Fluids And Electrolytes Flashcards
What are the causes of hypophasphatemia?PO4 < 2 mg/dL
Intestinal malabsorption related to vitamin D deficiency, magnesium/aluminum containing antacids, chronic alcohol misuse, malabsorption syndromes, respiratory alkalosis, increased renal excretion associated with hyperparathyroidism
What is the primary cation in the extracellular fluid?
Sodium
What does angiotensin 2 do in the body? (3 things)
- Vasoconstriction
- Stimulates renal tubules to reabsorb sodium and water.
- Stimulates the adrenal cortex to release aldosterone
What does the ascending portion of the Frank Starling curve represent?
Preload dependence
What area of the adrenal cortex releases aldosterone?
Zona glomerulosa
What causes hypovolemic hypotonic hyponatremia?
Diuretics, ketonuria, Addison’s disease, vomiting, diarrhea, third spacing, excess sweating, salt loss nephropathy
What is the gold standard for direct cardiac function and volume status monitoring?
TEE
What can prophylactic fluid replacement on a healthy fasted patient lead to?
Disruption of the glycocalyx and fluid overload
In consideration of the glycocalyx, would you administer colloids or crystalloids to increase intravascular volume?
Colloids
What is the formula to calculate free water deficit?
[(Na/140)-1] x TBW
How can we explain how hypotensive patients actually likely have an appropriate fluid status? (2)
Related to impaired cardiac function
Altered vascular tone
What symptoms will we see with magnesium levels of 10?
Respiratory paralysis and coma
What hormone maintains serum calcium levels?
Parathyroid hormone
What is the most abundant form of calcium?
Ionized and physiologically active 50%
Bound to proteins 40%
Bound to anions 10%
How do you calculate the estimated deficit?
Maintenance requirement (from 4-2-1) x fasting hours
What is the gold standard for direct cardiac function and volume status monitoring?
TEE
What is isotonic hyponatremia (pseudohyponatremia) serum osmolality 270-300 caused by?
Hyperlipidemia, hyperproteinemia, multiple myeloma, excess isotonic nonelectrolyte solutions
A patient is considered fluid responsive if their pulse contour analysis value is what?
Greater than 13-15%
What hormone maintains serum calcium levels?
Parathyroid hormone
At sodium levels of 129-125 what are patients signs and symptoms?
Nausea, malaise
What does parathyroid hormone insufficiency do to calcium levels?
Cause hypocalcemia
What are benefits of crystalloids? (3)
Lack allergic potential
Easily metabolized and cleared
Preserve electrolyte balance
If you notice biochemical evidence of Hyperkalemia and no ECG changes what is your interventions, their onset and mechanism?
K binding resins in the GI tract, onset 1-2 hours, GI excretion of potassium
Promotion of renal K excretion, Lasix 40mg, onset 15-30 minutes, renal excretion of potassium
Which solution would you give to a patient with active blood loss that needs fluid but not a transfusion?
Albumin
What are the traditional nonspecific indicators of fluid balance?
MAP, CVP, and urine output
What substances are unable to freely move between the vascular and interstitial space?
Proteins like albumin and globulins
What happens to contractility for people with a normal Frank Starling curve, that are given fluids?
Contractility increases.
When potassium reaches >8 QRS widening can lead to what?
Sine waves, V fib and cardiac arrest
What is the value of sodium in the extracellular fluid?
142 mEq/L
Which electrolyte condition can make it difficult for the kidney to conserve potassium?
Hypochloridemia
The Frank Starling Mechanism is the relationship between which two variables?
LVEDV and myocardial contractility
What is the value of calcium in the extracellular fluid?
5 mEq/L
Why can you administer plasmalyte, isolyte, and normosol with blood products?
They do not contain calcium
What are treatment options for hypercalcemia?
Infusion of NS to increase secretion Loop diuretics Bisphosphonates Mithramycin Calcitonin Glucocorticoids Phosphate salts Hemodialysis for life threatening hypercalcemia
What is the goal Potassium range before surgery?
Potassium > 4
Potassium < 5.5
Which medication will facilitate redistribution of potassium into the intracellular space
Insulin
What is the most consequential effect of hyponatremia?
Cerebral edema, cells swell. There is limited diffusion of solutes across the BBB, preventing equilibrium.
What is the goal Potassium range before surgery?
Potassium > 4
Potassium < 5.5
What causes transcellular shifts leading to hyperkalemia?
Acidosis (due to hydrogen ions), hypertonicity, insulin deficiency, beta blockers, digitalis, succinylcholine, exercise, hyperkalemia periodic paralysis
What is one likely explanation for a normovolumic patient having low urine output?
High levels of ADH. They are retaining fluid.
What mechanisms control phosphate balance? (3)
Parathyroid hormone
Vitamin D
Calcitonin
What is interstitial hydrostatic pressure?
Hydrostatic pressure of interstitial fluid. (Pushes fluid into the capillary)
What is the effect on contractility for people with decreased cardiac function who are given fluids?
They can only respond to small volumes without compromise.
What are the two functions of ADH?
- Cause aquaphorin channels in the kidney to reabsorb water
2. Potent arterial vasoconstrictor
Which medications cause hypomagnesium?
Aminoglycosides, amphotericin, beta-agonists, cisplatin, cyclosporine, diuretics, foscarnet, pentamidine, PPI, theophylline
What measures global tissue oxygen balance by comparing blood gases with oxygen consumption and delivery?
Measures of tissue oxygenation
What is the osmolality, tonicity and pH of Plasmalyte?
294 mOsm
Isotonic
PH 7.4
Contains potassium, magnesium, acetate, and gloconate
For infants 0-10kg what is the 4-2-1 fluid replacement?
4mL/kg/hr
Concentration of phosphate in the plasma is inversely proportional to which electrolyte?
Calcium
What are the GI signs of hypercalcemia?
Nausea vomiting, anorexia, peptic ulcers, pancreatitis, constipation/ileus
What electrolytes are in the intracellular fluid?
Potassium, magnesium, calcium, phosphate
What arrhythmias are causes by a serum potassium < 3.5
1st and 2nd degree blocks, atrial or ventricular fibrillation, asystole
Which hormone stimulates the excretion of potassium?
Aldosterone
What are the cardiovascular signs of hypercalcemia?
HTN, St segment elevation, sinus bradycardia/arrest, AV block, short Qt, BBB, ventricular dysrhythmias, potentiation of digoxin toxicity
What are the 6 complications of under resuscitation?
Hypovolemia Decreased perfusion/O2 delivery PONV Renal Dysfunction Myocardial ischemia Hemoconcentration/thrombotic events
Hypokalemia caused by renal losses is due to what?
Diuretics, drugs, steroids, metabolic acidosis, hyper aldosterone, renal tubular acidosis, DKA, alcohol consumption
What is the value of magnesium in the extracellular fluid?
3 mEq/L
The increased sodium load of Normal Saline causes what effects on the vascular space and bowel? (3)
Water retention
Hemodilution
Interstitial edema
Decreased bowel motility
How does the glycocalyx impact administration of crystalloids?
Crystalloids are able to freely cross the glycocalyx
What is the treatment of hyponatremia?
Fluid restriction, diuresis
What mechanism causes laparoscopic surgery to stimulate ANP?
Mechanical suppression of splanchnic blood flow and ischemia which also predisposes to reperfusion injury, shunts blood to the thorax -> increasing CVP.
How do we correcting hypernatremia over 24 hours?
Hypotonic solutions, 1-2mEq/hr
For adults > 20kg what is the 4-2-1 fluid replacement?
4mL/kg/hr for the first 10kg
2mL/kg/hr for the next 10kg
1mL/kg/hr for every kg > 20kg
What is the osmolality, tonicity and pH of NS?
308 mOsm
Isotonic
PH 5
What is the treatment suggestions of hyponatremia?
Correct 1-2mEq/L/hr with 3% saline at 1-2mL/kg/hr and not raised more than 10-15mmol/L in 24 hours.
What Utilizes individualized hemodynamics end points monitored by hemodynamics modalities to support oxygen transport balance, minimize oxygen demand, optimize CO, tissue oxygenation, capillary and micro vascular flow, oxygen/nutrient delivery and end organ perfusion?
Goal directed fluid therapy
What is the order of EKG changes related to hyperkalemia?
T wave changes, P wave and PR interval, QRS changes.
What does the ascending portion of the Frank Starling curve represent?
Preloads dependence
Explain the Renin-Angiotensin Aldosterone System response to hypotension. (4 steps)
- Hypotension detected by baroreceptors
- Sympathetic Nervous System stimulation of juxtaglomerular cells of the kidney to release renin.
- Renin interacts with angiotensinogen creating angiotensin 1
- Angiotensin Converting Enzyme converts angiotensin 1 to angiotensin 2
As preload increases, contractility…. according to the Frank Starling Law
Increases, up to a point
Hypernatremia with an serum osmolality of 401-430 will cause what signs and symptoms?
Hyperreflexia, muscle twitching/spasm
Which medication will facilitate redistribution of potassium into the intracellular space
Insulin
What maintains the osmotic equilibrium between ECV and ICV?
The cell membranes permeability to water
Why is magnesium used in the treatment of pheochromocytoma?
Reduces catecholamine release and dilates vasculature
What is the function of ANP?
- Stimulate removal of sodium and water by the kidneys
- Increase GFR
- Inhibits release of renin and ADH
What are some miscellaneous causes of hypomagnesmia?
Pregnancy, excessive alcohol intake, citrate binding with blood administration
What patients should you avoid giving hydroxyethyl starches to?
Preexisting renal injury, sepsis, neurological injury, organ donors, CABG with CPB.
What are symptoms of a serum potassium < 2.5 mEq/L?
Parasthesia, depressed deep tendon reflexes, fasciculations, weakness, altered level of consciousness
What is the value of sulfate in the extracellular fluid?
1 mEq/L
What is the value of sulfate in the intracellular fluid?
2 mEq/L
What are the cardiovascular signs of hypocalcemia?
Bradycardia, angina, hypotension, CHF, cardiac arrest, digitalis insensitivity, Qt prolongation
Where is magnesium regulated?
Intestines and kidneys
What is the value of phosphates in the extracellular fluid?
4 mEq/L
How do you replace blood loss with colloids?
1:1 ratio
1mL of colloid for every 1mL of blood loss
Hypokalemia as a result of decreased intake is due to what?
Ethanol, malnutrition
What causes increased K intake/absorption leading to hyperkalemia?
K supplements, salt substitutes, stored blood, K containing medications
What solution contains macromolecules suspended in electrolyte solutions that promote volume expansion by directly increasing plasma oncotic pressure.
Colloids- hydroxyethyl starches
What is the dilution technique?
Administration of a fixed volume of injectate into the vascular space and measurement of CO based on area under a time-temperature or concentration-time curve.
What are the manifestations of hyphosphatemia? PO4<2mg/dL
Decreased oxygen transport and ATP creation, platelet dysfunction, bone reabsorption, altered nerve and muscle function, confusion, coma, seizures, muscle weakness, respiratory failure, cardiomyopathy
What can rapid correction of hyponatremia cause?
Neurological complications like central pontine myelinolysis.
Hypernatremia with an serum osmolality of 350-375 will cause what signs and symptoms?
Confusion, restlessness, agitation, headache
What are the manifestations of hyperphosphatemia? PO4 > 4.7 mg/dL
Symptoms related to hypocalcemia
chronic calcification of soft tissues (joints, lungs, kidneys)
How is fluid in the interstitial space returned to the circulation?
Via lymph
What is the value of sodium in the intracellular fluid?
10 mEq/L
What is the value of chloride in the extracellular fluid?
103 mEq/L
Why do hydroxyethyl starches carry a black box warning?
Renal injury
What is normal total serum calcium?
8.5-10.5 mg/dL
How does the hypothalamus respond to increased serum osmolality?
- Osmoreceptors in the hypothalamus detect the increased osmolality
- Stimulate thirst
What is the value of phosphates in the intracellular fluid?
75 mEq/L
What affects do magnesium have on dysrhythmias?
Blocks calcium influx decreasing SA node activity and prolonging AV conduction time
What causes hypertonic hyponatremia (serum osmolality > 300)?
Hyperglycemia, mannitol excess glycerol therapy