Week 5 and 6 MDC 2 Notes Acid & Base
Acids: release H ions when dissolved in H20
Bases: bind with H ions in solutions
Buffers: maintain normal body fluid pH
Normal levels
o pH: 7.35 to 7.45 (acidic basic)
o paCO2: 35-45 (basic acidic)
o HCO3: 22-26 (acid basic)
o paO2L: 80-100
**If there is less H ion [], the pH rises and becomes more alkaline or basic
**More H ion [], the pH drops and becomes acidic
3 systems maintaining pH
o Buffers: moves or releases H ions
o Respiratory system: hyperventilation or hypoventilation; regulates
carbonic acid by elimination or retaining CO2
o Renal system: kidney movement of bicarbonate and long term
regulation of acid base in body
May take hours or days for this to have an impact on the body
Compensation (body correcting blood pH changes)
o Body attempts to correct changes in blood pH to maintain acid-base
balance. Respiratory compensation occurs through the lungs by
increasing CO2
o pH <6.9 or >7.8 are usually fatal
Aerobic metabolism = 2 forms of acid
o Respiratory acid (carbonic acid)
o Metabolic acids
Steps to determine ABG
1. Figure out if pH is acidic or basic
2. Evaluate pCO2 (acid) to see where it falls.
a. If paCO2 falls below= respiratory alkalosis
b. If paCO2 falls above= respiratory acidosis
3. Evaluate HCO3 to see the direction of the metabolic component
4. ABG Interpretation- Compensation
Respiratory Acidosis Metabolic Acidosis
Deficit HCO3 Deficit HCO3
Caused by hypoventilation Common in cases of kidney disease and
diabetes
Respiratory Alkalosis Metabolic Alkalosis
Excess HCO3 Excess HCO3
Caused by hyperventilation Caused by steroid or diuretic therapy,
, or excessive anti-acids
Acid-base imbalances
** Potassium goes up in acidosis
o Acidosis
pH below 7.35
Respiratory cause: retention of CO2
Metabolic cause: loss of bicarbonate
o Metabolic acidosis
pH <7.35
HCO3 <22 mEq/L
Causes: over production of H+ ions, underproduction of
bicarbonate ions, under elimination of H+ ions, and over
elimination of bicarbonate ions
Sings and symptoms: hypotension, depressed activity,
hyporeflexia, skeletal muscle weakness, warmed, flushed, and
dry skin in metabolic acidosis
Diagnostic tests: ABG & electrolytes
Multidimensional care: improve airway and oxygenation, drug
therapy, O2 therapy, pulmonary hygiene, ventilation support,
prevention complication
o Respiratory acidosis
pH <7.35
PaCO2 > 45mmHg
Causes: retention of CO2 (causing production of free H ions)
Signs and symptoms: variable respirations, kussmal
respirations, pale to cyanotic and dry skin in respiratory
acidosis
Diagnostic test: arterial blood gas & serum electrolytes
Multidimensional care: improve airway and oxygen, drug
therapy (bronchodilators, anti-inflammatory, mucolytic),
oxygen therapy, pulmonary hygiene, ventilation support,
prevention of complications
o Patient centered care
CNS changes
Neuromuscular changes: decreased muscle tone, deep tendon
reflexes
Cardiovascular changes: (early) increased HR, cardiac output
changes; (worsening) hyperkalemia, decreased HR, EKG
changes, hypotension
Acids: release H ions when dissolved in H20
Bases: bind with H ions in solutions
Buffers: maintain normal body fluid pH
Normal levels
o pH: 7.35 to 7.45 (acidic basic)
o paCO2: 35-45 (basic acidic)
o HCO3: 22-26 (acid basic)
o paO2L: 80-100
**If there is less H ion [], the pH rises and becomes more alkaline or basic
**More H ion [], the pH drops and becomes acidic
3 systems maintaining pH
o Buffers: moves or releases H ions
o Respiratory system: hyperventilation or hypoventilation; regulates
carbonic acid by elimination or retaining CO2
o Renal system: kidney movement of bicarbonate and long term
regulation of acid base in body
May take hours or days for this to have an impact on the body
Compensation (body correcting blood pH changes)
o Body attempts to correct changes in blood pH to maintain acid-base
balance. Respiratory compensation occurs through the lungs by
increasing CO2
o pH <6.9 or >7.8 are usually fatal
Aerobic metabolism = 2 forms of acid
o Respiratory acid (carbonic acid)
o Metabolic acids
Steps to determine ABG
1. Figure out if pH is acidic or basic
2. Evaluate pCO2 (acid) to see where it falls.
a. If paCO2 falls below= respiratory alkalosis
b. If paCO2 falls above= respiratory acidosis
3. Evaluate HCO3 to see the direction of the metabolic component
4. ABG Interpretation- Compensation
Respiratory Acidosis Metabolic Acidosis
Deficit HCO3 Deficit HCO3
Caused by hypoventilation Common in cases of kidney disease and
diabetes
Respiratory Alkalosis Metabolic Alkalosis
Excess HCO3 Excess HCO3
Caused by hyperventilation Caused by steroid or diuretic therapy,
, or excessive anti-acids
Acid-base imbalances
** Potassium goes up in acidosis
o Acidosis
pH below 7.35
Respiratory cause: retention of CO2
Metabolic cause: loss of bicarbonate
o Metabolic acidosis
pH <7.35
HCO3 <22 mEq/L
Causes: over production of H+ ions, underproduction of
bicarbonate ions, under elimination of H+ ions, and over
elimination of bicarbonate ions
Sings and symptoms: hypotension, depressed activity,
hyporeflexia, skeletal muscle weakness, warmed, flushed, and
dry skin in metabolic acidosis
Diagnostic tests: ABG & electrolytes
Multidimensional care: improve airway and oxygenation, drug
therapy, O2 therapy, pulmonary hygiene, ventilation support,
prevention complication
o Respiratory acidosis
pH <7.35
PaCO2 > 45mmHg
Causes: retention of CO2 (causing production of free H ions)
Signs and symptoms: variable respirations, kussmal
respirations, pale to cyanotic and dry skin in respiratory
acidosis
Diagnostic test: arterial blood gas & serum electrolytes
Multidimensional care: improve airway and oxygen, drug
therapy (bronchodilators, anti-inflammatory, mucolytic),
oxygen therapy, pulmonary hygiene, ventilation support,
prevention of complications
o Patient centered care
CNS changes
Neuromuscular changes: decreased muscle tone, deep tendon
reflexes
Cardiovascular changes: (early) increased HR, cardiac output
changes; (worsening) hyperkalemia, decreased HR, EKG
changes, hypotension
