Critical illness and cholesterol levels

Cholesterol is an essential component of animal cell membranes. During the day, 250–500 mg of cholesterol are absorbed continuously from normal food. In a healthy person, maximum cholesterol synthesis ranges between 0.5 and 1 g per day, often occurring at night, between 2:00 and 3:00 a.m. Hypocholesterolemia is a phenomenon that can be observed especially in severe acute conditions. Epidemiological and interventional studies indicate that cholesterol optimal level is restricted to 4.5–5.0 mmol/L; further, the associated normal plasma LDL cholesterol level has been estimated in 2.5–3.0 mmol/L. The accompanying acute inflammatory process produces hypocholesterolemia on a regular basis; therefore, cholesterol can be seen as a “negative reactant” of the acute inflammatory process. Severe depletion of serum cholesterol and LDL cholesterol manifests cortisol deficiency under stress. High mortality rate was observed when the concentration of plasma cholesterol was less than 1.50 mmol/L, or less 40% than their presurgery or pretrauma level, persisting in this manner for more than 6 days.