Intravenous fat preparations are used in the nutrition of those requiring parenteral alimentation. Although parenteral nutrition is recognized as a limited substitute for oral alimentation, and should be used for as short a time as possible, widespread use has resulted in some adverse effects.
Fat has the highest caloric density of any nutrient. In addition, intravenously infused fat emulsions exert negligible osmotic effects. Thus, for a number of years, the possibility of providing calories by the intravenous administration of fat emulsions has been an attractive one. In fact, one of the first attempts at intravenous nutrition was infusion of various nonemulsified oils.1 Approximately 30 years ago, a fat emulsion suitable for intravenous use was developed and used extensively. Although it was efficacious as an intravenous calorie source, it was unstable and the serious, short-term effects of this instability resulted in its withdrawal from the market in the late 1960s.
Subsequently, advances in manufacturing technology allowed preparation of stable fat emulsions, and several such preparations are available today. All currently available emulsions are efficacious calorie sources; moreover, they appear to be extremely stable and have been associated with relatively few adverse effects.2-5 All allow delivery of lipid to patients requiring parenteral nutrition. In fact, they may make it possible to deliver adequate nutrients solely by peripheral vein, thus avoiding in many patients the use of central vein catheters and their associated complications.6 This possibility, plus the possibility of providing linoleic acid and thereby preventing essential fatty acid deficiency, which occurs with fat-free total parenteral nutrition,7,8 has generated considerable enthusiasm for these products.
