Fluid Balance Flashcards
What happens if intravascular space becomes depleted?
Fluid moves from intracellular to intravascular to try to compensate
What affects fluid in each compartment?
Available water
Hydrostatic pressure
Oncotic pressure
Solute concentration
What is hydrostatic pressure?
Pressure which blood exerts on the vessel wall created by systole and intravascular volume
How is oncotic pressure created?
Pull of proteins in the plasma, albumin create osmotic pressure holding water in the intravascular space
What are the indications of the fluid status of intravascular fluid?
Pulse, BP, CVP, urine output, capillary refill, O2 saturation, peripheral skin colour + temp, core temperature, U+E
What are the key requirements for adequate circulation and oxygenation?
Effective cardiac function Systemic vascular resistance Sufficient blood volume Appropriate distribution of fluids Oncotic pressure Hydrostatic pressure Sufficient ventilation Sufficient haemoglobin
What are the indications of the fluid status of intracellular fluid?
Thirst Dry oral membranes Poor skin turgur Headache Concentrated urine Lower urine output
What are the indications of fluid status of interstitial fluid?
Assessment of skin for signs of oedema
Excess fluid in interstitial space can be referred to as third spacing
What is a good indicator of adequate circulation?
MAP
What is the minimum MAP for tissue perfusion?
60 mmHg
What is the normal MAP value?
70-110 mmHg
How do you manually work out MAP?
[(diastolic x 2) + systolic] / 3
What is central venous pressure?
Invasive hemodynamic assessment using a central venous catheter and transducer system
What is the normal CVP range?
3-8 mmHg
What does high CVP pressure mean?
Fluid excess
What does low CVP pressure mean?
Fluid deficit
What are some of the causes of fluid deficit?
NMB, diarrhoea, vomiting, haemorrhage, fever, burns, wounds, excess diuretics
What are some of the potential causes of fluid excess?
Retention of sodium and water, heart failure, liver failure, renal failure, steroids, excess IV fluid administrations or blood transfusion
What is pulmonary oedema?
Accumulation of fluid in the lungs from a massive volume overload or left ventricular failure
It is a medical emergency
What are the symptoms of pulmonary oedema?
SOB, use of accessory muscles, hypoxia, anxiety, restlessness, coarse crackles on ausculation and percussion, pink frothy fluid
What are the treatments for pulmonary oedema?
Urgent medical assessment, assess oxygenation + tissue perfusion + breathlessness, position for max lung expansion + coughing, high flow O2,
diuretics, treat the cause
What are the types of hypovolaemia?
Covert compensated (reduced intravascular volume without clinical signs) Overt compensated (BP maintained but tachy, wide pulse pressure, cool peripheries) Decompensated hypovolaemia (shock£
How do you manage fluid deficits?
Risk of fluid loss, ascertain cause, fluid replacement, fluid challenge, electrolyte replacement, monitor fluid balance, monitor U+E
What are the short term venous access devices!
Peripheral catheter
Non-tunnelled CVAD
What are the intermediate use venous access devices?
Midline catheter
PICC
What are the long term venous access devices?
PICC
Tunnelled CVAD
Implantable port
What are isotonic solutions?
Concentration of dissolved particles equal to that of intracellular fluid (0.9% sodium chloride, 5% dextrose, Hartmanns)
What are hypotonic solutions?
Tonicity less than intracellular fluid
Osmotic pressure draws water into the cells from extra cellular fluid (0.45% sodium chloride)
What are hypertonic solutions?
Tonicity greater than intracellular fluid
Osmotic pressure is unequal inside and outside cell (high concentration dextrose)
What are crystalloids?
Small molecule solutes containing electrolytes and glucose (0.9% sodium, 5% dextrose in water)
What are colloids?
Large molecules containing gelatines, starches (fresh frozen plasma, blood, albumin)
What should be first line treatment for low intravascular blood volume?
Crystalloids
