Methods of Enteral Nutrition Administration in Critically Ill Patients: Continuous, Cyclic, Intermittent, and Bolus Feeding.

There are several methods of enteral nutrition (EN) administration, including continuous, cyclic, intermittent, and bolus techniques, which can be used either alone or in combination. Continuous feeding involves hourly administration of EN over 24 hours assisted by a feeding pump; cyclic feeding involves administration of EN over a time period of <24 hours generally assisted by a feeding pump; intermittent feeding involves administration of EN over 20-60 minutes every 4-6 hours via pump assist or gravity assist; and bolus feeding involves administration of EN over a 4- to 10-minute period using a syringe or gravity drip. In practice, pump-assisted continuous feeding is generally acceptable for critically ill patients to prevent EN-related complications. However, a limited number of studies have been conducted to support this practice. In addition, regarding muscle protein synthesis and gastrointestinal hormone secretion, intermittent or bolus feeding may be more beneficial than continuous EN feeding for critically ill patients. For medically stable patients with feeding tubes terminating in the stomach, bolus feeding is favored with respect to practical factors, such as cost, convenience, and patient mobility. However, few studies have shown whether intermittent or bolus feeding is beneficial in a critical care setting at present. Additional randomized controlled studies comparing intermittent with bolus feeding are required.