The brachial artery is a major blood vessel in the upper arm, continuing from the axillary artery in the armpit. It extends down the arm, along the bicep, and divides at the elbow crease into the radial and ulnar arteries, which supply the forearm and hand. This artery is the primary conduit for oxygenated blood and essential nutrients to the entire arm, forearm, and hand.
Immediate Physiological Response
When the brachial artery is severed, the body experiences an immediate and severe physiological reaction due to rapid and extensive blood loss. Arterial bleeding is characterized by bright red blood that spurts rhythmically with each heartbeat, reflecting the high pressure at which blood is pumped directly from the heart. This uncontrolled hemorrhage can lead to a significant reduction in total blood volume within minutes, posing an immediate threat to life.
Such rapid blood loss often triggers hypovolemic shock, a life-threatening condition where the body cannot circulate enough blood to its organs. Symptoms of hypovolemic shock include a rapid heart rate, low blood pressure, and a fast, shallow breathing pattern as the body attempts to compensate for the reduced blood volume. The skin may appear pale, cool, and clammy as the body prioritizes blood flow to essential organs like the brain and heart, diverting it away from the extremities.
Locally, the affected arm and hand will exhibit distinct signs of lost blood flow. There will be sudden, intense pain at the injury site. Immediately below the injury, the pulse will be absent, and the skin will become extremely pale (pallor) and cold to the touch.
Consequences of Unresolved Blood Loss and Ischemia
If blood flow through the brachial artery is not quickly restored, the lack of oxygen and nutrients, known as ischemia, progressively damages the tissues of the arm and hand. Muscles, nerves, and other cells in the affected limb begin to suffer irreversible injury within a few hours. Prolonged ischemia leads to tissue necrosis, which is the death of cells and tissues due to insufficient blood supply.
Muscle tissue is particularly vulnerable to ischemia, and its damage can result in a serious condition called compartment syndrome. This occurs when swelling and bleeding within the confined muscle compartments of the arm increase pressure to dangerous levels, further compromising blood flow to muscles and nerves. If left untreated, the elevated pressure can lead to permanent muscle damage, contractures, and functional disability.
Nerve tissue is also highly susceptible to oxygen deprivation, and prolonged ischemia can cause irreversible nerve damage. This can manifest as a permanent loss of sensation, tingling, numbness, or even complete paralysis in the affected arm and hand. Such damage can severely impair the limb’s function, potentially necessitating amputation.
Emergency First Aid Measures
In an emergency involving a severed brachial artery, immediate first aid is essential to control bleeding and preserve life. The first step involves applying direct, firm pressure to the wound using a clean cloth, gauze, or even a bare hand. Continuous pressure helps to compress the injured artery and reduce blood flow, which is crucial given the high pressure of arterial bleeding.
If direct pressure alone cannot control the severe bleeding, a tourniquet should be applied as a last resort. Place the tourniquet high and tight on the limb, approximately two to three inches above the wound and between the injury and the heart. Ensure the tourniquet is tightened sufficiently to stop the bleeding entirely; this may cause considerable pain but is necessary to prevent life-threatening blood loss.
Once applied, note the time of tourniquet application, as this information is vital for medical professionals. Do not remove or loosen the tourniquet once it is in place, as this can dislodge clots and restart severe bleeding. Immediately call for emergency medical services.
Professional Medical Intervention
Upon arrival at a healthcare facility, medical professionals prioritize diagnosing the full extent of the brachial artery injury and stabilizing the patient. This typically involves a physical examination to assess the limb’s viability and imaging techniques, such as angiography, to precisely locate the injury and evaluate blood flow. Blood tests are also performed to assess blood loss and overall physiological status.
The primary treatment for a severed brachial artery is surgical repair, with the goal of restoring blood flow to the limb as quickly as possible. Surgeons often perform an arterial anastomosis, which involves carefully rejoining the severed ends of the artery. If a segment of the artery is missing or too damaged, a graft, often from a vein in the patient’s leg, may be used to bridge the gap.
Restoring blood flow promptly is crucial to prevent long-term complications such as tissue death and permanent loss of function. Supportive care, including blood transfusions to replace lost blood volume and pain management, is also administered. Post-operative monitoring helps detect and manage potential complications.