Life-threatening bleeding is a severe medical emergency where rapid, uncontrolled blood loss quickly compromises the body’s ability to circulate oxygen, potentially leading to death within minutes. Recognizing this danger requires immediate assessment. The two primary ways a bystander can determine if bleeding is life-threatening are by visually assessing the volume and speed of the blood loss and by recognizing the physiological signs of the body’s response, known as hypovolemic shock.
Assessing the Volume and Speed of Blood Loss
The first way to assess a hemorrhage is by examining the external wound for the volume and flow of the blood. A quick visual assessment should focus on how fast the blood is leaving the body and how much has already accumulated. Bleeding is considered life-threatening if the blood loss is continuous, or if a significant volume (roughly half a soda can or more) has been lost quickly.
The physical characteristics of the blood flow provide a direct clue about the damaged vessel. Arterial bleeding is the most dangerous, characterized by bright red blood that often spurts or pulses rhythmically with the heartbeat. This indicates a breach in a high-pressure artery, causing rapid blood escape.
In contrast, venous bleeding is dark red and flows in a steady, continuous stream or gush. While less dramatic than arterial spurting, venous bleeding can still lead to fatal blood loss quickly. If clothing or bandages rapidly become saturated—soaking completely through in less than a minute—the speed of the loss indicates a severe hemorrhage. The quick formation of a large pool of blood on the ground also signals a rate of loss too high for the body’s clotting mechanisms to manage.
Recognizing Signs of Hypovolemic Shock
The second way to identify life-threatening bleeding focuses on the victim’s internal reaction, which is important if the bleeding is internal or not fully visible. When the body loses about 20% or more of its total blood volume, it enters hypovolemic shock. This means there is not enough circulating blood to supply oxygen to the organs, causing the body to shift blood flow away from the extremities toward the heart and brain.
One of the earliest physiological signs is a change in the victim’s mental status, manifesting as confusion, anxiety, restlessness, or agitation. As the brain receives less oxygenated blood, the person might also become dizzy or lose consciousness.
The circulatory system responds by increasing the heart rate (tachycardia) to pump the remaining blood faster, resulting in a rapid, often weak pulse. The skin of the extremities, lips, and nail beds will become pale, cool, and clammy as blood is diverted away from the surface. Breathing may also become rapid and shallow as the body attempts to increase oxygen intake to compensate for the compromised circulation.
Immediate Life-Saving Interventions
Once life-threatening bleeding is identified, immediate action is necessary. The first step is to call 911 or your local emergency number to summon professional medical help. If possible, put the phone on speaker so you can communicate with the dispatcher while simultaneously providing care.
While waiting for help, the most effective intervention is applying firm, continuous pressure directly to the wound using a clean cloth, gauze, or a hand. This mechanical pressure helps compress the damaged vessel, promoting clot formation and slowing blood loss. Do not remove any blood-soaked dressing; instead, add more material on top and maintain the pressure.
Managing the onset of shock is another immediate priority, even while controlling the bleeding. Help the injured person lie down flat, which assists in keeping blood flowing toward the brain and heart. To combat the body’s efforts to conserve heat, cover the victim with a blanket or coat to maintain their body temperature until emergency services arrive.