Prokinetic agents in critical care

Prokinetic agents in adult intensive care unit patients (PATIENCE)-An international inception cohort study protocol

BACKGROUND

Feeding intolerance is common in critically ill patients and can lead to malnutrition. Prokinetic agents may be used to enhance the uptake of nutrition. However, the evidence on the effectiveness and safety of prokinetic agents is sparse, and there is a lack of data on their use in intensive care units (ICU).

METHODS

We will conduct an international 14-day inception cohort study of 1000 acutely admitted adult ICU patients. Data will be collected from ICU admission and daily during ICU stay for up to 90 days. The primary outcome will be the proportion of ICU patients who receive prokinetic agents. Secondary outcomes include mortality, days alive without life support, days alive out of ICU, days alive out of hospital (all within 90 days) and the number of patients with one or more serious adverse events.

RESULTS

We will present data on the use of prokinetic agents descriptively and use Cox regressions with death and ICU discharge as competing events to evaluate the association between patient characteristics and the use of prokinetic agents. We will use extended Cox models with time-varying covariates and linear regression models to assess the associations between the use of prokinetic agents and the secondary outcomes.

CONCLUSION

The outlined international cohort study will provide valuable epidemiological data on the use of prokinetic agents in adult, acutely admitted ICU patients.

Use of prokinetic agents in hospitalised adult patients: A scoping review

BACKGROUND

Gastrointestinal motility is important for adequate uptake of fluids and nutrition but is often impaired in hospitalised patients. Prokinetic agents enhance gastrointestinal motility and are prescribed for many hospitalised patients. In this scoping review, we aimed to systematically describe the body of evidence on the use of prokinetic agents in hospitalised patients. We hypothesised, that the body of evidence would be limited and derive from heterogeneous populations.

METHODS

We conducted this scoping review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews statement. We searched Medline, Embase, Epistemonikos and the Cochrane Library for studies assessing the use of prokinetic agents on any indication and outcome in adult hospitalised patients. We used a modified version of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) to assess the certainty of evidence.

RESULTS

We included 102 studies with a total of 8830 patients. Eighty-six studies were clinical trials (84%), and 52 (60%) of these were conducted in the intensive care unit, with feeding intolerance as the main indication. In the non-intensive care setting the indications were wider; most studies assessed use of prokinetic agents before gastroscopy to improve visualisation. The most studied prokinetic agent was metoclopramide (49% of studies) followed by erythromycin (31%). In total 147 outcomes were assessed with only 67% of the included studies assessing patient-centred outcomes, and with gastric emptying as the most frequently reported outcome. Overall, the data provided no firm evidence on the balance between the desirable and undesirable effects of prokinetic agents.

CONCLUSIONS

In this scoping review, we found that the studies addressing prokinetic agents in hospitalised adults had considerable variations in indications, drugs and outcomes assessed, and that the certainty of evidence was judged to be low to very low.

Use of prokinetic agents in hospitalised adult patients: Protocol for a scoping review

BACKGROUND

Gastrointestinal motility is an important contributor to the effective uptake of water and nutrition. However, it is often impaired in acutely ill hospitalised patients. Amongst other indications, prokinetic agents are used to improve GI motility, but the body of evidence is not well described. Accordingly, we aim to systematically describe and explore the body of evidence on the use of prokinetic agents in hospitalised adults.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews statement, we plan to conduct a scoping review of studies assessing the use of prokinetic agents, for any indication, in hospitalised adults. We plan to assess study design, population, agents, indications and outcomes across included studies. When applicable, we plan to assess the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

We plan to provide descriptive analyses of the included studies accompanied by tabulated results and characterise knowledge gaps.

CONCLUSION

The outlined scoping review will provide a summary of the body of evidence on the use, indications, effects and side effects of prokinetic agents in hospitalised adults.

Comparing the Effect of Neostigmine and Metoclopramide on Gastric Residual Volume of Mechanically Ventilated Patients in Intensive Care Unit: A Double-Blind Randomized Clinical Trial

Introduction

The gastric residual volume (GRV) monitoring in patients with mechanical ventilation (MV) is a common and important challenge. The purpose of this study was to compare the effect of neostigmine and metoclopramide on GRV among MV patients in the intensive care unit (ICU).

Methods

In a double-blind randomized clinical trial, a total of 200 mechanically ventilated ICU patients with GRV > 120 ml (6 hours after the last gavage) were randomly assigned into two groups (A and B) with 100 patients in each group. Patients in groups A and B received intravenous infusion of neostigmine at a dose of 2.5 mg/100 ml normal saline and metoclopramide at a dose of 10 mg/100 ml normal saline, within 30 minutes, respectively. GRV was evaluated 5 times for each patient, once before the intervention and 4 times (at 3, 6, 9, and 12 hours) after the intervention. In addition, demographic characteristics including age and gender, as well as severity illness based on the sequential organ failure assessment score (SOFA), were initially recorded for all patients.

Results

After adjusting of demographic and clinical characteristics (age, gender, and SOFA score), the generalized estimating equation (GEE) model revealed that neostigmine treatment increased odds of GRV improvement compared to the metoclopramide group (OR = 2.45, 95% CI: 1.60-3.76, P < 0.001). However, there is a statistically significant time trend (within-subject differences or time effect) regardless of treatment groups (P < 0.001).

Conclusion

According to the results, although neostigmine treatment significantly improved GRV in more patients in less time, within 12 hours of treatment, all patients in both groups had complete recovery. Considering that there was no significant difference between the two groups in terms of side effects, it seems that both drugs are effective in improving the GRV of ICU patients.

Selective toxicity of antibacterial agents-still a valid concept or do we miss chances and ignore risks?

BACKGROUND

Selective toxicity antibacteribiotics is considered to be due to interactions with targets either being unique to bacteria or being characterized by a dichotomy between pro- and eukaryotic pathways with high affinities of agents to bacterial- rather than eukaryotic targets. However, the theory of selective toxicity oversimplifies the complex modes of action of antibiotics in pro- and eukaryotes.

METHODS AND OBJECTIVE

This review summarizes data describing multiple modes of action of antibiotics in eukaryotes.

RESULTS

Aminoglycosides, macrolides, oxazolidinones, chloramphenicol, clindamycin, tetracyclines, glycylcyclines, fluoroquinolones, rifampicin, bedaquillin, ß-lactams inhibited mitochondrial translation either due to binding to mitosomes, inhibition of mitochondrial RNA-polymerase-, topoisomerase 2ß-, ATP-synthesis, transporter activities. Oxazolidinones, tetracyclines, vancomycin, ß-lactams, bacitracin, isoniazid, nitroxoline inhibited matrix-metalloproteinases (MMP) due to chelation with zinc and calcium, whereas fluoroquinols fluoroquinolones and chloramphenicol chelated with these cations, too, but increased MMP activities. MMP-inhibition supported clinical efficacies of ß-lactams and daptomycin in skin-infections, and of macrolides, tetracyclines in respiratory-diseases. Chelation may have contributed to neuroprotection by ß-lactams and fluoroquinolones. Aminoglycosides, macrolides, chloramphenicol, oxazolidins oxazolidinones, tetracyclines caused read-through of premature stop codons. Several additional targets for antibiotics in human cells have been identified like interaction of fluoroquinolones with DNA damage repair in eukaryotes, or inhibition of mucin overproduction by oxazolidinones.

CONCLUSION

The effects of antibiotics on eukaryotes are due to identical mechanisms as their antibacterial activities because of structural and functional homologies of pro- and eukaryotic targets, so that the effects of antibiotics on mammals are integral parts of their overall mechanisms of action.

A Double-Blind Randomized Clinical Trial Comparing the Effect of Neostigmine and Metoclopramide on Gastric Residual Volume of Mechanically Ventilated ICU Patients

BACKGROUND

In critically ill patients, enteral feeding through the nasogastric tube is the method of choice for nutritional support. Gastrointestinal feeding intolerance and disturbed gastric emptying are common challenges in these patients. The aim of this study was to compare the effect of Neostigmine and Metoclopramide on gastric residual volume (GRV) in mechanically ventilated ICU patients.

METHODS

In a double blind, randomized clinical trial, a total of 60 mechanically ventilated ICU patients with GRV >120 mL (3 hours after the last gavage), were randomly assigned into two groups A and B. At baseline and 6 hours later, patients in group A and B received intravenous infusion of neostigmine in a dose of 2.5 mg and metoclopramide in a dose of 10 mg in 100 ml of normal saline, within 30 minutes. Patients' gastric residual volumes were evaluated before the beginning of the intervention, and 3, 6, 9 and 12 hours after the intervention.

RESULTS

After adjusting of other variables (Sex, BMI and ICU stay period) generalized estimating equation (GEE) model revealed that neostigmine treatment increased odds of GRV improvement compare to metoclopramide group (Estimate 1.291, OR= 0.3.64, 95% CI 1.07-12.34). However there is a statistically significant time trend (within-subject differences or time effect) regardless of treatment groups (P<0.001). The median time from intervention to GRV improvement was 6 hours (95% CI 3.75-8.25) and 9 hours (95% CI 7.38-10.17) in neostigmine and metoclopramide groups, respectively. This difference was statistically significant (P<0.05).

CONCLUSION

It seems that neostigmine is more effective than metoclopramide in reducing GRV and improving gastric emptying in mechanically ventilated ICU patients without significant complication and this protocol may be effective on the tolerance of enteral feeding in ICU patients. Further well-designed randomized clinical trials are needed.

Preliminary Report on Efficacy of Acupuncture versus meToclopramide for Management of Post-Operative Gastroparesis (EAT POSTOP Trial)

Introduction:

Gastroparesis is common in intensive care patients and may increase the incidence of malnutrition and nosocomial pneumonia, leading to poorer patient outcomes. Current pharmacotherapy has shown only modest efficacy. Acupuncture without pharmacotherapy has been shown to improve gastroparesis in animal studies and in recent clinical trials. However, no trials studying the efficacy of acupuncture as an adjunctive therapy for surgical intensive care patients have been done. This study aims to evaluate the effectiveness of adding electro-acupuncture therapy to pharmacotherapy in the management of gastroparesis in these patients.

Methods:

For this prospective block randomised controlled trial, we aim to recruit 200 adult surgical intensive care patients who require gastric enteral nutrition, and mechanical-assisted ventilation, and who have gastroparesis (gastric residual volumes more than 120 mL twice four hours apart). Patients will receive either metoclopramide 20 mg intravenously thrice daily (Group M) or electro-acupuncture comprising four sessions of 30-minute electro-acupuncture at specific sites over 48 hours in addition to intravenous metoclopramide 20 mg thrice daily (Group A). Gastroparesis resolution is defined as 24-hour cumulative gastric residual volumes less than 200 mL. Patients are followed-up for 48 hours from the commencement of therapy.

Results:

Three patients have been recruited in a four-month period thus far. Two are in Group A and one in Group M. All have met the study definition of gastroparesis resolution. The incidence of gastroparesis in this period among longer stayers in the unit (n = 92) is 8.7%.

Conclusions:

The trial is on-going. Reasons for the low incidence of gastroparesis are discussed. The study of the use of acupuncture in the treatment of intensive care patients with gastroparesis is worthwhile due to its excellent side-effect profile and if successful, will be a tool to improve nutritional support.

Motility disorders of the upper gastrointestinal tract in the intensive care unit: pathophysiology and contemporary management

Upper gastrointestinal (GI) dysmotility, an entity commonly found in the intensive care unit setting, can lead to insufficient nutrient intake while increasing the risk of infection and mortality. Further, overcoming the altered motility with early enteral feeding is associated with a reduced incidence of infectious complications in intensive care unit patients. Upper GI dysmotility in critical care patients is a common occurrence, and there are many causes for this problem, which affects a very heterogenous population with a multitude of underlying medical abnormalities. Therefore, it is of utmost importance to identify this widespread problem and subsequently institute a proper therapy as rapidly as possible. Prokinetic pharmacotherapies are currently the mainstay for the management of disordered upper GI motility. Future therapies, aimed at the underlying pathophysiology of this complex problem, are under investigation. These aim is to reduce the side effects of the currently available options, while improving on nutrition delivery in the critically ill. This review discusses the pathophysiology, clinical manifestations, diagnosis, and treatment of upper GI motility disturbances in the critically ill.

Acupuncture in critically ill patients improves delayed gastric emptying: a randomized controlled trial

BACKGROUND

Malnutrition remains a severe problem in the recovery of critically ill patients and leads to increased in-hospital morbidity and in-hospital stay. Even though early enteral nutrition has been shown to improve overall patient outcomes in the intensive care unit (ICU), tubefeed administration is often complicated by delayed gastric emptying and gastroesophageal reflux. Acupuncture has been successfully used in the treatment and prevention of perioperative nausea and vomiting. In this study we evaluated whether acupuncture can improve gastric emptying in comparison with standard promotility drugs in critically ill patients receiving enteral feeding.

METHODS

Thirty mechanically ventilated neurosurgical ICU patients with delayed gastric emptying, defined as a gastric residual volume (GRV) >500 mL for ≥ 2 days, were prospectively and randomly assigned to either the acupoint stimulation group (ASG; bilateral transcutaneous electrical acupoint stimulation at Neiguan, PC-6) or the conventional promotility drug treatment group (DTG) over a period of 6 days (metoclopramide, cisapride, erythromycin). Patients in the ASG group did not receive any conventional promotility drugs. Successful treatment (feeding tolerance) was defined as GRV <200 mL per 24 hours.

RESULTS

Demographic and hemodynamic data were similar in both groups. After 5 days of treatment, 80% of patients in the ASG group successfully developed feeding tolerance versus 60% in the DTG group. On treatment day 1, GRV decreased from 970 ± 87 mL to 346 ± 71 mL with acupoint stimulation (P = 0.003), whereas patients in the DTG group showed a significant increase in GRV from 903 ± 60 mL to 1040 ± 211 mL (P = 0.015). In addition, GRV decreased and feeding balance (defined as enteral feeding volume minus GRV) increased in more patients in the ASG group (14 of 15) than in the DTG group (7 of 15; P = 0.014). On treatment day 1, the mean feeding balance was significantly higher in the ASG group (121 ± 128 mL) than in the DTG group (-727 ± 259 mL) (P = 0.005). Overall, the feeding balance improved significantly on all days of treatment in comparison with the DTG group. Patients in the DTG group did not show an increase in feeding balance until day 6.

CONCLUSIONS

We introduce a new protocol for acupuncture administration in the critical care setting. We demonstrated that this protocol was more effective than standard promotility medication in the treatment of delayed gastric emptying in critically ill patients. Acupoint stimulation at Neiguan (PC-6) may be a convenient and inexpensive option (with few side effects) for the prevention and treatment of malnutrition in critically ill patients.

Effectiveness of prokinetic agents against diseases external to the gastrointestinal tract

Prokinetic agents are effective not only for disease of the gastrointestinal (GI) tract but also for those external to the GI tract such as the central nervous system, and the respiratory, urologic, and metabolic organs. This article reviews the effectiveness of prokinetic agents against diseases external to the GI tract. Studies were identified by computerized and manual searches of the available literature. A Medline search was performed (1975-July, 2008) using the following medical subject headings: prokinetic agent, metoclopramide, domperidone, trimebutine, cisapride, itopride, mosapride, tegaserod, and human. The identified diseases for which prokinetic agents may be effective are various: bronchial asthma, chronic cough, hiccup, spontaneous bacterial peritonitis, cholelithiasis, diabetes mellitus, acute migraine, Parkinson's disease, anorexia nervosa, Tourette's disorder, urologic sequelae of spinal cord injury and of radical hysterectomy for cervical cancer, laryngeal dysfunction and so on. These agents are also useful for prevention of aspiration pneumonia during anesthesia, and in tube-fed patients. Prokinetic agents should be a valuable addition to our currently limited pharmacological armamentarium not only for functional bowel disease, but also for diseases external to the GI tract.

Prokinetic Drugs in the Intensive Care Unit: Reviewing the Evidence

Delay in gastric emptying is common in the critically ill, and can lead to abdominal distension, diarrhoea or constipation, and vomiting, and may contribute to increased incidence of reflux and nosocomial infection. Prokinetic agents increase the rate of luminal transit as well as the force of contraction, and are commonly used in the intensive care unit. This article summarises the current state of knowledge about the use of prokinetics and explores potential agents which might be used in the future in this group of patients.

Decisions to be made when initiating enteral nutrition

Enteral nutrition support is preferred to parenteral or no nutritional support, but many patients who could benefit receive inadequate enteral feeding. Many decisions must be made before initiating enteral nutrition support; including if and when enteral nutrition should be started, which formula should be used, and how enteral nutrition support should be monitored. The gastroenterologist should be able to understand and evaluate these decisions in all patients potentially requiring nutritional support.

Erythromycin is more effective than metoclopramide in the treatment of feed intolerance in critical illness

OBJECTIVE

This study aimed to a) compare the efficacy of metoclopramide and erythromycin in the treatment of feed intolerance in critical illness; and b) determine the effectiveness of "rescue" combination therapy in patients who fail monotherapy.

DESIGN

Randomized controlled trial.

SETTING

Level III mixed medical and surgical intensive care unit.

PATIENTS

Ninety mechanically ventilated, medical patients with feed-intolerance (gastric residual volume>or=250 mL).

INTERVENTIONS

Patients received either metoclopramide 10 mg intravenously four times daily (n=45) or erythromycin 200 mg intravenously twice a day (n=45) in a double-blind, randomized fashion. After the first dose, nasogastric feeding was commenced and 6-hourly nasogastric aspirates were performed. If a gastric residual volume>or=250 mL recurred on treatment, open-label, combination therapy was given. Patients were studied for 7 days. Successful feeding was defined as 6-hourly gastric residual volume<250 mL with a feeding rate>or=40 mL/hr.

MEASUREMENTS AND MAIN RESULTS

Demographic data, blood glucose levels, and use of inotropes, opioids, and benzodiazepines were similar between the two groups. After 24 hrs of treatment, both monotherapies reduced the mean gastric residual volume (metoclopramide, 830+/-32 mL to 435+/-30 mL, p<.0001; erythromycin, 798+/-33 mL to 201+/-19 mL, p<.0001) and improved the proportion of patients with successful feeding (metoclopramide=62% and erythromycin=87%). Treatment with erythromycin was more effective than metoclopramide, but the effectiveness of both treatments declined rapidly over time. In patients who failed monotherapy, rescue combination therapy was highly effective (day 1=92%) and maintained its effectiveness for the study duration (day 6=67%). High pretreatment gastric residual volume was associated with poor response to prokinetic therapy.

CONCLUSIONS

In critical illness, erythromycin is more effective than metoclopramide in treating feed intolerance, but the rapid decline in effectiveness renders both treatments suboptimal. Rescue combination therapy is highly effective, and further study is required to examine its role as the first-line therapy.

The use of erythromycin as a gastrointestinal prokinetic agent in adult critical care: benefits versus risks

Erythromycin A, the first macrolide, was introduced in the 1950s and after years of clinical experience it still remains a commonly relied upon antibiotic. In the past, pharmacodynamic characteristics of macrolides beyond antimicrobial action such as anti-inflammatory and immune-modulating properties have been of scientific and clinical interest. The function of erythromycin as a prokinetic agent has also been investigated for a range of gastrointestinal motility disorders and more recently within the context of critically ill patients. Prokinetic agents are drugs that increase contractile force and accelerate intraluminal transit. Whilst the anti-inflammatory action may be a desirable side effect to its antibiotic action, using erythromycin A merely for its prokinetic effect alone raises the concern about promoting emergence of macrolide resistance. The objectives of this review article are: (i) to briefly summarize the modes and epidemiology of macrolide resistance, particularly in respect to that found in the Streptococcus species (a potential reservoir for the dissemination of macrolide resistance on the critical care unit); (ii) to discuss in this context the evidence for conditions promoting bacterial resistance against macrolides; and (iii) to assess the potential clinical benefit of using erythromycin A as a prokinetic versus the risks of promoting emergence of macrolide resistance in the clinical setting. We conclude, that in view of the growing weight of evidence demonstrating the potential epidemiological impact of the increased use of macrolides upon the spread of resistance, versus a lack of sufficient and convincing evidence that erythromycin A is a superior prokinetic agent to potential alternatives in the critically ill patient population, at this stage we do not advocate the use of erythromycin A as a prokinetic agent in critically ill patients unless they have failed all other treatment for impaired gastrointestinal dysmotility and are intolerant of metoclopramide. Further large and methodologically robust studies are needed to ascertain the effectiveness of erythromycin A and other alternative agents in the critically ill.

Erythromycin for prokinesis: imprudent prescribing?

Problems with antibiotic resistant bacteria are increasing in the hospital and particularly in the intensive care unit. Methicillin-resistant Staphylococcus aureus, Acinetobacter baumanii and extended spectrum beta-lactamase producing Gram-negative bacilli constitute a therapeutic and infection control challenge. Early enteral feeding improves survival in patients in the intensive care unit. Prokinetic agents are routinely used in patients with inappropriate gastrointestinal motility. The use of erythromycin at sub-therapeutic doses as a prokinetic agent is a cause of concern for the following reasons: it can increase the emergence and spread of antibiotic resistance and the likelihood of Clostridium difficile disease. The use of an antibiotic as a prokinetic agent does not constitute prudent antimicrobial prescribing and should be avoided. Alternative agents, whenever possible, should be used.

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.

Rational design of macrolides by virtual screening of combinatorial libraries generated through in silico manipulation of polyketide synthases

Bacterial secondary metabolites display diverse biological activities, thus having potential as pharmacological agents. Although most of these compounds are discovered by random screening, it is possible to predict and re-design their structures based on the information on their biosynthetic pathways. Biosynthesis of macrolides, governed by modular polyketide synthases (PKS), obeys certain rules, which can be simulated in silico. PKS mode of action theoretically allows for a huge number of macrolides to be produced upon combinatorial manipulation. Since engineering of all possible PKS variants is practically unfeasible, we created Biogenerator software, which simulates manipulation of PKS and generates virtual libraries of macrolides. These libraries can be screened by computer-aided prediction of biological activities, as exemplified by analysis of erythromycin and macrolactin libraries. This approach allows rational selection of macrolides with desired biological activities and provides instructions regarding the composition of the PKS gene clusters necessary for microbial production of such molecules.