Acid Secretion and Pathophysiologic Consequences

Gastric Mucosal Defense

The gastric mucosa is exposed to acid pH and to large volumes of gastric acid secretion. To prevent the development of mucosal damage, mechanisms have evolved to afford the mucosal lining protection (gastric mucosal defense). These normal defense mechanisms can be disrupted in various pathophysiologic situations, such as mucosal stress that is caused by NSAIDs or H. pylori, and in patients that are being treated in the icu.

In the hospital setting, medical and surgical patients develop the risk of peptic ulcerations because of the development of gastric mucosal hypoxia with consequent disruption to the tight junctions that inherently prevent the back-diffusion of gastric acid as well as from the release of inflammatory mediators (Cook et al, 1994). Patients that are at particular risk for the development of stress PUD include those with severe sepsis, those requiring mechanical ventilation or coagulopathy, and burn and neurosur-gical patients. The risk of GI bleeding is the greatest in those patients with respiratory failure and coagulopathy. Importantly, patients in the ICU that undergo enteral feedings may fare better than those patients who are maintained without feeding by mouth (NPO).

Stress ulceration results from a combination of reduced blood flow to the gastric mucosa as well as disturbances in acid-base balance. During periods of stress there is constriction of splanchnic blood vessels resulting in local gastric mucosal hypoxia with consequent acidemia. One hypothesis is that cytokines released during periods of respiratory compromise result in the release of catecholamine that occurs in the ICU setting. Stress ulcerations are perhaps the most common manifestation of PUD in the hospitalized patient. Our current thinking is that the release of albeit small levels of gastric acid in these patients, in combination with the release of pepsinogen and bile salt reflux, act as injurious agents to the mucosa that is compromised by hypoperfusion. Increased bleeding occurs in those patients with diminished clotting factors or with platelet dysfunction.

Constipation Prescription

Constipation Prescription

Did you ever think feeling angry and irritable could be a symptom of constipation? A horrible fullness and pressing sharp pains against the bladders can’t help but affect your mood. Sometimes you just want everyone to leave you alone and sleep to escape the pain. It is virtually impossible to be constipated and keep a sunny disposition. Follow the steps in this guide to alleviate constipation and lead a happier healthy life.

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