Nurse! Come quickly! There are bubbles entering the infusion!

Audit expert: Qu Bo

Chief Physician of General Surgery, Yangtze River Shipping General Hospital

Cold, fever, diarrhea, dehydration... no matter what the reason is, you have probably received an IV drip in a hospital or clinic.

There is one thing that almost everyone has in common when it comes to intravenous drips. When they are getting an IV drip, they will involuntarily look up from time to time to observe the level of the liquid in the infusion bottle, always wondering if there is air mixed in the infusion tube? Or are they worried that a bubble will accidentally flow into their body through the infusion tube?

Source: Internet photo/Sohu News

Air will not enter the human body through infusion

Generally speaking, the pressure inside human blood vessels is higher than the external atmospheric pressure . Due to the existence of this pressure, even after the infusion of medicine is completed, air will not easily enter the blood vessels through the infusion needle.

Generally speaking, the blood in the blood vessels will flow outward into the infusion tube , which is also called blood return . However, a small amount of blood return after infusion will not affect the body if it is handled promptly by medical staff.

Infusion bag source: Wikipedia

In addition, current infusion tubes are also equipped with air and impurity filters, which are flat disc-shaped structures at the bottom of the infusion tubes. Generally, the filter element inside can be seen through the transparent shell. Therefore, there is no need to worry about bubbles entering the human body with the infusion.

If air is introduced, it is indeed dangerous.

How much volume of air does it take for a person to be life-threatening? The data is generally controversial, but generally speaking, 200-300 ml of intravenous air can be fatal! However, to reach this amount, an ordinary syringe is not enough, at least an air pump is needed to inject it.

Generally speaking, a dose of 20 ml of air will cause air embolism, which may cause serious damage to the body. In 1949, Hermann Sander, a doctor in New Hampshire, USA, euthanized a terminally ill cancer patient by injecting 40 ml of air, ending the patient's life. However, some people have survived with larger doses. In 2006, a French doctor reported that an 82-year-old man was injected with 90 ml of air instead of 90 ml of contrast agent during a CT scan. Fortunately, he was saved by pure oxygen therapy in time.

The capacity of a common larger syringe is generally around 10 ml. Source: Wikipedia/Jkgroove

In the case of air entering the body, it is necessary to distinguish between large and small bubbles, and different bubbles will cause different damage. Small bubbles can block capillaries, causing pain at the least and nerve damage or even paralysis at the most. A small bubble obstructs blood flow in the same way as a solid obstruction: the surface tension of the bubble exists, and the force of the blood cannot break it up or push it. If the injected air remains in the venous circulation, symptoms may range from no symptoms to cardiopulmonary failure caused by right ventricular infarction. In symptomatic air embolism, hypoxemia and hypotension are common, as well as inflammatory changes in the lungs that increase airway resistance.

On the other hand, large bubbles can cause air embolism (air embolism refers to the phenomenon that when liquid flows in a capillary tube, if there are bubbles mixed in the liquid in the tube, the flow of the liquid will be hindered. When the number of bubbles is too large, the tube may be blocked, making it impossible for the liquid to flow).

Air embolism under CT Image source: Wikipedia/Cerevisae

The human heart is like an old car fuel pump. Normally, the heart contracts to squeeze blood through the circulatory system. If a large air embolism forms somewhere in the body, the heart starts to squeeze it. The air just keeps compressing but doesn't move , so the blood stops flowing and eventually the heart stops beating.

Source: News Photo/Sohu News

The consequences vary depending on where the bubbles enter. Embolism from an injection or IV is usually confined to a vein, but if bubbles enter an artery, they can block blood supply to the coronary arteries or the brain, and a blockage in the coronary arteries can mean death.

I don’t know how to give an infusion, so what if I inject air into the body?

Under normal procedures, safe and complete medical procedures and preventive measures can prevent this from happening. If it does occur, air embolism is not an untreatable disease.

So what if air is accidentally injected during the injection process and air embolism forms in the blood vessels?

Although it is rare to accidentally inject air into a vein during an injection, it can cause serious complications. If air has entered the bloodstream, the best thing to do is to seek professional medical attention.

1. Call emergency services as soon as possible: An embolism looks a lot like a heart attack or stroke, and the consequences are just as serious. Emergency services should be called as soon as possible for medical intervention.

Source: wikihow.com/Treat-an-Air-Embolism

2. Position: If an arterial embolism is suspected, the patient should be kept horizontal. Shortness of breath, chest pain, dizziness, confusion/loss of consciousness are signs of an arterial embolism. To prevent bubbles from migrating to the brain, the patient should lie flat.

Source: wikihow.com/Treat-an-Air-Embolism

If venous embolism is suspected, the patient's feet should be elevated. Venous embolism is particularly common in the lower extremities and symptoms may be similar to those of a blood clot, including swelling, firmness, and redness. If these symptoms are noted along with other air embolism symptoms, position the patient so that they lie on their left side with their feet 15-30 degrees above their head.

Source: wikihow.com/Treat-an-Air-Embolism

3. Oxygen inhalation: If a large amount of air is accidentally injected and air embolism is caused, the patient will experience difficulty breathing. At this time, the patient should promptly follow the doctor's instructions for high-flow oxygen inhalation to increase the blood oxygen concentration and correct the hypoxic state.

4. Other treatment methods: For patients who have the conditions, a central venous catheter can be inserted under the operation of a professional doctor to extract the air injected into the body. At the same time, family members should closely observe the patient's condition and inform the doctor in time if there is any abnormality.

Having said so much, the conclusion is actually very simple: when the drip is being administered, the pressure in the human blood vessels is higher than the outside atmospheric pressure, so air will not easily enter the human body. And if an accident causes air to enter the human body, it is an extremely rare event, so there is no need to worry about the childhood shadow of "air entering the blood vessels after the drip is finished" .