Altered Acid-Base Balance

Flashcards on Acid-Base Balance

Acid-Base Balance

Body fluids have a specific pH and compensatory mechanisms leading to a balance between acidity and alkalinity

Acids

Substances that donate hydrogen ions (H+)

Bases

Substances that accept hydrogen ions (H+)

pH

Clinical measurement of acid:base ratio

Anion Gap

Calculation of major cations and anions in plasma, using sodium, chloride and bicarbonate to indicate acid-base balance

Buffer Systems

Mix acids and bases to resist pH change, trading stronger acids/bases for weaker ones.

Plasma Buffer System

Reacts in seconds to hydrogen ion level

Respiratory Buffer System

Reacts in minutes to excrete CO2

Renal Buffer System

Reacts in hours to days to produce, absorb, and excrete acids, bases, and ions

Metabolic Acidosis/Alkalosis

Maintains Homeostasis; imbalance of acids by the kidneys. Can be caused by conditions like diabetic ketoacidosis, renal failure, or severe diarrhea

Respiratory Acidosis/Alkalosis

Maintains Homeostasis; imbalance of CO2 by the lungs

Buffer System

Carbon dioxide formed during cellular respiration combines with water to create carbonic acid

Pulmonary System (Lungs)

Adjusts pH by using Carbon Dioxide, upon expiration

Renal System (Kidneys)

Affects pH by reabsorbing Bicarbonate and excreting fixed acids

Normal Arterial Blood Gases (ABG's)

pH: 7.35-7.45 (acid-base); pCO2: 35-45 mmHg (ventilation); HCO3: 22-26 (buffer); po2: 80-100 mmHg (oxygenation)

The renal system

Attempt to ameliorate the effects of pathological metabolic acidosis by excreting ammonium (NH4+) into the urine

Anion Gap

Formula: [Na]- ([Cl] + [HCO3])

Arterial Blood Gas (ABG) Sampling

Test performed in the inpatient intensive care setting to assess the acid-base status of a client