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| ==Treatment==
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| [[Image:Shocktherapy2.png|thumb|300px|left|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]]
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| ===General Principles===
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| The management of shock can be difficult. There are several basic modalities
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| ===Look for and treat the cause===
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| Perhaps obvious but often overlooked. If patients are bleeding they need [[blood]] and the bleeding stopped. Treating [[hypotension]] due to variceal bleeding with [[inotrope]]s is doomed. A Sengstaken tube or [[endoscopy]] with definitive treatment more promising.
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| In those with [[ischaemic heart disease|IHD]] an urgent angiogram with PCI may reperfuse hibernating myocardium and improve the situation. An [[intra-aortic balloon pump]] may augment coronary and cerebral [[perfusion]] from a failing myocardium as a bridge to a definite procedure. [[Pericardiocentesis|Drainage of pericardial fluid]] might restore haemodynamics quickly.
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| ===Restoring Physiology===
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| See [[Trendelenburg position]]
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| In general, address the pathophysiology in this order:
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| #[[Heart rate]]
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| #[[Preload]]
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| #[[Afterload]]
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| #[[Inotrope|Contractility]]
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| ====Fluid resuscitation====
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| Vital in most cases. In those with cardiac disease, excessive [[intravenous fluids|fluid]] may cause [[pulmonary oedema]] and so should be used judiciously. A CVP line is then indicated or even better a measurement of LVEDP. However be aware that numbers can be wrong and treat the whole patient.
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| *crystalloid versus [[colloid]] debate
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| *[[blood transfusion|blood]]
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| *hypertonic solutions
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| ====Vasoactive Drugs====
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| (incl. [[vasopressor]]s, [[inotrope]]s and [[chronotrope]]s)
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| *[[Epinephrine]]
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| *[[Norepinephrine]]
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| *[[Dopamine]]
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| *[[Dobutamine]]
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| ===Evidence and Clinical Condition Based Management===
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| In the early stages, shock requires immediate intervention to preserve life. Therefore, the early recognition and treatment depends on the transfer to a hospital.
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| 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.e. [[Glasgow Coma Scale|diminished levels of consciousness]], [[hyperventilation]] due to [[acid-base]] disturbances or [[pneumonia]]) [[intubation]] and [[mechanical ventilation]] may be necessary. A [[emergency medical technician|paramedic]] may intubate in emergencies outside the hospital, whereas a patient with respiratory insufficiency in-hospital will be intubated usually by a [[physician]].
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| 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.
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| A compromise must be found between:
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| * 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);
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| * respecting the [[golden hour (medicine)|golden hour]]. If surgery is required, it should be performed within the first hour to maximise the patient's chance of survival.
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| This is the ''stay and play'' versus the ''load and go'' debate.
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| ===Hypovolemic shock===
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| In [[hypovolemic 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. [[Blood transfusion]]s are necessary for loss of large amounts of blood (e.g. greater than 20% of blood volume), but can be avoided in smaller and slower losses. [[Hypovolaemia]] due to burns, diarrhoea, vomiting, etc. 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. 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.<ref name="IrwinRippe"/><ref name="Marino"/><ref name="FCCS"/><ref name="InternalMedicine"/>
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| 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.
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| Opinion varies on the type of fluid used in shock. The most common are:
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| *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.
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| *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.
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| *Combination - Some clinicians argue that individually, colloids and crystalloids can further exacerbate the problem and suggest the combination of crystalloid and colloid solutions.
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| *Blood - Essential in severe hemorrhagic shock, often pre-warmed and rapidly infused.
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| Vasoconstrictor agents have no role in the initial treatment of hemorrhagic shock, due to their relative inefficacy in the setting of acidosis, and due to the fact that 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.
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| ===Cardiogenic shock===
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| In [[cardiogenic shock]], depending on the type of myocardal infarction, one can infuse fluids or in shock refractory to infusing fluids, [[Inotrope|inotropic agents]]. 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 [[afterload|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.)<ref name="IrwinRippe"/><ref name="Marino"/><ref name="FCCS"/><ref name="InternalMedicine"/>
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| 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.
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| 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]]). The main way to avoid this deadly consequence is to make the blood pressure rise again with
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| * fluid replacement with [[intravenous infusion]]s;
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| * use of vasopressing drugs (e.g. to induce [[vasoconstriction]]);
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| * use of [[Military Anti-Shock Trousers|anti-shock trousers]] that compress the legs and concentrate the blood in the vital organs (lungs, heart, brain).
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| * use of blankets to keep the patient warm - metallic [[PET film (biaxially oriented)|PET film]] emergency blankets are used to reflect the patient's body heat back to the patient.
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| ===Distributive shock===
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| In [[distributive shock]] caused by sepsis the infection is treated with [[antibiotic]]s and supportive care is given (i.e. [[Inotrope|inotropica]], [[mechanical ventilation]], [[hemodialysis|renal function replacement]]). [[Anaphylaxis]] is treated with [[adrenaline]] to stimulate cardiac performance and [[corticosteroid]]s to reduce the [[SIRS|inflammatory response]]. 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. 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 [[vasoconstrictor|vasopressors]].<ref name="IrwinRippe"/><ref name="Marino"/><ref name="FCCS"/><ref name="InternalMedicine"/>
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| ===Obstructive shock===
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| 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 [[pericard]]ial space through [[pericardiocentesis]].<ref name="IrwinRippe"/><ref name="Marino"/><ref name="FCCS"/><ref name="InternalMedicine"/>
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| ===Endocrine shock===
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| 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.e. [[methimazole]] (Tapazole®) or PTU ([[propylthiouracil]]). Adrenal insufficiency is treated by supplementing corticosteroids.
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| <ref name="IrwinRippe"/>
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| ==Related Chapters== | | ==Related Chapters== |