Methods of prophylaxis in stress ulcer disease

Pharmacological Approach to the Prevention and Treatment of Stress Ulcers

The mortality associated with bleeding stress ulcers in patients in intensive care units exceeds 50%. Iden tification of patients at risk and use of early and effec tive prophylaxis are necessary in the management of patients in intensive care units. The use of antacids is inconvenient, expensive, and associated with electro lyte disturbances and erratic pH control. H2-receptor antagonists are the preferred agents for stress ulcer pro phylaxis because of their proven efficacy, safety, and ease of administration. Adjunct therapy with cyto protective agents may be useful in patients with com promised mucosal defences.

Stress Ulcer Syndrome

Stress ulcer syndrome refers to gastroduodenal erosions or ulcers that develop acutely in relation to major physi ological stress, usually manifested clinically as upper gastrointestinal (UGI) bleeding. These lesions occur most often in the gastric fundus. Endoscopy has shown gastroduodenal mucosal lesions in 75 to 100% of inten sive care unit (ICU) patients within 72 hours of admis sion. Patients at high risk for stress ulcer include those with large body surface area burns, intracranial lesions associated with coma, fulminant hepatic failure, sepsis, and trauma and abdominal, cardiovascular, and thoracic surgery patients. Also considered high risk are ICU pa tients with superimposed complications such as shock, mechanical ventilation for more than 3 days, coagulopa thy, jaundice, and sepsis. Approximately 15% of ICU pa tients will experience UGI bleeding from stress ulcer. Patients bleeding from stress ulcer have an overall mor tality rate approaching 65% compared with 9 to 22% mortality in patients without stress ulcer. When strati fied according to occult blood loss versus clinically significant bleeding, mortality can be as high as 90% in patients overtly bleeding; 30% of deaths are directly related to bleeding. Both antacids and H2 receptor an tagonists are effective in prophylaxis for stress ulcer bleeding.

GI complications in patients receiving mechanical ventilation

Mechanical ventilation (MV) can be lifesaving by maintaining gas exchange until the underlying disorders are corrected, but it is associated with numerous organ-system complications, which can significantly affect the outcome of critically ill patients. Like other organ systems, GI complications may be directly attributable to MV, but most are a reflection of the severity of the underlying disease that required intensive care. The interactions of the underlying critical illness and MV with the GI tract are complex and can manifest in a variety of clinical pictures. Incorporated in this review are discussions of the most prevalent GI complications associated with MV, and current diagnosis and management of these problems.

A prospective study of omeprazole suspension to prevent clinically significant gastrointestinal bleeding from stress ulcers in mechanically ventilated trauma patients

OBJECTIVE

To prospectively evaluate the incidence of clinically significant bleeding, side effects, and cost of therapy in mechanically ventilated trauma patients at high risk for stress ulcers who received simplified omeprazole suspension (SOS).

METHODS

Prospective, evaluative study in a Level I trauma center. Mechanically ventilated trauma patients admitted with at least one additional risk factor for stress ulcer development received SOS for stress ulcer prophylaxis.

RESULTS

Sixty trauma patients were enrolled. The mean Injury Severity Score was 27.3. After starting SOS, there were no cases of clinically significant upper gastrointestinal bleeding related to stress ulceration. Baseline pH was 3.3, and mean gastric pH after SOS was increased to 6.7 (p < 0.005). There were no adverse effects thought to be related to omeprazole suspension. Incidence of nosocomial pneumonia after beginning SOS was 28.3%. The cost of acquisition plus administration of SOS was $13.13 per day, whereas the cost of drug acquisition alone was $3.83 per day.

CONCLUSION

In a prospective, evaluative study of 60 trauma patients who required mechanical ventilation and had at least one additional risk factor for stress ulcer development, omeprazole suspension prevented clinically significant gastrointestinal bleeding, maintained excellent control of gastric pH, produced no toxicity, and was the least costly medication alternative.

A prospective study of simplified omeprazole suspension for the prophylaxis of stress-related mucosal damage

OBJECTIVES

To determine the efficacy, safety, and cost of simplified omeprazole suspension in mechanically ventilated critically ill patients who have at least one additional risk factor for stress-related mucosal damage.

DESIGN

Prospective, open-label study.

SETTING

Surgical intensive care and burn unit at a university tertiary care center.

PATIENTS

Seventy-five adult, mechanically ventilated patients with at least one additional risk factor for stress-related mucosal damage.

INTERVENTIONS

Patients received 20 mL of simplified omeprazole suspension (containing 40 mg of omeprazole) initially, followed by a second 20-mL dose 6 to 8 hrs later, then 10 mL (20 mg) daily. Simplified omeprazole suspension was administered through a nasogastric tube, followed by 5 to 10 mL of tap water. The nasogastric tube was clamped for 1 to 2 hrs after each administration.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure was clinically significant gastrointestinal bleeding determined by endoscopic evaluation, nasogastric aspirate examination, or heme-positive coffee ground material that did not clear with lavage, which was associated with at least a 5% decrease in hematocrit. Secondary efficacy measures were gastric pH measured 4 hrs after omeprazole was first administered, mean gastric pH after omeprazole was started, and the lowest gastric pH during omeprazole therapy. Safety-related outcomes included the occurrence rate of adverse events and pneumonia. No patient experienced clinically significant upper gastrointestinal bleeding after receiving omeprazole suspension. The 4-hr postomeprazole mean gastric pH was 7.1, the mean gastric pH after starting omeprazole was 6.8, and the mean lowest pH after starting omeprazole was 5.6. The occurrence rate of pneumonia was 12%. No patient in this high-risk population experienced an adverse event or a drug interaction that was attributable to omeprazole.

CONCLUSIONS

Simplified omeprazole suspension prevented clinically significant upper gastrointestinal bleeding and maintained gastric pH of > 5.5 in mechanically ventilated critical care patients without producing toxicity.

Stress ulcer prophylaxis in the critically ill: a meta-analysis

PURPOSE

To examine the differential effect of stress ulcer prophylaxis on overt bleeding, clinically important bleeding, and mortality in critically ill patients.

DATA IDENTIFICATION

Computerized bibliographic search of published and unpublished research.

STUDY SELECTION

Independent review of 168 articles identified 42 relevant randomized trials for inclusion.

DATA ABSTRACTION

The validity, population, intervention, and outcomes of each trial were evaluated.

RESULTS

Stress ulcer prophylaxis with antacids (odds ratio 0.40 [95% confidence interval (CI) 0.20 to 0.79]) or histamine-2-receptor antagonists (odds ratio 0.29 [95% CI 0.17 to 0.45]) decreases the incidence of overt gastrointestinal bleeding. Histamine-2-receptor antagonists are more effective than antacids at reducing overt hemorrhage (odds ratio 0.56 [95% CI 0.33 to 0.97]). A significant reduction in clinically important gastrointestinal hemorrhage is evident only with histamine-2-receptor antagonist therapy. There is a trend favoring antacids over sucralfate in the outcome of clinically important bleeding (odds ratio 0.65 [95% CI 0.16 to 2.49]); however, there are insufficient data to evaluate histamine-2-receptor antagonists versus sucralfate. No difference in mortality between treated and untreated patients was found.

CONCLUSIONS

Overt gastrointestinal bleeding in critically ill patients is reduced by prophylaxis with antacids or histamine-2-receptor antagonists. Histamine-2-receptor antagonists are more effective than antacids at decreasing overt bleeding and are more effective than no treatment at reducing the incidence of clinically important bleeding. Mortality rates in the intensive care unit are not decreased by stress ulcer prophylaxis.

A graded combination regimen for maintenance of gastric pH above 3.5 in critically ill patients

Prophylaxis of acute upper gastrointestinal bleeding by control of gastric pH has been widely advocated for intensive care patients. H2-blockers and antacids have been used and demonstrated to be incompletely effective at maintaining gastric pH above 4. A study of 100 patients measured the efficacy of two-hourly gastric pH measurement and titrated therapy consisting of five levels: 1. no therapy 2. ranitidine 50 mg 8 hourly intravenously 3. ranitidine plus Mylanta 30 ml 2 hourly by nasogastric tube 4. ranitidine plus Mylanta 60 ml 2 hourly and 5. ranitidine 100 mg 8 hourly intravenously plus Mylanta II 60 ml 2 hourly. The level of treatment required by proportions of the total study group were (1) 15%, (2) 71%, (3) 96%, (4) 100%. Head-injured and intubated patients generally fell in the more resistant group while patients having had major elective surgery required lower levels of therapy. If control of gastric pH is to be uniformly achieved, a technique of titrated therapy based on gastric pH measurements is supported as cheaper and more effective than other standardised treatment regimens.

Preventive measures for stress ulcers in burn patients

Between January 1981 and December 1985 336 patients with deep partial and full skin thickness burn injuries covering more than 20 per cent of the body surface area (BSA) were treated in our burn unit. During the first 3.5 years prophylactic therapy for stress ulcers consisted of cimetidine or ranitidine whereas during the last 18 months a combination of ranitidine and sucralfate was used. Over the whole period a protein-rich enteral feeding was instituted as early as possible after injury. Six times 200 mg/day cimetidine were administered intravenously during the first 4-6 days after injury, followed by a reduction to 4 x 200 mg/day usually until the end of the third week. Subsequently cimetidine was given orally in doses of 5 x 200 mg/day. Ranitidine (3 x 112 mg) was given intravenously until enteral feeding started, usually for the first 4 days, after oral nutrition had started the dosage was reduced to 3 x 56 mg/day. Over the past 18 months 4 x 1 g/day granular powdered sucralfate in combination with 3 x 56 mg/day ranitidine were given. The incidence of gastrointestinal bleeding was 2.5 per cent and no patient required surgical therapy. With respect to prophylaxis of bleeding and perforation of stress ulcers the triple regimen using sucralfate, ranitidine in low dosages and protein-rich enteral feeding appeared to be as effective as the earlier use of cimetidine or ranitidine. Side-effects of H2-blockade treatment, especially the high incidence of pneumonias caused by ascending infection from the gastrointestinal tract, were not seen. The high incidence of diarrhoea during H2-blockade treatment in combination with high protein enteral feeding remains to be solved.

Therapeutic goals and treatment options for prevention of stress ulcer syndrome

Stress ulcer syndrome, the occurrence of acute upper gastrointestinal bleeding or perforation from stress-related mucosal damage, is a significant cause of morbidity and mortality in critically ill patients. The mortality rate in critically ill patients who have bled from stress ulcers ranges from 50 to 77 percent, whereas the mortality rate for similar patients without stress ulcer bleeding ranges from 9 to 22 percent. The mortality rate may be as high as 90 percent in patients with clinically overt bleeding; as many as one-third of these deaths can be directly related to bleeding. Prophylactic therapy for prevention of stress ulcer bleeding is based on three premises: (1) morbidity and mortality related to stress ulcer syndrome are significant; (2) the population at risk can be identified prior to bleeding; and (3) therapy that decreases gastric acidity or improves gastric mucosal defense mechanisms will prevent ulcer formation or progression to bleeding. A review of prospective clinical studies utilizing prophylactic therapy in critically ill patients and patients undergoing surgery revealed a 17 percent overall bleeding rate for placebo groups compared with lower bleeding rates for antacid- and histamine (H2)-receptor-antagonist-treated groups (4 and 7 percent, respectively). Studies varied greatly in definition of bleeding, dosage regimens, and gastric pH goals. The need to measure gastric pH during treatment is controversial, and the optimal pH goal and the length of time for which it must be maintained remain unknown. Controversy exists as to the best therapeutic option for prophylaxis of stress ulcer syndrome, but when prevention of clinically significant bleeding is the therapeutic goal, antacids and H2-receptor antagonists appear to be equally efficacious.

Erosive gastritis and gastrointestinal bleeding in a female runner. Prevention of the bleeding and healing of the gastritis with H2-receptor antagonists

A 33-yr-old female runner presented with upper gastrointestinal symptoms and iron deficiency anemia. She was found to have erosive gastritis that was present when she exercised and which was associated with symptoms. Gastrointestinal blood loss during exercise periods was confirmed by measuring fecal blood loss using 51Cr-labeled red cells. Symptoms, gastritis, and blood loss disappeared with cessation of running or with H2-receptor antagonist therapy.

Effect of omeprazole on acute gastric stress ulceration in cervical cord transected rats

Patients with acute paraplegia from trauma have an increased frequency of developing gastric stress ulceration and subsequent hemorrhage. Current treatment of gastric stress ulcer is by antacids or H2 antagonists, but despite such therapy stress ulceration still occurs, probably because these agents are unable to maintain gastric pH above 4. Omeprazole, which blocks the terminal step of acid secretion--the proton pump, can produce long-lasting achlorhydria. This study examined the efficacy of omeprazole in preventing stress ulcer in rats with acute cervical cord transection. Omeprazole was administered intraduodenally at 1.725, 2.625, 3.5, and 17.5 mg/kg, and the ulcer incidence and gastric acid output were measured. Omeprazole produced a dose-dependent inhibition of gastric acid output in the cervical cord transected rat. At the highest dose, complete achlorhydria was achieved. The quantity of gastric ulceration was inversely proportional to the omeprazole dosage with nearly complete prevention of ulceration at the highest dose. In conclusion, omeprazole is very effective in preventing gastric stress ulcers in the spinal cord transected rat. This appears to be related to its potent long-lasting inhibitory effect on gastric acidity.

Prophylaxis of stress ulcers: antacid titration vs. histamine2-receptor blockade

The near universal occurrence of stress ulcers in critically ill patients emphasizes the need for early and effective prophylaxis. Intraluminal gastric acidity, ischemic insult to the bowel, and the presence of stress factors are the major precipitants of stress ulcers. The use of H2-receptor antagonists vs. antacid titration for stress ulcer prophylaxis is reviewed. The goals of preventive therapy are to eliminate the stress factors and to maintain intragastric pH greater than 5. Hourly gastric pH monitoring and antacid titration are the mainstay of stress ulcer prophylaxis, with high potency antacids being the preferred agents. H2-receptor antagonists may serve as adjuncts in patients requiring large doses of antacids or having acid-base abnormalities from high gastric output states.

Acute stress ulceration

Stress ulceration is usually considered a mucosal abnormality of the oesophagus, stomach or duodenum in the critically ill. It is found to a varying degree in all such patients. Only about one-quarter of lesions are associated with blood loss and less than 5% need resuscitation and treatment. However, because treatment of established bleeding is unsatisfactory, and associated with a high mortality, prophylactic measures are usually employed. These include optimising gastric mucosal blood flow and oxygen delivery, correcting coagulation abnormalities and treating underlying infection. Enteral feeding should also be employed whenever possible. Other prophylactic measures currently used involve raising gastric pH above 4, with either antacids or H2 receptor antagonists. This is best achieved by measuring the gastric pH hourly and titrating it against an appropriate dose of either type of drug or a combination of both. Newer drugs, such as omeprazole, sucralfate and prostaglandins, are proving very successful in the treatment and prevention of gastric and duodenal ulcers and may prove even more effective than currently available agents.

Endoscopic bipolar electrocoagulation in massive upper gastrointestinal bleeding

We have reviewed 50 cases of upper gastrointestinal bleeding treated by endoscopic bipolar electrocoagulation (BPEC) and assessed its value in the management of massive bleeding. Initial hemostasis was achieved in 94% of cases with an overall rebleeding rate of 19.1%. The rebleeding rate was high among patients requiring blood transfusions more than 2,000 ml (47.3%) and those with acute gastric mucosal lesion (AGML) (35.3%). In AGML one or two primary sites of bleeding can be effectively controlled initially, but rebleeding tends to occur from other sites. Mortality from the direct effects of bleeding was also high in massive bleeders (33.3%) and those with AGML (22.2%); the overall mortality, including deaths from ongoing underlying diseases, was 38%. Although BPEC failed to alter the fatal outcome of patients with massive acute mucosal bleeding, permanent or temporary hemostasis contributed to reducing the amount of blood transfusions, avoiding emergency operation, preventing rapid deterioration and prolonging the survival time. Endoscopic BPEC has proven to be an effective emergency hemostatic method in massive bleeding of the upper gastrointestinal tract as an alternative to surgical intervention.

pH-control via secretin or antacid: prophylaxia of stress ulcers in high-risk surgical patients

The efficacy of an antacid or synthetic secretin in elevating the intragastric pH above 4 was tested in a controlled, prospective study. Twenty-one high-risk surgical patients received an antacid and 17 secretin. Antacid prophylaxis resulted in a significantly higher intragastric pH than with secretin. This was especially true in patients with several risk factors. The percent of secretin patients with a pH below 4 was higher. An increase in dosage was necessary in 4 of the 17 patients receiving secretin and in none of those receiving antacids. One stress ulcer hemorrhage occurred during secretin prophylaxis.

pH testing paper for measurement of intragastric acidity: an assessment

Regular evaluation of the pH of aspirated gastric juice is an important part of the routine prevention of the stress ulceration syndrome. This study has examined the use of commercially available pH paper for this purpose. Both clear buffer solutions and samples of gastric aspirate were used to assess the reliability of four products, Merck Universal pH Indicator strips (Art. 9535), Lyphan Universal pH Indicator paper, Whatman Wide Range pH paper and Macherey-Nagel Universal pH paper. The results show that the Merck strips and Lyphan paper are very reliable for measuring gastric aspirate pH and that intensive care nursing staff can make accurate observations when using these papers.