Chapter 13: Shock Lecture Notes

A comprehensive set of vocabulary flashcards covering the pathophysiology, types, progression, and emergency treatment of shock as presented in Chapter 13.

Shock

A state of inadequate cellular perfusion where cells do not receive enough oxygen, water, and glucose to carry out cellular processes.

Adenosine triphosphate (ATP)

The form of energy produced by cells through cellular processes using oxygen, water, and glucose.

Homeostasis

A balance of all systems of the body, which the body attempts to maintain in the early stages of shock.

Perfusion

The circulation of blood to the tissues in adequate amounts to meet the cells' needs, including the delivery of oxygen and removal of toxic waste.

Diffusion

A passive process in which molecules move from an area of higher concentration to an area of lower concentration, such as oxygen moving from alveoli into the blood.

Bicarbonate

A form in which carbon dioxide is transported in the blood, created when carbon dioxide combines with water.

Perfusion triangle

The three components of the cardiovascular system required for adequate perfusion: the heart (pump), the blood vessels (container), and the blood (content).

Anaerobic metabolism

Cellular metabolism that occurs without oxygen, creating lactic acidosis and reducing the body's ability to produce energy.

Systolic pressure

The peak arterial pressure, or the pressure generated when the heart contracts.

Diastolic pressure

The pressure maintained within the arteries while the heart is at rest, or between beats.

Pulse pressure

The difference between the systolic and diastolic pressures, calculated as $\text{Systolic} - \text{Diastolic}$, signifying the force the heart generates with each contraction.

Capillary sphincters

Circular muscular walls that constrict and dilate under the control of the autonomic nervous system to regulate blood flow through capillary beds.

Myocardial contractility

The ability of the heart muscle to contract, which determines the strength of the heart's output.

Preload

The pressure in the heart as the volume of blood increases and stretches the ventricles just before contraction.

Afterload

The force or resistance against which the heart pumps; as it increases, cardiac output generally decreases.

Edema

The presence of abnormally large amounts of fluid between cells in body tissues, causing swelling.

Cardiogenic shock

Shock caused by inadequate function of the heart, or pump failure, often resulting from a heart attack.

Obstructive shock

Shock caused by a mechanical obstruction that prevents blood from returning to the heart, filling the ventricles, or leaving the heart.

Cardiac tamponade

A condition where blood or fluid leaks into the pericardial sac and compresses the heart, preventing it from refilling; also known as pericardial tamponade.

Beck triad

A set of three signs indicative of cardiac tamponade: jugular venous distention, muffled heart sounds, and a narrowing pulse pressure.

Tension pneumothorax

A life-threatening condition where air accumulates in the chest cavity and applies pressure to the heart and great vessels, shifting the mediastinum.

Pulmonary embolism

A blood clot in the pulmonary arteries that blocks blood flow through the lungs and can lead to obstructive shock.

Distributive shock

Shock resulting from widespread dilation of the small arterioles, small venules, or both, causing blood to pool in expanded vascular beds.

Septic shock

A form of distributive shock caused by severe bacterial infection where toxins cause widespread vasodilation and increased vessel permeability.

Neurogenic shock

Shock caused by damage to the spinal cord (usually high cervical levels) resulting in the loss of sympathetic nervous system control over blood vessel tone.

Sensitization

The process of becoming sensitive to a substance that did not initially cause an allergic reaction.

Anaphylactic shock

A severe, life-threatening allergic reaction characterized by widespread vascular dilation, increased permeability, and bronchoconstriction.

Syncope

Fainting caused by a temporary, generalized vasodilation that reduces blood supply to the brain.

Hypovolemic shock

Shock resulting from an inadequate amount of fluid or volume in the circulatory system, including hemorrhagic and nonhemorrhagic causes.

Compensated shock

The early stage of shock where the body can still maintain blood pressure and perfusion using compensatory mechanisms.

Decompensated shock

The late stage of shock when blood pressure is falling, mental status is declining, and the body's compensatory mechanisms fail.

Golden Period

The critically important period for early resuscitation and treatment of severely injured trauma patients, emphasizing rapid transport within $10\,\text{minutes}$ or less on scene.