How long can the saline solution be kept after it is opened

Physiological saline can be stored for a period of time after opening, but it should be used up as soon as possible to achieve the best effect. If it is left for too long, the saline may become ineffective. Also, it should be noted that it should be stored at room temperature. This substance does not need to be stored in the refrigerator, so that the cells in it can remain in a normal state.

Physiological saline refers to a sodium chloride solution commonly used in physiological experiments or clinical practice, whose osmotic pressure is basically equal to the osmotic pressure of animal or human plasma. Concentration: 0.67-0.70% for amphibians and 0.85-0.9% for mammals and humans. The concentration of sodium chloride injection that people usually use for intravenous drips (hanging injections) is 0.9%, and it can be used as normal saline.

Its osmotic pressure is similar to that of human blood, and its sodium content is also similar to that of plasma, but its chloride content is significantly higher than that in plasma. Therefore, normal saline is only relatively physiological, and its purpose is to supply electrolytes and maintain the tension of body fluids. It can also be used externally, such as cleaning wounds or changing dressings. 0.9% sodium chloride solution (i.e. normal saline) can maintain the normal morphology of cells

(1) Excessive secretion of mineralocorticoids: When there is an excess of primary mineralocorticoids, it can increase the reabsorption of Na+ and H2O by the distal convoluted tubules and collecting ducts of the kidneys, and promote the excretion of K+ and H+. Therefore, excessive aldosterone can lead to increased renal loss of H+ and reabsorption of NaHCO3, causing metabolic alkali poisoning and hypokalemia. At this time, supplementation with normal saline cannot correct the condition, so it is called "chloride-unresponsive alkali poisoning."

(2) Potassium deficiency: Potassium deficiency in the body can cause metabolic alkali poisoning. This is because in hypokalemia, the extracellular fluid K+ concentration decreases, the intracellular K+ transfers to the extracellular space, and the H+ in the extracellular fluid moves into the cells; at the same time, the lack of K+ in the renal tubular epithelial cells can lead to increased H+ excretion, thereby increasing the H+-Na+ exchange and HCO3- reabsorption, thus causing metabolic alkali poisoning. At this time, the patient's urine is still acidic, which is called paradoxical acid urine. Potassium salt supplementation is required during treatment; sodium chloride solution alone cannot correct this type of metabolic alkali poisoning.

(3) Excessive intake of alkaline substances: This is seen in patients with ulcer disease who take excessive amounts of NaHCO3 for a long time. This type of drug is rarely used to treat peptic ulcers, so alkali poisoning caused by this reason is less common. Transfusion of large amounts of sodium bicarbonate and stored blood can cause iatrogenic metabolic alkali poisoning because the citrate anticoagulant in the transfused blood can produce excessive HCO3- through metabolism.