Decreased peristalsis- immobility causes gastrointestinal disturbances such as decreased appetite and slowing of peristalsis. in the immobilized client, decreased circulating fluid volume, pooling of blood in the lower extremities, and decreased autonomic response occur. these factors result in decreased venous return, followed by a decrease in cardiac output, which is reflected by a decline in blood pressure. recumbency increases cardiac workload and results in an increased pulse rate. fluid intake can diminish with immobility, and this combined with other causes, such as fever, increases the risk for dehydration. urinary output may decline on or about the fifth or sixth day after immobilization, and the urine is often highly concentrated.