How long is the shelf life of saline solution

Normal saline solution is something we use frequently in our daily life. Generally, the shelf life of unopened normal saline solution is about two years, and generally at least one year. The dates of normal saline solutions sold in pharmacies are basically relatively new, so if it is unopened normal saline solution, it can be stored for a long time. If it is opened, it is best to use it up within a week.

Precautions for using normal saline

1. Use normal saline for debridement; if using chlorhexidine or iodine preparations, please rinse well with normal saline.

2. Because the hydrogel contained in U-Tuo SSD/U-Tuo will adhere to rubber, it is recommended to soak the surgical gloves or dressing tweezers with saline when changing the dressing to avoid this situation.

3. Cover the wound directly with Utop SSD or Utop. It can be cut according to the condition of the wound. The edge should extend 3 cm beyond the outer edge of the wound to protect the surrounding vulnerable skin. Do not fold for use.

4. Use gauze or cotton pad as secondary dressing and self-adhesive elastic bandage Nalecon for pressure bandage.

Generally, 0.9% NaCl or 5% glucose solution is used for infusion. When you have a fever, the body loses more water, so you need to replenish water and electrolytes. As for why it is 0.9%, it is because only NaCl at this concentration is an isotonic solution and does not harm human cells. As for why saline is sometimes used and sugar water is sometimes used, there are many factors. The main consideration for outpatient infusion is the drug issue. Some drugs can only use saline as a carrier. They will precipitate or their efficacy will be reduced or become ineffective in sugar water. After strenuous exercise, you should drink appropriate amounts of saline to replenish the energy lost by excessive sweating. (Today's science knows that sweating can also excrete toxic substances from the body. Therefore, normal sweating is a good thing.)

Physiological saline can prevent cell rupture, and its osmotic pressure is the same as that outside the cells, so it will not cause cells to become dehydrated or absorb excessive water. Therefore, it is used in many medical operations where liquids are needed. It is the concentration of the liquid environment in which human cells live. In order to correct dehydration and acidosis, different liquids are often mixed in proportion and used clinically. Why can't a single saline solution or 5% or 10% GS solution be used to correct dehydration and acidosis? This is because severe diarrhea in infants and young children, in addition to the loss of sodium bicarbonate and resulting in metabolic acidosis, also causes malnutrition (the so-called "starvation") ketoacidosis and a large loss of electrolytes and water. Therefore, a mixed solution is needed that can replenish electrolytes, correct acidosis, overcome ketosis, and replenish water and calories. The use of normal saline or 5% to 10% glucose solution alone cannot meet the above pathophysiological requirements. If normal saline is used alone for infusion, when sodium chloride has been replenished but dehydration has not been replenished, continuing to use normal saline will cause salt diuresis, and in severe cases, salt poisoning may occur. When only 5% to 10% GS is used for infusion, it will cause an extracellular hypotonic state, thereby reducing the secretion of antidiuretic hormone, causing diuresis. In severe cases, water intoxication may occur, causing neurological symptoms. The clinical manifestation is that the more fluid is replaced, the more urine is produced. This is the reason. However, since adults have sound liver and kidney functions, dehydrated patients can use the mixed solution as well as alternating intravenous injection of normal saline and 5% or 10% GS solution, that is, transfuse a 500ml bottle of normal saline and then a 500ml bottle of GS solution. When correcting acidosis, add alkaline solution into the GS solution bottle and drip it.

Normal saline solution is generally used to treat rhinitis only for atrophic rhinitis. According to the efficacy of normal saline, metabolic alkali poisoning is divided into two categories: metabolic alkali poisoning that is effectively treated with normal saline and metabolic alkali poisoning that is not effectively treated with normal saline.

Effective treatment of metabolic alkali poisoning with normal saline

(1) Excessive loss of H+ in the gastrointestinal tract: This is common in cases where severe vomiting and gastrointestinal drainage caused by pyloric obstruction, high intestinal obstruction, etc. lead to the loss of a large amount of gastric juice containing HCl. At this time, the HCO3- in the intestinal fluid cannot be neutralized with HCl as normally, but is absorbed in large quantities by the small intestinal mucosa, causing the plasma HCO3- concentration to increase, causing metabolic alkali poisoning. The loss of gastric juice is often accompanied by the loss of Cl- and K+, which can cause hypochloremia and hypokalemia, the latter two of which can aggravate or promote the occurrence of metabolic alkali poisoning.

(2) Hypochloric alkali poisoning: A large loss of chlorine and insufficient chlorine intake can lead to hypochloric alkali poisoning, which is common in patients who use diuretics for a long time. Diuretics such as furosemide (Lasix) and ethacrynic acid (ethacrynic acid) can inhibit the reabsorption of Na+ and Cl- by the proximal tubule, thereby increasing the excretion of Na+ and Cl- and exerting a diuretic effect. Due to the decrease in Na+ reabsorption in the proximal tubule, the Na+ concentration in the distal convoluted tubule increases, leading to enhanced H+-Na+ exchange. As H+-Na+ exchange is enhanced, the reabsorption of HCO3- by the renal tubules increases accordingly. The plasma HCO3- concentration increases, while the excretion of C1- in the urine in the form of NH4Cl increases, resulting in hypochloric alkali poisoning. In addition, the large amount of gastric juice loss mentioned above may also cause hypochlorite alkali poisoning. Hypochloric alkali poisoning can be corrected by supplementing with normal saline, so it is also called "chlorine-responsive alkali poisoning."

Metabolic alkali poisoning that is not responsive to saline

(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 saline solution cannot correct the problem.

So it is called "alkali poisoning unresponsive to chlorine".

(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.