Ch 45. Agents Affecting the Volume and Ion Content of Body Fluids Flashcards
What is the decrease in total body water?
vol contraction
What is the increase in total body water?
volume expansion
What are the causes of isotonic contraction?
vomiting, diarrhea, kidney disease, and misuse of diuretics
What is isotonic contraction?
Volume contraction in which Na and H2O are lost in isotonic proportions
Decrease in total volume but no change in osmolarity
Treatment for isotonic contraction?
fluids isotonic to plasma
.9% NS
give fluids slowly
What is hypertonic contraction?
- loss of water exceeds loss of Na
- reduced ECF volume and increase in osmolarity
What are the causes of hypertonic contraction?
- excessive sweating, osmotic diuresis.
- secondary to extensive burns or CNS disorders that interfere with thirst.
Treatment for hypertonic contraction?
hypotonic fluids (.45% NaCl) or fluids that contain no solutes
intial therapy: drink water
What is hypotonic contraction?
= loss of Na exceeds loss of H2O
= both volume and osmorality of ECF are reduced
Causes of hypotonic contraction?
excessive loss of Na through kidney
Tx for hypotonic contraction?
Mild: infusing isotonic NaCl solution for injection
Severe: hypertonic solution 3% NaCl
What is the cause of volume expansion?
- overdose with therapeutic fluids
- disease states
What are acid-base disturbances?
- respiratory alkalosis
- respiratory acidosis
- metabolic alkalosis
- metabolic acidosis
Tx for volume expansion
diuretics and agents used for heart failure
What is the cause of respiratory alkalosis?
hyperventilation causes decrease in CO2
Treatment for respiratory alkalosis?
Mild: none
Severe: rebreathe CO2 laden expired breath
What is the cause of respiratory acidosis?
retention of CO2 secondary to hypoventilation
Tx for respiratory acidosis?
- correction of respiratory impairment
- infusion of NaHCO3 if severe
What is the cause of metabolic akalosis?
- excessive loss of gastric acid
- administration of alkalinizing salts.
Tx for metabolic alkalosis?
solution of NaCl + KCl
What are the causes of metabolic acidosis?
- chronic renal failure
- loss of bicarbonate during severe diarrhea
- metabolic disorders
- poisoning by methanol and certain medications.
Tx of metabolic acidosis?
correction of the underlying cause of acidosis
alkalinizing salt if severe
What is the most abundant intracellular cation?
Potassium
What are the major role of K+?
conduction nerve impulses
maintaining the electrical excitability of muscle
regulating acid-base balance
What is HYPOkalemia?
serum potassium levels are less than 3.5
Tx for hypokalemia?
thiazide or loop diuretic
Consequences of hypokalemia?
adverse effects on skeletal & smooth muscles, b.p. and heart
Hypokalemia increases risk for ______ and ______
hypertension and stroke
___ Deficiency frequently coexists with hypokalemia?
Chloride
What is the tx for mild hypokalemia?
oral potassium chloride (KCl)
What is the tx for severe hypokalemia or if client cannot take oral meds?
IV potassium chloride
What is hyperkalemia?
excessive elevation of serum potassium
What causes hyperkalemia?
- severe tissue trauma, untreated Addison’s disease
- acute acidosis
- potassium-sparing diuretics or OD with oral or IV potassium
What are some consequences of hyperkalemia?
- disruption of electrical activity of the heart
What is the mild elevation of hyperkalemia?
5-7 mmol/L
What is the consequence of mild elevation hyperkalemia?
T wave heightens; PR prolonged
What is the severe elevation for hyperkalemia?
8-9 mmol/L
What is the consequence of severe elevation hyperkalemia?
cardiac arrest
What are the noncardiac signs consequences for hyperkalemia?
- confusion, anxiety, dyspnea, weakness or heaviness of legs, numbness/tingling of hands/feet/lips
Tx for hyperkalemia?
- withholds foods that contain potassium
- withholds meds that promote potassium accumulation: potassium supplements, potassium- sparing diuretics
- lower extracellular levels of potassium
Causes of hypomagnesemia?
- diarrhea
- hemodialysis
- kidney disease
- prolonged IV feeding
- chronic alcoholism
- hypermagnesemia
What are the adverse effects for hypomagnesemia?
- respiratory paralysis at 12-15 mEq/L
- cardiac arrest when Mg levels exceed 25 mEq/L
Prevention & Tx for hypomagnesemia?
- magnesium oxide
- magnesium sulfate
- IM o r Iv
Who are susceptible to hypermagnesemia?
pts with renal insufficiency esp when pt uses magnesium- containing antacids or cathartics
What are the symptoms of mild intoxication for hypermagnesemia?
muscle weakness, hypotension, sedation and ECG changes
What is the consequence for higher magnesium concentrations?
risk of cardiac arrest.