Basic principles of intravenous infusion
Intravenous infusion is to use the physical principles of hydrostatic pressure and atmospheric pressure to inject liquid into human veins. The infusion bottle is a glass bottle with an inlet connected to the atmosphere and connected to a rubber tube. The liquid in the bottle is subjected to atmospheric pressure, causing the liquid to flow into the rubber tube to form a water column. When the pressure of the water column is greater than the venous pressure, the liquid in the bottle flows into the vein smoothly.
The three conditions that must be met are:
1. The liquid bottle has a certain height to form sufficient water column pressure;
2. The upper surface of the liquid must be open to the atmosphere (except for the liquid soft packaging bag) so that the liquid surface is affected by atmospheric pressure; the infusion pipeline is unobstructed, must not be twisted or compressed, the needle must not be blocked, and ensure that it is in the venous lumen.
3. Water column pressure. Under normal circumstances, the venous pressure is greater than atmospheric pressure. The solution bottle should be hung at a height of about 50~60cm from the puncture site to form a certain water column pressure so that the water column pressure is greater than the venous pressure, and the infusion solution flows smoothly into the patient’s blood vessel.
Advantages of intravenous infusion:
1. It is easy to reach the therapeutic concentration of the drug, and can maintain the constant concentration required for the therapeutic effect.
2. Drugs that stimulate muscles and subcutaneous tissues can be administered intravenously.
3. It can quickly replenish the fluid or blood lost by the body.
Disadvantages of intravenous infusion:
1. Improper handling may cause systemic or local infections.
2. Overdose or rapid infusion of the drug can easily cause adverse reactions and even life-threatening.
3. Continuous over-infusion can easily cause excessive circulating load or electrolyte imbalance.
4. The increase of iatrogenic diseases.