The principles behind why liquids in an infusion sling drip at an even rate involve principles of physics and device design. First, the structure of the bottom of the bottle is crucial. Liquid flows out through one tube while another tube allows air to enter the bottle. As the liquid flows out, the air pressure inside the bottle drops, and the external atmospheric pressure presses air into the bottle, keeping the air pressure above the liquid level in the bottle slightly below atmospheric pressure. This acts as an automatic balancing system that keeps the liquid flow rate stable.
The Murphy's dropper is the key regulating element that keeps the infusion pressure stable by regulating the rate at which the drug is dripped. The medication must be left below the dropper to maintain a constant infusion pressure, which ensures a uniform fluid drip rate. The infusion process utilizes fluid hydrostatic pressure, which means that the fluid is subjected to atmospheric pressure and forms a column of water that flows into the blood vessels, and the fluid flows smoothly only when the column pressure exceeds the venous pressure.
In practice, skill is needed in how to control the drip rate and change fluids. Infusion rate should be adjusted according to the nature of the drug and therapeutic needs, to avoid excessive drip rate due to changes in the patient's position or personal needs leading to adverse reactions. When changing fluids, air needs to be expelled first to prevent the drug from decreasing or air from entering the vein. When removing the needle, it should be done when the liquid in the drip pot has finished dripping and the level of the infusion tube has steadily decreased to minimize damage to the blood vessel and the potential risk of thrombosis.
In short, the uniform drip of liquid in the infusion sling is achieved through the cooperation of precise physics and medical equipment to ensure the stable flow of liquid under pressure balance, and at the same time, it requires healthcare workers to have professional operation skills to ensure the safety of the patients and the therapeutic effect.