Card Set Information

2010-03-20 17:37:00
Acid Base Balance and Fluid Electrolytes

Acid Base Balance
Show Answers:

  1. Water Body Comp
    • Infants 70-80%
    • Adult 50-60%
    • Older Adult 45-55%
  2. Body weight percentages
    • Extracellular 20%
    • Plasma 5%
    • Interstitial 15%
    • Intracellular 40%
  3. •Oncotic Pressure
    • Colloidal osmotic
    • pressure is osmotic pressure exerted by colloids (proteins) in solution

    • Protein molecules
    • attract water, pulling fluid from the tissue space
  4. •Hydrostatic pressure
    • ▫The force within a
    • fluid compartment

    • ▫Hydrostatic pressure
    • is the major force that pushes water out of the vascular system
  5. ▫Shifts of plasma to
    interstitial fluid
    • Elevation of venous
    • hydrostatic pressure

    –Think “edema”

    • –Decrease in plasma
    • oncotic pressure

    • –Albumin losses,
    • malnutrition

    • –Elevation of
    • interstitial oncotic pressure
  6. Shifts
    of interstitial fluid to plasma
    • –Adm. of hypertonic
    • solutions
  7. •Hypernatremia Na>145mEq/L
    ▫Clinical manifestations

    –Intense thirst


    –Agitation, sz, coma

    –Weight gain


    –Elevated BP & CVP
  8. hypernatremia nursing dx
    •Nursing diagnoses


    ▫Osmotic diuresis

    • ▫Saltwater near
    • drowning
  9. •Hyponatremia Na <135

    –Postural hpn


    –Dry mucous membranes
  10. Hyponatremia
    •Nursing diagnoses
    ▫Diarrhea, vomiting


    ▫Adrenal insufficiency

    ▫Burns, weeping wounds

  11. •Hyperkalemia


    –Abdominal cramping

    –Irregular pulse

    –Tall peaked T wave

    –Widening QRS

    –Cardiac irritability
  12. Affect of K+ on cardiac cycle
  13. Hyperkalemia Nursing diagnosis

    ▫Tissue catabolism

    ▫Crush injury

    ▫Lysis of cells

    ▫Renal disease

    ▫ACE inhibitors
  14. Hypokalemia K+<3.5

    clinical manifestations

    –Muscle cramps


    –Decreased DTR

  15. Hypokalemia Nursing Diagnosis
    ▫GI losses

    ▫Renal losses


    ▫Tissue repair

    • ▫Insulin
    • administration

  16. •Hypercalcemia Ca+ >11

    –Lethargy weakness

    –Confusion, ataxia


    –Bone fractures
  17. Hypercalcemia Nursing Diagnosis
    ▫Multiple myeloma


    ▫Vit. D overdose
  18. •Hypocalcemia

    ▫Chvosteks sign

    ▫Trousseaus sign

    ▫Laryngeal spasm

    • ▫Tetany & seizures (far
    • more acute)
  19. Hypocalcemia Nursing Diagnoses

    ▫Elevated phosphorous

    ▫1° hypoparathyroidism

    ▫Acute pancreatitis

    ▫Chronic alcoholism
  20. •Hypermagnesemia
    ▫Renal failure

    ▫Adrenal insufficiency
  21. Hypomagnesemia
    ▫Chronic alcoholism

    ▫NG suction

    • ▫Prolonged
    • malnutrition
  22. Hypotonic
    (.45% NS)
    • –Provides more water
    • then electrolytes , diluting the ECF. Expands both compartments.
    • Will not replace the vascular space, do not use for fluid resuscitation
  23. ▫Isotonic (.9%NS)
    • –Expands only the ECF,
    • ideal fluid replacement for a patient with a volume deficit (burns, GSW,
    • dehydration).
    • These solutions have tonicity similar to plasma, will distribute in ECF
  24. ▫Hypertonic (D10%)
    • –Raises the osmolality of the ECF and expands it by drawing water out of the cells, unchecked can
    • cause volume overload.
    • Used occasionally for osmotic therapy or intravascular volume expansion
  25. Blood Gas Values
    check in the following order
    ▫PO2 (90-110)

    ▫Ph (7.35-7.45)

    • ▫ PCO2
    • (35-42)

    • ▫ HCO3-
    • (22-26 mmol)

    • ▫ Base Excess (BE) (-2
    • +/-2)*** we will not focus on
  26. Resp. Acidosis: decreased pH increased PCO2
    •Increase in CO2 increases hydrogen ion concentrations, and the pH drops
  27. Compensation
    • •Role of lungs
    • ▫In resp. acidosis,there is a high CO2 and low pH, there will be an automatic increase RR
    • •Role of kidneys
    • ▫As the blood acidityincreases, renal mechanisms act slowly in maintaining pH…retained CO2combines with H2O to form carbonic acid. Carbonic acid dissociates torelease H+ and HCO3- and stimulates the kidneys to retain HCO3-and Na ions
  28. Metabolic
    Both pH & HCO3 decreased
    • •XS acid or reduced HCO3-
    • in the body, over production or XS H+ will lead to
    • decreased pH of less than 7.40. This is followed by a reduction in bicarb.
  29. Compensatory Mechanisms
    • •When H+ accumulate in the
    • body chemical buffers in cells and ECF bind with the XS H+.
    • As H+
    • reaches XS proportions, buffers cannot bind with them and blood pH drops.

    • •The compensation for an accumulation of resp. or
    • metabolic acids occurs in the lungs and kidneys.
  30. Metabolic
    Both pH & HCO3 increased
    •Results from XS bicarb or decreased hydrogen ions
  31. Compensation
    for resp. & metabolic alkalosis

    • ▫The CO2 (while it may
    • have been normal drops)

    • ▫Hydrogen ion
    • concentration drops in order to bind with bicarb to form carbonic acid (which
    • will be excreted via the kidneys

    • ▫Once the compensatory
    • mechanisms are in effect there
    • will be a drop in bicarb ions and pH


    • ▫After approx. 6 hours
    • the kidneys to increase excretion
    • of bicarb reduce the excretion of hydrogen ions
  32. Alkalosis
    in severe vomiting
    • •Alkalosis can ensue if there is severe vomiting; loss of
    • electrolytes are no longer available to the body from the alimentary canal to
    • replace those lost in the vomit and in the urine (Na+, Cl-,
    • HCO3-)

    •The greatest losses are chloride ions
  33. •pH 7.36
    •PaCO2 67 mm Hg
    •PaO2 47 mm Hg
    •HCO3 37 mEq/L
    What is this?
    ▫Respiratory acidosis
  34. •pH 7.18

    •PaCO2 38 mm Hg

    •PaO2 70 mm Hg

    •HCO3- 15 mEq/L

    What is
    ◦Metabolic acidosis
  35. •pH 7.60

    •PaCO2 30 mm Hg

    •PaO2 60 mm Hg

    •HCO3- 22 mEq/L

    •What is this?
    • ▫Respiratory
    • alkalosis

  36. •pH 7.58

    •PaCO2 35 mm Hg

    •PaO2 75 mm Hg

    •HCO3- 50 mEq/L

    •What is this?
    • ▫Metabolic
    • alkalosis
  37. •pH 7.28

    •PaCO2 28 mm Hg

    •PaO2 70 mm Hg

    •HCO3- 18 mEq/L

    •What is this ?
    • ▫Metabolic
    • acidosis partial
    • bc lungs
    • are compensating but PH is not normal
  38. •Jeri’s been on a 3-day party binge

    •Friends are unable to awaken her

    •Assessment reveals level of consciousness difficult to

    •Respiratory rate 8

    •Shallow breathing pattern

    •Diminished breath sounds
    • 1.What
    • ABGs do
    • you expect?

    • Respiratory
    • acidosis reflected by pH <7.35 and PCO2 >45 mm Hg. The
    • HCO3
    • will be normal (20-30 mEq/L) if her
    • respiratory depression has lasted less than 24 hours; if more than 24 hours,
    • the HCO3
    • may be elevated due to compensation. The PaO2 may be <80 mm Hg
    • because of respiratory depression leading to hypoxemia.

    • 2.What
    • is your treatment?
    • Determine
    • the cause of the respiratory depression. If induced by opioids or benzodiazepines,
    • treat with appropriate antagonists. If induced by alcohol or other CNS
    • depressants, breathing must be stimulated until the effects of drugs have worn
    • off. Mechanical ventilation may be necessary to increase respiratory rate and
    • depth, increasing oxygenation and promoting excretion of carbon dioxide.
  39. •Presented to the ER after a sexual assault

    •Physical examination reveals hysterical emotional

    •Respiratory rate 38

    •Lungs clear

    sat 96%

    1.WhatABGs doyou expect?
    2.What is your treatment?
    • Respiratory
    • alkalosis indicated by pH >7.45 and PCO2 <35 mm Hg. The
    • HCO3
    • will be normal (20-30 mEq/L) because
    • compensation will not occur in this acute event.

    • Relieve
    • her anxiety and coax her to take slow breaths. Carbon dioxide may be
    • administered by mask, or she may be asked to breathe into a paper bag placed
    • over her nose and mouth.
  40. •History of fever, aches, and chills

    •Generally feeling ill

    •Cough productive of yellow, thick sputum for the past 4

    •Examination reveals temp 38.4° C

    •Respiratory rate 20

    •Lungs with crackles in left lower lobes

    ABGs do you expect?

    is your treatment?
    • 1.
    • What
    • ABGs do
    • you expect?

    • The
    • possible pneumonia in this case may cause hypoxemia with the PaO2
    • <80 mm Hg. If untreated, the patient could trend to respiratory acidosis
    • with decreasing pH and increasing PCO2.

    • 2.
    • What
    • is your treatment?

    • Promote
    • coughing to clear the lungs, administer oxygen, and treat the underlying
    • infection.
  41. DKA ABG's?
    • 1.
    • What
    • ABGs do
    • you expect?

    • The diabetic ketoacidosis is a metabolic
    • acidosis indicated by a pH <7.35 and an HCO3 <20 mEq/L. The PCO2
    • will be within normal range if the acidosis is uncompensated but will be <35
    • mm Hg if compensation has occurred. The PaO2 will not be
    • affected.

    • 2.
    • What
    • is your treatment?

    • Administer
    • insulin to promote normal glucose metabolism, and administer fluids and
    • electrolytes to replace those lost because of the hyperglycemia.
  42. •History of nausea and vomiting for the past week

    •Has been self-medicating himself with baking soda to
    control his abdominal discomfort

    What are the ABG's and what is the trmt?
    • The
    • metabolic alkalosis in this case would be reflected by a pH >7.45 and an HCO3
    • >30 mEq/L. Because of the
    • duration of this condition, compensation may be indicated by a PCO2
    • >45 mm Hg.

    • 2.
    • What
    • is your treatment?

    • Determine
    • the underlying cause of the vomiting if possible, and stop the use of baking
    • soda (sodium bicarbonate). Antiemetic drugs and nasogastric intubation may help relieve the vomiting, and IV
    • replacement of fluids and electrolytes may be necessary.