Assisted Nutrition and Hydration
Parenteral or intravenous feeding is generally considered "more hazardous and more expensive" than enteral feeding. It can be subdivided into peripheral intravenous feeding (using a needle inserted into a peripheral vein) and central intravenous feeding, also known as total parenteral feeding or hyperalimentation (using a larger needle inserted into a central vein near the heart). Peripheral intravenous lines can provide fluids and electrolytes as well as some nutrients; they can maintain fluid balance and prevent dehydration, but cannot provide adequate nutrition in the long term.  Total parenteral feeding can provide a more adequate nutritional balance, but poses significant risks to the patient and may involve costs an order of magnitude higher than other methods of tube feeding. It is no longer considered experimental, and has become "a mainstay for helping critically ill patients to survive acute illnesses where the prognosis had previously been nearly hopeless," but its feasibility for life-long maintenance of patients without a functioning gastrointestinal tract has been questioned.
Because of the limited usefulness of peripheral intravenous feeding and the special burdens of total parenteral feeding--and because few patients so completely lack a digestive system that they must depend on these measures for their sole source of nutrition -- enteral tube feeding is the focus of the current debate over medically assisted nutrition and hydration. Such methods are used when a patient has a functioning digestive system but is unable or unwilling to ingest food orally and/or to swallow. The most common routes for enteral tube feeding are nasogastric (introducing a thin plastic tube through the nasal cavity to reach into the stomach), gastrostomy (surgical insertion of a tube through the abdominal wall into the stomach), and jejunostomy (surgical insertion of a tube through the abdominal wall into the small intestine). These methods are the primary focus of this document.
Each method of enteral tube feeding has potential side-effects. For example, nasogastric tubes must be inserted and monitored carefully so they will not introduce food or fluids into the lungs. They may also irritate sensitive tissues and create discomfort; confused or angry patients may sometimes try to remove them, and efforts to restrain a patient to prevent this can impose additional discomfort and other burdens. On the positive side, insertion of these tubes requires no surgery and only a modicum of training.
Gastrostomy and jejunostomy tubes are better tolerated by many patients in need of long-term feeding. Their most serious physical burdens arise from the fact that their insertion requires surgery using local or general anesthesia, which involves some risk of infection and other complications. Once the surgical procedure is completed, these tubes can often be maintained without serious pain or medical complications, and confused patients do not often attempt to remove them.
42. David Major, M.D., "The Medical Procedures for Providing Food and Water: Indications and Effects," in Lynn (ed.), By No Extraordinary Means (Indiana University Press 1986) (hereinafter "Major"), page 27.
43. Peripheral veins (e.g., those found in the arm or leg) will eventually collapse after a period of intravenous feeding, and will collapse much faster if complex nutrients such as proteins are included in the formula. See U.S. Congress, Office of Technology Assessment, Life-Sustaining Technologies and the Elderly, OTA-BA-306 (Washington, D.C.: U.S. Government Printing Office, July 1987) herinafter "OTA"), pages 283-4.
44. Major, pages 22, 24-5. Also see OTA, pages 284-6.
45. See Major, pages 22, 25-6.
46. Major, page 22; OTA, pages 282-3; Rose Laboratories, Tube Feedings: Clinical Application (1982), pages 28-30.
47. Major, page 22; OTA, page 282. Many ethicists observe that there is no morally significant difference in principle between withdrawing a life-sustaining procedure and failing to initiate it. However, surgically implanting a feeding tube and maintaining it once implantaed may involve a different proportion of benefit to burden, because the transient risks of the intital surgical procedure will not continue or recur during routine maintenance of the tube.