N212 Lecture 13 Flashcards
fluid, electrolyte and acid base balances in the body maintain the health and function of all body systems, true or false
true
extracellular fluid (ECF) is outside of the cell and is 1/3 of total body water
intracellular fluid (ICF) is inside cells and is 2/3 of total body water
ECF has 2 major divisions, intravascular (liquid part of blood plasma) and interstitial fluid ( between cells and outside the blood vessels) and minor division transcellular fluids (cerebrospinal, pleural, peritoneal and synovial fluids)
osmolality of fluid is a measure of the number of particles per kg of water
Na does not pass easily through the cell membrane
isotonic fluid is a fluid with the same tonicity
hypotonic solution is more dilute than blood
hypertonic solution is more concentrated than normal blood
fluid homeostasis is the dynamic interplay of 3 processes: fluid intake and absorption, fluid distribution and fluid output
normal daily fluid output is hypotonic salt ( urine, salt)solution, people must have equivalent fluid intake of hypotonic sodium containing fluid( water plus food with some salt)
average fluid intake for adult is 2300mL
Thirst is a regulator of fluid intake when plasma osmolality increases
thirst control mechanism located within the hypothalamus
fluid output occurs in 4 organs, skin lungs, GI tract and kidneys
hormonal influences for fluid balance are antidiuretic hormone, renin angiotensin aldosterone mechanism and atrial natriurectic peptides
Na lab value
135-145
potassium
3.5-5
Bun
5-20
creatinine
0.6-1.2
glucose
70-100
chloride
95-105
magnesium
1.5-2.5
phosphorus
2.5-4.5
calcium
9-11
hgb
13-18m, 12-16f
hct
39-54m, 36-48f
wbc
4000-11000
hypernatremia -> water deficit->hypertonic
excess Na = deficit of water
hyponatremia->water excess-> hypotonic
not a lot of Na =excess of water
when there is ECV deficit and hypernatremia combined is called
clinical dehydration
ABG values of normal pH
7.3(acid) -7.45
Normal ABG values of carbon dioxide/PaCO2
35-45(acid)
normal ABG values of bicarbonate/HCO3
22(acid) -26
respiratory acidosis = Low pH acid, high paco2
cause of hypoventilation , cns depression
Respiratory alkalosis = high pH, low Paco2
cause of hyperventilation or fever
metabolic acidosis and metabolic alkalosis caused by levels of HCO3( bicarbonate ion)
metabolic acidosis -> pH is acid and Hco3 is acid
metabolic alkalosis -> ph is base and hco3 is base
inadequate excretion of acids due to renal disease, loss of K from diuretic therapy
low pH= acidosis
high pH=alkalosis
co2 out of normal range (35-35) = respiratory issue
HCO3 out of normal range ( 22-26) -> metabolic issue
ABG lab results are for monitoring acid base balance
respiratory acidosis - the lungs are unable to excrete enough co2 ( COPD, respiratory failure, drug OD)
respiratory alkalosis is the lungs excrete too much carbonic acid( hypoxemia, acute pain, anxiety sobbing)
metabolic acidosis an increase in metabolic acid or a decrease of base( ketoacidosis, circulatory shock, end stage renal cance)
metabolic alkalosis is a direct increase of base or a decrease of metabolic acid( too much sodium bicarbonate, excessive vomiting, hypokalemia)
the lungs are unable to excrete enough CO2 is caused by
respiratory acidosis ( COPD, respiratory failure and drug overdose)
the lungs excrete too much carbonic acid is caused by
respirator alkalosis( hypoxemia, acute pain, anxiety sobbing)
occurs from an increase of metabolic acid or a decrease of base is caused by(ketoacidosis, circulatory shock, end stage renal disease)
metabolic acidosis
occurs from a direct increase of base (HCO3) or a decrease of metabolic acid is caused by ( too much sodium bicarbonate, excessive vomiting, hypokalemia)
metabolic alkalosis
on 2nd -5th postoperative days increased secretion of aldosterone, glucocorticoids and ADH causes increased ECV, decreased osmolality and increased potassium excretion.
increased output of fluid through the GI tract is a common and important cause of fluid, electrolyte and acid base imbalances
acute conditions place patients at high risk for fluid, electrolyte and acid base alterations which include respiratory diseases, burns, trauma, GI alterations and acute oliguric renal disease
acute respiratory disorders predispose patients to respiratory acidosis
examples bacterial pneumonia
crush injuries destroy cellular structure causing hyperkalemia by massive release of intracellular K into blood
head injury alters ADH secretion and can cause diabetes insipidus which is when patients excrete large volumes of very dilute urine and develop hypernatremia.
head injury may cause the syndrome of inappropriate antidiuretic hormone ( SIADH) which is excess secretion of ADH causes hyponatremia by retaining too much water and concentrating the urine
many patient with cancer develop hypercalcemia
chronic heart failure patients are at risk for hypokalemia, most diuretics increase the risk of hypokalemia while reducing the ECV excess.
oliguria occurs when the kidneys have a reduced capacity to make urine
acute nephritis causes oliguria
chronic kidney disease lead to chronic oliguria
oliguric renal disease results in hyperkalemia, hypermagnesemia, hyperphosphatemia and metabolic acidosis
metabolic acidosis -> base bicarbonate deficit
metabolic alkalosis-> base bicarbonate excess
respiratory acidosis-> carbonic acid excess
respiratory alkalosis-> carbonic acid deficit
ABG analysis reveals acid base status and the adequacy of ventilation and oxygenation
RN and healthcare provider draws arterial blood from the peripheral artery (radial) or from an existing arterial line
before arterial blood draw, perform an Allen test which assesses arterial circulation in the hand
