Hallmarks in the history of enteral and parenteral nutrition: from antiquity to the 20th century.

Parenteral nutrition (PN) and enteral nutrition (EN) have a very long history, emerging in the ancient world and developing throughout the common epoch. This history dates back as far as 3500 bc to the ancient Egyptians, Indians, and Chinese. Their medical practices were the first reports of enteral feeding therapy, provided via rectum with enemas of wine, milk, whey, wheat, and barley. Hippocrates and Plato, in ancient Greece, were the first personalities to emphasize the importance of diet on health. In the following centuries, Erasistratus and Herophilus described the first notion of the circulatory system, and Oribasius and Celsus described the role of nutrition and disease. There is a great historical gap between the times of Galen (2nd century), who elaborated on the circulatory system; Ibn Zuhr (12th century), who constructed the first model of PN; and Capivacceus (16th century), who placed the first tube for EN. The 17th-19th centuries showed major developments in modern nutrition elements. Steps toward artificial nutrition began in 1628 with the detailed description of blood circulation by William Harvey; however, most of the advances in enteral and parenteral feeding techniques, solutions, and formulas took place in the 20th century. Over the last decade of the 20th century, research focused on metabolic control, multitude formulas, timing and the combination of EN and PN for intensive care patients.

An essential infusion for an essential organ.

Essential amino acid-based parenteral nutrition (PN) was found to be superior to hypertonic dextrose for patients with acute renal failure in a classical randomized trial that was published in 1973. However, subsequent trials were not able to duplicate this finding when this formulation was compared to hypertonic dextrose or to standard amino acid-based PN. As a result, this intervention has not been recommended in various guidelines for the nutrition support of patients with renal failure. However, all of these trials were relatively small, and none of them compared the intervention to a true control group-namely, patients who were not receiving any artificial nutrition. Because no trials have compared any form of artificial nutrition to no nutrition support in patients with acute renal failure, there really is no basis on which to make any level 1 evidence-based recommendation. Furthermore, a close look at all of the trials suggests that the essential amino acid-based formulation may be superior to the other types of intravenous nutrient supplementation to which it was compared. To determine whether this should be offered to patients with acute renal failure, we need data from one or more large, well-designed and executed, low risk of bias randomized trial(s) comparing essential amino acid-based PN to no nutrition therapy.

Nutrition in critical care.

Critical care has evolved from a prolonged recovery room stay for cardiac surgery patients to a full medical and nursing specialty in the last 5 decades. The ability to feed patients who cannot eat has evolved from impossible to routine clinical practice in the last 4 decades. Nutrition in critically ill patients based on measurement of metabolism has evolved from a research activity to clinical practice in the last 3 decades. The authors have been involved in this evolution and this article discusses past, present, and likely future practices in nutrition in critically ill patients.

Effect of glutamine-supplemented parenteral nutrition on mortality in critically ill patients.

Glutamine is recognized as a critical amino acid involved in immunity, intestinal health, and nitrogen transport between organs. Prior to the pivotal study by Griffiths and colleagues in 1997, no clinical trials had demonstrated a positive effect from glutamine supplementation on improving long-term survival in critically ill intensive care unit patients receiving parenteral nutrition. Subsequent investigations have confirmed these findings, but further data are needed to determine the optimal dose and timing of glutamine as well as the form of glutamine (ie, free vs dipeptide) that produces the most significant improvement in outcome parameters.

Brief history of parenteral and enteral nutrition in the hospital in the USA.

The meteoric rise in parenteral and enteral nutrition was largely a consequence of the development of total parenteral nutrition and chemically defined diets in the late 1960s and early 1970s and the recognition of the extensive prevalence of protein calorie malnutrition associated with disease in this same period. The establishment of Nutrition Support Services (NSS) using the novel, multidisciplinary model of physician, clinical nurse specialist, pharmacist, and dietitian, which, at its peak in the 1990s, approached 550 well-established services in about 10% of the US acute care hospitals, also fostered growth. The American Society of Parenteral and Enteral Nutrition, a multidisciplinary society reflecting the interaction of these specialties, was established in 1976 and grew from less than 1,000 members to nearly 8,000 by 1990. Several developments in the 1990s initially slowed and then stopped this growth. A system of payments, called diagnosis-related groups, put extreme cost constraints on hospital finances which often limited financial support for NSS teams, particularly the physician and nurse specialist members. Furthermore, as the concern for the nutritional status of patients spread to other specialties, critical care physicians, trauma surgeons, gastroenterologists, endocrinologists, and nephrologists often took responsibility for nutrition support in their area of expertise with a dwindling of the model of an internist or general surgeon with special skills in nutrition support playing the key MD role across the specialties. Nutrition support of the hospitalized patient has dramatically improved in the US over the past 35 years, but the loss of major benefits possible and unacceptable risks of invasive nutritional support if not delivered when appropriate, delivered without monitoring by nutrition experts, or employed where inappropriate or ineffective will require continued attention by medical authorities, hospitals, funding agencies, and industry in the future.

Intestinal failure: A new era in clinical management.

Only 50 years ago intestinal failure was considered incompatible with life. Since then, developments in parenteral nutrition, and, more recently, small intestinal transplantation, have provided new therapeutic options with the potential to offer long-term survival with a good quality of life. Current medical and surgical strategies are aimed at enhancing intestinal adaptation, improving absorption to achieve nutritional independence, and minimizing the complications of parenteral nutrition therapy. An integrated, multidisciplinary approach to the management of patients with intestinal failure, closely linked to a transplantation program to facilitate early referral, is recognized as a key factor in optimizing patient outcomes.

Micronutrients in parenteral nutrition: too little or too much? The past, present, and recommendations for the future.

This research workshop in 2009 grew out of a concern in the United States, Europe, and other countries with advanced medicine that it was time to revisit the parenteral requirements for a number of micronutrients. Critical questions sought to be answered included the following: Were there micronutrients not routinely added that should be part of a parenteral nutrition (PN) formula? Were other micronutrients present but in inappropriate amounts? How are various micronutrient requirements altered in the critically or chronically ill?