Three lows and one high: central venous pressure (CVP), cardiac output (CO), and arterial blood pressure decrease, and peripheral resistance (PR) increases

During this period, microcirculatory blood perfusion is reduced, tissue ischemia and hypoxia

Features: 1. Precapillary resistance vasoconstriction is more obvious 2. A large number of true capillary networks are closed, and the blood flow rate in the microcirculation slows down. 3. Direct access or arteriovenous short-circuit return, tissue perfusion is significantly reduced

Perfusion characteristics: less perfusion and less flow, less perfusion than flow, and the tissue is in a state of ischemia and hypoxia.

Sympathetic nerves are excited, catecholamines are released into the blood in large quantities, and true capillary volume is reduced.

Release of other vasoconstrictor humoral factors

Helps maintain arterial blood pressure: increased blood return to the heart (autotransfusion, autologous infusion), increased cardiac output, and increased peripheral resistance

Helps blood supply to the heart and brain

Pale face, clammy limbs, cold sweat, rapid pulse, decreased pulse pressure, decreased urine output, irritability

Characteristics of perfusion: less flow, more flow, and the tissue is in a state of congestion and hypoxia.

Microvascular dilation (acidosis, increased production of vasodilator substances)

Blood stasis (white blood cells adhere to venules, blood becomes concentrated)

The amount of blood returned to the heart decreases sharply, self-infusion stops, and the blood perfusion of the heart and brain decreases.

Blood pressure and pulse pressure progressively decrease, blood pressure often drops significantly, pulse is thin and rapid, and veins atrophy.

Cerebral blood perfusion is significantly reduced leading to central nervous system dysfunction

Renal blood flow is severely insufficient, resulting in oliguria or even anuria

microcirculatory congestion

Microthrombosis forms, blood flow stops, and a state of no perfusion and no flow occurs.

microvascular paralytic dilation

DIC formation

Circulatory failure (refractory hypotension)

Complicated DIC (bleeding, anemia, subcutaneous ecchymosis)

vital organ dysfunction

Shock is the first to change

Swelling, loss of dense structures and ridges, calcium salt deposition, and even membrane rupture

Swelling, vacuolation and release of lysosomal enzymes