Hi,
Intravenous fluids play an important role in the management of many patients, especially if they are (1) dehydrated or not drinking well; (2) losing bodily fluids rapidly, eg through vomiting, diarrhoea, high fever or certain kidney diseases or other medical problems; (3) should be fasting and told not to drink because going for surgery; (4) when need certain fluids to correct salt imbalances in the body; or (5) to administer certain medicines intravenously.
Thus, intravenous fluids can contribute to the improvement of patient's condition. They even can save lives in cases of bleeding, shock or burns.
However, one of their side-effects is causing overload to the body of both water and salts, and this occurs unevenly. This can be experienced by the patient as swelling of the legs and other parts of the body, increment in blood pressure, and even causing flooding of the lungs with water, making them feel breathless and even putting at risk their life triggering an episode of lung failure or heart failure.
Even with the cautious and judicious use of intravenous fluids, these problems can occur. The administered intravenous fluids and salts do not distribute evenly in the body, or where the doctor thinks your body needs it. It is also difficult to calculate the right amount of fluids and salts your body need, although doctors always do their best. And importantly, different patients will handle the administered fluids and salts differently and will eliminate them in different speeds and fashions. The kidneys will be the main responsible organs to eliminate the excess of water and salts. Thus, patients suffering from medical problems affecting the kidneys, or other related organs like the heart and liver, are more susceptible to suffer severe fluid retention or salt imbalances. Some medicines can also affect the way the body can eliminate the excess of fluids. Certain groups of patients like the debilitated, the elderly or children need more careful intravenous fluid administration.
Thus, it is very difficult to answer the question, as it depends on the condition of the patient, the amount and type of intravenous fluids given, how well his or her kidneys work to eliminate the excess of fluids and how much water or other drinks the patient is drinking. So, it could take from hours to few days. But some patients with the conditions mentioned above would have more difficulties in eliminating the excess of fluids and even will need water tablets (diuretics) to pass more urine to help them eliminate the excess of water. Some patients even require dialysis to remove the excess of water; especially if they have kidney problems or if the fluid overload is severe.
Dr Francisco, wishing you the best possible health.
