Patho Pharm: Exam #3 - Fluids & Acid-base

diffusion

movement of particles

osmosis

area of low concentration of solutes (lots of water) to an area of high concentration of solutes (less water)

manifestations of dehydration

- low BP

- hypotension

- orthostatic hypotension

- compensatory tachycardia

- dizziness, dry mouth, thirst

ICF

intracellular fluids

ECF

extracellular fluids

hypotonic

lower osmolality than the body

isotonic

when the concentration of two solutions is the same (equal)

true or false: saline is an example of a isotonic solution

true

hypertonic

higher osmolality than the body

what is the renin-angiotensin-aldosterone system?

system of hormones, protein, enzymes that regulates the blood pressure by increasing sodium reabsorption, water retention & vascular tone

what is the long term regulation of the RAAS system?

- renin is released by the kidney when BP drops

- aldosterone tells the kidney to reabsorb sodium & water

- activation of angiotensin II causing vasoconstriction

sodium is primarily ______ the cell

outside (ECF)

sodium

- primary ECF cation

- regulates osmotic forces

- primary solute that drives osmosis

chloride

- primary ECF anion

- follows sodium

potassium is primarily ______ the cell

inside (ICF)

isotonic alterations

normal concentration of sodium (solutes) in the ECF and no change in shifts of fluid in or out of the cells

isotonic fluid loss (FVD)

loss of TBW with proportional change in concentration of electrolytes

true or false: fluid drainage & excessive sweating is an example of isotonic fluid loss

true

isotonic fluid excess (FVE)

gain of TBW with proportional change in change in concentration of electrolytes

hypertonic fluid alterations

- related to water loss or sodium gain

- water deficit

- hypernatremia

water deficit

- dehydration

- both sodium & water loss

water deficit manifestations

- low BP

- weak pulse

- postural hypotension

- elevated hematocrit & serum sodium levels

- headache, dry skin, & dry mucous membranes

water deficit treatment

- oral fluids

- hypotonic saline solution (5% dextrose in water)

hypernatremia

- serum sodium >145 mEq/L

- water movement from ICF to ECF

- intracellular dehydration

hypernatremia manifestations

- intracellular dehydration

- seizures

- muscle twitching

- hyperreflexia

hypernatremia treatments

isotonic salt free fluids

hypotonic alterations

hyponatremia & water excess

hyponatremia

decreases the ECF osmotic pressure & water moves into the cell (low sodium)

water excess

- compulsive water drinking, causing water intoxication

- cellular edema

- manifestations: cerebral edema, pulmonary edema

water excess treatment

- fluid restriction

- may need hypertonic saline solutions

signs & symptoms of FVD

- Low BP, hypotension, & orthostatic hypotension

- compensatory tachycardia

- dizziness, dry mouth, thirst

late signs & symptoms of FVD

poor skin turgor, weakness, symptoms of electrolyte imbalance

causes of FVD

blood loss, fluid loss, NPO, underlying illness

treatment of FVD

fluid replacement (same osmolality, tonicity, & isotonic)

signs & symptoms of FVE

- high BP

- bounding pulse

- pulmonary congestion, SOB

- JVD

- later: edema

causes of FVE

heart failure, liver failure, cancer, endocrine disorders, kidney failure

treatment of FVE

- fluid & sodium restriction

- hypertonic fluids

- diuretics

examples of isotonic solutions

0.9% NS, lactated ringers (LR)

examples of hypotonic solutions

0.45% NS or 0.25% NS (D5W)

examples of hypertonic solutions

- D5/0.45% NS

- D5/0.9% NS

- hypertonic saline (HS): 3%, 5%

hypotonic fluids shifts...

fluid out of the veins and into the cells

isotonic fluids shifts...

no fluid shifts, vascular expansion, support BP, electrolyte replacement

hypertonic fluid shifts...

-from cells back to veins,

-replaces electrolytes,

-vascular expansion

edema

accumulation of fluid in interstitium

causes of edema

- hypertonic alterations

- increased capillary hydrostatic pressure (venous obstruction)

- increased capillary permeability (inflammation & immune response)

- lymphatic obstruction (lymphedema)

manifestations of edema

- localized vs generalized

- pitting edema

- "third space" (all over body)

- swelling & puffiness

- tight fitting clothing & shoes

- weight gain

treatment of edema

- treat fluid imbalance

- elevate edematous limbs

- use compression stockings or devices

- avoid prolonged standing

- restrict salt intake

- take diuretic agents

normal levels of sodium

135-145 mEq/L

signs of sodium deficiency

muscle cramping, memory loss, anorexia, seizure

signs of sodium excess

fluid retention, hypertension, disorientation

treatment for hyponatremia

restrict water intake

treatment for hypernatremia

- hypotonic solution

- encourage fluids

- restrict sodium

normal levels of potassium

3.5-5.0 mEq/L

signs of potassium imbalance

cardiac dysrhythmias, changes in pH, insulin, & aldosterone levels

treatment for hypokalemia

- replace potassium orally and/or intravenously

- skeletal muscle weakness

signs of hyperkalemia

- peaked T waves

- muscle weakness

- loss of muscle tone

- paralysis

- tingling in the lips & fingers

- restlessness

- intestinal cramping

- diarrhea

treatment for hyperkalemia

- polystyrene sulfonate (kayexalate)

- limit dietary K+

- isotonic fluid

- insulin & glucose

- buffered solutions

- dialysis

normal levels of calcium

8.5-10.5 mg/dL

signs of hypocalcemia

paresthesia, facial spasms, and muscle tremors

signs of hypercalcemia

lethargy, fatigue, weakness, depressed reflexes, muscle flaccidity, heart block, anorexia, nausea, and vomiting.

treatment for hypocalcemia

IV calcium gluconate

treatment for hypercalcemia

- fluid intake to prevent stone formation

- high fiber

- eliminate calcium

- supplements and limit foods

- renal dialysis may be required

normal pH

7.35-7.45

pH below 6.8 & a pH above 7.8 indicates

death

normal arterial blood pH from ABG sampling

7.35-7.45

acidosis

- pH less than 7.35

- systemic increase in H+ concentration

alkalosis

- pH is greater than 7.45

- systemic decrease in H+ concentration or excess of base

systems that regulate acid base balance

respiratory and renal

respiratory function in acid base balance

increase or decrease ventilation to hold in or secrete acid

if _______ is abnormal it is most likely a respiratory issue

PaCO2 (carbon dioxide)

normal levels of PaCO2

35-45 mmHg

renal function in acid base balance

absorb bicarbonate, produce more acidic or more alkaline urine

if _______ is abnormal it is most likely a renal issue

HCO3 (metabolic)

normal levels of HCO3

22-26 mEq/L

metabolic acidosis

acid from other than our lungs

manifestations of metabolic acidosis

- pH less than 7.35

- PaCO2 normal

- HCO3 less than 22 mEq/L

causes of metabolic acidosis

- lactic acidosis

- renal failure

- diabetic ketoacidosis

- diarrhea

- starvation

treatment of metabolic acidosis

- buffering solution (sodium bicarb)

- treat the underlying causes

- correct sodium & water deficits

manifestations of metabolic alkalosis

- pH greater than 7.45

- PaCO2 normal

- HCO3 greater than 26 mEq/L

causes of metabolic alkalosis

- prolonged vomiting or gastric suctioning

- excessive bicarbonate intake

- hyperaldosteronism with hypokalemia

- diuretic therapy

treatment of metabolic alkalosis

- sodium chloride

- potassium

- chloride IV

(HCO3- is replaced by CI-)

manifestations of respiratory acidosis

- pH less than 7.35

- PaCO2 greater than 45 mmHg

- HCO3 normal

causes of respiratory acidosis

- depression of the respiratory center (brainstem trauma, oversedation)

- respiratory muscle paralysis

- disorders of the chest wall/lung tissue and alveolar hypoventilation

treatment of respiratory acidosis

- restore adequate ventilation

- may need mechanical ventilation

- oxygen therapy

manifestations of respiratory alkalosis

- pH greater than 7.46

- PaCO2 less than 35 mmHg

- HCO3 normal

causes of respiratory alkalosis

- high altitudes

- hypermetabolic states, fever, anemia, and thyrotoxicosis (hyperthyroid)

- early salicylate intoxication

- anxiety or panic disorder

- hyperventilation

treatment of respiratory alkalosis

paperbag; treat hypoxemia and hypermetabolic states