Hydrocolloids, such as karaya compounds, offer the primary advantage of increased absorptive ability
Although the simplest dressing of gauze and tape combined with the use of antibacterial ointment can achieve moist wound healing for most patients, a multitude of other products are available. These products can be classified into films, foams, hydrocolloids, hydrogels, and absorptive powders. Films are semipermeable to water, generally made of polyurethane, and nonabsorptive. They are useful to achieve a moist wound-healing environment over a minimally exudative wound such as split-thickness skin graft donor sites. The hydrocolloids deserve special mention because they have achieved widespread use. These agents contain hydrophilic materials such as karaya or carboxymethyl cellulose with an adhesive material and are covered by a semipermeable polyurethane film. The material adheres to the skin surrounding the wound, is highly absorptive, and achieves a moist healing environment. Impregnates are generally fine-mesh gauze impregnated with moisturizing, antibacterial, or bactericidal compounds. They are generally not adherent and require a secondary dressing. They promote reepithelialization and have an anti-infective effect when combined with antibacterial or bactericidal agents. The variety of absorptive powders and pastes consist of starch copolymers or colloidal hydrophilic particles. These agents have high absorbency for tissue wound fluid and débride necrotic and fibrous material from a wound.
Hypovolemic shock secondary to hemorrhage has been classified based on the volume of blood lost. With loss of 20% to 30% of blood volume, physical findings include hypotension, tachycardia, narrow pulse pressure, poor capillary refill, and increasing anxiety. The clinical definition of cardiogenic shock is decreased cardiac output with tissue hypoperfusion, despite the presence of adequate intravascular volume. Cardiogenic shock is caused by a primary problem with the cardiac muscle, electrical conduction system, or valves. The most common cause is anterior wall myocardial infarction, although in surgical patients it is often precipitated by pulmonary embolus, myocardial contusion, or pulmonary hypertension. Early septic shock is distinguished by peripheral vasodilation, flushed and warm extremities, and a compensatory elevation in cardiac output. Neurogenic shock is defined as failure of the nervous system to provide effective peripheral vascular resistance, resulting in inadequate end-organ perfusion. Warm, flushed, flaccid extremities; paraplegia; confusion; oliguria; and hypotension are the classic clinical findings. Injury to the spinal cord, with interruption of the autonomic sympathetic vasomotor pathways, disrupts basal vasoconstrictor tone to peripheral veins and arterioles. Profound vasodilation of all microvascular beds below the level of cord injury diminishes venous return to the heart, reduces cardiac output, and precipitates hypotension. Signs and symptoms of diverticulitis include fever, tachycardia, leukocytosis with left shift of the differential count, abdominal pain, and a tender lower abdominal mass. Most patients with an acute episode of diverticulitis can be treated with intravenous fluids, bowel rest, broad-spectrum antibiotics, and analgesics. If the patient's condition does not improve within 48 hours, complications of diverticulitis may exist, and further investigation is necessary. Only approximately 20% of patients have complications of diverticulitis with their first episode. This percentage increases to 60% with recurrent episodes. Although water-soluble contrast enema radiography can provide the diagnosis of diverticulitis, CT has become the preferred diagnostic test for patients who do not improve within 48 hours. CT is especially useful in delineating the complications of diverticulitis, including perforation and abscess formation. At CT, percutaneous drainage catheters can be placed if an abscess is identified. After CT drainage of an abscess, 50% to 90% of patients can undergo successful one-stage segmental colectomy and primary anastomosis. If percutaneous drainage is not feasible or an abscess is not identified, surgical intervention is recommended. There are more than 100,000 species of hymenoptera. More envenomations and more deaths, approximately twice as many as that from snakebites, occur in the United States annually. The venom is primary hemolysin and neurotoxin, known for triggering anaphylactic reactions. Most deaths from hymenoptera stings are a result of severe anaphylactic reaction. Africanized bees are a more aggressive subspecies of native European bees. Currently located primary in the southwestern United States, these bees pose a significant threat because massive envenomations (>50 stings) have occurred, resulting in nausea, vomiting, shock, hemolysis, rhabdomyolysis, disseminated intravascular coagulopathy, coma, and renal failure. Although there are more than 650 types of scorpions worldwide, most are not lethal. If a fatal response occurs, it is the result of sympathetic storm with hypertension, tachycardia, and high-output cardiac failure.