Shock is a serious, life-threatening medical condition where insufficient blood flow reaches the body tissues. Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the Tissue is a cellular organizational level intermediate between cells and a complete organism As the blood carries oxygen and nutrients around the body, reduced flow hinders the delivery of these components to the tissues, and can stop the tissues from functioning properly. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the A nutrient is food or chemicals that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment The process of blood entering the tissues is called perfusion, so when perfusion is not occurring properly this is called a hypoperfusional (hypo = below) state. In Physiology, perfusion is the process of nutritive delivery of Arterial Blood to a Capillary bed in the Biological tissue.

Medical shock should not be confused with the emotional state of shock, as the two are not related. Acute stress reaction (also called acute stress disorder, psychological shock, mental shock, or simply shock) is a psychological Medical shock is a life-threatening medical emergency and one of the most common causes of death for critically-ill people. A medical emergency is an Injury or Illness that is acute and poses an immediate risk to a person's life or long term health Shock can have a variety of effects, all with similar outcomes, but all relate to a problem with the body's circulatory system. For example, shock may lead to hypoxia (a lack of oxygen in the body tissues) or cardiac arrest (the heart stopping). Chronic Hypoxia is a pathological condition in which the body as a whole ( generalized hypoxia) or region of the body ( tissue hypoxia) is deprived of adequate A cardiac arrest, also known as cardiorespiratory arrest, cardiopulmonary arrest or circulatory arrest, is the abrupt cessation of normal circulation of ^{[1][2][3][4][5][6][7]}

Stages of shock

Effects of inadequate perfusion on cell function.

There are four stages of shock. As it is a complex and continuous condition there is no sudden transition from one stage to the next. ^[8]

Initial 

During this stage, the hypoperfusional state causes hypoxia, leading to the mitochondria being unable to produce adenosine triphosphate (ATP). Chronic Hypoxia is a pathological condition in which the body as a whole ( generalized hypoxia) or region of the body ( tissue hypoxia) is deprived of adequate In Cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed Organelle found in most eukaryotic cells. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Due to this lack of oxygen, the cell membranes become damaged, they become leaky to extra-cellular fluid, and the cells perform anaerobic respiration. The cell membrane (also called the plasma membrane, plasmalemma, or "phospholipid bilayer" is a Selectively permeable Lipid bilayer See also Fermentation (biochemistry Anaerobic respiration (anaerobiosis refers to the Oxidation of molecules in the absence of Oxygen to produce This causes a build-up of lactic and pyruvic acid which results in systemic metabolic acidosis. Lactic acid ( IUPAC Systematic name: 2-hydroxypropanoic acid) also known as milk acid, is a Chemical compound that plays a role Pyruvic acid (CH3COCO2H is an alpha-keto acid. The Carboxylate Anion of pyruvic acid is known as pyruvate. In Medicine, metabolic acidosis is a process which if unchecked leads to acidemia (i The process of removing these compounds from the cells by the liver requires oxygen, which is absent. The liver is a vital organ in the human body and is present in Vertebrates and some other animals

Compensatory (Compensating) 

This stage is characterised by the body employing physiological mechanisms, including neural, hormonal and bio-chemical mechanisms in an attempt to reverse the condition. As a result of the acidosis, the person will begin to hyperventilate in order to rid the body of carbon dioxide (CO₂). Acidosis is an increased Acidity (ie an increased Hydrogen ion Concentration) In Medicine, hyperventilation (or overbreathing) is the state of Breathing faster and/or deeper than necessary bringing about lightheadedness and other CO₂ indirectly acts to acidify the blood and by removing it the body is attempting to raise the pH of the blood. The baroreceptors in the arteries detect the resulting hypotension, and cause the release of adrenaline and noradrenaline. Baroreceptors (or baroceptors) in the Human body detect the pressure of blood flowing through them and can send messages to the Central nervous system Arteries are Blood vessels that carry blood away from the Heart. In Physiology and Medicine, hypotension refers to an abnormally low Blood pressure. Norepinephrine ( INN) (abbreviated norepi or NE) or noradrenaline ( BAN) (abbreviated NA or NAd) is a Noradrenaline causes predominately vasoconstriction with a mild increase in heart rate, whereas adrenaline predominately causes an increase in heart rate with a small effect on the vascular tone; the combined effect results in an increase in blood pressure. Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels particularly the large Arteries, Arterioles Measuring heart rate The Pulse rate (which in most people is identical to the heart rate can be measured at any point on the body where an Artery 's pulsation Measuring heart rate The Pulse rate (which in most people is identical to the heart rate can be measured at any point on the body where an Artery 's pulsation The blood vessels are part of the Circulatory system and function to transport Blood throughout the body Blood pressure is also the title of a short story by Damon Runyan in Guys and Dolls and Other Stories Renin-angiotensin axis is activated and arginine vasopressin is released to conserve fluid via the kidneys. Renin (pronounced "Ree-nin" or "Rē-nin" (ˈriːnɨn also known as Angiotensinogenase, is a circulating Enzyme that participates in the body's Angiotensin causes blood vessels to constrict and drives blood pressure up Arginine vasopressin ( AVP) also known as vasopressin, argipressin or antidiuretic hormone ( ADH) is a Hormone found in Also, these hormones cause the vasoconstriction of the kidneys, gastrointestinal tract, and other organs to divert blood to the heart, lungs and brain. The kidneys are complicated organs that have numerous biological roles lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain The lack of blood to the renal system causes the characteristic low urine production. The kidneys are complicated organs that have numerous biological roles Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra. However the effects of the Renin-angiotensin axis take time and are of little importance to the immediate homeostatic mediation of shock. Renin (pronounced "Ree-nin" or "Rē-nin" (ˈriːnɨn also known as Angiotensinogenase, is a circulating Enzyme that participates in the body's Angiotensin causes blood vessels to constrict and drives blood pressure up Homeostasis (from Greek: ὅμος hómos, "equal" and ιστημι istēmi, "to stand" lit

Progressive (Decompensating) 

Should the cause of the crisis not be successfully treated, the shock will proceed to the progressive stage and the compensatory mechanisms begin to fail. Due to the decreased perfusion of the cells, sodium ions build up within while potassium ions leak out. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 As anaerobic metabolism continues, increasing the body's metabolic acidosis, the arteriolar and precapillary sphincters constrict such that blood remains in the capillaries. A sphincter is a structure usually a circular Muscle, that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological Capillaries are the smallest of a body's Blood vessels measuring 5-10 μm in diameter which connect Arterioles and Venules and enable the interchange Due to this, the hydrostatic pressure will increase and, combined with histamine release, this will lead to leakage of fluid and protein into the surrounding tissues. Histamine is a Biogenic amine involved in local immune responses as well as regulating physiological function in the gut and acting as a Neurotransmitter Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl As this fluid is lost, the blood concentration and viscosity increase, causing sludging of the micro-circulation. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. The prolonged vasoconstriction will also cause the vital organs to be compromised due to reduced perfusion.

Refractory (Irreversable)

At this stage, the vital organs have failed and the shock can no longer be reversed. Brain damage and cell death have occurred. Brain damage, or Acquired brain injury, is the destruction or degeneration of Brain cells. Death will occur imminently.

Types of shock

In 1972 Hinshaw and Cox suggested the following classification which is still used today. ^[1] It uses four types of shock: hypovolaemic, cardiogenic, distributive and obstructive shock:^{[2][3][4][7][9]}

• Hypovolemic shock - This is the most common type of shock and based on insufficient circulating volume. In Physiology and Medicine, hypovolemia (also hypovolaemia is a state of decreased Blood volume more specifically decrease in volume of Blood plasma Its primary cause is loss of fluid from the circulation from either an internal or external source. This is an article about the rock music band "Circulatory System" An internal source may be haemorrhage. Bleeding, technically known as hemorrhaging / haemorrhaging (see American and British spelling differences) is the loss of Blood from External causes may include extensive bleeding, high output fistulae or severe burns. In Medicine, a stoma (Greek - pl stomata is an opening either natural or surgically created (artificial which connects a portion of the body cavity to the outside A burn is a type of Injury that may be caused by Heat, cold, Electricity, Chemicals, Light, Radiation, or
• Cardiogenic shock - This type of shock is caused by the failure of the heart to pump effectively. Cardiogenic shock is based upon an inadequate circulation of Blood due to primary failure of the ventricles of the Heart to function effectively This can be due to damage to the heart muscle, most often from a large myocardial infarction. Myocardial infarction ( MI or AMI for acute myocardial infarction) also known as a heart attack, occurs when the blood supply Other causes of cardiogenic shock include arrhythmias, cardiomyopathy, congestive heart failure (CHF), contusio cordis or cardiac valve problems. Dysrhythmia redirects here For the American band see Dysrhythmia (band. Cardiomyopathy, which literally means "heart muscle disease" is the deterioration of the function of the Myocardium (i Heart failure is a Cardiac condition that occurs when a problem with the structure or function of the Heart impairs its ability to supply Commotio cordis (from Latin commotion of the heart - a functional effect of mechanical stimulation in the absence of structural damage as opposed to Myocardial In Anatomy, the heart valves are Valves in the Heart that maintain the unidirectional flow of blood by opening and closing depending on the difference
• Distributive shock - As in hypovolaemic shock there is an insufficient intravascular volume of blood. Distributive shock is as in Hypovolemic shock, caused by an insufficient Intravascular volume of Blood. This form of "relative" hypovolaemia is the result of dilation of blood vessels which diminishes systemic vascular resistance. Vascular resistance is a term used to define the resistance to flow that must be overcome to push Blood through the Circulatory system. Examples of this form of shock are:
  • Septic shock - This is caused by an overwhelming infection leading to vasodilation, such as by Gram negative bacteria i. Septic shock is a very serious medical condition caused by decreased tissue perfusion and oxygen delivery as a result of Infection and Sepsis, though the Gram-negative bacteria are those Bacteria that do not retain Crystal violet dye in the Gram staining protocol e. Escherichia coli, Proteus species, Klebsiella pneumoniae which release an endotoxin which produces adverse biochemical, immunological and occasionally neurological effects which are harmful to the body. Klebsiella pneumoniae is a Gram-negative, non- Motile, Encapsulated, Lactose fermenting, Facultative anaerobic Endotoxins (not to be confused with Enterotoxin) are potentially toxic, natural compounds found inside Pathogens such as Bacteria. Gram-positive cocci, such as pneumococci and streptococci, and certain fungi as well as Gram-positive bacterial toxins produce a similar syndrome. Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus Streptococcus is a Genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the
  • Anaphylactic shock - Caused by a severe anaphylactic reaction to an allergen, antigen, drug or foreign protein causing the release of histamine which causes widespread vasodilation, leading to hypotension and increased capillary permeability. Anaphylaxis is an acute systemic (multi-system and severe Type I Hypersensitivity allergic reaction in humans and other Mammals Anaphylaxis is an acute systemic (multi-system and severe Type I Hypersensitivity allergic reaction in humans and other Mammals An allergen is a nonparasitic Antigen capable of stimulating a Type-I hypersensitivity reaction in atopic individuals An antigen (from antibody-generating) or immunogen is a substance that prompts the generation of Antibodies and can cause an immune response A drug, broadly speaking is any chemical substance that when absorbed into the body Histamine is a Biogenic amine involved in local immune responses as well as regulating physiological function in the gut and acting as a Neurotransmitter
  • Neurogenic shock - Neurogenic shock is the rarest form of shock. Neurogenic shock is shock caused by the sudden loss of the Autonomic nervous system signals to the Smooth muscle in vessel walls It is caused by trauma to the spinal cord resulting in the sudden loss of autonomic and motor reflexes below the injury level. Treatment of physical trauma is described here and in First aid. The spinal cord is a long thin tubular bundle of Nerves that is an extension of the Central nervous system from the brain and is enclosed in and protected In Vertebrates the term motor neuron (or motoneuron) classically applies to Neurons located in the Central nervous system (or CNS that project Without stimulation by sympathetic nervous system the vessel walls relax uncontrolled, resulting in a sudden decrease in peripheral vascular resistance, leading to vasodilation and hypotension. The Sympathetic Nervous System ( SNS) is a branch of the Autonomic nervous system along with the Enteric nervous system and Parasympathetic nervous Total peripheral resistance (TPR is the sum of the resistance of all peripheral vasculature in the systemic circulation In Physiology and Medicine, hypotension refers to an abnormally low Blood pressure.
• Obstructive shock - In this situation the flow of blood is obstructed which impedes circulation and can result in circulatory arrest. A cardiac arrest, also known as cardiorespiratory arrest, cardiopulmonary arrest or circulatory arrest, is the abrupt cessation of normal circulation of Several conditions result in this form of shock.
  • Cardiac tamponade in which fluid in the pericardium prevents inflow of blood into the heart (venous return). Cardiac tamponade, also known as pericardial tamponade, is an emergency condition in which fluid accumulates in the Pericardium (the sac in which the Constrictive pericarditis, in which the pericardium shrinks and hardens, is similar in presentation. In many cases constrictive pericarditis is a late sequela of an inflammatory condition of the Pericardium. The pericardium is a double-walled sac that contains the Heart and the roots of the Great vessels.
  • Tension pneumothorax. A tension pneumothorax is a life-threatening condition that results from a progressive deterioration and worsening of a simple Pneumothorax, associated with the formation Through increased intrathoracic pressure, bloodflow to the heart is prevented (venous return).
  • Massive pulmonary embolism is the result of a thromboembolic incident in the bloodvessels of the lungs and hinders the return of blood to the heart. Pulmonary embolism (PE is a blockage of the Pulmonary artery or one of its branches usually occurring when a venous Thrombus (blood clot from a vein lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive
  • Aortic stenosis hinders circulation by obstructing the ventricular outflow tract

Recently a fifth form of shock has been introduced:^[1]

• Endocrine shock based on endocrine disturbances. A ventricular outflow tract is a portion of either the left or Right ventricle of the Human Heart through which Blood passes The endocrine system is an integrated system of small organs that involve the release of extracellular signaling molecules known as Hormones The endocrine system is instrumental
  • Hypothyroidism, in critically ill patients, reduces cardiac output and can lead to hypotension and respiratory insufficiency. Hypothyroidism is the disease state in humans and animals caused by insufficient production of Thyroid hormone by the Thyroid gland. Cardiac output (Q is the volume of blood being pumped by the Heart, in particular by a ventricle in a minute
  • Thyrotoxicosis may induce a reversible cardiomyopathy. Hyperthyroidism is the term for overactive tissue within the Thyroid gland resulting in overproduction and thus an excess of circulating free thyroid hormones Thyroxine
  • Acute adrenal insufficiency is frequently the result of discontinuing corticosteroid treatment without tapering the dosage. Adrenal insufficiency is a condition in which the Adrenal glands located above the Kidneys do not produce adequate amounts of steroid hormones (chemicals produced by the Corticosteroids are a class of Steroid hormones that are produced in the Adrenal cortex. However, surgery and intercurrent disease in patients on corticosteroid therapy without adjusting the dosage to accommodate for increased requirements may also result in this condition.
  • Relative adrenal insufficiency in critically ill patients where present hormone levels are insufficient to meet the higher demands

Signs and symptoms

• Hypovolemic shock
  • Anxiety, restlessness, altered mental state due to decreased cerebral perfusion and subsequent hypoxia. Cortisol is a Corticosteroid Hormone produced by the Adrenal gland (in the Zona fasciculata of the Adrenal cortex) The Glasgow Coma Scale or GCS, sometimes also known as the Glasgow Coma Score is a neurological scale which aims to give a reliable objective
  • Hypotension due to decrease in circulatory volume.
  • A rapid, weak, thready pulse due to decreased blood flow combined with tachycardia.
  • Cool, clammy skin due to vasoconstriction and stimulation of vasoconstriction.
  • Rapid and shallow respirations due to sympathetic nervous system stimulation and acidosis.
  • Hypothermia due to decreased perfusion and evaporation of sweat.
  • Thirst and dry mouth, due to fluid depletion.
  • Fatigue due to inadequate oxygenation.
  • Cold and mottled skin (cutis marmorata), especially extremities, due to insufficient perfusion of the skin.
  • Distracted look in the eyes or staring into space, often with pupils dilated.
• Cardiogenic shock, similar to hypovolaemic shock but in addition:
  • Distended jugular veins due to increased jugular venous pressure. The jugular veins are Veins that bring deoxygenated blood from the Head back to the heart via the Superior vena cava. The jugular venous pressure (JVP sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system.
  • Absent pulse due to tachyarrhythmia. Dysrhythmia redirects here For the American band see Dysrhythmia (band.
• Obstructive shock, similar to hypovolaemic shock but in addition:
  • Distended jugular veins due to increased jugular venous pressure. The jugular veins are Veins that bring deoxygenated blood from the Head back to the heart via the Superior vena cava.
  • Pulsus paradoxus in case of tamponade
• Septic shock, similar to hypovolaemic shock except in the first stages:
  • Pyrexia and fever, or hyperthermia, due to overwhelming bacterial infection. In Medicine, a pulsus paradoxus (PP also paradoxic pulse and paradoxical pulse, is an exaggeration of the normal variation in the pulse during the inspiratory Hyperthermia, in its advanced state referred to as heat stroke or sunstroke, is an acute condition which occurs when the Body produces or absorbs more
  • Vasodilation and increased cardiac output due to sepsis. Cardiac output (Q is the volume of blood being pumped by the Heart, in particular by a ventricle in a minute Sepsis is a serious medical condition characterized by a whole-body inflammatory state (called a Systemic inflammatory response syndrome or SIRS caused
• Neurogenic shock, similar to hypovolaemic shock except in the skin's characteristics. In neurogenic shock, the skin is warm and dry.
• Anaphylactic shock
  • Skin eruptions and large welts.
  • Localised edema, especially around the face. Oedema (or Edema in American English formerly known as dropsy or hydropsy, is the increase of Interstitial fluid in any organ &mdash swelling
  • Weak and rapid pulse.
  • Breathlessness and cough due to narrowing of airways and swelling of the throat. Bronchospasm is a sudden constriction of the muscles in the walls of the Bronchioles It is caused by the release ( Degranulation) of substances from Mast cells Oedema (or Edema in American English formerly known as dropsy or hydropsy, is the increase of Interstitial fluid in any organ &mdash swelling

Treatment

Modified and adapted from Alexander M. F. , Fawcett J. N. and Runciman, P. N. (2004) Nursing Practice. The Hospital and Home. The Adult. (2nd edition) Edinburgh: Churchill Livingstone

In the early stages, shock requires immediate intervention to preserve life. Therefore, the early recognition and treatment depends on the transfer to a hospital.

The management of shock requires immediate intervention, even before a diagnosis is made. Re-establishing perfusion to the organs is the primary goal through restoring and maintaining the blood circulating volume ensuring oxygenation and blood pressure are adequate, achieving and maintaining effective cardiac function, and preventing complications. Patients attending with the symptoms of shock will have, regardless of the type of shock, their airway managed and oxygen therapy initiated. In case of respiratory insufficiency (i. Respiratory failure is a medical term for inadequate Gas exchange by the Respiratory system. e. diminished levels of consciousness, hyperventilation due to acid-base disturbances or pneumonia) intubation and mechanical ventilation may be necessary. The Glasgow Coma Scale or GCS, sometimes also known as the Glasgow Coma Score is a neurological scale which aims to give a reliable objective In Medicine, hyperventilation (or overbreathing) is the state of Breathing faster and/or deeper than necessary bringing about lightheadedness and other Pneumonia is an inflammatory illness of the Lung. Frequently it is described as lung Parenchyma / alveolar inflammation and abnormal In Medicine, intubation refers to the placement of a tube into an external or internal orifice of the body In Medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing when patients cannot do so on their own A paramedic may intubate in emergencies outside the hospital, whereas a patient with respiratory insufficiency in-hospital will be intubated usually by a physician. The Emergency Medical Technician ( EMT) exists in many countries and is a health care provider trained to provide prehospital emergency medical care A physician, medical practitioner or medical doctor who practices Medicine, and is concerned with maintaining or restoring human Health

The aim of these acts is to ensure survival during the transportation to the hospital; they do not cure the cause of the shock. Specific treatment depends on the cause.

A compromise must be found between:

• raising the blood pressure to be able to transport "safely" (when the blood pressure is too low, any motion can lower the heart and brain perfusion, and thus cause death);
• respecting the golden hour. In Emergency medicine, the golden hour is the first sixty minutes after the occurrence of multi-system trauma If surgery is required, it should be performed within the first hour to maximise the patient's chance of survival.

This is the stay and play versus the load and go debate.

Hypovolaemic shock

In hypovolaemic shock, caused by bleeding, it is necessary to immediately control the bleeding and restore the victim's blood volume by giving infusions of balanced salt solutions. In Physiology and Medicine, hypovolemia (also hypovolaemia is a state of decreased Blood volume more specifically decrease in volume of Blood plasma Bleeding, technically known as hemorrhaging / haemorrhaging (see American and British spelling differences) is the loss of Blood from Blood transfusions are necessary for loss of large amounts of blood (e. Blood transfusion is the process of transferring Blood or blood-based products from one person into the Circulatory system of another g. greater than 20% of blood volume), but can be avoided in smaller and slower losses. Hypovolaemia due to burns, diarrhoea, vomiting, etc. In Physiology and Medicine, hypovolemia (also hypovolaemia is a state of decreased Blood volume more specifically decrease in volume of Blood plasma is treated with infusions of electrolyte solutions that balance the nature of the fluid lost. Sodium is essential to keep the fluid infused in the extracellular and intravascular space whilst preventing water intoxication and brain swelling. Metabolic acidosis (mainly due to lactic acid) accumulates as a result of poor delivery of oxygen to the tissues, and mirrors the severity of the shock. In Medicine, metabolic acidosis is a process which if unchecked leads to acidemia (i It is best treated by rapidly restoring intravascular volume and perfusion as above. Inotropic and vasoconstrictive drugs should be avoided, as they may interfere in knowing blood volume has returned to normal. ^[1][2][3][4]

Regardless of the cause, the restoration of the circulating volume is priority. As soon as the airway is maintained and oxygen administered the next step is to commence replacement of fluids via the intravenous route.

Opinion varies on the type of fluid used in shock. The most common are:

• Crystalloids - Such as sodium chloride (0. 9%), or Hartmann's solution (Ringer's lactate). Dextrose solutions which contain free water are less effective at re-establishing circulating volume, and promote hyperglycaemia.
• Colloids - For example, synthetic albumin (Dextran), polygeline (Haemaccel), succunylated gelatin (Gelofusine) and hetastarch (Hepsan). Colloids are, in general, much more expensive than crystalloid solutions and have not conclusively been shown to be of any benefit in the initial treatment of shock.
• Combination - Some clinicians argue that individually, colloids and crystalloids can further exacerbate the problem and suggest the combination of crystalloid and colloid solutions.
• Blood - Essential in severe haemorrhagic shock, often pre-warmed and rapidly infused.

Vasoconstrictor agents have no role in the initial treatment of hemorrhagic shock, due to their relative inefficacy in the setting of acidosis, and because the body, in the setting of hemorrhagic shock, is in an endogenously catecholaminergic state. Definitive care and control of the hemorrhage is absolutely necessary, and should not be delayed.

Cardiogenic shock

In cardiogenic shock, depending on the type of myocardal infarction, one can infuse fluids or in shock refractory to infusing fluids, inotropic agents. Cardiogenic shock is based upon an inadequate circulation of Blood due to primary failure of the ventricles of the Heart to function effectively An inotrope (ˈaɪnətroʊp is an agent that alters the force or energy of Muscular contractions Negatively inotropic agents weaken the force of muscular contractions Inotropic agents, which enhance the heart's pumping capabilities, are used to improve the contractility and correct the hypotension. Should that not suffice, an intra-aortic balloon pump can be considered (which reduces the workload for the heart and improves perfusion of the coronary arteries) or a left ventricular assist device (which augments the pump-function of the heart. The Intra-aortic balloon pump (IABP is a mechanical device that is used to decrease myocardial oxygen demand while at the same time increasing Cardiac output. In cardiac Physiology, afterload is used to mean the tension produced by a chamber of the Heart in order to contract. Coronary circulation is the circulation of blood in the Blood vessels that supply Blood to and from the Heart muscle A Ventricular assist device, or VAD, is a mechanical device that is used to partially or completely replace the function of a failing Heart. )^[1][2][3][4]

The main goals of the treatment of cardiogenic shock are the re-establishment of circulation to the myocardium, minimising heart muscle damage and improving the heart's effectiveness as a pump. This is most often performed by percutaneous coronary intervention and insertion of a stent in the culprit coronary lesion or sometimes by cardiac bypass.

Although this is a protection reaction, the shock itself will induce problems; the circulatory system being less efficient, the body gets "exhausted" and finally, the blood circulation and the breathing slow down and finally stop (cardiac arrest). A cardiac arrest, also known as cardiorespiratory arrest, cardiopulmonary arrest or circulatory arrest, is the abrupt cessation of normal circulation of The main way to avoid this deadly consequence is to make the blood pressure rise again with

• fluid replacement with intravenous infusions;
• use of vasopressing drugs (e. In Pharmacology and Toxicology, a route g. to induce vasoconstriction);
• use of anti-shock trousers that compress the legs and concentrate the blood in the vital organs (lungs, heart, brain). Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels particularly the large Arteries, Arterioles Military Anti-Shock Trousers are medical devices used to treat severe blood loss
• use of blankets to keep the patient warm - metallic PET film emergency blankets are used to reflect the patient's body heat back to the patient. Biaxially-oriented Polyethylene terephthalate (boPET Polyester film is used for its high Tensile strength, Chemical and dimensional Stability

Distributive shock

In distributive shock caused by sepsis the infection is treated with antibiotics and supportive care is given (i. Distributive shock is as in Hypovolemic shock, caused by an insufficient Intravascular volume of Blood. In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa e. inotropica, mechanical ventilation, renal function replacement). An inotrope (ˈaɪnətroʊp is an agent that alters the force or energy of Muscular contractions Negatively inotropic agents weaken the force of muscular contractions In Medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing when patients cannot do so on their own In Medicine, hemodialysis (also haemodialysis) is a method for removing waste products such as Potassium and Urea, as well as free water Anaphylaxis is treated with adrenaline to stimulate cardiac performance and corticosteroids to reduce the inflammatory response. Anaphylaxis is an acute systemic (multi-system and severe Type I Hypersensitivity allergic reaction in humans and other Mammals Corticosteroids are a class of Steroid hormones that are produced in the Adrenal cortex. In Medicine, systemic inflammatory response syndrome ( SIRS) is an inflammatory state of the whole body (the "system" without a proven source In neurogenic shock because of vasodilation in the legs, one of the most suggested treatments is placing the patient in the Trendelenburg position, thereby elevating the legs and shunting blood back from the periphery to the body's core. Neurogenic shock is shock caused by the sudden loss of the Autonomic nervous system signals to the Smooth muscle in vessel walls However, since bloodvessels are highly compliant, and expand as result of the increased volume locally, this technique does not work. More suitable would be the use of vasopressors. Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels particularly the large Arteries, Arterioles ^[1][2][3][4]

Obstructive shock

In obstructive shock, the only therapy consists of removing the obstruction. Pneumothorax or haemothorax is treated by inserting a chest tube, pulmonary embolism requires thrombolysis (to reduce the size of the clot), or embolectomy (removal of the thrombus), tamponade is treated by draining fluid from the pericardial space through pericardiocentesis. A hemothorax (or haemothorax) is a condition that results from blood accumulating in the Pleural cavity. A chest tube ( chest drain or tube thoracostomy) is a flexible plastic tube that is inserted through the side of the chest into the pleural space. Thrombolysis is the breakdown ( lysis) of blood clots by pharmacological means A thrombus, or blood clot, is the final product of the Blood coagulation step in Hemostasis. The pericardium is a double-walled sac that contains the Heart and the roots of the Great vessels. In Medicine, pericardiocentesis is a procedure where fluid is aspirated from the Pericardium (the sac enveloping the Heart) ^[1][2][3][4]

Endocrine shock

In endocrine shock the hormone disturbances are corrected. Hypothyroidism requires supplementation by means of levothyroxine, in hyperthyroidism the production of hormone by the thyroid is inhibited through thyreostatica, i. Hypothyroidism is the disease state in humans and animals caused by insufficient production of Thyroid hormone by the Thyroid gland. Levothyroxine, also known as L-thyroxine, synthetic T4, or 353'5'-tetraiodo-L-thyronine, is a synthetic form Hyperthyroidism is the term for overactive tissue within the Thyroid gland resulting in overproduction and thus an excess of circulating free thyroid hormones Thyroxine The thyroid is one of the largest Endocrine glands in the body e. methimazole (Tapazole) or PTU (propylthiouracil). Methimazole (also known as Tapazole) is an antithyroid drug similar in action to Propylthiouracil, and part of the Thioamide Propylthiouracil ( PTU) or 6-N-Propylthiouracil (PROP is a Thioamide drug used to treat Hyperthyroidism by decreasing the amount of Adrenal insufficiency is treated by supplementing corticosteroids. ^[1]

Prognosis

The prognosis of shock depends on the underlying cause and the nature and extent of concurrent problems. Hypovolemic, anaphylactic and neurogenic shock are readily treatable and respond well to medical therapy. Septic shock however, is a grave condition and with a mortality rate between 30% and 50%. The prognosis of cardiogenic shock is even worse. ^[1]

Shock is said to evolve from reversible to irreversible in experimental hemorrhagic shock involving certain animal species (dogs, rats, mice) that develop intense vasoconstriction of the gut. Death is due to hemorrhagic necrosis of the intestinal lining when shed blood in reinfused. In pigs and humans 1) this is not seen and cessation of bleeding and restoration of blood volume is usually very effective; however 2) prolonged hypovolemia and hypotension does carry a risk of respiratory and then cardiac arrest. Perfusion of the brain may be the greatest danger during shock. Therefore urgent treatment (cessation of bleeding, rapid restoration of circulating blood volume and ready respiratory support) is essential for a good prognosis in hypovolemic shock.

See also

• Acute respiratory distress syndrome (ARDS)
• Military Anti-Shock Trousers
• Physical trauma
• Sepsis
• Stress (medicine)
• Systemic inflammatory response syndrome (SIRS)

Notes

References

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