The difference between saline and alcohol

Saline solution and alcohol are things we use frequently in our daily lives, but many people think that saline solution and alcohol are the same substance. In fact, there is a difference between saline solution and alcohol. Just from the appearance, alcohol can be ignited and has an odor. Alcohol is generally suitable for sterilization and disinfection, but saline solution has no antibacterial and anti-inflammatory effects. Therefore, you must distinguish them when using them.

Effect of saline solution

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

1. Avoid cell rupture

The osmotic pressure of normal saline is the same as that outside the cells, so the cells will not be dehydrated or ruptured due to excessive water absorption.

2. Clean the wound

Normal saline is actually low-concentration saline, which is often used to clean wounds and replenish blood volume.

3. Correct acidosis

The method of alternating intravenous injection of normal saline and 5% or 10% GS solution can replenish electrolytes, correct acidosis, overcome ketosis, and replenish water and calories.

4. Maintain the tension of body fluids

Physiological saline can supply electrolytes and maintain the tension of body fluids. It can be used for fluid replacement and other medical purposes. It is also often used for in vitro culture of living tissues and cells.

The medicinal value of saline

Normal saline is generally only used to treat 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.

1. Saline is effective in treating metabolic alkali poisoning

(1) Excessive loss of H+ in the gastrointestinal tract

We often see that gastrointestinal drainage caused by some diseases such as high intestinal obstruction can lead to the loss of a large amount of gastric juice containing HCl.

(2) Hypochlorite alkali poisoning

Large-scale loss of chlorine and insufficient chlorine intake can lead to hypochloremic 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.

2. Metabolic alkali poisoning that is not responsive to saline treatment

(1) Excessive secretion of mineralocorticoids

When there is an excess of primary mineralocorticoids, the reabsorption of Na+ and H2O by the distal convoluted tubules and collecting ducts of the kidneys is increased, and the excretion of K+ and H+ is promoted.

Therefore, excessive aldosterone leads 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, and the patient's urine remains acidic, which is called paradoxical aciduria. 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

It is common for patients with ulcer disease to take too much 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.