Fluid Balance, Electrolytes, and pH

Flashcards by cpeters, updated more than 1 year ago
Created by cpeters over 5 years ago


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Question Answer
Osmosis Water moves from a chamber of low solute concentration to one of high solute concentration to establish equilibrium
Filtration Movement of fluid through cell or blood vessel membrane because of differences in water volume pressing against confining walls (hydrostatic pressure)
Diffusion Free movement of particles (solute) across permeable membrane from area of higher to lower concentration - Important in transport of most electrolytes; other particles diffuse through cell membranes
Hydrostatic Pressure “Water-pushing pressure” Force that pushes water outward from a confined space through a membrane
What sign develops with changes in normal hydrostatic pressure? Edema
What are the sensible (measurable) means through which fluid is lost? Kidneys, wound drains, GI tract
What are the insensible (immeasurable) means through which fluid is lost? Lungs (respiration) and skin (evaporation, perspiration)
Fluid loss can be increased during a hypermetabolic state. What is a hypermetabolic state? An abnormally increased rate of metabolism such as a fever, burn, trauma, thyroid crisis, and tachypnea.
What is the minimum urine amount needed to excrete toxic waste products? 400 to 600 mL
What role does ADH play in regulating Na+ and water balance? ADH (antidiuretic hormone) from the posterior pituitary acts on the kidney to promote water reabsorption, thus preventing its loss in the urine
What role does aldosterone play in regulating Na+ and water balance? ↓BP (↓blood volume) causes kidneys to secrete renin – activates angiotensinogen (angiotensin I) – angiotensin converting enzyme activates angiotensin II – vasoconstriction – causes adrenal gland to secrete Aldosterone which acts on the kidney to promote sodium reabsorption, thus preventing its loss in the urine
What role does ANH play in regulating Na+ and water balance? ANH (atrial natriuretic hormone) from the atrium of the heart acts on the kidney to promote sodium excretion so that it is excreted in the urine
Which pathway is greatly stimulated with shock, or when stress response is stimulated? Renin-angiotensin II. This is why urine output is used as an indicator of perfusion adequacy after surgery or any time the patient has undergone an invasive procedure.
What is hypovolemic shock? Vital organ hypoxia/anoxia
If a patient is dehydrated but incontinent and a fall risk, is it appropriate to let them decrease their fluid intake before bed? No. They need to continue to increase their fluids.
When a patient is receiving IV therapy for dehydration, what things do you need to be monitoring for? Pulse quality, urine output, weight (every 8 hours), IV site, and fluid overload (bounding pulse, difficult breathing, JVD in upright position, edema)
What are the common causes of fluid overload? Excess fluid replacement, kidney failure (late stage), heart failure, long term corticosteroid use, SIADH, psych disorders w/ polydipsia, interstitial to plasma fluid shifts (burns, excess Na+ intake)
Severe hypervolemia can lead to... pulmonary edema and heart failure.
If your patient has fluid overload, what position should they be placed in? Semi-Fowler's
mannitol (Osmitrol) is an example of what kind of diuretic? Osmotic diuretic
Which drugs are - rarely used in the management of HTN d/t short duration of action & availability of better drugs? Loop diuretics like Lasix
Besides ototoxicity and potasium depletion, what is another possible adverse effect of Lasix? Precipitation of gout by means of blocking renal excretion of uric acid
What is the primary use of mannitol (Osmitrol)? decrease intracranial pressure (it is not metabolized so it is freely filtered at the glomerulus)
What is one of the most common causes of hyponatremia? Prolonged use/overuse of diuretics
What does isotonic mean? When the concentration of dissolved particles is similar to that of plasma. Isotonic solutions have an osmolality of 250 to 375 mOsm/L.
Which solution is the most physiologically adaptable fluid? Lactated Ringer's Solution
What does D5W do? -Rapidly metabolized by the body. -Provides free unbound water molecules (can pass into cells providing hydration, provides free water to the kidneys which aids renal excretion of solutes) -Treats hypernatremia
What is the net result when dextrose is added to isotonic or hypotonic solutions? a slightly hypertonic solution
What are some examples of pH buffers? -bicarbonate and phosphate together -proteins (albumin, globulin, hemoglobulin)
When cells metabolize glucose under anaerobic conditions, this produces... lactic acid
Where does bicarbonate come from? Ingestion and pancreatic production
How do kidneys control acid-base mechanisms? movement of bicarbonate- either excrete it or reabsorb depending on level of H+
How does ammonium effect acid-base levels? secreted in urine, traps excess H+, both are excreted
When referring to the kidney's role in pH regulation, what does full compensation mean? If the pH is brought back to normal range
When the kidneys bring the pH almost back to a normal range, this is referred to as... partial compensation.
When looking at lab values for respiratory and metabolic pH, which is inversely proportional? Respiratory
What is combined metabolic and respiratory acidosis? Uncorrected respiratory acidosis leads to poor oxygenation and lactic acidosis
Who is at risk for combined respiratory and metabolic acidosis? Combined problem of Diabetic Ketoacidosis (DKA) and COPD
What are some S/S of acidosis? -Creates imbalance with positive ions – especially K -Disrupts function nerves, cardiac/skeletal muscles(early s/s) -Reduces excitability of membranes -CNS changes; lethargy, confusion to coma -Neuromuscular changes – behavioral changes seen early -↓ muscle tone, deep tendon reflexes
What is the hallmark of respiratory acidosis? Decreased pH, PaO2 with rising PaCO2
What is the hallmark of base excess acidosis? ABG result with ↑ pH and ↑ bicarbonate level with normal O2 and CO2 levels
What is the hallmark of respiratory alkalosis? -ABG result with ↑ pH coupled with low CO2 level -O2 and bicarbonate usually normal
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