What ways can absolute fluid loss occur?
- External haemorrhage
- Internal haemorrhage
o Concealed and revealed
Concealed may come out mouth or anus - Plasma loss (burns)
- Water and minerals
o Dehydration
o Diarrhoea and vomiting
o Decreased fluid intake
o Excessive diuresis
What constitutes as a significant haemorrhage?
- Adults – 1,000mls
- Child – 500mls
- Infant - 100 – 200mls
What are signs and symptoms of a PT with absolute fluid loss or a significant haemorrhage?
- Altered conscious state
o Most likely later sign - Skin – pale, cool, clammy
- Dizziness
- Nausea +/- Vomiting
o Consequence of vagal stimulation - Increase respirations
- Increased Heart rate – rapid weak thread
- BLOOD PRESSURE – Hypotension as a late sign
o This will be maintained during the compensatory process as adults generally have extra blood vessels floating about.
What is relative fluid loss?
- Blood volume remains essentially the same, but the blood vessels capacity is increased due to vasodilation.
- Plasma moves into the interstitial space due to increased permeability of vessel walls.
o This can be seen in anaphylaxis
What does relative fluid loss mean for the bodies blood volume?
- It will remain essentially the same, but the ability of the cardiovascular system to maintain adequate perfusion pressure is adversely affected.
What are causes of relative fluid loss?
- Neural mediated causes o Syncope / fainting o Pain o Emotion - Sepsis - Anaphylaxis - Vasoactive drugs and substances o For example, GTN, morphine - Spinal injury
What are signs and symptoms of relative fluid loss?
- Altered conscious state
- Nausea, dizziness +/- vomiting
- Skin; may be warm and flushed due to pooing in the periphery of pale and cool.
- Tachypnoea
- Tachycardia
- Hypotension
o Recent collapse or fainting
What causes may impair oxygen transport?
- Insufficient cardiac output
o Myocardial hypoxia
Form of hypoxia due to the myocardium being able to transport oxygen to the tissues - Low RBC count
o Anaemic hypoxia - Low systemic vascular resistance and perfusion pressure
o This is generally neuro mediated
What are the results of impaired oxygen transport?
- Anaerobic metabolism
- Failure of sodium-potassium pumps
- Acidosis
- Sever tissue ischemia/tissue death
- Death of the organism
What are the mechanics of blood pressure?
- Blood pressure is reliant upon two main factors, stroke volume and peripheral resistance.
What occurs when BP drops ion the body?
- The body initiates compensatory mechanisms
o Increasing myocardial contractility (Cardiac output) also referred to as inotroping
o Promote peripheral vasoconstriction
o Tachycardia may accompany this increase myocardial contractility but they are not actively linked together.
Define shock.
- A continuing process defined by a chain of events leading to widespread reduction in tissue perfusion and subsequent impairment of cellular metabolism
- Shock is a continuing process not a condition.
o Shock will continue until interventions are initiated. - Shock may result from a variety of disease states and injuries. If the process involved in the condition are not stopped the patients will die.
What is shock in terms related to body systems?
- An inability of the cardiovascular system to adequately maintain perfusion
What is perfusion mediated by?
- Perfusion is mediated by the cardiovascular system which is reliant upon the following three mechanisms.
o Heart as a pump
o Vessels as a container both the arterial arteries and veins
o Blood as it creates volume.
What are the stages of shock if left untreated?
- Compensation
- Decompensation
- Irreversible
What factors determine how fast a PT will travel through the stages of shock?
- It is highly dependent on what has caused it and what interventions are put in place.
How is blood pressure determined?
- Heart Rate X Stroke Volume = Cardiac Output X Peripheral Vascular Resistance = Blood Pressure
- ↑ HR x SV = CO x PVR = BP
What factors are altered for BP to be maintained in compensated shock?
- When need to increase our cardiac output or peripheral vascular resistance to maintain blood pressure.
o Heart Rate may be increased (cronotroping)
o Stroke volume with definitely be increased (inotroping, increasing the force of contraction)
What are you signs in symptoms in PT that is in a compensating state?
- Tachycardia
- Slightly Pale
- BP will remain stable. However, you may see a slight rise in systolic BP as pulse pressure increases.
What are some warning signs of the PT that is in the compensatory stage?
- A reduced mental state/ agitation in this Pt is likely due to decreased cerebral perfusion.
- The Pt stating that they feel as though they are going to die is highly likely that they are.
o This statement lets us need to know what we have missed and act on it! - These Pt may be difficult to cannulate due to the peripheral vasoconstriction.
What compensatory mechanisms are seen at the initial offset of shock?
- Sympathetic response
- Hormonal response
- Adrenal response
What is the max compensating HR?
- 140 to 160 BPM
In the decompensating PT what are we likely to see in regards to how our BP is obtained?
- Heart Rate X Stroke Volume = Cardiac Output X Peripheral Vascular Resistance = Blood Pressure
- ↑ HR x SV = CO x PVR = BP
o Increased HR
o Decreased SV
o Decreased CO
o Increased Peripheral Vascular Resistance
o Decreased BP
What is our Decompensating PT likely to present as?
- Hypotension – pulse pressure redcued
- Tachycardia
- Tachypnoea
- Pale and severely diaphoretic
- Developing Altered conscious state (agitation/irritability)
- Delayed Cap refill.
o This will be a Pt with a cap refill of two seconds. A healthy pt has a cap refill of less than 2 seconds.
Describe Irreversible Shock
- Cellular ischemia and necrosis lead to release of contents into circulation
- Acidosis worsens
- Sludging of blood flow in capillary beds leads to formation of micro emboli
- Cerebral hypoxia
o This PT If they survive will have brain damage.
What are signs and symptoms of irreversible shock?
- The myocardium become hypoxic which has the potential to lead to the following.
o Dysrhythmias and infarctions - Sympathetic response fails
o In the short term this fail in sympathetic response leads to the following
Unbated hypotension
o In the long term this fail in sympathetic response leads to the following
Disseminating intravascular coagulation, Adult raspatory distress syndrome and organ failure
What are the PT presentation of irreversible shock?
- Bradycardia o If they have a HR - Life threatening dysrhythmias - Sever unabated hypotension - Abnormal respiratory patterns o Due to cerebral hypoxic effects on the respiratory drive - Alt conscious state – normally unconscious - Cyanosis and mottling of the skin - Death
What factors may cause shock to process at different rates and stages?
- Age
- Paediatric patients do not have the ability to compensate as well
- Pre- e existing disease, what condition is the PT in before this occurs?
- The PT ability to activate compensatory mechanisms.
o This becomes more challenging as the PT becomes older - Mediations
o Beta blockers, Diuretics - Specific organs that are affected by trauma or disease
What are the TYPES of Shock?
- Cardiogenic
o Occurs as a result of an inability of the heart to adequately to pump.
o These Pts will generally skip compensatory phase as these mechanisms are compromised.
For example, APO PT with hypotension - Neurogenic
o Occurs as a result of reduced peripheral vascular resistance
Compensatory are not activated as there is no sympathetic response - Anaphylactic
o Caused by a severe allergic reaction
This causes a relative fluid shift
• And compensatory mechanisms fail due to the vasodilation - Septic
o Occurs due to gross overwhelming infection
Often seen in those with low immune systems or low mobility (OLD CUNTS)
• The process of septic shock is as follows
o Release of bacterial toxins
o Vasodilation and permeability of vessel walls
o Relative fluid loss
o Cellular necrosis and inflammatory response interferes with compensatory mechanisms - Hypovolemic
o Fluid loss may be absolute or relative
Offset by compensatory methods initially
o Loss of whole blood, plasma or interstitial fluid
o Renal compensatory methods
What are common causes of cardiogenic shock?
- AMI
- Tension pneumothorax
- Cardiac tamponade
- Pulmonary Embolism
- Valvular disease
- Cardiomyopathies
What are management options in the setting of cardiogenic shock?
- Reperfusion strategies
- Possible circulatory support
o Fluid replacement – MICA Only - Drug Therapy
o Vasodilators to reduce afterload
o Positive inotropes to increase Stroke Volume and contractility
o Positive chronotropes to increase HR
Why is systemic Inflammatory Response Syndrome (SIRS) important in regards to septic shock?
- It is a key component due to the inflammatory response in this condition
What is the PT presentation of Septic Shock?
- Low arterial pressure
- Low Systemic Vascular resistance
o This is due to vasodilation - Tachycardia
- Temperature instability
o You can have hot or cold sepsis
This depends on the type of injection and its impact on the temperature regulatory systems - Affected organ systems
o Renal, resp and brain
What is the treatment of septic shock?
- Management of hypovolemia if present
- Correction of metabolic acid-base imbalances
- fluid resuscitation
- Respiratory support
- Vasopressors to improve cardiac output
- Thorough history to identify the source of sepsis
What are the causes of hypovolaemic shock/
- Haemorrhage
- Burns (plasma loss)
- Dehydration
o Through diarrhoea, vomiting, diuresis and diabetes
How will a PT with hypovolaemic shock present?
- Poor perfusion
- Poor skin turgor
o This shows significant fluid loss - Thirst
- Oliguria
- Need to elicit good history with these PT
What are key factors that need to be recognised for positive PT outcome for severe haemorrhage or shock?
- Rapid recognition
- Early initiation of treatment
- Prevention of additional injury
- Rapid transport to appropriate hospital
- Advance notification to receiving facility
What is the best way to achieve fluid resuscitation
- Blood transfusions are the most effective way, but fluids will buy time for the PT.
What reasons do we administer fluid replalcement?
- In volume depleted patients
- To expand the fluid volume, for example, anaphylaxis
o Must be careful once conditions has reversed not to place these PT into APO - As a fluid challenge in PEA/EMD
- Vehicle for drug administration
- TKVO
What type of fluid solutions are available?
- Isotonic solutions
o Concentration of solutes are the same a s those in body fluids - Hypotonic solutions
o Solution has a lower concentration of solutes than those of body fluids - Hypertonic solutions
o Solution ha a higher concentration of solutes than those of body fluids
What are the causes of aggressive fluid resuscitation?
- Additional bleeding, clot dissolution and dilution of clotting factors
o All this adds to increase in haemorrhage.