Emergency states

The State Education Institution of Higher Professional Training The First Sechenov Moscow State Medical University

under Ministry of Health of the Russian Federation

Lecture presentation

Professor Pirozhkov S.V.

 Department of Pathophysiology

2014-2015 education year

Collapse – acute severe decrease in systemic blood pressure due to rapidly developing incongruity between the volume of circulating blood and the capacity of the vascular bed

TYPES OF COLLAPSE BY ORIGIN

cardiogenic

orthostatic

hypovolemic

vasodilatory

● postinfarction

● arrhythmic

● cardiomyopathic

● posthemorrhagic

● dehydrationary

● toxico-infectious

● hyperthermic

● toxico-infectious

● psychogenic

Shock is the state in which failure of the circulatory system to maintain adequate tissue perfusion results in widespread reduction in delivery of O2 and nutrients to cells

CLASSIFICATION OF SHOCK

1. HYPOVOLEMIC

decrease in CPV decrease in SV and CO shock

2. CARDIOGENIC

decrease in myocardial contractility

decrease in CO (cardiac index < 1.8 L/min/m2) shock

3. EXTRACARDIAC OBSTRUCTIVE

increased pericardial pressure

impaired ventricular diastolic filling

decrease in SV and CO shock

4. DISTRIBUTIVEconsiderable increase in the peripheral vascular capacity discrepancy between the perfusionpressure and the demand of tissues and organs in blood flow, despite N or increased CO shock

stroke volume

cardiac output

circulating plasma volume

ADAPTIVE REACTIONS AT THE NONPROGRESSIVE STAGE

OF SHOCK ► Activation of the sympathetic nervous system by: - baroreceptor reflex - low-pressure vascular stretch receptors - central nervous system ischemic response (when BP <

50 mm Hg) ► Activation of the renin-angiotensin-aldosterone

mechanism ► Increased secretion of vasopressin by the posterior

pituitary ► Activation of mechanisms that return the blood

volume back toward normal: - increased absorption of water from the intestinal tract - conservation of water and salt by the kidneys - thirst and increased appetite for salt

IMPORTANT FACTORS THAT CAUSE IRREVERSIBLE CHANGES IN THE PROGRESSING SHOCK

Ischemia of tissues, O2 and substrate deficiency

AcidosisActivation of endothelial

cellsActivation of leukocytes

Excessive, uncontrolled release of inflammatory mediators and active oxygen species (О2

-, ОН*)

Progressively developing and extending inflammatory process

Massive injury to cellular membranes

Intense release of lysosomal enzymes

Widespread depletion of the cellular energy

stores

TYPES OF DISTRIBUTIVE SHOCK

● Neurogenic shock

- deep general anesthesia

- spinal anesthesia

- brain damage in concussion or contusion

● Pain shock

● Anaphylactic shock

● Drug overdose shock

● Adrenal shock (Addisonian crisis)

● Septic shock

Heart failure

Shock

Deterioration of the heart function in shock

Ventricular diastolic pressure

Pressure gradient for coronary

perfusion Ischemia

Heart rateDiastolic compliance

THE MOST COMMON CAUSES OF COMA

■ Wide-spread damage in both hemispheres

(ischemia, trauma etc.).

■ Suppression of cerebral function by extrinsic

drugs, toxins, hypoxia, internal metabolic

derangements (hypoglycemia, azotemia,

hepatic failure etc.).

■ Brainstem lesions that cause proximate

damage to the reticular activating system

(RAS).