Final answer:
The 421 rule is a guideline for estimating intravenous fluid administration rates. In cases of dehydration, an ordinary NaCl solution or a mixture of isotonic saline and Na lactate can be used intravenously to replace fluids and electrolytes.
Step-by-step explanation:
The 421 rule for adult fluid replacement is a medical guideline used to estimate the initial rate of intravenous fluid administration in adults who need to be rehydrated, typically in a hospital setting. This guideline, however, is not specifically about the treatment of dehydration but relates to the preoperative fasting period in which patients are required to abstain from oral intake prior to surgery to prevent aspiration. The guideline is as follows: for each kilogram of body weight, 4 mL for the first 10 kg, 2 mL for the next 10 kg, and 1 mL for each additional kilogram should be administered over the course of one hour.
When a human patient is dehydrated and needs to be given fluids intravenously, the typical treatment involves administering an ordinary NaCl solution parenterally to repair the losses. In cases where the excretion of fluid is high in Na and HCO3, resulting in significant fluid and electrolyte loss, a mixture of 2/3 isotonic saline and 1/3 Na lactate is recommended for intravenous administration.
Such fluid replacement strategies ensure that patients receive the essential electrolytes and fluids necessary to maintain or restore proper physiological function. Proper correction of dehydration is essential in many medical treatments and recovery processes.