Fluids Flashcards
2/3 of body water is found as __ fluid. 1/3 as __ fluid
2/3 of body water is found as intracellular fluid. 1/3 as extracellular fluid
What are the compartments of extracellular fluid?
Extracellular fluid is divided into three compartments: interstitial, intravascular, and transcellular (or transitional)
Interstitial fluids surround the cells. Intravascular fluid is found within blood. Transcellular fluids are those fluids found in secretions within organs. These include gastrointestinal secretions, cerebrospinal fluid, and intraocular fluid.
what is ascites?
Ascites is the abnormal buildup of fluid in the abdomen.
What is the force that causes fluids to move across membranes?
osmotic pressure
(Determined by # solutes and
colloids (esp. albumin) in solution)
how does body water compare between men and women; young and old
older people has less fluid than young people
men have more fluid than women
fat has the lowest water content compared to all other tissues
Name
• Major electrolytes with positive charge
• Major electrolytes with negative charge
- Major electrolytes with positive charge: sodium, potassium
* Major electrolytes with negative charge: chloride, phosphorus
Describe Distribution of Electrolytes aka which ones predominate in intracellular fluid vs extracellular fluid
- Intracellular fluid: potassium (+), phosphate (-)
* Extracellular fluid: sodium (+), chloride and bicarb (-)
what is the rule of thumb to determine fluid needs? What does it not account for?
1kcal/ml or ~30ml/kg
Does not account for atypical losses and assumes euhydration (adequate hydration)
What are the basic average water requirements? What would that be in IVF rate?
What does this intake cover and does not cover?
Basic water intake requirements are generally 1500- 3000mL/day
(IVF rate of 75-125 mL/hour).
• This amount of fluid supports daily ongoing, routine losses like sweat, urined, water lost in breathn
• This doesn’t cover additional losses like fever, GI losses (vomiting). Important to be patient specific!!!
What can we look at to assess and monitor fluid needs?
- Assess I/O
- Urine output and colour
- Physical exam of current hydration status Lab values
- What is clinical status? Risk of dehydration?
• Dx and PMHx
• Meds
• NPOstatus?
• Excessive fluid losses?
What is considered as INs?
- Any foods liquid at room temperature E.g., ice cream
- Beverages
- IV fluids and meds
- Tube feeding: Free water
- Flushes: Meds + protocol
What is considered as OUTs?
- Feces
- Emesis (vomiting)
- Urine
- Ostomy output
- Fistula output
- NGT drain/suction
- Draining wounds
What is the healthy urine output
In the stable, non-critically-ill patient, twenty-four-hour urine output should be quantified with a goal of >1200mL per day.
Describe ways of fluid status assessment via physical tests
- Evaluate daily weights
- Physical exam of lips and oral cavity; dry skin; dry eyes and lack of tears: Decreased skin turgor
- Blood pressure
- Heart rate
- Ask pt if thirsty!
What is “third spaces” fluid
Fluids accumulating within body cavities b/w organ
E.g., Ascites is accumulation of fluid in peritoneal cavity (common with liver damage)s
What should we consider with “third spaces” fluid
Consider “dosing” for energy/protein estimations
What should you look at in lab analysis to assess fluid status
- Look for trends
- BUN and Cr are indicators of kidney function and can signal about dehydration
elevated BUN and/or Cr-> kidney problems or dehydration - Electrolyte levels can also indicate dehydration
What are the categories of disorders in fluid balance? How do they occur?
• General categories of alterations in fluid balance:
- Fluid volume
- Fluid concentration or osmolality
• Typically occur together
Describe Disorders of Fluid Balance: Alterations in Volume.
What is affected?
What are the types?
What is changed?
- Changes in fluid volume primarily affect the ECF
- Extracellular fluid deficit = hypovolemia
- Extracellular excess = hypervolemia
- Little change in ICF
- Osmolality of ECF unaffected
When do alterations in osmolality occur?
Generally occurs when there is a shift of water without a corresponding shift in solute
What is hyponatremia?
What may cause hyponatremia?
- low blood Na
causes:
- Na loss from diuretics + low Na diet
- Syndrome of inappropriate antidiuretic hormone (SIADH)- total body water increases without a subsequent increase in sodium
- Increase in fluid w/o increase in Na e.g., IV without electrolytes, or water intoxication observed in marathon runners and mental illness
- Hyperglycemia: hyperglycemia will cause ICF will go from interstitial space into the blood and dilute it
What may cause hypernatremia?
- Insufficient water intake e.g., elderly with decreased thirst mechanism
- Excessive fld losses e.g.,open wounds
What is Hypovolemic hyponatremic disorder
Water and Na+ are both lost from the body, but the sodium loss is greater; most common form of hyponatremia
What is Hypovolemic hypernatremic disorder
Deficit of both water and Na+, with greater loss of water; most common form of hypernatremia
What is the purpose of IV solutions?
- maintain vascular perfusion while avoiding fluid overload and volume depletion
- maintain normal serum biochemistries while avoiding hypo- or hypernatremia
What is used as normal osmolality range for body fluids? What is the value?
Blood osmolality is used as normal range for body fluids
• Ranges from 275-295 mOsm/kg H20
how is blood osmolality estimated?
Estimated using serum conc. of Na, K, glucose, and urea.
Hypertonic vs hypotonic solutions
Hypertonic: Solution with an
osmolality greater than blood
Hypotonic: Osmolality less than blood
What is the effect and purpose of isotonic IV solutions?
isotonic solution stays in the bloodstream
No osmosis when infused
Used to hydrate as it will stay in bloodstream when infused
What is the effect and purpose of hypertonic IV solutions?
fluid will move from cells to blood
might be used post-surgery as many people experience edema after surgery (fluid has moved from bloodstream to interstitial space)
we wanna reverse it-> hypertonic solution
this helps reduce the edema and normalize blood pressure
will also encourage urine output
What is the effect and purpose of hypotonic IV solutions?
- > hypotonic solution will disperse relatively equally into our fluid compartments (2/3 in intracellular fluid. 1/3 in extracellular fluid)
- > used for maintenance
Calculate mg of Na received when 124mL/hr is administered (1L = 3543mg of sodium)
Is it too little or too much? When should this be kept in midn
125 mL / hr × 24 hrs = ~ 462 mEq Na or 10,626 mg Na.
small amount of NaCl-> large amount of sodium
important to remember in sodium-restricted patients
Hypovolemia: causes and potential IV treatment
• Body volume losses; E.g.,
Diarrhea, vomiting, dehydration; diuretics
Tx = Isotonic soln to bring back to normal volume status as isotonic solution will stay in the bloodstream
Hypervolemia: causes and potential IV treatment
Elevated total body water E.g., CHF, edema, renal failure
• Tx: Fluid restriction and sodium restriction or hypertonic solution
Euvolemia: causes and potential IV treatment
Having a normal amount of body fluids e.g. NPO
Tx = Hypotonic soln, generally for maintenance fluids/freewater replacement
What is the potential IV treatment in hypernatremia?
• Free water replacement e.g. with hypotonic solution
What is the potential IV treatment in hyponatremia?
Water restriction or Na replacement
