Shock Flashcards
Definition of shock
Shock is a life-threatening condition. It’s the end condition of someone that has been deteriorating. Acute circulatory failure with inadequate or inappropriately distributed tissue perfusion resulting in generalised hypoxia and tissue cells are deprived of oxygen – leading to anaerobic metabolism to produce ATP and a lactate acid as a byproduct (metabolic acidosis).
What are the three stages of shock?
- Compensation
- Progressive
- Decompensated
What happens in the stages of compensation?
- Triggering of body’s natural mechanisms in an attempt to maintain adequate BP and tissue perfusion.
- Baroreceptors stimulate systematic vasoconstriction of the arterioles, kidneys and other abdominal viscera and an increase in the release of adrenaline and noradrenaline by the adrenal medulla. High RR- more oxygen perfusion. Chemoreceptors will increase HR- depending on the woman and her situation when the body tries to compensate. These are only subtle changes in colour, temperature and vital signs. The patient may complain of nausea and can be mildly agitated and restless.
- The release of antidiuretics hormone stimulated the kidneys to retain water and sodium resulting in reduced urine output- client possibly complaining of a dry mouth.
- If cells experience hypoxia, vasodilators, increases regional blood supply lower BP
What happens in the progressive stage?
- The compensatory mechanisms begin to fail.
- The patient will experience cardiac depression as the BP will start to decrease and excessive tachycardia leads to poor coronary artery perfusion- leading to myocardial ischaemia -> the release of myocardial depression factor, further compromising cardiac functions.
- Hypoxia leads to an increase in blood capillary permeability leading to an inappropriate fluid shift and further blood volume loss (leads to ventilation) falling cardiac output and intensified hypoxia (leads to platelets aggregation).
- The release of catacholamines, the production of lactic acid and the loss of cell wall permeability contribute to acidosis. The patient will display symptoms ranging from reduced neurological function and tachypnoea, to peripheral oedema
What happens in the decompensated stage?
- At this stage, the vital organs have failed and the shock can no longer be reversed. Brain damage and cell death have occurred. Death will occur imminently
What are the three main types of shock?
- Cardiogenic Shock
- Hypovolaemic Shock
- Distributive Shock
What are the signs and symptoms of cardiogenic shock?
Heart (left ventricle) unable to pump adequate blood into the aorta for transport around the rest of the body
- Decreased pumping ability
- Myocardial infarction
- Cardiac arrest
- Cardiomyopathy
- Cardiac failure
- Cardiac tamponade: is a clinical syndrome caused by the accumulation of fluid in the pericardial (a sac around the heart) space, resulting in reduced ventricular filling and subsequent hemodynamic compromise.
When can a cardiac shock occur?
- May result from electrocution/electric shock
o Obstructive shock - In pregnancy, cardiac complications fall into two categories:
o Complications due to clients presenting pregnant with pre-existing diseases
o Those who become compromised during pregnancy.
What are the consequences of a cardiogenic shock?
- Inadequate cardiac output; pulmonary oedema; reduced coronary artery perfusion; decreased systemic perfusion; organ impairment
Treatment for cardiogenic shock?
Aim - improve myocardial contractility, maintain blood pressure and tissue perfusion/oxygenation
- Oxygen therapy
- Morphine/diamorphine (dilate coronary BVs; analgesia; sedation; risk of respiratory impairment)
- Antiemetics
- 12-lead ECG + cardiac monitoring
- CVP monitoring
- Arterial ‘line’ for monitoring BP
- Inotropes (drugs to improve heart muscle contractility), e.g. dobutamine
- Vasodilator drugs
- Glyceryltrinitrate (GTN)- a spray used to relieve angina
What is hypovolaemic shock?
refers to the loss of extracellular fluid
- Too little fluid in the right place
- Normal blood volume increased in pregnancy
Fluid lost from the intravascular compartment
- Haemorrhage
- Fluid loss from GI tract; dehydration, hyperemesis and diarrhoea.
- Mass movement of fluid into another ‘compartment’- lungs
What are the signs of hypovolaemic shock?
- Tachycardia (catecholamines + increase in sympathetic activity)
- Weak pulse ( increase in stroke volume)
- Rise in diastolic BP initially (vasoconstriction)
- Cool periphery (vasoconstriction)
- Low urine output (diversion of renal blood flow)
- Concentrated urine ( increase in sodium and water reabsorption)
- Increased respiratory rate
- Nausea (blood diverted away from GI tract)
- Sweating (catecholamines)
- Increased blood glucose level (stress response; glycogen converted to glucose)
- Confusion/anxiety (stress response + catecholamines)
- Vital signs may remain near normal until more than 35% of the blood volume is lost (1200-1500ml)
- Tachycardia may be attributed to pain, stress, activity, labour, pregnancy
- Blood pressure may not alter until the client’s compensatory mechanisms are stretched to their limits
What are the causes oh hypovolaemia in pregnancy?
- Obstetric haemorrhage
- Ruptured ectopic pregnancy
What are the medical investigations that needs to be done for hypovoalemic shock?
- Central venous pressure (CVP)- anaesthetics
o Monitor body fluid volume
o Evaluate effectiveness of fluid replacement therapy - Arterial Line –BP & blood gas analysis (ABG)- vertical incision as there is a lot of pressure
- Blood tests
o FBC (Hb, haematocrit, red cell count)
o U&Es (urea and electrolytes), glucose, clotting screen, lactate - Electrocardiography (ECG)
- IDC in situ
What are the signs of inadequate organ/tissue perfusion?
- Metabolic Acidosis (anaerobic metabolism)
- Decreased arterial O2
- Chest pain
- Shortness of breath
- Cardiac dysrhythmia (seen on ECG)- is a disturbance in the rate of cardiac muscle contractions, or any variation from the normal rhythm or rate of heartbeat.
- Altered level of consciousness (GCS)- Glasgow Coma Scale (high-15 and low-3)
- Oliguria anuria- failure of the kidneys to produce urine
