Shock Flashcards
Shock
Shock is a clinical state in which the delivery of oxygenated blood (and the other nutrients such as glucose) to the body’s tissues is not adequate to meet metabolic demand.
Types of shock
Cardiogenic shock
Hypovolaemic shock
Obstructive shock
Distributive shock
Dissociative shock
Signs of hypovolaemic shoc
Pallor
Cool peripheries
Anxiety and abnormal behaviour
Increased heart rates and respiratory rates
Distributive shock
anaphylaxis
This kind of shock is caused by widespread dilation of the peripheral vascular system because of dilation in the arterioles and / or venules.
This in effect creates a larger container for the same blood volume, leading to decreased tissue perfusion.
In cases such as anaphylaxis and sepsis, the vessels become leaky, allowing fluid to escape into the tissue and so becoming removed from the general circulation.
Common causes of distributive shock include:
Anaphylaxis
Sepsis
Nervous system related causes such as a spinal cord injury (neurogenic shock)
Neurogenic shock
Neurogenic shock is circulatory failure caused by paralysis of the nerves that control the size of the blood vessels, leading to widespread dilation; seen in spinal cord injuries
Distributive shock
Clinical features
Nervous system
Circulatory system
Hypotension (BP often <80-90mmHg) with bradycardia
Warm peripheries or vasodilation in the presence of low blood pressure
Cardiogenic shock
This is due to a primary cardiac problem when the heart is unable to circulate sufficient blood to meet the body’s metabolic needs.
This is most common following a myocardial infarction, but can also be caused by acute heart failure or arrhythmia.
Cardiogenic shock
Clinical features
Central chest pain
Crushing or constricting in nature
Persist for >15 minutes
Pain may also present in the shoulders, upper abdomen, referred to neck, jaw and arms
Typically comes on over seconds and minutes rather than starting abruptly
Nausea/vomiting
Marked sweating
Breathlessness
Pallor
Combination of chest pain and haemodynamic instability
Feelings of impending doom
Skin that is clammy and cold to touch
Many patients do not have ‘classic presentation’ – some people especially the elderly and those with diabetes may not experience pain as the chief complaint.
Heart Failure Left Heart Failure
Blood flow ‘backs up’
Fluid from blood vessels leaks into lung tissue
Right Heart Failure
Blood flow ‘backs up’
Fluid from blood vessels leaks into body tissue
Cardiogenic shock
Causes
Causes
MI COPD PE LHF Valve disease
Cardiogenic shock
Clinical Presentation
Tachypnoea Crackles Dullness to percussion Reduced SpO2 Haemoptysis Tachycardia Peripheral oedema Hepatomegaly Ascites Oliguria Shortness of breath
Dyspnoea Orthopnoea Fatigue Paroxysmal nocturnal dyspnoea Reduced exercise tolerance Ankle swelling
Cardiogenic shock
Clinical sign
Pulmonary oedema – crackling on auscultation of lung
Productive cough – white/pink frothy sputum
Peripheral oedema
Raised JVP
Third heart sound (S3)
Obstructive shock
This is an uncommon cause of shock and is due to an obstruction of blood flow to/from the heart.
It can be caused by a tension pneumothorax, cardiac tamponade or a massive pulmonary embolism.
Cardiac tamponade
Obstructive shock
Cardiac tamponade – restriction of cardiac contraction, failing cardiac output, and shock, caused by the accumulation of blood in the pericardium
Beck’s Triad
Muffled heart sounds
Decreased blood pressure
Jugular vein distension
Obstructive shock
Pulmonary embolism
Clinical signs
Dyspnoea Pleuritic chest pain Substernal chest pain Apprehension Cough Haemoptysis Syncope Resp rate >20bpm Pulse rate >100 bpm SpO2 <92% Signs of deep vein thrombosis (DVT) Unilateral swelling of lower calf Warm, red, painful, tender calf
Tension pneumothorax
Obstructive shock
Tension pneumothorax – air enters the pleural cavity on inspiration, but can not escape during expiration due to the presence of a one-way valve formed by a pleural defect.
This leads to increasing intra-pleural pressure on the effected side of the chest, worsening the lung collapse and causing diaphragmatic depression.
In severe cases, and dependent on mediastinal distensibility, the can compress the contralateral lung.
Obstructive shock
Clinical signs
Tension pneumothorax
Pleuritic chest pain (sharp pain, worse on breathing in and out) Air hunger Respiratory distress Tachypnoea Tachycardia Failing SpO2 Agitation On the same side of the injury: Hyper-expansion Hypo-mobility Decreased breath sounds Pre-terminal Decreasing respiratory rate Hypotension Decreasing level of consciousness
Obstructive shock
Respiratory conditions
Cardiovascular conditions
Chest injuries
Dissociative shock
This occurs when the oxygen-carrying capability of the blood is affected because of inadequate numbers of red blood cells available to carry sufficient oxygen (anaemia).
Dissociative shock
Blood consists of 55% plasma and 45% red cells, white cells and platelets.
Ambulance Care Practice p220
Oxygen is carried in the blood in chemical combination with haemoglobin as oxyhaemoglobin (98.5%) and in solution in plasma (1.5%)
Dissociative shock
Signs and symptoms of anaemia
Tachycardia
Palpitations or angina pectoris
Breathlessness on exertion
Can also occur when competing molecules take up space on the red blood cells that would normally be used to carry oxygen, such as in cases of carbon monoxide poisoning.
Dissociative shock
Clinical presentation
Disorientation
Decreased consciousness
The supposed cherry red skin discoloration is rarely seen in practice
Sickle Cell Disease
Dissociative shock
Sickle cell disease is a red blood cell disorder characterised by haemolysis and vaso-occlusion.
SCD is a multi-organ disease, leading to a range of symptoms and complications often termed ‘sickle cell crisis.
Pain is often a presenting symptom.
Sickle Cell Disease
Dissociative shock
Clinical presentation
Severe pain, most common in the long bones and/or joints of the arms and legs, but also in the back and abdomen
Stroke
High temperature
Difficulty in breathing, reduced SpO2, cough and chest pain may indicate acute chest syndrome Pallor Tiredness/weakness Dehydration Headache Priapism
Dissociative shock
Cardiovascular system
Sepsis
Sepsis is a clinical syndrome caused by the body’s immune and coagulation systems being switched on by an infection.
Sepsis with shock is a life-threatening condition that is characterised by low blood pressure despite adequate fluid replacement, and organ dysfunction or failure.
Sepsis
Pathophysiology
The local inflammatory response is not contained.
Cytokines are signalling chemicals which co-ordinate the inflammatory response. A cytokine storm creates a systemic inflammatory response.
SIRS is not always related to infection and can be caused by ischemia, inflammation or trauma.
Sepsis screening and treatment
tools
Anaphylaxis
Anaphylaxis is a serious allergic reaction that is rapid in onset and may cause death.
Its hallmark is rapidly developing life-threatening airway/breathing/circulation problems (in any combination) and it is usually associated with skin and mucosal changes.
Anaphylaxis
Envenomation typically causes cardiac arrest within 15 minutes, and food takes on average around 30 minutes
Anaphylaxis
Clinical Presentation
Urticaria Itching Angio-oedema Petechial or purpuric rash Dyspnoea Clinical Presentation
Wheeze Stridor Hypoxia Hypotension Abdominal pain Diarrhoea/vomiting
JRCALC p 155
Anaphylaxis
Administration of medication - Intramuscular injections
