IV Fluids Flashcards
What is the distribution of total body water between different body compartments?
2/3= ICF (28L)
1/3= ECF (14L)
- blood 5L= intravascular space (2L RBC + 3L plasma)
- interstitial fluid 8L
- trans cellular fluid
What is the normal body osmolality?
285 mosmol/kg H20
ICF and ECF have the same osmolality. How do they differ?
Extra= Na+ dominant cation Intra= K+ dominant cation
What does it mean when a fluid is classified as physiological? Rank the different types of fluid from least to most physiological.
How similar the ion concentration of the fluid is to plasma
Dextrose
0.9% NaCl
Hartmann’s
Blood
What is the composition of dextrose solution? How does the solution act to increase circulating volume and when is it indicated?
Glucose dissolved in water
Glucose taken up by cells and water distributed in 2/3: 1/3 ration between ICF and ECF
Use:
- insulin shock
- hypoglycaemia
- dehydration
What is the composition of saline? Where does it distribute to? How much would 1 litre of saline raise the plasma volume by?
NaCl in water
Has same Na+ content as ECF (145mmol/L) meaning it distributes into this compartment
-8:3 (3:1) ratio of interstitial fluid: plasma
250ml (3:1 )
What causes hyperchloraemic acidosis?
Excess saline results in plasma HCO3- being replaced with Cl- leading to METABOLIC ACIDOSIS
What is Hartmann’s solution composed of?
Sodium Chloride Lactate Potassium Calcium
Where does Hartmann’s solution distribute to and by what ratio? What can this solution be used for?
3:1 ratio interstitial to plasma fluid
Use;
-resuscitation and maintenance fluids
What is the major differences between crystalloid and colloid? Give examples of the type of fluid for each.
Crystalloid -small molecules dissolved in water which quickly distributes throughout compartments Eg: -dextrose -0.9% saline -Hartmann’s
Colloid
-large molecules in isotonic fluid= gelatine/carbohydrates/starch
I.e. MW >30000
Eg:
- gelofusine
- hydroxyethyl starch
How do colloid fluids utilise starling forces to increase intravascular volume?
They counteract capillary hydrostatic forces by exerting oncotic pressure in BV to ensure fluid stays in vessels to maximise the plasma volume
What are the mains uses of crystalloid fluids?
BASIC= increase intravascular volume to increase tissue perfusion
Replace:
-distributive shock
Maintain:
-perioperative patient who is NBM but otherwise ok
Traumatic brain injury= saline + mannitol
Metabolic acidosis secondary to renal failure= sodium bicarbonate
When is the use of colloid fluids indicated?
Massive haemorrhage i.e. when intravascular space needs filling quickly
When is hydroxyethyl starch (colloid) contraindicated? Why?
Critically ill/ sepsis/ burns
Patients have increased vascular permeability which can result in colloid leaking out into vasculature
What are the different components that blood can be given in? Which part of the blood is usually removed and why?
Red cells Platelets Fresh frozen plasma Albumin Cryprecipitate
WCC
-decreases immunoreaction, febrile transfusion reactions and CMV
What are packed red cell solution formed from?
RBC suspended in iso-osmolality SAGM solution (saline/adenine/glucose/mannitol)
What are the most important antigens to look for in blood before transfusion? How are they formed?
Rhesus D antibodies
I.e. IgG anti-D antibodies can lead to haemolytic transfusion reaction
Cause:
-RHD -ve receives RHD +ve blood or has RHD +ve baby
What is 0 negative blood and when is it used?
No A or B antigens or RHD (no risk of incompatibility reactions)
Emergencies: Deranged physiology -class III/IV shock -SBP <80 -HR >120 -INR> 1.5
Trauma
Obstetric emergency
What is blood screened for in the UK?
Blood group
Rh type (+ve or -ve)
Syphilis
HBV
HIV
HCV
HEV
HTLV
What checks need to be done pre, during and after transfusion?
Vital signs
- temp
- BP
- HR
- RR
Signs of reaction
- rash
- fever
- headache
- swelling
What are the potential ABO incompatible transfusion reactions that can occur? What are the symptoms of this reaction?
Person with type A blood receiving type B or AB blood, they will create antibodies against the B antigens and lead to immune reaction to destroy the transfused RBC
Fevers + chills Breathing difficulty Muscle aches Nausea Chest + abdo pain Blood in urine Jaundice
How can you differentiate between the 4 classes of haemorrhagic shock?
Class 1
Blood loss= <750ml <15% BV
HR= same or slight +
BP= same
Class 2
Blood loss= 750-1000ml 15-30% BV
HR= +
BP= same
Class 3
Blood loss= 1500-2000ml 30-40% BV
HR= ++
BP= -
Class 4
Blood loss= >2000ml >40% BV
HR= ++
BP= - -
Why is blood pressure able to be maintained in class 2 haemorrhagic shock but falls in class 3?
Class 2= vasoconstriction able to maintain MABP
Class 3= vasoconstriction no longer able to compensate for fall in BV which leads to fall in BP
What needs to be assessed to determine a patients fluid status?
Clinical situation i.e. is patient suffering from sepsis or blood loss
Thirst i.e. indicator of dehydration
Vital signs
Urine output i.e. indicator of kidney perfusion
Skin turgor + capillary refill i.e. indicator of peripheral perfusion
Mucous membranes i.e. dry with dehydration
JVP
Lung fields for breathing sounds
Oedema
Daily weights
What is the process of fluid resuscitation?
500ml bolus of crystalloids containing Na+ 130-154mmol/L over <15mins i.e. STAT!
NOTE: bolus can range from 250-1000ml depending on body habitus and dehydration situation
Patient needs to be reassessed to see if the patient has responded to the fluid challenge
Bolus can be given until 2000ml bolus given
What action needs to be taken if patient not responding to >2000ml stat bolus?
Refer to ICU because it is possible that patient is fluid unresponsive
How do we assess whether patient it respond to fluid resuscitation?
ABCDE
Reassess parameters:
- pulse
- blood pressure
- conscious level (brain perfusion) i.e. GCS or AVPU
- urine output (kidney perfusion)
