What are the basic principles of clinical fluid replacement?

The basic principle of clinical fluid replacement is to administer colloid before crystalloid and fast before slow, aiming for less rather than more. During clinical fluid replacement, it is necessary to identify the cause of dehydration for treatment, as only by finding the cause can treatment be more targeted. A rough calculation of fluid replacement volume is to add 500ml to the urine volume. It is important to control the speed and total amount of fluid replacement to avoid adverse reactions.

1. Administer colloid before crystalloid: Colloid solutions have a larger molecular weight and a more durable volume expansion effect compared to crystalloid solutions. After metabolism in the body, the sugar content of sugar solutions becomes hypotonic, and their volume expansion effect is relatively weakened.

2. Administer fast before slow: To correct fluid imbalance in a timely manner, the infusion rate should be fast initially and gradually slowed down after stabilization. However, adjustments should be made based on factors such as the patient's condition, age, cardiopulmonary function, etc.

3. Administer less rather than more: Fluid replacement usually starts with replenishing lost fluids, followed by continuing to replenish water until water, electrolyte, and acid-base imbalances are completely corrected. Potassium should only be supplemented when urine is present. If there is no urine, potassium should not be administered, as it can lead to elevated potassium levels, malignant arrhythmias, or even cardiac arrest. For patients with long-term water loss, low potassium, and low sodium, the amount of water needed should be increased based on their daily water intake. This can be gradually replenished over 2-3 days. The speed and volume of fluid infusion should be controlled for the elderly and children to avoid infusion reactions.