Biology: Bleeding and Shock, Cardiac Cycle

Study Notes

Bleeding can be external and obvious or internal and hidden, and can cause weakness, shock, and death.
Perfusion is the circulation of blood within an organ or tissue in adequate amounts to meet the cell's current needs for oxygen, nutrients, and waste removal.
The autonomic nervous system monitors the body's needs and adjusts the blood flow as required, and when this fails, the body experiences hypoperfusion or shock.

The cardiac cycle is a repetitive pumping process that begins with the onset of cardiac muscle contraction and ends with the beginning of the next contraction.
Preload is the amount of blood returned to the heart to be pumped out, and afterload is the pressure in the aorta or peripheral vascular resistance against which the left ventricle must pump blood.
Stroke volume is the amount of blood ejected per contraction, and is dependent on heart rate, stroke volume, hemoglobin levels, and arterial oxygen saturation.

Hemorrhage is the discharge of blood from blood vessels, and can range from minor capillary bleeding to severely spurting artery bleeding.
External bleeding can be controlled using direct pressure, pressure dressings, splints, hemostatic dressings, tourniquets, and pressure bandages.
Internal hemorrhage can occur in any part of the body, and may appear with non-traumatic internal bleeding such as GI bleeding, ruptured ectopic pregnancies, or ruptured aneurysms.

Signs of bleeding may include weakness, shock, dizziness, faintness, pain, swelling, bruising, distension, and hematoma.
Patients may exhibit altered level of consciousness, tachycardia, weakness, fainting, dizziness, thirst, nausea, and vomiting.

Assessing patients for bleeding involves searching for signs of shock, controlling lifethreatening bleeding, and performing a rapid full body scan to determine the patient's level of consciousness.
Managing bleeding involves supporting the heart, brain, and spinal cord, and may require expedited transport to the hospital, depending on the severity of the bleeding.
Consider factors such as need for stitches, tetanus shot, and patient reliability when making transport decisions.

Trauma patients may experience hypovolemic shock, which can be fatal if not corrected.
The trauma "triad of death" consists of hypothermia, coagulopathy, and acidosis, which can increase mortality in trauma patients.
Identify and intervene in these conditions by keeping patients warm, managing bleeding, and providing oxygen and other necessary treatments.

Bleeding can be internal and hidden, causing weakness, shock, and death
Perfusion is the circulation of blood within an organ or tissue in adequate amounts to meet the cell's current needs
The autonomic nervous system monitors the body's needs and adjusts the blood flow as required, and when this fails, the body experiences hypoperfusion or shock

The cardiac cycle is a repetitive pumping process that begins with the onset of cardiac muscle contraction and ends with the beginning of the next contraction
Preload is the amount of blood returned to the heart to be pumped out
Afterload is the pressure in the aorta or peripheral vascular resistance against which the left ventricle must pump blood
Stroke volume is dependent on heart rate, stroke volume, hemoglobin levels, and arterial oxygen saturation

Hemorrhage is the discharge of blood from blood vessels, ranging from minor capillary bleeding to severely spurting artery bleeding
External bleeding can be controlled using direct pressure, pressure dressings, splints, hemostatic dressings, tourniquets, and pressure bandages
Internal hemorrhage can occur in any part of the body, and may appear with non-traumatic internal bleeding such as GI bleeding, ruptured ectopic pregnancies, or ruptured aneurysms

Signs of bleeding include weakness, shock, dizziness, faintness, pain, swelling, bruising, distension, and hematoma
Patients may exhibit altered level of consciousness, tachycardia, weakness, fainting, dizziness, thirst, nausea, and vomiting

Assessing patients for bleeding involves searching for signs of shock, controlling lifethreatening bleeding, and performing a rapid full body scan to determine the patient's level of consciousness
Managing bleeding involves supporting the heart, brain, and spinal cord, and may require expedited transport to the hospital, depending on the severity of the bleeding
Factors to consider when making transport decisions include need for stitches, tetanus shot, and patient reliability

Trauma patients may experience hypovolemic shock, which can be fatal if not corrected
The trauma "triad of death" consists of hypothermia, coagulopathy, and acidosis, which can increase mortality in trauma patients
Identify and intervene in these conditions by keeping patients warm, managing bleeding, and providing oxygen and other necessary treatments