PowerPoint: Acid-Base Imbalance & ABG
pH = “Potential Hydrogen”
• ↑Hydrogen ion concentration, ↓pH (acid)
• ↓Hydrogen ion concentration, ↑pH (base)
NL arterial blood pH is 7.35-7.45
Buffers: first line of defense. Chemically acts to change
strong acids to weak acids or bind acids
Bicarb & protein buffers (albumin & globulins) either bind of release H+ ions as needed
Respond quickly to changes in pH
Primary regulator of acid-base balance
Respiratory system: 2nd line of defense. Controls H+ ion in blood through retention of CO2
When there is a change in level of CO2 the brain alters the rate & depth of respirations
Renal system: 3rd line of defense. Conserves bicarb & excretes acid. Much slower to respond
but most effective
Respiratory Acidosis (Hypoventilation)
• ↑ CO2 in blood
• Causes: COPD, pneumonia, Airway obstruction, Asthma, Resp depression
• S&SX: low RR, shallow breathing, dizziness, confusion, restlessness, palpitations,
• Treatment: administer O2, maintain airway, monitor A B G, Monitor vital signs, high
fowler’s, deep breathing, bronchodilators, mucolytics
Respiratory Alkalosis (Hyperventilation)
• ↓ CO2 in blood
• Causes: fear, anxiety, pain, fever,
• S&Sx: SOB, restless, increase RR, tachypnea, CP, blurred vision, dry mouth, paresthesia
• Treatment: O2, anxiety reduction, rebreathing techniques, sedative or anxiolytic
therapy, Provide emotional support and reassurance
Metabolic Acidosis
• ↓ HCO3-
• Causes: starvation, diarrhea, fever, dehydration
• S&Sx: bradycardia, hypotension, confusion, warm flushed skin
• Treatment: antidiarrheals, rehydration, admin fluids and electrolytes, admin sodium
bicarbonate
Metabolic Alkalosis
• ↑ HCO3-
• Causes: vomiting, NG suctioning, excessive use of antacids, hypokalemia
• S&Sx: dizziness, decreased respirations
• Treatment: antiemetics, F&E, stop k+ diuretics & NG suctioning, admin acetazolamide
,Compensation
Fully compensated: pH is normal & both CO2 & HCO3- are abnormal
Partially compensated: all 3 are abnormal
Uncompensated: pH is abnormal & either CO2 or HCO3- are abnormal
,PowerPoint: Fluid Imbalance
One liter of water weighs 2.2 lb (1 kg)
Electrolytes are substances whose molecules split when placed in water
Cations: positively charged +
Anions: negatively charged -
ICF: prevalent cation is K+, prevalent anion is PO43-
ECF: prevalent cation is Na+, prevalent anion is Cl-
Mechanisms controlling fluid & electrolyte movement
Hydrostatic pressure: blood pressure generated by heart contraction
Oncotic pressure: osmotic pressure caused by plasma proteins
Measuring plasma osmolality is useful way to assess state of body’s water balance
Normal plasma osmolality is 275-295
>295 water deficit (concentration of solute too great or water content too little)
<275 water excess (too little solute or too much water)
Osmolality: Relationship of water to solute
1.010 (more water. pale) – 1.030 (more solute. amber)
Plasma to interstitial fluid = edema
Fluid spacing is the distribution of body water
• First spacing – normal
• Second spacing – abnormal (edema)
• Third spacing – fluid is trapped where it is difficult or impossible for it to move back into
cells/blood vessels (ascites)
Regulation of water balance
Hypothalamic-pituitary, renal, adrenal cortical, cardiac, GI
Fluid imbalances are deficits or excesses
Indicators of fluid status
• Body weight
• Serum osmolarity
• Blood Urea Nitrogen
• Creatinine
• Urine specific gravity
, Fluid Volume Deficit (FVD) aka hypovolemia
• Excessive loss of body fluids (diarrhea, vomiting, perspiration, hemorrhage, polyuria)
• Inadequate fluid intake
• Plasma to interstitial fluid shift
FVD Risk Factors
• Excess GI or renal loss, diaphoresis, fever, long term NPO, hemorrhage, diuretic therapy,
insufficient intake
FVD Manifestations
• Weight loss, thirst, dry mucous membranes, restlessness, confusion, lethargy, increase
heart rate & respirations, thready pulse, capillary refill >3 sec, weakness, fatigue,
orthostatic hypotension, poor skin turgor, concentrated urinary output & oliguria
FVD Labs
• Electrolytes: sodium & potassium
• Serum osmolarity: elevated as kidney works to conserve water
• BUN & Creatinine: elevation of BUN-to-creatinine ratio
• Urine: specific gravity & osmolarity: elevated as kidney works to conserve water
Interprofessional Care FVD
• Monitor VS & mental status
• Monitor skin turgor
• Maintain strict I&O
• Weight daily
• Monitor lab reports
• Initiate fall precautions
• Meds: electrolyte replacement and IV fluids (isotonic)
• Replace fluids: increase oral intake. IV fluids
pH = “Potential Hydrogen”
• ↑Hydrogen ion concentration, ↓pH (acid)
• ↓Hydrogen ion concentration, ↑pH (base)
NL arterial blood pH is 7.35-7.45
Buffers: first line of defense. Chemically acts to change
strong acids to weak acids or bind acids
Bicarb & protein buffers (albumin & globulins) either bind of release H+ ions as needed
Respond quickly to changes in pH
Primary regulator of acid-base balance
Respiratory system: 2nd line of defense. Controls H+ ion in blood through retention of CO2
When there is a change in level of CO2 the brain alters the rate & depth of respirations
Renal system: 3rd line of defense. Conserves bicarb & excretes acid. Much slower to respond
but most effective
Respiratory Acidosis (Hypoventilation)
• ↑ CO2 in blood
• Causes: COPD, pneumonia, Airway obstruction, Asthma, Resp depression
• S&SX: low RR, shallow breathing, dizziness, confusion, restlessness, palpitations,
• Treatment: administer O2, maintain airway, monitor A B G, Monitor vital signs, high
fowler’s, deep breathing, bronchodilators, mucolytics
Respiratory Alkalosis (Hyperventilation)
• ↓ CO2 in blood
• Causes: fear, anxiety, pain, fever,
• S&Sx: SOB, restless, increase RR, tachypnea, CP, blurred vision, dry mouth, paresthesia
• Treatment: O2, anxiety reduction, rebreathing techniques, sedative or anxiolytic
therapy, Provide emotional support and reassurance
Metabolic Acidosis
• ↓ HCO3-
• Causes: starvation, diarrhea, fever, dehydration
• S&Sx: bradycardia, hypotension, confusion, warm flushed skin
• Treatment: antidiarrheals, rehydration, admin fluids and electrolytes, admin sodium
bicarbonate
Metabolic Alkalosis
• ↑ HCO3-
• Causes: vomiting, NG suctioning, excessive use of antacids, hypokalemia
• S&Sx: dizziness, decreased respirations
• Treatment: antiemetics, F&E, stop k+ diuretics & NG suctioning, admin acetazolamide
,Compensation
Fully compensated: pH is normal & both CO2 & HCO3- are abnormal
Partially compensated: all 3 are abnormal
Uncompensated: pH is abnormal & either CO2 or HCO3- are abnormal
,PowerPoint: Fluid Imbalance
One liter of water weighs 2.2 lb (1 kg)
Electrolytes are substances whose molecules split when placed in water
Cations: positively charged +
Anions: negatively charged -
ICF: prevalent cation is K+, prevalent anion is PO43-
ECF: prevalent cation is Na+, prevalent anion is Cl-
Mechanisms controlling fluid & electrolyte movement
Hydrostatic pressure: blood pressure generated by heart contraction
Oncotic pressure: osmotic pressure caused by plasma proteins
Measuring plasma osmolality is useful way to assess state of body’s water balance
Normal plasma osmolality is 275-295
>295 water deficit (concentration of solute too great or water content too little)
<275 water excess (too little solute or too much water)
Osmolality: Relationship of water to solute
1.010 (more water. pale) – 1.030 (more solute. amber)
Plasma to interstitial fluid = edema
Fluid spacing is the distribution of body water
• First spacing – normal
• Second spacing – abnormal (edema)
• Third spacing – fluid is trapped where it is difficult or impossible for it to move back into
cells/blood vessels (ascites)
Regulation of water balance
Hypothalamic-pituitary, renal, adrenal cortical, cardiac, GI
Fluid imbalances are deficits or excesses
Indicators of fluid status
• Body weight
• Serum osmolarity
• Blood Urea Nitrogen
• Creatinine
• Urine specific gravity
, Fluid Volume Deficit (FVD) aka hypovolemia
• Excessive loss of body fluids (diarrhea, vomiting, perspiration, hemorrhage, polyuria)
• Inadequate fluid intake
• Plasma to interstitial fluid shift
FVD Risk Factors
• Excess GI or renal loss, diaphoresis, fever, long term NPO, hemorrhage, diuretic therapy,
insufficient intake
FVD Manifestations
• Weight loss, thirst, dry mucous membranes, restlessness, confusion, lethargy, increase
heart rate & respirations, thready pulse, capillary refill >3 sec, weakness, fatigue,
orthostatic hypotension, poor skin turgor, concentrated urinary output & oliguria
FVD Labs
• Electrolytes: sodium & potassium
• Serum osmolarity: elevated as kidney works to conserve water
• BUN & Creatinine: elevation of BUN-to-creatinine ratio
• Urine: specific gravity & osmolarity: elevated as kidney works to conserve water
Interprofessional Care FVD
• Monitor VS & mental status
• Monitor skin turgor
• Maintain strict I&O
• Weight daily
• Monitor lab reports
• Initiate fall precautions
• Meds: electrolyte replacement and IV fluids (isotonic)
• Replace fluids: increase oral intake. IV fluids
