Triage and Shock Flashcards
What is triage (2)
Processofquicklyexaminingpatientswho are taken to todecidewhichonesare the mostseriouslyilland must betreatedfirst
Processofexaminingproblemsinordertodecidewhichonesare the mostseriousand must bedealtwith first
What is shock
Inadequate cellular energy
Most commonly secondary to poor tissue perfusion (low or unevenly distributed blood flow)
Leads to critical decrease in oxygen delivery (DO2) compared to oxygen consumption in the tissues (VO2)
Signs of shock (4)
Altered mentation
Mucous membranes- pale to white or red
Capillary refill time >2 seconds (could also be shorter in SIRS & sepsis)
Cold extremities
Weak pulse
Why does mentation change in sock
Brain is an obligate user of oxygen and glucose and has few energy stores
Inadequate delivery of oxygen and glucose to the brain results in loss of the normal mental state
Descriptions used to describe mentation (4)
Alert and normally responsive
depressed or obtunded
stuporous or semi comatose (suggests functional brain disease)
Comatose (suggests functional brain disease)
Normal colour of mucous membrane (and how different in cats/horses)
Salmon pink
Cats/horses- normally paler
What does red mucous membranes suggest
Poor perfusion and vasodilation (blood trapped within the capillary beds) as in sepsis (or SIRS)
How is CRT different in different locations
buccal (lips/cheek) mucosa refills slower than gingival (gums) mucosa
What determines CRT
Pre-capillary Sphincter tone
increase in tone-> lengthening CRT (and vice versa)
What does pulse evaluation tell us
Estimation of stroke volume
Pulse gives us the difference between diastolic and systolic pressure- no info about blood pressure
Weak pulse= hypovolaemia
What is a hyperdynamic or bounding pulse and when does it occur
In early, compensated hypovolaemia
Pulse profile that is taller and narrower than normal reflecting decreased pulse volume, the heart is having to work harder
can also be due to increase CO as a result of increased oxygen demand e.g. after exercise
What happens as severe hypovolaemia progresses
Becomes decompensated hypovolaemic shock
Global tissue perfusion severely compromised
Increased heart rate (170-220bpm in dogs)
Femoral pulse is short and narrow- weak or thready and metatarsal pulses are absent- metatarsal lost first
What is SIRS
Systemic Inflammatory Response Syndrome
Wide variety of severe clinical insults manifested by 2 (dogs) or three (cats) of altered parameters (see one note for table)
Look at: HR, Temp, Resp. rate/ PaCO2 and WBCC
What is Sepsis
As for SIRS plus infectious agent identified (assumed in veterinary)
What is severe sepsis/SIRS
Sepsis (SIRS) associated with organ dysfunction, hypoperfusion, or hypotension
What is multiple organ dysfunction syndrome (MODS)
Presence of altered organ function in an acutely ill patient such that homeostasis cannot be maintained without intervention
Last phase, normally just before death
What is refractory (septic) shock/ SIRS shock
Subset of severe sepsis (SIRS)
Defined as sepsis (SIRS) induced hypotension despite adequate fluid resuscitation
Patients receiving inotropic or vasopressors may no longer be hypotensive yet they would still be considered to have septic (SIRS) shock
What is hypovolaemic shock
Decreased circulating blood volume
- Fluid loss from intravascular space
- Trauma
- Haemorrhage
What is cardiogenic shock
Decreased forward flow from the heart
- Congestive heart failure
- cardiac dysrhythmias
- cardiac tamponade (compression of heart)
- Drug overdose (anaesthetic agents, beta-blockers, calcium channel blockers)
What is distributive shock
Loss of systemic vascular resistance
- sepsis
- obstruction (saddle thrombis, heartworm)
- anaphylaxis
What is metabolic shock
Deranged cellular metabolic machinery
Hypoglycaemia
Cyanide toxicity
Mitochondrial dysfunction
Cytopathic hypoxia of sepsis
What is hypoxaemic shock
Decreased oxygen content in arterial blood
- Anaemia
- Severe pulmonary disease
- Carbon monoxide toxicity
- Methaemoglobinaemia
What is cryptic shock
Normal global circulation/ parameters but poor microcirculation- oxygen and glucose transport from capillaries into cells
- SIRS
- Sepsis
What is most common type of shock
Combines
Commonly hypovolaemic and distributive (and cryptic)
Most common mechanisms causing reduced oxygen delivery
Loss of intravascular volume (hypovolaemic shock)
Maldistribution of vascular volume (distributive and cryptic shock)
Failure of the cardiac pump (cardiogenic shock)
Examples of underlying diseases taht casue hypovolaemia
Blood loss- internal or external
Loss of other body fluids- burns, Diarrhoea. vommiting etc.
Examples of underlying diseases taht casue hypovolaemia
Blood loss- internal or external
Loss of other body fluids- burns, Diarrhoea. vommiting etc.
How does the heart compensate in hypovolaemic shock
Dec CO – reduced venous return triggers compensatory mechanisms
Increased sympathetic activity
Vasoconstriction
Inc contractility
Increased HR
CO=SVxHR
Compensatory mechanisms to increase IV volume in hypovolaemic shock (venous and renal)
Extreme vasoconstriction and changes in microcirculation- mobilisation of fluid from interstitial and extracellular spaces to IV space
Decreased renal circualtion
-> activates RASS
-> upregulated SNS
-> Na and H2O retention due to increased aldosterone and ADH
Signs of compensated shock
Mild to moderate depression
Tachycardia with normal to prolonged CRT
Cool extremities
Tachypnoea
Normal blood pressure
Pulse quality normal
Signs of decompensated shock
Compensatory mechanisms inadequate and fail
Pale mucous membranes
Poor peripheral pulse quality
Depressed mentation
Fall in blood pressure
What is oliguria
Low urine output
Does sepsis lead to hypovolaemic shock
no
leads to distributive shock
what is the hyperdynamic phase of shock
Abnormally increased circulatory volume
Signs of hyperdynamic phase of sock
tachycardia
fever
bounding peripheral pulses
hyperaemic (increase blood flow) mucous membranes secondary to cytokine (NO) mediated vasodilation
Also referred to as vasodilatory shock
Shock organ for dogs
GI tract
see ileus, diarrhoea and melaena
what is melaena
the production of dark sticky faeces containing partly digested blood, as a result of internal bleeding or the swallowing of blood.
What is shock organ of cat
lungs
Rarely see hyperdynamic phase
Changes in heart rate unpredictable cf dogs/horses- tachy or bradycardia!!
Pale/icteric MM, weak pulses, cold extremities, hypothermia and generalised weakness/ collapse
What is shock organ of cow
GI- same as dog
How can pulse be used to estimate stroke volume
Stroke volume is the amount of blood ejected by the heart with each beat. The pulse and stroke volume are related, and changes in pulse can give an estimation of stroke volume.
by measuring the pulse and assessing its strength, it is possible to estimate the stroke volume.
This is often done using a technique called pulse pressure analysis, which involves measuring the difference between the systolic blood pressure (the highest pressure generated by the heart during a contraction) and diastolic blood pressure (the lowest pressure between contractions). The pulse pressure is then used as an indicator of stroke volume.
What is cytopathic hypoxia
Cytopathic hypoxia is a type of tissue hypoxia that can occur in sepsis,
In sepsis, the body’s immune system releases a variety of chemicals that can damage the lining of blood vessels, leading to a decrease in blood flow to vital organs such as the lungs, liver, and kidneys -> the cells in these organs are unable to use the available oxygen to produce energy due to damage to their internal machinery caused by the immune system chemicals. This leads to cellular dysfunction and can contribute to the development of organ failure in sepsis.
it is thought to involve a combination of factors, including impaired mitochondrial function, altered metabolic pathways, and oxidative stress.
Treatment of sepsis typically involves aggressive management of the underlying infection, supportive care, and interventions to improve tissue oxygenation and prevent organ dysfunction
