The nurse is giving instructions to parents of a 4-month-old infant with tetralogy of Fallot. Important teaching points should include:

Choice A reason: Clear liquids are not the best intervention for acute diarrhea and dehydration in children. Clear liquids are fluids that are transparent or translucent, such as water, broth, tea, or juice. They may provide some hydration, but they do not contain enough electrolytes (sodium, potassium, chloride) to replace the losses from diarrhea. They may also worsen diarrhea by increasing the osmotic load in the gut.

Choice B reason: Absorbents such as kaolin and pectin are not recommended for acute diarrhea and dehydration in children. Absorbents are substances that bind to toxins, bacteria, or water in the gut, and are supposed to reduce the frequency and volume of stools. However, there is no evidence that they are effective or safe for children with diarrhea. They may also interfere with the absorption of other medications or nutrients.

Choice C reason: Oral rehydration solution (ORS) is the preferred intervention for acute diarrhea and dehydration in children. ORS is a specially formulated solution that contains water, glucose, and electrolytes in the right proportions to replenish the losses from diarrhea. ORS can prevent or treat dehydration, and can also reduce the duration and severity of diarrhea. ORS is widely available, inexpensive, and easy to use. It should be given to children with diarrhea as soon as possible, and continued until the diarrhea stops.

Choice D reason: Antidiarrheal medications are not advised for acute diarrhea and dehydration in children. Antidiarrheal medications are drugs that slow down the movement of the gut, reduce the secretion of fluids, or kill the bacteria that cause diarrhea. However, they are not effective for viral diarrhea, which is the most common cause of diarrhea in children. They may also have serious side effects, such as constipation, abdominal pain, drowsiness, or allergic reactions. They may also mask the symptoms of more serious conditions, such as appendicitis or bowel obstruction.

Choice A reason: Mechanical ventilation does not necessarily increase the fluid requirements of a child. Mechanical ventilation is a method of providing artificial breathing support to a child who has respiratory failure or insufficiency. Mechanical ventilation may affect the fluid balance of a child by altering the insensible losses, the renal function, or the hemodynamics. However, the net effect may vary depending on the type, mode, and settings of the ventilator, as well as the underlying condition of the child. Therefore, the fluid requirements of a child on mechanical ventilation should be individualized and monitored closely¹.

Choice B reason: Increased intracranial pressure (ICP) does not increase the fluid requirements of a child. Increased ICP is a condition in which the pressure inside the skull is higher than normal, due to various causes such as head injury, brain tumor, infection, or hydrocephalus. Increased ICP may affect the fluid balance of a child by impairing the cerebral blood flow, the cerebrospinal fluid drainage, or the hypothalamic-pituitary axis. However, the net effect may vary depending on the severity, duration, and cause of the increased ICP, as well as the presence of other complications such as cerebral edema or diabetes insipidus. Therefore, the fluid requirements of a child with increased ICP should be individualized and monitored closely².

Choice C reason: Congestive heart failure does not increase the fluid requirements of a child. Congestive heart failure is a condition in which the heart is unable to pump enough blood to meet the body's needs, due to various causes such as congenital heart defects, cardiomyopathy, or infection. Congestive heart failure may affect the fluid balance of a child by causing fluid retention, edema, or pulmonary congestion. However, the net effect may vary depending on the type, severity, and stage of the heart failure, as well as the presence of other complications such as renal failure or liver failure. Therefore, the fluid requirements of a child with congestive heart failure should be individualized and monitored closely³.

Choice D reason: Fever increases the fluid requirements of a child. Fever is a condition in which the body temperature is higher than normal, due to various causes such as infection, inflammation, or immunization. Fever increases the fluid requirements of a child by increasing the metabolic rate, the insensible losses, and the urine output. The amount of fluid loss due to fever depends on the degree and duration of the fever, as well as the ambient temperature and humidity. A general rule of thumb is that for every degree Celsius increase in body temperature, the fluid requirements increase by 10%⁴. Therefore, the fluid requirements of a child with fever should be adjusted and monitored closely.