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Electrolytes/Fluids
CAPA Fluid and Electrolyte imbalances
Question | Answer |
---|---|
What is the normal rquired daily fluid intake | 2L |
What population may become significantly dehydrated and hypoglycemic pre-operatively? | Children (NPO status) |
Percentage of body water decreases with what? | age (muscle decreases, fat increases, kidney function decreases - ability to conserve fluid) |
Percentage of body water is less in ____________ patients. | Obese (also elderly) |
Third spacing of fluid causes what problems? | hypovolemis and ongoing hypotension (fluid is migrating OUT of vascular spaces) |
Edema (esp. around eyelids, fingers, and ankles) is signs of what fluid problem? | Second spacing |
What causes in increased risk of apnea in preterm infants less than 60 weeks old who are having surgery? | Hematocrit less than 30% |
Name some complications of post op N/V. | Increased risk for hypovolemia, delays discharge, increases cost of care. |
What populations dehydrate easily? | Infants, children, and elderly patients. |
Post Op N/V is highly associated with what types of surgeries? | Laparoscopy, strabismus correction, and ear surgery |
What effect does anesthestic medications have on the vascular and fluid levels? | They dilate the vasculature and expand the Extracellular fluid capacity (eases fluid overload and improves diastolic filling in the heart) |
What types of events may cause electrolyte imbalances? | 1. Transient mild resp acidemia related to anesthetic-induced hypoventilation and sedation. 2. Preoperative hypokalemia related to bowel preps or chronic meds such as diuretics or digoxin. 3. Physiologic stress related to surgery (anxiety increases sodium |
What is the function of Sodium? | Regulates fluid balance and reflects serum osmolality. |
Na+ and K+ have what type of relationship? | Inverse. |
What electrolyte is an immediately available acid-base buffer? | Bicarbonate |
Chloride competes with waht other electrolyte to combine with sodium? | Bicarbonate |
What cations (positively charged ions) are critical for cardiac function? | Potassium, Magnesium, and Calcium |
Bicarbonate to carbonic acid ratio must be maintained at what ratio? | 20 to 1 |
List the chemical buffers. | Phosphate, hemoglobin, and protein |
Low protein causes what problem? | Third spacing (fluid leaks from vascular spaces due to low osmalality) |
Where are changes in osmolality sensed in the body? | Baroreceptors at right atrium |
How is osmalality primarily adjusted? | ADH (antidiuretic Hormone) |
What is the most important determinant of osmalality? | Serum Sodium. (Water follows sodium and will go wherever the sodium is higher concentrated) |
What governs FLUID movement between ECF and ICF? | Osmosis |
What governs SOLUTE distribution through a selectively permeable membrane? | Diffusion |
Normal value for Sodium? | 135-145 |
Normal value for Chloride | 96-106 |
Normal Potassium value | 3.5-5.0 |
Normal value for Magnesium | 1.5-2.5 |
Normal value for Calcium | 4.5-5.3 |
Normal Phosphate value? | 1-2 |
What does ADH do to blood volume? | adjust serum osmalality and concentrates electrolytes |
What causes the body to increase ADH secretion? | increased serum osmalality |
Other than osmolality, what other factors can cause increased ADH secretion? | Stress such as pain, trauma, surgery, hypovolemia, opioids, hypoxia, or hypercapnia |
A hypophysectomy may cause what disorder? | Diabetes Insupidus (inability to concentrate urine from a decrease in ADH) |
What does a decrease in ADH result in? | a promotion of water elimination (results in dilute urine) |
What stimulates the Renin-angiotensin system to be activated? | Blood flow changes at the glomerulus |
How does renin-angiotensin regulate the circulating blood volume? | changing the flomerular filtration rate (GFR) in the kidneys. |
Release of renin is the kidneys effort to do what? | Raise blood pressure and GFR |
Angiotensin II is what type of chemical | A Potent Vasoconstrictor to peripheral blood vessel and the lungs. |
What stimulates the adrenal cortex to release aldosterone? | Fluid volume status and renal perfusion (GFR) |
What is the function of Aldosterone? | It regulates SODIUM REABSORPTION (increases total body water). It acts at the kidney's renal tubule. |
What is the end result of Aldosterone regulation? | Prevention of Hypovolemia and Hypotension. |
Aldosterone causes Sodium to be retained and what to be excreted? | Potassium or hydrogen ions (to maintain ion balance) |
A decrease in Aldosterone has what effect? | excretion of sodium and water, retention of potassium |
What fluid concern can rewarming after intraoperative hypothermia cause? | Peripheral vasodilation, expnasion of the vascular compartment and significant hypotension. (Treatment with fluid volume expansion) |
Spinal and epidural anesthesitc techniques have what effect on the fluid balance? | They expand the ECF by dilating peripheral vasculature. |
What interventions may be needed post operatively until anesthetic effects have resolved? | Vasopressors and fluid volume expansion may be needed until normal vessel tone has returned |
When is the reabsorption phase following fluid shift post surgery or trauma? | within 72 hours post surgery or injury |
What are signs and symptoms of Dehydration and hemoconcentration? | Thirst, oliguria (<15 ml/hr), poor skin turgor, dry skin and mucous membranes, decreased cardiac output, inadequate cerebral perfusion (confusion, lethargy) |
What are some causes of Hypervolemia? | renal failure, congestive heart failure, and remobilization of third space fluid postoperatively, excess sodium intake (IV or hyperadlosteronism) |