Shock

Question 1

Define shock

Answer 1

-An acute circulatory crisis marked by hypotension and inadequate blood flow

-this can be severe and potentially fatal symptoms develop as the tissues become starved of oxygen and nutrients

Question 2

What are the 3 basic stages of shock?

Answer 2

1. compensatory stage- when arterial pressure and tissue perfusion are reduced, compensatory mechanisms are activated to maintain perfusion to the heart and brain- warm stage
2. progressive stage- begins as compensatory mechanism fail to maintain cardiac output and tissues become hypoxic because of poor perfusion- cold stage
3. irreversible or refractory stage- as shock syndrome progresses, permanent organ damage occurs as compensatory mechanisms can no longer maintain cardiac output

Question 3

How is shock treated and cared for?

Answer 3

-re-establish haemodynamic stability (fluid bolus up to 100mls/ kilo can be given to replace circulating volume, but can dilute haemoglobin)

-establish adequate ventilation and oxygenation (oxygen given with a non rebreathe mask)

-medications such as inotropic (change force of heart contractions), antibiotics, noradrenaline

-increase cardiac function by reducing the work and improving efficiency of the heart

-provide adequate nutrition and metabolic state

-prevent any complications that result

Question 4

What are the possible complications of shock?

Answer 4

-acute respiratory distress syndrome (ARDS)
-acute kidney injury (AKI)
-multi-organ dysfunction (MODS)
-disseminated intravascular coagulation (DIC)

Question 5

What is preload?

Answer 5

the stretching of the heart muscle before contraction and the volume of blood in the heart’s chambers at the end of diastole

Question 6

What is contractility?

Answer 6

force exterted by myocardium to push blood out into aorta or pulmonary artery

Question 7

What is afterload?

Answer 7

the amount of resistance the heart must overcome to open the aortic valve and push the blood volume out into the systemic circulation

Question 8

Explain the pathophysiology of shock?

Answer 8

-Blood circulating volume affects cardiac output, which creates arterial blood pressure

-if BCV drops, cardiac output drops, which causes hypoxia in tissues from inadequate perfusion

-this causes acidosis and vasoconstriction, which increases BP, but acidosis can also result in multi-organ failure

-arterial BP decreases renal blood flow, possibly causing renal failure

-reduced renal blood flow causes the RAAS response in the distal convoluted tubule, which increases water retention and therefore BCV increases

-infection or increased acidosis causes more tissue mediators to be released, which can result in arteriolar and capillary dilation, which can increase permeability, making them leaky, reducing BCV

Question 9

Explain the symptoms of shock and what causes them

Answer 9

-increased respiratory rate= helps alleviate systemic acidosis by removing excess CO2
-gradual drop of oxygen saturation= less blood flow around body= hypoxia

-increased HR (tachycardia)= heart pumping faster and harder to keep blood circulating
-falling BP= able to compensate, a pre terminal sign, of the last signs, indicating cardiac arrest may occur
-increased capillary refill time and cold hands and feet= body shutting down peripherally

-decrease in conscious level and pupil change= reduced blood flow to brain and dropping BP

-reduced urine output= indicates low BCV

-temperature changes

Question 10

What are the 3 causes of shock?

Answer 10

1. Hypovolaemia= loss of fluid (BCV) occurs as a result of dehydration, D&V, injury, trauma
2. Cardiogenic= inadequate pump, issues with contractibility, heart failure may occur as a result of congenital anomalies, infections, myopathy
3. distributive= can be anaphylactic shock (allergen), neurogenic (spinal injury), or septic (infection). Hypotension may occur in this type of shock