The role of glucose in preventing stress gastric mucosal injury

Effects of oral/enteral nutrition alone versus plus pantoprazole on gastrointestinal bleeding in critically ill patients with low risk factor: a multicenter, randomized controlled trial

Background/aim

Critically ill patients are at risk of developing gastrointestinal (GI) bleeding due to stress causing mucosal damage. Aim of the study was to determine the effect of oral/enteral nutrition with or without concomitant pantoprazole on upper GI bleeding in low risk critically ill patients.

Materials and methods

This was a prospective, randomized, open-label, multicenter study conducted with intensive care unit (ICU) patients receiving oral/enteral nutritional support. Patients were randomly assigned into two groups including intervention group (received oral/EN plus pantoprazole) and control group (received only oral/EN).

Results

A total of 300 patients (intervention group: 152, control group: 148) participated in the study. Overall, 226 (75%) patients were fed by orally and 74 (25%) patients fed by enteral tube feeding. Median duration of nutritional support 4 (range: 2–33) days. Overt upper GI bleeding was noted only in one patient (0.65%) who was in the intervention group. The overall length of ICU stay of 4 (2–105) days, while ICU stay was significantly longer in the intervention group than in the control group (P = 0.006).

Conclusions

Our findings seems to indicate that in patients who are at low risk for GI bleeding and under oral/enteral nutritional support, the use of PPIs may not reduce the risk of bleeding, however these results are imprecise because of low event (GI bleeding) rate and limited power.

Combined application of nasogastric tubes and nasointestinal tubes in neurosurgical intensive care patients with stress ulceration: a novel solution to treatment and early enteral nutrition

Objective

Stress ulcers occur frequently in neurosurgical intensive care patients and can pose serious risks. We summarized the clinical experience of the combined application of nasointestinal tubes for early restoration of enteral nutrition and of nasogastric (NG) tubes for stress ulceration treatment in patients hospitalized in a neurosurgical intensive care unit.

Methods

From January 2011 to June 2011, a series of 67 patients with stress ulceration hospitalized in a neurosurgical intensive care unit were randomized to two groups. The control group (33 patients) received treatment with NG tube decompression and drainage according to international guidelines, and parenteral nutrition was changed to enteral feeding until there was no grossly visible blood in the NG tube. The nasointestinal tube group (34 patients) received treatment combining application of NG tubes and nasointestinal tubes. Drainage was performed with NG tubes as in the control group, with concurrent placement of nasointestinal tubes. Duration until resolution of stress ulceration and days until start of enteral nutrition were compared between the two groups.

Results

Duration until resolution of stress ulceration was 4.5 days in the control group and 4.3 days in the nasointestinal tube group. There was no difference between the two groups (P > 0.05). Duration until start of enteral nutrition was 4.5 days in the control group and 1 day in the nasointestinal tube group. There was an obvious difference between the two groups (P < 0.01).

Conclusions

The combined application of NG tubes and nasointestinal tubes in neurosurgical intensive care patients with stress ulceration is an effective means of treating stress ulceration and restoring early enteral nutrition.

[Prophylaxis for stress ulcer bleeding in the intensive care unit]

BACKGROUND

The critically ill patient can develop gastric erosions and, on occasion, stress ulcers with severe gastrointestinal bleeding that can be fatal.

AIMS

The purpose of this review was to provide current information on the pathophysiology, risk factors, and prophylaxis of digestive tract bleeding from stress ulcers in the intensive care unit.

METHODS

We identified articles through a PubMed search, covering the years 1970 to 2013. The most relevant articles were selected using the search phrases "stress ulcer", "stress ulcer bleeding prophylaxis", and "stress-related mucosal bleeding" in combination with "intensive care unit".

RESULTS

The incidence of clinically significant bleeding has decreased dramatically since 1980. The most important risk factors are respiratory failure and coagulopathy. Proton pump inhibitors (PPIs) or H2 receptor antagonists (H2RAs) are used in stress ulcer bleeding prophylaxis. Both drugs have been shown to be superior to placebo in reducing the risk for gastrointestinal bleeding and PPIs are at least as effective as H2RAs. Early enteral feeding has been shown to reduce the risk for stress ulcer bleeding, albeit in retrospective studies.

CONCLUSIONS

Admittance to the intensive care unit in itself does not justify prophylaxis. PPIs are at least as effective as H2RAs. We should individualize the treatment of each patient in the intensive care unit, determining risk and evaluating the need to begin prophylaxis.

Stress Ulcer Prophylaxis in the New Millennium!

Clinical trials conducted in the latter part of the past millennium suggested that bleeding from gastric stress ulceration was an important cause of morbidity and mortality in intensive care unit (ICU) patients and that treatment with acid-suppressive therapy reduced the risk of clinically significant bleeding. Stress ulcer prophylaxis therefore became regarded as the standard of care in all ICU patients. However, more recent clinical trials have demonstrated that the risk of clinically significant bleeding is extremely low (about 1%) and not altered by the use of acid-suppressive therapy. Furthermore, a critical review of the “historical” clinical trials, as well as the data from experimental and more recent clinical trials, suggests that enteral feeding (gastric) is at least as effective as acid-suppressive therapy in the prevention of gastric stress ulceration and is the prophylactic measure of choice in most ICU patients.

Use of enteral nutrition for stress ulcer prophylaxis

OBJECTIVE

To review the controversies involving the use of enteral nutrition support for stress ulcer prophylaxis and formulate recommendations.

DATA SOURCES

A MEDLINE search (1966-December 2000) was conducted using the MeSH of nutrition, ulcer, critical care, and acid to identify relevant articles. References of selected articles were reviewed, and relevant abstracts from critical care or gastrointestinal journals identified.

DATA EXTRACTION

Animal and human data from prospective studies, retrospective studies, and case series were evaluated for the effects of enteral nutrition on gastric pH, intramucosal pH, gastrointestinal blood flow, development of macroscopic mucosal erosions, and hemorrhage.

DATA SYNTHESIS

Intragastric administration of enteral nutrition has variable effects on gastric pH, enhances regional distribution of gastrointestinal blood flow, and may lower intramucosal pH. All substrates (carbohydrate, lipid, amino acid), when administered into the stomach, reduce the occurrence of mucosal erosions but do not entirely prevent their development. Few studies of stress ulcer prophylaxis regimens have reported use of enteral nutrition. Limited retrospective data suggest enteral nutrition support may be effective for preventing gastrointestinal hemorrhage, but the results of prospective studies are confounded by poor study design.

CONCLUSIONS

Definitive recommendations regarding the role of enteral nutrition for stress ulcer prophylaxis are not possible due to the lack of prospective, randomized studies. Therefore, the use of enteral nutrition as the only therapeutic agent for stress ulcer prophylaxis should be discouraged until definitive data are available. Initiation and discontinuation of pharmacologic stress ulcer prophylaxis should be independent of enteral nutrition.

Restraint stress in biomedical research: an update

Since the publication of our initial review of restraint stress in 1986, much work has continued with this technique, either as a tool for the investigation of other pharmacological, physiological, or pathologic phenomena or with restraint stress itself serving as the object of the study. As we noted in 1986, the major use of restraint has been for the induction of stress responses in animals and, more specifically, for the investigation of drug effects, particularly as they affect typical stress-related pathology--gastrointestinal, neuroendocrine, and immunological agents have been extensively studied. In compiling this update on restraint stress and its effects, we noted an increasing emphasis on central nervous system mechanisms in peripheral disease, especially gastrointestinal disease. In particular, many CNS-active agents have been tested for their effects on gastric and duodenal lesion formation and gastric secretion, including antidepressants, antipsychotics, anxiolytics, noradrenergic, serotonergic, dopaminergic, and peptidergic compounds. Some of these agents are especially active in the gastrointestinal tract even when administered centrally, further solidifying the concept of a brain-gut axis. The present update includes studies of: methods and procedures, pre-restraint manipulations, post-restraint/healing effects, and drug effects. In addition, a current bibliography of reports that have employed restraint is included.

Effects of intragastric and intravenous glucose on restraint model of stress ulceration

Intragastric glucose prevents acute stress-induced gastric mucosal injury in the restrained rat. Because increased gastric contractions contribute to mucosal injury in this model and because parenteral glucose infusions have been shown to suppress gastric contractility, we hypothesized that centrally mediated responses to hyperglycemia might contribute to the cytoprotective effect of intragastric glucose. We compared intragastric and intravenous 25% glucose with saline infusions during cold restraint and measured their impact on gastric lesions, serum glucose levels, gastric residual volume (an indirect indicator of net gastric contractility), acidity, and mucin concentration. We found that both intravenous and intragastric glucose infusions increased serum glucose to over 500 mg/dl after 4 hr of stress. Intragastric glucose increased residual volume and gastric pH, as well as decreased gastric mucosal injury, but intravenous glucose had no effects on gastric function. We found that none of the potentially protective effects of intragastric glucose are mediated by central responses to hyperglycemia, and likewise that intravenous glucose has no effect on gastric mucosal injury.

Cholecystokinin does not mediate glucose's cytoprotective effects

Cold restraint stress produces acute gastric mucosal injury in association with altered gastric motility. Enteral nutrients prevent this injury in conjunction with inhibition of gastric emptying. Because cholecystokinin (CCK) is released by nutrients known to be cytoprotective and is thought to inhibit gastric emptying, we performed three experiments to see if CCK contributes to the gastric mucosal protection afforded by enteral nutrients. Our data show that enteral glucose protects the gastric mucosa and increases gastric volume, gastric luminal pH, and gastric mucin. Neither physiologic nor pharmacologic doses of CCK protected the mucosa. None of the other significant effects of glucose on gastric function during cold restraint were affected by exogenous CCK. Furthermore, antagonism of CCK receptors with L-364,718 did not have any independent effects, nor did it diminish the protection associated with enteral glucose. We conclude that enteral glucose protects the gastric mucosa from cold restraint injury in association with a number of potentially beneficial effects on gastric physiology, but none of the effects of glucose in this model appear to be mediated by CCK.

Stress ulcers: current understanding of pathogenesis and prophylaxis

Stress-related gastrointestinal bleeding is known to occur in approximately 25 percent of untreated seriously ill patients, but with appropriate prophylaxis is largely preventable. Since the treatment of stress bleeding is generally unsatisfactory and has a high mortality, routine prophylaxis should be instituted for susceptible patients. Multiple mechanisms contribute to stress ulcer formation, the most important of which appear to be mucosal ischemia and the inability to control back-diffused hydrogen. Antacids and histamine2-blocking agents are presently the cornerstone of effective prophylaxis, but because they have been implicated as contributors to nosocomial pneumonias due to bacterial overgrowth in the stomach, investigation is ongoing into such alternative prophylactic agents as sucralfate and prostaglandins that do not alter the normal gastric acidity. This article presents a review of the literature on the development and prevention of stress ulcer disease.

Comparison of approaches to stress ulcer prophylaxis in hemorrhagic shock

Stress ulceration can be prevented clinically by prophylaxis with antacids or sucralfate, while hyperosmolar glucose and prostaglandins have prevented gastric mucosal injury in experimental models. We compared these four agents' effectiveness in gastric mucosal protection as well as their interaction with the pathophysiology of hemorrhagic shock. Gastric mucosal injury was produced in a canine model with the insults important in clinical situations: intragastric acid, intragastric bile, and gastric mucosal ischemia. Hypotension was maintained at a constant level for 3 hr, during which one of the prophylactic treatments or vehicle (H2O) was given hourly intragastrically. The stomachs were harvested for quantification of gastric mucosal injury after return of shed blood. The percentage of gastric area damaged was significantly decreased to 1.0 +/- 0.7% by antacids but was increased to 43.5 +/- 4.9% by 16,16-dimethyl prostaglandin E2 (16,16-dmPGE2), in comparison to vehicle treatment which caused 28.4 +/- 4.7% lesioned mucosa. Additionally, hemodynamic function differed between treatment groups after 1 hr of shock. Irrespective of treatment group, parameters reflecting volume status and hemodynamic function correlated significantly with the amount of gastric mucosal injury measured in individual animals. Intragastric treatments did not variably affect systemic pH or systemic glucose, and neither of these parameters was related to gastric mucosal injury. In conclusion, antacids effectively prevent stress ulceration in canine hemorrhagic shock, while the worsening of gastric mucosal injury and hemodynamic function we observed with 16,16-dmPGE2 treatment indicates that this agent could be hazardous in hypotensive patients.