Methodologies in health services research for critical carePathophysiology and prophylaxis of stress ulcer in intensive care unit patients
Introduction
An estimated 4.4 million patients are admitted to intensive care units (ICUs) each year. Of these, about 12%, or 500 000 patients, die in the ICU [1]. Gastrointestinal (GI) complications (eg, gastric and intestinal motor dysfunction as well as stress-related mucosal disease [SRMD]) frequently occur in these patients and adversely affect patient outcomes. Gastrointestinal motor dysfunction may predispose patients to impaired enteral nutrition and pulmonary aspiration of gastric contents [2]. Stress-related mucosal damage—an acute erosive gastritis—occurs in many critically ill patients in ICUs and may develop within 24 hours of admission [3]. The incidence of clinically important GI bleeding, defined as overt bleeding complicated by hemodynamic instability, decrease in hemoglobin, and/or need for blood transfusion, from SRMD in the ICU population was 1.5% in a prospective study of 2252 patients [4]. In addition, the morbidity associated with this type of severe ulceration and bleeding can increase the length of stay in the ICU by up to 8 days, and mortality is as much as 4-fold higher than it is in ICU patients without this complication [5].
Section snippets
Pathophysiology and pathogenesis of SRMD
Several factors have a role in the pathogenesis of SRMD, including gastric acid secretion, mucosal ischemia (as a result of splanchnic hypoperfusion), and reflux of upper intestinal contents into the stomach (Fig. 1) [6], [7]. Gastric hypoperfusion leads to an imbalance between oxygen supply and demand that may induce mucosal damage. Moreover, reperfusion after prolonged hypoperfusion may itself result in nonocclusive mesenteric ischemia and mucosal damage. As a result of ischemia, there is
Complications associated with SRMD
Mortality rates increase proportionately with the incidence and severity of SRMD. In 2 prospective multicenter studies, Cook et al [4], [5] found significant differences in mortality between clinically important GI bleeding and nonbleeding patients (Fig. 2). In these studies, patients who bled as a result of SRMD had mortality rates of 49% and 46%. In contrast, mortality rates for nonbleeding patients were 9% and 21% (P < .001 and P < .0001, respectively) [4], [5]. These findings are consistent
Risk factors for stress ulcer–related bleeding
As noted, critically ill patients admitted to ICUs are at risk for developing stress ulceration and subsequent bleeding as a result of both underlying disease and therapeutic interventions. Prophylaxis against stress ulcers can significantly minimize bleeding, but such therapy may be costly and can have adverse effects. Therefore, it is important to identify risk factors that would substantiate the need for prophylaxis and target interventions to those at highest risk. A study involving more
Stress ulcer prophylaxis options
Prevention of stress-related bleeding is clearly the most effective strategy for patients at risk for SRMD in the ICU. This can be accomplished by preventing gastric ischemia or acid injury. Although high acid concentrations are not the only factor that contributes to SRMD, controlling acid production in at-risk patients seems to be protective against bleeding episodes [9]. A metaanalysis of clinical trials by Cook et al [30] reported that various prophylactic therapies such as antacids,
Cost of prophylaxis
When evaluating the cost of regimens used for prevention of stress ulcer–related bleeding, it is important to recognize that acquisition cost is only one of several factors that need to be considered. Other factors include cost of preparing and administering the agent, as well as the potential for overuse, adverse effects, and risk of bleeding.
Evidence strongly suggests that stress ulcer prophylaxis should be limited to patients with established risk factors for clinically significant GI
Conclusions
The etiology of SRMD is multifactorial, but 2 conditions that seem to be necessary are intraluminal acid and gastric mucosal ischemia. Therefore, prophylaxis and treatment require maintenance of perfusion and protection against acid damage through elevation of gastric pH. Underlying disease and risk factors including surgery, burns, trauma, respiratory failure requiring mechanical ventilation, and coagulopathy predispose patients to SRMD. Gastrointestinal bleeding exacerbates the underlying
Acknowledgment
This work is supported by Wyeth Pharmaceuticals, Philadelphia, PA, with editorial support provided by Accel Medical Education, New York, NY.
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