Introduction
Blood is an important fluid that circulates throughout the body and is carried through blood vessels which are tube-like structures. These vessels may be damaged due to accidental injuries resulting in leaks or blood loss. Any injury to the blood vessel causes serious complications if left untreated and may sometimes be life-threatening. A proper understanding of these injuries and their subsequent consequences helps to take necessary measures to treat them.
What Are Blood Vessels?
Blood is a bodily fluid carried through blood vessels. The blood vessels are tube-like structures that help to transport and circulate blood throughout the body. It carries oxygen to various cells and tissues for energy and releases carbon dioxide for purification. The varying types of blood vessels are listed below:
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Arteries.
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Veins.
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Capillaries.
What Are Arteries?
Arteries are blood vessels that distribute oxygen throughout the body. They are tube-like structures thick-walled to withstand the pressure exerted by the heart while pumping out blood. The walls of the arteries are made up of muscles and elastic fibres, which help them stretch under pressure and have a narrow lumen (opening). The blood is transported from the heart to other organs via the arteries and branches out or diverges to form smaller arteries which are the arterioles.
Generally, arteries are deep-seated in the body and do not have valves. Hence they do not collapse in the absence of blood. All arteries except the pulmonary artery carry oxygenated blood.
What Are Veins?
The deoxygenated blood, which lacks oxygen, is carried by the vein toward the heart to add oxygen. The veins are also tube-like structures but are thin-walled as the pressure exerted is lesser in veins. The walls of the veins are made of lesser elastic tissue and have larger lumen. Larger veins branch out to form smaller veins called venules. The veins are superficial and are found near the skin. They have valves that prevent backflow and help to direct the flow of deoxygenated blood. The veins collapse in the absence of blood. Except for the pulmonary vein, all other veins carry deoxygenated blood.
What Are Capillaries?
Capillaries connect blood vessels between the arteries and veins. They are not made up of muscles or valves. Capillaries act as a medium of exchange of oxygen and nutrients with carbon dioxide and waste products.
How Does Blood Travel Through the Vessels?
The heart is a vital organ that pushes blood to other body parts by acting as a pump. As the heart contracts, it forces blood into larger arteries. The blood then flows into smaller arteries and reaches the arterioles. These arterioles feed into the capillaries present in the organs and tissues.
The blood drains from the capillaries into the smaller veins, the venules, and reaches larger veins that ultimately empty blood into the heart.
What Are Arterial and Venous Injuries?
Any trauma or blow that occurs in the artery and vein is called arterial and venous injury, respectively. The arterial and venous injuries are collectively called vascular injuries.
The most common causes of vascular injuries are road traffic accidents (RTA), blunt trauma, and accidental injuries at sports, work, or home. Occasionally vascular injuries may also occur due to trauma caused by sharp objects or stab wounds.
How to Differentiate Arterial and Venous Injury?
Arterial injuries can be identified by the colour of blood from the injured site. They tend to appear bright red due to the oxygen content. When pressure is applied to the artery, it tends to spurt (a sudden gushing stream) because of the high pressure exerted by the blood in the arterial walls. Other ways to identify arterial bleeding are listed below:
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Pulsatile haemorrhage (bleeding shoots out with each heartbeat).
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Rapidly developing hematoma (clots).
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Signs of distal ischemia (lack of blood supply to the arms and legs).
Venous injury is usually identified as dark red bleeding from the veins as they contain carbon dioxide and have a steady blood flow due to lesser pressure.
How to Diagnose Arterial and Venous Injury?
A thorough physical examination is done to identify the source of the bleeding. Other methods that are beneficial to identify the injury are mentioned below:
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Angiography:
Angiography is also known as arteriography, an imaging technique that helps evaluate blood vessels. A specific dye is punctured to view the images, which helps to identify the injured site. The images obtained in an angiography are called angiograms.
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Doppler Ultrasound:
Doppler ultrasound is a non-invasive technique to determine the flow of blood through the blood vessels. This technique uses high-frequency sound waves to produce images.
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Duplex Ultrasound:
Duplex ultrasound uses conventional ultrasound and doppler to determine blood flow through arteries and veins.
What Are the Measures to Control Arterial and Venous Bleeding?
Arterial bleeding is usually life-threatening as they carry oxygenated blood to other organs and may cause ischemia (lack of blood supply) in case of any arterial injury. However, venous bleeding is not life-threatening like arterial bleeding; it is also serious. Bleeding can be controlled in the following ways:
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If the bleeding occurs due to a small injury, identifying the source and applying mild pressure on the wounded surface helps to control the initial blood loss. Once this is achieved, dressing the wound in gauze helps to prevent infections.
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In case of accidental nicking of the artery during surgery, identify the origin of bleeding and apply finger pressure. Compression of the artery over a bony prominence is also helpful in arresting bleeding. Avoid using a tourniquet (a medical device that applies pressure to control blood loss) in arterial bleeding, as it may cause venous stasis (improper blood flow in veins). If a tourniquet is used, it should be used cautiously with less tension for a shorter period.
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In case of massive bleeding due to accidents, the amount of blood loss should be replaced with fluids or blood of the same group. Proper matching should be done before a blood transfusion to avoid allergic reactions.
What Are the Complications of Arterial and Venous Injuries?
Arterial and venous injuries left untreated may cause life-threatening or serious delayed complications, which occur months or years after the injury. The complications of vascular injuries are listed below:
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Excess loss of blood.
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Pain.
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Scarring.
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Thrombosis (blood clot).
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Swelling.
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Bruising.
In case of severe injuries, excessive blood loss results in a lack of blood supply to vital organs, which can be fatal.
Conclusion
Therefore, depending on the arterial and venous injury severity, there may be mild to heavy blood loss. It is essential to have a first aid kit that can be helpful during emergencies. Following proper measures to control bleeding will help prevent complications and casualties.
