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Ch. 12: Assessment and care of patients with acid-base balance

Terms in this set (15)

acid base balance
-Fluid contains equal number of positive charges, ions with negative charges
-Balance occurs by matching rate of hydrogen ion production with loss
normal blood pH
-Balance of acids and bases in body fluids
-Normal for:
Arterial blood = 7.35 to 7.45
Venous blood = 7.31 to 7.41
-Changes can affect:
--Shape of hormones and enzymes
--Distribution of other electrolytes (fluid and electrolyte imbalance)
--Excitable membranes
-Effectiveness of hormones and drugs
acids
-release hydrogen ions when in dissolved water
-Incomplete breakdown of glucose
-Breakdown of protein and fats
-Destruction of cells
bases
bind with hydrogen ions in solutions
buffers
critical in maintaining normal body fluid pH
body fluid chemistry
-Bicarbonate ions (HCO3-)
-Relationship between CO2 and hydrogen ions
-Calculation of free hydrogen ion level
bicarbonate
-Weak base
-Major buffer of extracellular fluid (ECF)
-From intestinal absorption of ingested bicarbonate into ECF, kidney absorption and breakdown of carbonic acid
-Level is typically 20 times greater than that of carbonic acid
acid-base control actions and mechanisms: respiratory
-When chemical buffers alone cannot prevent blood pH changes, respiratory system is second line of defense:
--Hyperventilation
--Hypoventilation
-Lungs compensate for acid-base imbalances of metabolic origin
acid-base control actions and mechanisms: kidneys
-Third line of defense against pH changes
-Stronger for regulating acid-base balance; take longer than chemical and respiratory
-Kidney movement of bicarbonate
-Formation of acids and ammonium
-Kidneys can correct/compensate for pH changes when respiratory system is overwhelmed or unhealthy
compensation
-Body attempts to correct blood pH changes
-pH <6.9 or >7.8 usually fatal
-Respiratory system more sensitive to acid-base changes; can begin compensating in seconds to minutes
-Kidneys more powerful; result in rapid changes in ECF composition; fully triggered for imbalance of several hours to days
acid base imbalances
-Metabolic acidosis
-Respiratory acidosis
-Combined metabolic and respiratory acidosis
-Metabolic alkalosis
-Respiratory alkalosis
*ROME= respiratory opposite, metabolic equal*
metabolic acidosis
-Hydrogen ions
--Overproduction
--Under-elimination
-Bicarbonate ions
--Under-production
--Over-elimination

Labs:
-pH <7.35
-Bicarbonate <21 mEq/L
-Pao2 normal
-Paco2 normal or slightly decreased
-Serum potassium high
interventions: respiratory acidosis
-Focus is on improving ventilation and oxygenation, maintaining patent airway
-Drug therapy
--Bronchodilators
--Anti-inflammatories
--Mucolytics
-Oxygen therapy
-Pulmonary hygiene
-Ventilation support
-Prevention of complications
interventions: metabolic acidosis
-Hydration
-Drug therapy
--Insulin to treat DKA
--Antidiarrheals
--Bicarbonate (only with low serum level)
alkalosis: patient-centered collaborative care
-Assessment (same for metabolic and respiratory alkalosis)
--Hypocalcemia
--Hypokalemia
-CNS changes - Positive -Chvostek's and Trousseau's signs
-Neuromuscular changes - Tetany
-Cardiovascular changes
-Respiratory changes
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