Fluid Balance Fluid Compartments 60 adult body weight composed of water Decreases with age Two compartments Intracellular 66 inside the cell Extracellular 33 Interstitial fluid between cells Vascular compartment blood in veins and arteries and lymph in the lymphatic system Water moves passively between compartments by 1 Osmosis Movement of particles across a semi permeable membrane from greater to lesser concentration to balance solute to solvent content 2 Sodium potassium pump 3 Protein shifts and other ion shifts Tonicity Isotonic concentration of solutes solvent is equal Hypotonic concentration of solutes is lower than the solvent fluid is dilute Hypertonic concentration of solutes is higher than the solvent fluid is more concentrated Regulates fluid balance Thirst mechanism with age Kidneys output urination Aldosterone from the adrenal glands promotes sodium retention and water Atrial natriuetic peptide brain natriuetic peptide ANP BNP causes more sodium to be released and more water built up Antidiuretic hormone ADH from the posterior pituitary prevents diuresis prevents urination WATER REGULATION Osmolarity measures concentration of solutes particles like Na K glucose in a solution Serum osmolality levels assessed fluid status Normal range adults 285 300 mOsm kg Urine osmolality levels Normal range 850 mOsm kg Specific Gravity 1 005 1 030 Values become more dilute with age Osmolality easy calculation 2x the sodium Na level Hematocrit the of red blood cells RBCs in total blood volume Normal hematocrit Men 41 5 50 4 Women 35 9 44 6 Hemodilution fluid overload and dehydration affect hematocrit level in opposite directions Critical values 55 dehydration viscous thick blood 35 fluid overload dilute blood Sodium extracellular 135 145 Hypo 135 fluid overload Hyper 145 dehydration Blood Urea Nitrogen BUN measures end product of protein metabolism evaluates renal function Regulated by Kidneys and liver Diet protein intake Hydration status Drugs Blood level 10 20mg dl adult Increases with age Elevates with DEHYDRATION and renal failure CREATININE Directly reflects kidney function More to come for urinary renal lecture Hypovolemic dehydration from vomiting diarrhea sweating NG drainage diuretics mild loss of 1 2L 2 body weight moderate loss of 3 5 5 severe loss of 5 10 8 Third spacing excess fluid in the body leaves the vascular space gets into the tissues causes swelling edema o Extremities Sacrum o o Periorbital areas HAPPENS IN POST OP Ex ascites joint spaces pleural pericardial So patients have fluid overload in the interstitial space but are dehydrated in the vascular space causing s s of dehydration NORMAL FLUID INTAKE 1500 2000 ml day 800 ml from food Orthostatic hypotension 20mmhg drop in systolic bp within 3 mintues of standing up Nursing interventions for fluid volume deficit o Encourage oral intake what if they are NPO o Administer Intravenous fluids o Monitor I O 15 ml urine per kidney per hour o Monitor weight same time DAILY o Monitor osmolality electrolytes especially sodium BUN hematocrit know what normal values are o AVOID dark drinks cola caffine 1 Isotonic solutions fluid electrolytes are equal Normal Saline 0 9 NS or Lactated Ringers LR Amounts of electrolytes solutes and water are close to plasma blood levels Caution lactated ringers can alter acid base balance o do not use in alkalosis state o do not use for liver failure can t process lactate o Considered a volume expander stays in vascular space EXTRACELLULAR SPACE INTRAVASCULAR o Used for fluid losses SEVERE INTRACELLULAR DEHYDRATION Use Mild to severe DEHYDRATION 2 Hypotonic solutions FEWER SOLUTES 5 Dextrose in water D5W 45 normal saline 0 45 NS burns bleeding vomiting o PUSHES FLUID BACK INTO CELLS o Fluid no electrolytes Dextrose is metabolized and water is left Electrolyte status can become diluted 3 Hypertonic Solutions MORE SOLUTES Usually any solution with Dextrose added will become hypertonic o D5 0 45 NACL D5 0 22 NS o D5 0 9 NS o Adds both water and electrolytes Extra solutes pull fluid from extracellular space back into the intracellular space Good for postoperative swelling Good for patients with mild to moderate fluid overload Must know examples of each of these IV solutions Sodium Normal levels are 136 145 Major extracellular cation Responsible for WATER BALANCE electrolyte balance and acid base balance o osmolarity o intravascular osmotic pressure Kidneys will maintain sodium balances by excreting sodium if we take in too much unless we have diseased kidneys Aldosterone directly regulates sodium Sodium and potassium are inversely proportional as one goes up the other goes down Hyponatremia burns Very common in elderly Plasma volume Na 135mEq L Excessive sodium loss through fluid losses such as GI losses third spacing Not enough aldosterone from the adrenal glands Addison s disease Kidney disease sodium is diluted due to fluid overload N V D Weak lethargy seizures Restoring Fluid Restriction o 1500ml per 24 hours High sodium foods IV replacement slow replacement Medication inhibit antidiuretic hormone ADH Hypernatremia Na 145 mEq L Sodium retention or fluid losses will raise the serum sodium level o Lots of urine output o Diarrhea o Burns fluid loss from skin Excessive aldosterone secretion Interventions o Fluid replacement o Encourage fluids o Low sodium foods o IV fluids slow infusion Hypotonic D5W 0 45 Normal saline NS o Medications Diuretics Lasix Potassium Normal values 3 5 5 5 meq L Major INTRAcellular cation Maintains acid base balance in the body Very important in regulating membrane potentials in neuromuscular tissue and the heart Hypokalemia Increase cell excitability and coma o Neural fatigue decreased reflexes paresthesia irritability to seizures o Cardiac cardiac problems such as fibrillation ECG changes decreased muscle contraction o Muscular muscle weakness and cramps o GI anorexia nausea o Sagging ST segment flat T waves Potassium supplements TAKE WITH FOOD o IV 10 20 mEq in 50 100ml fluid over 1 hr max rate Never Must be diluted on a intravenous pump push the medication device not by gravity Phlebitis Vesicant medication Hyperkalemia Interventions Dietary restriction Increase urine output o Diuretics Hydration Medications o Sodium polystyrene sulfonate Kayexalate K ion exchanged for Na ion in GI tract given orally and or rectally Calcium NORMAL CALCIUM 9 11 mg dl o HYPOCALCEMIA 9 mg dl o greater concern if calcium is less than 6 0 Hypocalcaemia o Parathesis numbness tingling