Acid Base Balance and Fluid Balance

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Acid Base Balance and Fluid Balance

• Dr. Kathleen Ethridge
• Northeast Texas Community College

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Homeostasis

• A delicate balance of fluids, electrolytes, and
  acids and bases is required to maintain good
  health.
• This balance is called Homeostasis.

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Body Fluids

• Intracellular fluid (ICF)
• found within the cells of the body
• constitutes 2/3 of total body fluid in adults
• major cation is potassium
• Extracellular fluid (ECF)
• found outside the cells
• accounts of 1/3 of total body fluid
• major cation is sodium

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Terms

• Osmosis
• movement of water across cell membranes from less
  concentrated to more concentrated
• Solutes
• substances dissolved in a liquid
• Osmolality
• the concentration within a fluid

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More Terms

• Diffusion
• movement of molecules in liquids from an area of
  higher concentration to lower concentration
• Filtration
• fluid and solutes move together across a membrane
  from area of higher pressure to one of lower
  pressure
• Active Transport
• substance moves across cell membranes from less
  concentrated solution to more concentrated -
  requires a carrier

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Routes of Fluid Loss

• Urine
• Insensible fluid loss
• Feces

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Electrolytes

• Sodium
• Potassium
• Chloride
• Phosphate

• Magnesium
• Calcium
• Bicarbonate

Electrolytes are important for . Maintaining
fluid balance . Contributing to acid-base
regulation . Facilitating enzyme reactions .
Transmitting neuromuscular reactions
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Acid-Base Balance

• Acid-Base balance is
• the regulation of HYDROGEN ions.

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pH

• The acidity or alkalinity of a solution is
  measured as pH.
• The more acidic a solution, the lower the pH.
• The more alkaline a solution , the higher the
  pH.
• Water has a pH of 7 and is neutral.
• The pH of arterial blood is normally between
  7.35 and 7.45

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Hydrogen ions

• The more Hydrogen ions, the more acidic the
  solution and the LOWER the pH
• The lower Hydrogen concentration, the more
  alkaline the solution and the HIGHER the pH

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pH

• Know what is normal.

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Buffer Systems

• Regulate pH by binding or releasing Hydrogen
• Most important buffer system
• Bicarbonate-Carbonic Acid Buffer System
• (Blood Buffer systems act instantaneously and
  thus constitute the bodys first line of defense
  against acid-base imbalance)

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Acid Base Balance
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Respiratory ComponentRenal Component
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Respiratory Regulation

• Lungs
• help regulated acid-base balance by
  eliminating or retaining carbon dioxide
• pH may be regulated by altering the rate and
  depth of respirations
• changes in pH are rapid,
• occurring within minutes
• normal CO2 level
• 35 to 45 mm Hg

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Renal Regulation

• Kidneys
• the long-term regulator of acid-base balance
• slower to respond
• may take hours or days to correct pH
• kidneys maintain balance by excreting or
  conserving bicarbonate and hydrogen ions
• normal bicarbonate level
• 22 to 26 mEq/L.

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Factors Affecting Balance

• Age
• especially infants and the elderly
• Gender and Body Size
• amount of fat
• Environmental Temperature
• Lifestyle
• stress

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Acid-Base Imbalances

• Respiratory Acidosis
• Respiratory Alkalosis
• Metabolic Acidosis
• Metabolic Alkalosis

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See Chart
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Respiratory Acidosis

• Mechanism
• Hypoventilation or Excess CO2 Production
• Etiology
• COPD
• Neuromuscular Disease
• Respiratory Center Depression
• Late ARDS
• Inadequate mechanical ventilation
• Sepsis or Burns
• Excess carbohydrate intake

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Respiratory Acidosis (cont)

• Symptoms
• Dyspnea, Disorientation or coma
• Dysrhythmias
• pH lt 7.35, PaCO2 gt 45mm Hg
• Hyperkalemia or Hypoxemia
• Treatment
• Treat underlying cause
• Support ventilation
• Correct electrolyte imbalance
• IV Sodium Bicarb

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Respiratory Alkalosis

• Risk Factors and etiology
• Hyperventilation due to
• extreme anxiety, stress, or pain
• elevated body temperature
• overventilation with ventilator
• hypoxia
• salicylate overdose
• hypoxemia (emphysema or pneumonia)
• CNS trauma or tumor

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Respiratory Alkalosis (cont)

• Symptoms
• Tachypnea or Hyperpnea
• Complaints of SOB, chest pain
• Light-headedness, syncope, coma, seizures
• Numbness and tingling of extremities
• Difficult concentrating, tremors, blurred vision
• Weakness, paresthesias, tetany
• Lab findings
• pH above 7.45
• CO2 less than 35

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Respiratory Alkalosis (cont)

• Treatment
• Monitor VS and ABGs
• Treat underlying disease
• Assist client to breathe more slowly
• Help client breathe in a paper bag
• or apply rebreather mask
• Sedation

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Metabolic Acidosis

• Risk Factors/Etiology
• Conditions that increase acids in the blood
• Renal Failure
• DKA
• Starvation
• Lactic acidosis
• Prolonged diarrhea
• Toxins (antifreeze or aspirin)
• Carbonic anhydrase inhibitors - Diamox

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Metabolic Acidosis (cont)

• Symptoms
• Kussmauls respiration
• Lethargy, confusion, headache, weakness
• Nausea and Vomiting
• Lab
• pH below 7.35
• Bicarb less than 22
• Treatment
• treat underlying cause
• monitor ABG, IO, VS, LOC Sodium Bicarb?

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Metabolic Alkalosis

• Risk Factors/Etiology
• Acid loss due to
• vomiting
• gastric suction
• Loss of potassium due to
• steroids
• diuresis
• Antacids (overuse of)

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Metabolic Alkalosis (cont)

• Symptoms
• Hypoventilation (compensatory)
• Dysrhythmias, dizziness
• Paresthesia, numbness, tingling of extremities
• Hypertonic muscles, tetany
• Lab pH above 7.45, Bicarb above 26
• CO2 normal or increased w/comp
• Hypokalmia, Hypocalcemia
• Treatment
• IO, VS, LOC
• give potassium
• treat underlying cause

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Pneumonic

• Respiratory
• Opposite
• Metabolic
• Equal

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Interpreting ABGs

• 1. Look at the pH
• is the primary problem acidosis (low) or
  alkalosis (high)
• 2. Check the CO2 (respiratory indicator)
• is it less than 35 (alkalosis) or more than 45
  (acidosis)
• 3. Check the HCO3 (metabolic indicator)
• is it less than 22 (acidosis) or more than 26
  (alkalosis)
• 4. Which is primary disorder (Resp. or
  Metabolic)?
• If the pH is low (acidosis), then look to see if
  CO2 or HCO3 is acidosis (which ever is acidosis
  will be primary).
• If the pH is high (alkalosis), then look to see
  if CO2 or HCO3 is alkalosis (which ever is
  alkalosis is the primary).
• The one that matches the pH (acidosis or
  alkalosis), is the primary disorder.

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Compensation

• The Respiratory system and Renal systems
  compensate for each other
• attempt to return the pH to normal
• ABGs show that compensation is present when
• the pH returns to normal or near normal
• If the nonprimary system is in the normal range
  (CO2 35 to 45) (HCO3 22-26), then that system is
  not compensating for the primary.
• For example
• In respiratory acidosis (pHlt7.35, CO2gt45), if the
  HCO3 is gt26, then the kidneys are compensating by
  retaining bicarbonate.
• If HCO3 is normal, then not compensating.