Critical Care Flashcards
What is starling forces
the balance of forces defining the rate of fluid movement across the capillary endothelial barrier
The movement of fluid is increased with conditions associated with systemic inflammation such as trauma and sepsis owing to the increased capillary permeability
crystalloids are
- sodium chloride 0.9% balanced solutions (154 mol of each)
- various strengths of glucose (comes in various strengths, 50% very irritant - central line only) Provides 200kcal
They are iso-osmotic with plasma. distribution is determined by sodium concentration.
colloids are
- blood products (packed red cells, platelets, fresh frozen plasma, albumin (various strengths)
- gelatin
5 R’s (but not all R’s)
1) Resuscitation (hypovolaemia)
2) Maintenance
3) Replacement
4) Redistribution
5) Reassessment
daily requirements
water 25-35ml//kg/day
sodium and potassium 1mmol/kg/day
what is shock?
life threatening condition of low blood perfusion to tissues resulting in cellular injury and inadequate tissue function
signs of shock
low BP tachycardia poor end organ perfusion such as olig/anuria confusion/loss of consciousness weak pulses
Shock can be divided into the following categories
1) hypovolaemic - usually due to direct loss of circulating blood volume e.g. trauma
2) cariogenic eg post myocardial infarction
3) distributive(Septic), this includes septic, anaphylactic, endocrine, neurogenic shock. vasodilation, fluid leaks out into tissues
4) obstructive iclusing cardiac tamponate, PU, aortic stenosis
what is sepsis
infection
organ dysfunction - SOFA SCORE
what is QSOFA (quick score at bedside) SOFA is more extensive
1) RR >22 BPM
2) systolic BP < 100mmHh
3) altered mentation (mentation activity)
2 = 8% 3 = 20%
Cardiac output
Range 4-6
Determined by LV function, HR, preload and after load, by altering these factors we can alter cardiac output
Cardiac index
Range 2.5-3.5
cardiac output adjusted for body surface area
central venous pressure
Range 2-6
right atrium pressure = right ventricular preload
- if low = hypovolaemia, vasodilation
- if raised - inc intravascular volume, RV failure, PE, cor pulonale and others
systemic vascular resistance
960-1400
measure of left ventricular after load
low value could be vasodilation due to septic shock
mean arterial pressure
- the average mean arterial pressure across one full cardiac cycle
- 80-100
- commonly used measure of BP on ICU
- this is measured using an arterial catheter
PICCO and LIDCO
advanced hamody namic monitoring systems
both invasive measure arterial pule pressures to derive a set of cardiovascular parameters
- measures CO, CI, SVR
SIRS criteria
pyrexia, neutrophilic, increased HR ( unhelpful in identifying sepsis as many patients have this)
Persisting hypotension requires….
vasopressors such as noradrenaline or vasopressin to maintain a mean arterial pressure >65mmHg and having serum lactate >2 despite adequate fluid resuscitation
This plus sepsis is known as septic shock
fluid initially given in sepsis is
500ml hartmans or NaCl (has to be glucose free)
timescale to get IV ABX in a patient with sepsis is
60 mins
vasopressors cause
a rise in blood pressure and are used to reverse circulatory failure in critically ill patients
- noradrenaline or dopamine
Vasopressin (also known as anti-diuretic hormone) has two primary functions
- increase water retention via tubular reabsorption while causing smooth muscle contraction, particularly in the capillary bed sense diminishing leaky capillaries in patients with sepsis
inotropes are
adrenaline and dobumatine
They preferentially stimulate the B1 adrenoeceptors which leads to increased myocardial contractility. However they can also contribute to myocardial schema therefore the minimum dose should be used for the shortest time. adrenaline as vasoconstrictor properties as well as being an inotropic/
drotrecogin alfa
recombinant human activated protein
levosimendan
positive ion trope with dual mechanism of action
inotropic
cardiac contraction force
chronotropic
rate of contractions
sepsis
can cause AF which can then cause an MI which can then cause cariogenic shock
Albumin
4.5% albumin is the same amount as blood
20% albumin will draw fluid from the tissues back into the circulation
gellyfuse is a plasma volume replacer
ideal sedative
anxiolytic somnolent analgesic respiratory depressant no accumulation properties no effects of haemodynamic amnesic properties suppress gag reflect amti-tussive(prevent or relief cough)/reduce bronchospasm inexpensive minimal/no interactions
Problems if we over sedate
excessively prolonged respiratory depression haemodynamic disturbances immunosuppression GI stasis cost
If we undersedate
agitation/stess pain removal of tubes/lines by patient poor ventilation HTN tachycadic