgery (ERAS) protocols, minimally invasive surgical approaches, and the use of specific pharmaceutical therapies. Recent studies have shown that the ERAS pathway and laparoscopic approach are generally effective in reducing patient morbidity with early return of gut function. Out of many studies on pharmacological agents over the recent years, alvimopan has shown the most promising results. However, due to its potential complications and cost, its clinical use is limited. Therefore, this article aimed to review the pathophysiology of POI and explore recent advances in treatment modalities and prevention of postoperative ileus.

Daikenchuto accelerates the recovery from prolonged postoperative ileus after open abdominal surgery: a subgroup analysis of three randomized controlled trials

Purpose

Prolonged postoperative ileus (POI) is a common complication after open abdominal surgery (OAS). Daikenchuto (DKT), a traditional Japanese medicine that peripherally stimulates the neurogenic pathway, is used to treat prolonged POI in Japan. To analyze whether DKT accelerates the recovery from prolonged POI after OAS, we conducted a secondary analysis of three multicenter randomized controlled trials (RCTs).

Methods

A secondary analysis of the three RCTs supported by the Japanese Foundation for Multidisciplinary Treatment of Cancer (project numbers 39-0902, 40-1001, 42-1002) assessing the effect of DKT on prolonged POI in patients who had undergone OAS for colon, liver, or gastric cancer was performed. The subgroup included 410 patients with no bowel movement (BM) before the first diet, a DKT group (n = 214), and a placebo group (n = 196). Patients received either 5 g DKT or a placebo orally, three times a day. The primary endpoint was defined as the time from the end of surgery to the first bowel movement (FBM). A sensitivity analysis was also performed on the age, body mass index and dosage as subgroup analyses.

Results

The primary endpoint was significantly accelerated in the DKT group compared with the placebo group (p = 0.004; hazard ratio 1.337). The median time to the FBM was 113.8 h in the placebo group and 99.1 h in the DKT treatment group.

Conclusions

The subgroup analysis showed that DKT significantly accelerated the recovery from prolonged POI following OAS.

Trial registration number

UMIN000026292.

The H2S-Releasing Naproxen Derivative ATB-346 and the Slow-Release H2S Donor GYY4137 Reduce Intestinal Inflammation and Restore Transit in Postoperative Ileus

Objective: Intestinal inflammation triggers postoperative ileus (POI), commonly seen after abdominal surgery and characterized by impaired gastrointestinal transit; when prolonged, this leads to increased morbidity. Hydrogen sulfide (H2S) is recognized as an important mediator of many (patho)physiological processes, including inflammation, and is now investigated for anti-inflammatory application. Therefore, the aim of this study was to investigate the effect of the H2S-releasing naproxen derivative ATB-346, developed to reduce gastrointestinal injury by naproxen, and the slow-release H2S donor GYY4137 on intestinal inflammation and delayed gastrointestinal transit in murine POI. Methods: C57Bl6J mice were fasted for 6 h, anesthetized and after laparotomy, POI was induced by compressing the small intestine with two cotton applicators for 5 min (intestinal manipulation; IM). GYY4137 (50 mg/kg, intraperitoneally), ATB-346 (16 mg/kg, intragastrically) or naproxen (10 mg/kg, intragastrically) were administered 1 h before IM. At 24 h postoperatively, gastrointestinal transit was assessed via fluorescent imaging, and mucosa-free muscularis segments were prepared for later analysis. Inflammatory parameters and activity of inducible nitric oxide synthase (iNOS) and cyclo-oxygenase (COX)-2 were measured. Histological examination of whole tissue sections was done on hematoxylin-eosin stained slides. Results: Pre-treatment with GYY4137 (geometric center; GC: 7.6 ± 0.5) and ATB-346 (GC: 8.4 ± 0.3) prevented the delayed transit induced by IM (GC: 3.6 ± 0.5 vs. 9.0 ± 0.4 in non-operated controls) while naproxen only partially did (GC: 5.9 ± 0.5; n = 8 for all groups). GYY4137 and ATB-346 significantly reduced the IM-induced increase in muscular myeloperoxidase (MPO) activity and protein levels of interleukin (IL)-6, IL-1β and monocyte chemotactic protein 1; the reduction by naproxen was less pronounced and only reached significance for MPO activity and IL-6 levels. All treatments significantly reduced the increase in COX-2 activity caused by IM, whereas only GYY4137 significantly reduced the increase in iNOS activity. Naproxen treatment caused significant histological damage of intestinal villi. Conclusion: The study shows that naproxen partially prevents POI, probably through its inhibitory effect on COX-2 activity. Both ATB-346 and GYY4137 were more effective, the result with GYY4137 showing that H2S per se can prevent POI.

Effect of patient-controlled epidural analgesia versus patient-controlled intravenous analgesia on postoperative pain management and short-term outcomes after gastric cancer resection: a retrospective analysis of 3,042 consecutive patients between 2010 and 2015

Background

Effective postoperative analgesia is essential for rehabilitation after surgery. Many studies have compared different methods of postoperative pain management for open abdominal surgery. However, the conclusions were inconsistent and controversial. In addition, few studies have focused on gastric cancer (GC) resection. This study aimed to determine the effects of patient-controlled epidural analgesia (PCEA) on postoperative pain management and short-term recovery after GC resection compared with those of patient-controlled intravenous analgesia (PCIA).

Methods

We analyzed retrospectively collected data on patients with non-metastatic GC diagnosed between 2010 and 2015 who underwent resection in a university hospital. PCIA and PCEA documented by the acute pain service team were retrospectively analyzed. A propensity score-matched analysis that incorporated preoperative variables was used to compare the short-term outcomes between the PCIA and PCEA groups.

Results

In total, 3,042 patients were identified for analysis. Propensity score matching resulted in 917 patients in each group. The PCEA group exhibited lower pain scores in the recovery room and on the first and second postoperative days (P=0.0005, P=0.0065, and P=0.0034 respectively). The time to the first passage of flatus after surgery was shorter in the PCEA group than in the PCIA group (P=0.032). The length of the hospital stay was 12.6±7.2 and 11.8±6.6 days in the PCEA and PCIA groups, respectively. No significant differences were observed in the length of hospital stay or the incidence of complications after surgery.

Conclusion

PCEA provided more effective postoperative pain management and a shorter time to the first passage of flatus than PCIA after GC resection. However, it did not have an effect on the length of hospital stay or the incidence of postoperative complications.

Epidurals in Pancreatic Resection Outcomes (E-PRO) study: protocol for a randomised controlled trial

INTRODUCTION

Epidural analgesia provides an important synergistic method of pain control. In addition to reducing perioperative opioid consumption, the deliverance of analgesia into the epidural space, effectively creating a sympathetic blockade, has a multitude of additional potential benefits, from decreasing the incidence of postoperative delirium to reducing the development of persistent postsurgical pain (PPSP). Prior studies have also identified a correlation between the use of epidural analgesia and improved oncological outcomes and survival. The aim of this study is to evaluate the effect of epidural analgesia in pancreatic operations on immediate postoperative outcomes, the development of PPSP and oncological outcomes in a prospective, single-blind, randomised controlled trial.

METHODS

The Epidurals in Pancreatic Resection Outcomes (E-PRO) study is a prospective, single-centre, randomised controlled trial. 150 patients undergoing either pancreaticoduodenectomy or distal pancreatectomy will be randomised to receive an epidural bupivacaine infusion following anaesthetic induction followed by continued epidural bupivacaine infusion postoperatively in addition to the institutional standardised pain regimen of hydromorphone patient-controlled analgesia (PCA), acetaminophen and ketorolac (intervention group) or no epidural infusion and only the standardised postoperative pain regimen (control group). The primary outcome was the postoperative opioid consumption, measured in morphine or morphine-equivalents. Secondary outcomes include patient-reported postoperative pain numerical rating scores, trend and relative ratios of serum inflammatory markers (interleukin (IL)-1β, IL-6, tumour necrosis factor-α, IL-10), occurrence of postoperative delirium, development of PPSP as determined by quantitative sensory testing, and disease-free and overall survival.

ETHICS AND DISSEMINATION

The E-PRO trial has been approved by the institutional review board. Recruitment began in May 2016 and will continue until the end of May 2018. Dissemination plans include presentations at scientific conferences and scientific publications.

TRIAL REGISTRATION NUMBER

NCT02681796.

Effectiveness of Acupuncture for Early Recovery of Bowel Function in Cancer: A Systematic Review and Meta-Analysis

Objectives

The aim of this study was to evaluate the effects of acupuncture therapy to reduce the duration of postoperative ileus (POI) and to enhance bowel function in cancer patients.

Methods

A systematic search of electronic databases for studies published from inception until January 2017 was carried out from six databases. Randomized controlled trials (RCTs) involving the use of acupuncture and acupressure for POI and bowel function in cancer patients were identified. Outcomes were extracted from each study and pooled to determine the risk ratio and standardized mean difference.

Results

10 RCTs involving 776 cancer patients were included. Compared with control groups (no acupuncture, sham acupuncture, and other active therapies), acupuncture was associated with shorter time to first flatus and time to first defecation. A subgroup analysis revealed that manual acupuncture was more effective on the time to first flatus and the time to first defecation; electroacupuncture was better in reducing the length of hospital stay. Compared with control groups (sham or no acupressure), acupressure was associated with shorter time to first flatus. However, GRADE approach indicated a low quality of evidence.

Conclusions

Acupuncture and acupressure showed large effect size with significantly poor or inferior quality of included trials for enhancing bowel function in cancer patients after surgery. Further well-powered evidence is needed.

Acupuncture for enhancing early recovery of bowel function in cancer: Protocol for a systematic review

BACKGROUND

Cancer patients undergoing surgical procedure often suffer from bowel dysfunction and postoperative ileus (POI). Cancer management for early recovery of bowel function is still a challenging topic. Acupuncture has been commonly used in a variety of gastrointestinal diseases. The aim of this study is to evaluate the effects of acupuncture therapy to reduce the duration of POI and enhance bowel function in cancer patients.

METHODS

We will systematically screen all randomized controlled trials (RCTs) published through electronically and hand searching. The following search engines including Medline, EMBASE, Cochrane CENTRAL, the Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, the Chinese Biomedical Literature Database, the China National Knowledge Infrastructure, VIP Information, Wanfang Data, one Japanese database (Japan Science and Technology Information Aggregator, Electronic) and 2 Korean Medical Databases (Korean Studies Information, and Data Base Periodical Information Academic) will be retrieved. Supplementary sources will be searched including gray literature, conference proceedings, and potential identified publications. Two reviewers will independently conduct the trial inclusion, data extraction and assess the quality of studies. The time to first passing flatus and time to first bowel motion will be assessed as the primary outcomes. Adverse effects, time to first bowel sound, visual analog scale (VAS) pain score, hospital stay, and postoperative analgesic requirement will be measured as secondary outcomes. Methodological quality will be evaluated according to the Cochrane risk of bias. Details of interventions will be assessed by the Standards for Reporting Interventions in Controlled Trials of Acupuncture (STRICTA) checklist. All analyses will be applied by RevMan (version 5.3) and StataSE (version 12).

ETHICS AND DISSEMINATION

This systematic review will provide up-to-date information on acupuncture therapy for early recovery of bowel function in cancer patients. This review does not require ethical approval and will be reported in a peer-reviewed journal and presented at a relevant conference.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42016049633.

Randomized clinical trial of postoperative chewing gum versus standard care after colorectal resection

Background

Chewing gum may stimulate gastrointestinal motility, with beneficial effects on postoperative ileus suggested in small studies. The primary aim of this trial was to determine whether chewing gum reduces length of hospital stay (LOS) after colorectal resection. Secondary aims included examining bowel habit symptoms, complications and healthcare costs.

Methods

This clinical trial allocated patients randomly to standard postoperative care with or without chewing gum (sugar‐free gum for at least 10 min, four times per day on days 1–5) in five UK hospitals. The primary outcome was LOS. Cox regression was used to calculate hazard ratios for LOS.

Results

Data from 402 of 412 patients, of whom 199 (49·5 per cent) were allocated to chewing gum, were available for analysis. Some 40 per cent of patients in both groups had laparoscopic surgery, and all study sites used enhanced recovery programmes. Median (i.q.r.) LOS was 7 (5–11) days in both groups (P = 0·962); the hazard ratio for use of gum was 0·94 (95 per cent c.i. 0·77 to 1·15; P = 0·557). Participants allocated to gum had worse quality of life, measured using the EuroQoL 5D‐3L, than controls at 6 and 12 weeks after operation (but not on day 4). They also had more complications graded III or above according to the Dindo–Demartines–Clavien classification (16 versus 6 in the group that received standard care) and deaths (11 versus 0), but none was classed as related to gum. No other differences were observed.

Conclusion

Chewing gum did not alter the return of bowel function or LOS after colorectal resection. Registration number: ISRCTN55784442 (http://www.controlled-trials.com).

No advantage observed

Risk factors for prolonged postoperative ileus after colorectal cancer surgery

BACKGROUND

The aim of this study was to analyze factors contributing to prolonged postoperative ileus (POI) after elective bowel resection in patients with colorectal cancer.

METHODS

This was a retrospective review of a prospectively maintained database of patients operated on for colorectal cancer during 2006-2009. Patients with abdominal procedures and bowel resection without anastomotic leakage were included. Prolonged POI was defined as no flatus by postoperative day (POD) 6, with or without intolerance to oral intake by POD 6. Variables studied included demographics, prior medical conditions, details of the surgical procedure, and hospital stay.

RESULTS

A total of 773 patients met the inclusion criteria. POI occurred in 15.9%. The mean hospital stay was 11 days without POI and 20 days for POI patients (P < 0.001). Factors associated with POI in the univariate analysis were ASA III-IV (P < 0.005), male sex (P < 0.004), smoking (P < 0.015), chronic pulmonary disease (COPD) (P < 0.002), rectal cancer (P < 0.02), and ileostomy (P < 0.001). Multivariate logistic regression analysis showed male sex [odds ratio (OR) 1.6, 95% confidence interval (CI) 1.04-3.5]; COPD (OR 1.9, 95% CI 1.25-31.0), and ileostomy (OR 1.9; 95% CI 1.23-3.07) as risk factors for POI.

CONCLUSIONS

The risk of POI seems increased in patients with preoperative COPD and patients with an ileostomy, especially in men. Consideration of these factors could be important for the prevention and treatment of POI.

Kinetics of proinflammatory cytokines after intraperitoneal injection of tribromoethanol and a tribromoethanol/xylazine combination in ICR mice

Tribromoethanol (2,2,2-tribromoethanol, TBE) is a popular injectable anesthetic agent used in mice in Korea. Our goal was to assess the risks associated with side effects (lesions) in the abdominal cavity, especially at high doses. To understand the underlying pathophysiological changes, we examined levels of cytokines through ELISA of abdominal lavage fluid and spleen collected from mice treated with low and high-dose TBE. ICR mice were anesthetized using one of the following protocols: a combination of TBE 200 mg/kg (1.25%) and xylazine 10 mg/kg; TBE 400 mg/kg (1.25%); and TBE 400 mg/kg (2.5%). Administration of high-dose TBE (400 mg/kg) increased the interleukin-1β and interleukin-6 levels in the peritoneal cavity over the short term (<1 day) compared with sham controls and low-dose TBE (200 mg/kg) groups. Cytokine expression in the low-dose TBE group was similar to the control group, whereas in the high-dose TBE group cytokine levels were higher in abdominal lavage fluid and spleen over the long term (10 days post-injection). We conclude that a combination of TBE 200 mg/kg (1.25%) and xylazine (10 mg/kg) is a safe and effective anesthetic for use in animals.

The opioid component of delayed gastrointestinal recovery after bowel resection

INTRODUCTION

Patients undergoing bowel resection or other major abdominal surgery experience a period of delayed gastrointestinal recovery associated with increased postoperative morbidity and longer hospital length of stay. Symptoms include nausea, vomiting, abdominal distension, bloating, pain, intolerance to solid or liquid food, and inability to pass stool or gas. The exact cause of delayed gastrointestinal recovery is not known, but several factors appear to play a central role, namely the neurogenic, hormonal, and inflammatory responses to surgery and the response to exogenous opioid analgesics and endogenous opioids.

DISCUSSION

Stimulation of opioid receptors localized to neurons of the enteric nervous system inhibits coordinated gastrointestinal motility and fluid absorption, thereby contributing to delayed gastrointestinal recovery and its associated symptoms. Given the central role of opioid analgesics in delayed gastrointestinal recovery, a range of opioid-sparing techniques and pharmacologic agents, including opioid receptor antagonists, have been developed to facilitate faster restoration of gastrointestinal function after bowel resection when used as part of a multimodal accelerated care pathway. This review discusses the etiology of opioid-induced gastrointestinal dysfunction as well as clinical approaches that have been evaluated in controlled clinical trials to reduce the opioid component of delayed gastrointestinal recovery.

Risk factors for postoperative ileus after urologic laparoscopic surgery

Purpose

Although its incidence has decreased with the widespread use of less invasive surgical techniques including laparoscopic surgery, postoperative ileus remains a common postoperative complication. In the field of urologic surgery, with the major exception of radical cystectomy, few studies have focused on postoperative ileus as a complication of laparoscopic surgery. The present study aims to offer further clues in the management of postoperative ileus following urological laparoscopic surgery through an assessment of the associated risk factors.

Methods

The medical records of 267 patients who underwent laparoscopic surgery between February 2004 and November 2009 were reviewed. After excluding cases involving radical cystectomy, combined surgery, open conversion, and severe complications, a total of 249 patients were included for this study. The subjects were divided into a non-ileus group and an ileus group. The gender and age distribution, duration of anesthesia, American Society of Anesthesiologists Physical Status Classification Score, body mass index, degree of operative difficulty, presence of complications, surgical procedure and total opiate dosage were compared between the two groups.

Results

Of the 249 patients, 10.8% (n = 27) experienced postoperative ileus. Patients with ileus had a longer duration of anesthesia (P = 0.019), and perioperative complications and blood loss were all correlated with ileus (P = 0.000, 0.004, respectively). Multiple linear regression analysis showed that the modified Clavien classification was an independent risk factor for postoperative ileus (odds ratio, 5.372; 95% confidence interval, 2.084 to 13.845; P = 0.001).

Conclusion

Postoperative ileus after laparoscopic urologic surgery was more frequent in patients who experienced more perioperative complications.

Anesthetic Routines: The Anesthesiologist's Role in GI Recovery and Postoperative Ileus

All patients undergoing bowel resection experience postoperative ileus, a transient cessation of bowel motility that prevents effective transit of intestinal contents or tolerance of oral intake, to varying degrees. An anesthesiologist plays a critical role, not only in the initiation of surgical anesthesia, but also with the selection and transition to effective postoperative analgesia regimens. Attempts to reduce the duration of postoperative ileus have prompted the study of various preoperative, perioperative, and postoperative regimens to facilitate gastrointestinal recovery. These include modifiable variables such as epidural anesthesia and analgesia, opioid-sparing anesthesia and analgesia, fluid restriction, colloid versus crystalloid combinations, prokinetic drugs, and use of the new peripherally acting mu-opioid receptor (PAM-OR) antagonists. Review and appropriate adaptation of these multiple modifiable interventions by anesthesiologists and their surgical colleagues will facilitate implementation of a best-practice management routine for bowel resection procedures that will benefit the patient and the healthcare system.

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

Background

A pooled post hoc responder analysis was performed to assess the clinical benefit of alvimopan, a peripherally acting mu-opioid receptor (PAM-OR) antagonist, for the management of postoperative ileus after bowel resection.

Methods

Adult patients who underwent laparotomy for bowel resection scheduled for opioid-based intravenous patient-controlled analgesia received oral alvimopan or placebo preoperatively and twice daily postoperatively until hospital discharge or for 7 postoperative days. The proportion of responders and numbers needed to treat (NNT) were examined on postoperative days (POD) 3–8 for GI-2 recovery (first bowel movement, toleration of solid food) and hospital discharge order (DCO) written.

Results

Alvimopan significantly increased the proportion of patients with GI-2 recovery and DCO written by each POD (P < 0.001 for all). More patients who received alvimopan achieved GI-2 recovery on or before POD 5 (alvimopan, 80%; placebo, 66%) and DCO written before POD 7 (alvimopan, 87%; placebo, 72%), with corresponding NNTs equal to 7.

Conclusions

On each POD analyzed, alvimopan significantly increased the proportion of patients who achieved GI-2 recovery and DCO written versus placebo and was associated with relatively low NNTs. The results of these analyses provide additional characterization and support for the overall clinical benefit of alvimopan in patients undergoing bowel resection.

Systematic review and meta-analysis of chewing-gum therapy in the reduction of postoperative paralytic ileus following gastrointestinal surgery

BACKGROUND

Postoperative ileus has long been considered an inevitable consequence of gastrointestinal surgery. It prolongs hospital stay, increases morbidity, and adds to treatment costs. Chewing is a form of sham feeding reported to stimulate bowel motility. This analysis examines the value of chewing-gum therapy in treatment of postoperative ileus.

METHODS

A search for randomized, controlled trials studying elective gastrointestinal surgery was undertaken using MEDLINE, Embase, Cochrane Controlled Trials Register, and reference lists. Outcomes were extracted including time to first flatus and bowel motion, length of stay, and complications. Statistical analysis was undertaken using the weighted mean difference (WMD) and random-effects model with 95% confidence intervals (CI).

RESULTS

Seven studies with 272 patients were included. For time to first flatus the analysis favored treatment with a WMD of 12.6 h (17%) reduction (95% CI -21.49 to -3.72; P = 0.005). For time to first bowel motion, treatment was favored with a WMD of 23.11 h (22%) reduction (95% CI -34.32 to -11.91; P < 0.001). For length of stay, the analysis showed a nonsignificant trend toward treatment with WMD of 23.88 h (12%) reduction (95% CI -53.29 to +5.53; P = 0.11). There were no significant differences in complication rates.

CONCLUSIONS

Chewing-gum therapy following open gastrointestinal surgery is beneficial in reducing the period of postoperative ileus, although without a significant reduction in length of hospital stay. These outcomes are not significant for laparoscopic gastrointestinal surgery.

Pathogenesis and management of postoperative ileus

Postoperative ileus (POI) is a predictable delay in gastrointestinal (GI) motility that occurs after abdominal surgery. Probable mechanisms include disruption of the sympathetic/parasympathetic pathways to the GI tract, inflammatory changes mediated over multiple pathways, and the use of opioids for the management of postoperative pain. Pharmacologic treatment of postoperative ileus continues to be problematic as most agents are unreliable and unsubstantiated with robust clinical trials. The selective opioid antagonist alvimopan has shown promise in reducing POI, but needs more rigorous investigation. Clinician interventions proven to be of benefit include laparoscopy, thoracic epidural anesthesia, avoidance of opioids, and early feeding. Early ambulation may also contribute to early resolution of POI; however, routine nasogastric decompression plays no role and may increase complications. Multimodal care plans remain the mainstay of treatment for POI.

Controlling postoperative ileus by vagal activation

Postoperative ileus is a frequently occurring surgical complication, leading to increased morbidity and hospital stay. Abdominal surgical interventions are known to result in a protracted cessation of bowel movement. Activation of inhibitory neural pathways by nociceptive stimuli leads to an inhibition of propulsive activity, which resolves shortly after closure of the abdomen. The subsequent formation of an inflammatory infiltrate in the muscular layers of the intestine results in a more prolonged phase of ileus. Over the last decade, clinical strategies focusing on reduction of surgical stress and promoting postoperative recovery have improved the course of postoperative ileus. Additionally, recent experimental evidence implicated antiinflammatory interventions, such as vagal stimulation, as potential targets to treat postoperative ileus and reduce the period of intestinal hypomotility. Activation of nicotinic receptors on inflammatory cells by vagal input attenuates inflammation and promotes gastrointestinal motility in experimental models of ileus. A novel physiological intervention to activate this neuroimmune pathway is enteral administration of lipid-rich nutrition. Perioperative administration of lipid-rich nutrition reduced manipulation-induced local inflammation of the intestine and accelerated recovery of bowel movement. The application of safe and easy to use antiinflammatory interventions, together with the current multimodal approach, could reduce postoperative ileus to an absolute minimum and shorten hospital stay.

[Concepts for perioperative pain therapy. A critical stocktaking]

Despite numerous publications, new guidelines for the treatment of acute pain and efforts from a number of initiatives, there is still a tremendous need for improvement in postoperative pain therapy. One of the reasons for the shortcomings in the care of patients with postoperative pain is the lack of applicability of guidelines in daily clinical practice. Therefore, simple but effective and easy to implement concepts need to be developed. In the following review, different concepts that have been developed over recent years are presented and evaluated for their effectiveness. One of these is the notion of balanced analgesia, currently probably one of the most widely used perioperative therapy concepts. The idea of this concept is to reduce the doses of analgesics, e.g. opioids, through combinations of different classes of analgesics, thereby reducing their side effects. However, recent studies and essential meta-analyses indicate pitfalls using this concept. The pros and cons will be discussed and ideas on how to deal with balanced analgesia in daily practice will be given. Another pain concept of "procedure-specific postoperative pain therapy", is an appealing idea of an international initiative from surgeons and anaesthesiologists and an essential part of the German S3 guidelines for acute pain released last year. Critical evaluation of the available recommendations for procedure-specific analgesia together with the presentation of relatively simple but evidence-based algorithms for specific procedures may help to implement this concept in clinical routine.

Efficacy and safety of mu-opioid antagonists in the treatment of opioid-induced bowel dysfunction: systematic review and meta-analysis of randomized controlled trials

CONTEXT

Opioid-induced bowel dysfunction (OBD) is characterized by constipation, incomplete evacuation, bloating, and increased gastric reflux. OBD occurs both acutely and chronically, in multiple disease states, resulting in increased morbidity and reduced quality of life.

OBJECTIVE

To compare the efficacy and safety of traditional and peripherally active opioid antagonists vs conventional interventions for OBD.

DESIGN

We searched MEDLINE, the Cochrane Central Register of Controlled Trials and EMBASE. Additional reports were identified from the reference lists of retrieved articles.

STUDY SELECTION

Studies were included if they were randomized controlled trials that investigated the efficacy of mu-opioid antagonists for OBD.

DATA EXTRACTION

Data were extracted by two independent investigators and included demographic variables, diagnoses, interventions, efficacy, and adverse events.

RESULTS OF DATA SYNTHESIS

Twenty-two articles met inclusion criteria and provided data on 2,352 opioid antagonist-treated patients. The opioid antagonist investigated was alvimopan (eight studies), methylnaltrexone (six), naloxone (seven), and nalbuphine (one). Meta-analysis demonstrated that methylnaltrexone and alvimopan are efficacious in reversing opioid-induced increased gastrointestinal transit time and constipation, and that alvimopan is safe and efficacious in treating postoperative ileus. The incidence of adverse events with opioid antagonists was similar to placebo and generally reported as mild-to-moderate.

CONCLUSIONS

Insufficient evidence exists for the safety or efficacy of naloxone or nalbuphine in the treatment of OBD. Long-term efficacy and safety of any of the opioid antagonists is unknown, as is the incidence or nature of rare adverse events. Alvimopan and methylnaltrexone both show promise in treating OBD, but further data will be required to fully assess their place in therapy.

Methylnaltrexone, a new peripherally acting mu-opioid receptor antagonist being evaluated for the treatment of postoperative ileus

Postoperative ileus (POI), a transient impairment of bowel function, is considered an inevitable response after open abdominal surgery. It leads to significant patient morbidity and increased hospital costs and length of stay. The pathophysiology is multifactorial, involving neurogenic, hormonal, inflammatory and pharmacologic mediators. Several treatments have been shown to reduce the duration of POI, and a multimodal approach combining several of these interventions seems to be the most effective treatment option. Various drug therapies have been evaluated for the treatment of POI, although most have not shown any benefit. Peripherally active mu-opioid receptor antagonists are a new class of compounds that selectively block the peripheral (i.e., gastrointestinal [GI]) effects of opioids while preserving centrally mediated analgesia. Recently, alvimopan was approved in the US for the treatment of POI after abdominal surgery with bowel resection. Methylnaltrexone is a peripherally active mu-opioid receptor antagonist that has been shown to antagonize the inhibitory effects of opioids on GI transit without impairing analgesia. Phase II data indicated that methylnaltrexone was effective for improving GI recovery, reducing POI and shortening the time to discharge readiness in patients who underwent segmental colectomy. Two Phase III trials have been completed, and one is underway at present. Preliminary results from the two completed trials indicate that methylnaltrexone was not better than placebo for the primary or secondary outcomes. Further analyses of these data, clinical trial designs and the various dosage forms are necessary to determine the potential role of methylnaltrexone in the treatment of POI.

Effect of bisacodyl on postoperative bowel motility in elective colorectal surgery: a prospective, randomized trial

BACKGROUND

Postoperative ileus is a common condition after abdominal surgery. Many prokinetic drugs have been evaluated including osmotic laxatives. The data on colon-stimulating laxatives are scarce. This prospective, randomized, double-blind trial investigates the effect of the colon-stimulating laxative bisacodyl on postoperative ileus in elective colorectal resections.

MATERIALS AND METHODS

Between November 2004 and February 2007, 200 consecutive patients were randomly assigned to receive either bisacodyl or placebo. Primary endpoint was time to gastrointestinal recovery (mean time to first flatus passed, first defecation, and first solid food tolerated; GI-3). Secondary endpoints were incidence and duration of nasogastric tube reinsertion, incidence of vomiting, length of hospital stay, and visual analogue scores for pain, cramps, and nausea.

RESULTS

One hundred sixty-nine patients were analyzed, and 31 patients discontinued the study. Groups were comparable in baseline demographics. Time to GI-3 was significantly shorter in the bisacodyl group (3.0 versus 3.7 days, P = 0.007). Of the single parameters defining GI-3, there was a 1-day difference in time to defecation in favor to the bisacodyl group (3.0 versus 4.0 days, P = 0.001), whereas no significant difference in time to first flatus or tolerance of solid food was seen. No significant difference in the secondary endpoints was seen. Morbidity and mortality did not differ between groups.

CONCLUSION

Bisacodyl accelerated gastrointestinal recovery and might be considered as part of multimodal recovery programs after colorectal surgery.

Mu-opioid antagonists for opioid-induced bowel dysfunction

BACKGROUND

Opioid-induced bowel dysfunction (OBD) is characterized by constipation, incomplete evacuation, bloating, and increased gastric reflux. OBD occurs both acutely and chronically, in multiple disease states, resulting in increased morbidity and reduced quality of life.

OBJECTIVES

To compare the efficacy and safety of traditional and peripherally active opioid antagonists versus conventional interventions for OBD.

SEARCH STRATEGY

We searched MEDLINE, the Cochrane Central Register of Controlled Trials and EMBASE in January 2007. Additional reports were identified from the reference lists of retrieved papers.

SELECTION CRITERIA

Studies were included if they were randomized controlled trials that investigated the efficacy of mu-opioid antagonists for OBD.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent review authors and included demographic variables, diagnoses, interventions, efficacy, and adverse events.

MAIN RESULTS

Twenty-three studies met inclusion criteria and provided data on 2871 opioid antagonist-treated patients. The opioid antagonists investigated were alvimopan (nine studies), methylnaltrexone (six), naloxone (seven), and nalbuphine (one). Meta-analysis demonstrated that methylnaltrexone and alvimopan were better than placebo in reversing opioid-induced increased gastrointestinal transit time and constipation, and that alvimopan appears to be safe and efficacious in treating postoperative ileus. The incidence of adverse events with opioid antagonists was similar to placebo and generally reported as mild-to-moderate.

AUTHORS' CONCLUSIONS

Insufficient evidence exists for the safety or efficacy of naloxone or nalbuphine in the treatment of OBD. Long-term efficacy and safety of any of the opioid antagonists is unknown, as is the incidence or nature of rare adverse events. Alvimopan and methylnaltrexone both show promise in treating OBD, but further data will be required to fully assess their place in therapy.

Use of novel prokinetic agents to facilitate return of gastrointestinal motility in adult critically ill patients

PURPOSE OF REVIEW

Intolerance of enteral feeding due to impaired gastrointestinal motility is common in critically ill patients. Strategies to prevent or treat gastrointestinal hypomotility include the use of prokinetic agents. Many currently employed prokinetic agents are associated with serious adverse drug reactions. The novel prokinetic agents - alvimopan, tegaserod, and dexloxiglumide - are reviewed.

RECENT FINDINGS

Alvimopan exerts mixed, but generally favorable, effects on restoration of gastrointestinal motility in patients with postoperative ileus. The observation of increased opioid requirements (without increased pain scores) and associated clinical ramifications requires further study. Tegaserod stimulates the peristaltic reflex and improves motility in multiple sites along the gastrointestinal tract. Its efficacy in improving gastrointestinal hypomotility in the critically ill population has not yet been determined. Furthermore, its use has been associated with the development of ischemic colitis and increased requirement for abdominal/pelvic surgery. Dexloxiglumide may be beneficial for improving gastric emptying in critically ill patients, especially those receiving lipid-enriched enteral feeds.

SUMMARY

Novel prokinetic agents show promise for management of gastrointestinal hypomotility in the critically ill population. However, further study is required before these agents can be recommended for use.