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Fluid, Chapter Electrolyte and Acid Base Balance
Body fluids and electrolytes
Distribution of body fluids
Intracellular Extracellular
Interstitial
Intravascular
Composition of body fluids
Electrolytes
Ions + Anions
Movement of body fluids and electrolytes
Osmosis Diffusion Filtration
Active transport
Regulating body fluids
Fluid intake
Fluid output
Urine Insensible losses Feces
Maintaining homeostasis
Kidneys
Control fluid and electrolyte excretion
Antidiuretic hormone (ADH)
Synthesized by anterior hypothalamus Regulates water excretion from kidney
Maintaining homeostasis
Reninangiotensinaldosterone
Atrial natriuretic factor
Receptors in kidney respond to perfusion Promotes H2O and electrolyte retention Stimulates release of aldosterone to reabsorb sodium in the distal nephron Atrial wall stretching stims this factor to dump sodium and therefore H2O
Fluid imbalances
Fluid volume deficit
Fluid volume excess
Third space syndrome Edema Dehydration Overhydration
Fluid replacement
Isotonic Fluid has the same osmolarity as plasma
Normal Saline (N/S or 0.9% NaCl), Ringers Lactate (RL)
Fluid replacement
Hypotonic
Fluid has fewer solutes than plasma
Water, 1/2 N/S (0.45% NaCl), and D5W (5%
dextrose in water) after the sugar is used up
Fluid replacement
Hypertonic
Fluid has more solutes than plasma
saline solution, D5 in RL.
5 % Dextrose in Normal Saline (D5 N/S), 3%
ACID
Acids are anything which gives off H+ ions In the body CO2 acts as an acid (forms The lower the pH, the more acid is present
carbonic acid) Lungs are the mechanism primary for regulating CO2
BASE
Bases are anything that absorb H+ ions The higher the pH, the more base is
present In the body HCO3 acts as a base (buffers the acids) Kidneys are the primary mechanism for regulating HCO3
Respiratory Acidosis
Low pH caused by High CO2 Causes
High HCO3 will develop later to help balance pH COPD CHF Head injury with respiratory depression Lung Cancer Pneumonia Asthma
Respiratory Alkalosis
High pH caused by Low CO2 Causes
Low HCO3 will develop later to help balance pH Fever Severe Pain Anxiety ASA overdose Thyrotoxicosis Overventilation with a mechanical ventilator
Metabolic Acidosis
Low pH caused by Low HCO3
Caused by anything which increases respirations
Low HCO3 will develop later to help balance pH
Fever Severe Pain Anxiety ASA overdose Thyrotoxicosis Overventilation with a mechanical ventilator
Metabolic Alkalosis
High pH caused by High HCO3
Causes
High CO2 develops quickly to help balance pH Prolonged Vomiting Prolonged NG suctioning Excessive intake of HCO3 antacids Prolonged diuretic therapy with K+ wasting diuretics
Determining Imbalance
If pH is low (acidosis) look at CO2
If CO2 is high, it's respiratory acidosis If HCO3 is low it's metabolic acidosis
Determining Imbalance
If pH is high (alkalosis) look at CO2
If CO2 is low, its respiratory alkalosis If HCO3 is high, its metabolic alkalosis
Nursing diagnoses
Deficient fluid volume Excess Fluid volume Risk for Imbalanced fluid volume Risk for Deficient fluid volume Impaired Gas Exchange