Many of today's experienced clinicians grew up with the belief that clear liquids by mouth are appropriate in the treatment of vomiting and diarrhea. We have recommended a variety of liquids, such as tea, cola syrup from the local soda fountain diluted in water, chicken broth, consommé and apple juice. Thus, when the United Nations International Children's Emergency Fund (UNICEF) adopted the use of oral rehydration therapy (ORT) in a major campaign to treat this leading cause of death in infants and children of developing countries, we tended to say “What else is new?” Moreover, U.S. physicians have often admitted dehydrated infants to the hospital for intravenous therapy with saline and glucose mixtures.
What we missed was what was really new, that is, new back in 1968—the critical discovery, occurring in the early 1960s, of coupled transport of sodium and glucose in a 1:1 molar ratio in the intestine.1
This discovery formed the scientific basis of ORT. In 1968, Hirschhorn and colleagues2
described a “decrease in net stool output in cholera during intestinal perfusion with glucose-containing solutions.”2
In 1985, Santosham and associates3
went a step further, demonstrating the efficacy of oral rehydration in a double-blind comparison of four different solutions. Meanwhile, many clinical trials of carbohydrate and sodium salts mixed in a 1:1.4 ratio (World Health Organization) and a 2:1 ratio (American Academy of Pediatrics) established the safety and efficacy of these mixtures.
However, 30 years later, oral rehydration with appropriate solutions is still not universally used. The reasons may be multiple and include lack of knowledge of the appropriate concentration of sodium, potassium and glucose and, importantly, the proper technique for administration. In developing countries, ORT is administered by giving a teaspoon of solution every few minutes over a period of hours. In the United States, although oral rehydration solutions are readily available, they often fail because thirsty and hungry infants who are given a bottle are likely to consume too much too fast, with swallowed air, and then will promptly vomit. Parents then complain that their child is not able to keep down the fluid. And even if properly instructed, many parents are unwilling to provide oral feeds slowly—to say nothing of nurses and doctors in a busy emergency department or office—when the alternative is 30 minutes of intravenous rehydration.
Despite its attraction, a few arguments for avoiding intravenous therapy in favor of ORT (except in patients with shock) are awareness that the child's thirst protects against overhydration with oral therapy, and ORT is less expensive. Yes, it is counterintuitive to state that a less expensive treatment is more effective than a complicated technology.4
However, here are the words of Charles Carpenter, published in the New England Journal of Medicine
“We physicians all presumably accept the ‘primum non nocere’ principle. On the basis of . . . studies . . . this principle would dictate that oral rehydration be accepted not only as an equal, but perhaps as the superior, means of treating acute diarrheal illnesses in the sophisticated and sanitized medical centers of the Western world as well as in rural Bangladesh.”5
It is now more than 30 years since oral rehydration therapy was first advocated for routine use in the treatment of dehydration caused by acute diarrheal disease. In this issue of AFP
does a good job of reminding us why and how to do it right.