disorders of acid-base balance

acid

a molecule that can relase H+

base

an ion or molecule that can accept or combine with a H+

normal blood pH

7.35-7.45

pH scale

each whole number change represents a 10-fold change in hydrogen ion concentration

neutral pH

7 (distilled water)

acidic pH

less than 7

basic pH

greater than 7

HCO3- (bicarbonate)

primary blood buffer that neutralize hydrogen ions

strong acids

acids that dissociate completely into their ions in water

HCL (hydrochloric acid)

strong acid

HNO3- (nitric acid)

strong acid

H2SO4 (sulfuric acid)

weak acid

weak acids

acids that do not completely dissociate into their ions in water

metabolic acids

by-products of metabolic processes released from cells

volatile acids

acid related to carbon dioxide that can be converted into gas and eliminated by the lungs

• CO2 in plasma: 10% dissolved as a gas

• CO2 as a bicarbonate: 70% transported as bicarbonate ion

• Carbaminohemoglobin: CO2 bound to hemoglobin

Carbonic Acid

acid that can be breathed out by the lungs

Novolatile acid (fixed acids)

acids that cannot be converted to a gas and must be excreted by the kidneys

• lactic acid: fixed acid seen in DKA

• beta-hydroxybutyric acid: fixed acid

• aceotoacetic acid: fixed acid

• salicylic acid: produced from aspirin metabolism in the liver

source of metabolic acids

dietary protein metabolism

sulfur-containing amino acid oxidation

produced metabolic acids

• aginine

• lysine

phosphorous-containing nucleic acid oxidation

produced metabolic acids

incomplete glucose oxidation

produces metabolic acids

fat metabolism

produced metabolic acids

henderson-hasselbalch equation

pH = 6.1 + log[HCO3-]/[H2CO3]

acid-base balance

maintenance of ECF pH between 7.35-7.45

pH regulation

determined by the ratio of bicarbonate to carbonic acid

kidneys

regulate metabolic acids and bicarbonate; only organ that restore pH to normal

respiratory system

regulate CO2 concentration

davenport curve

graph showing the relationship betwen pH, bicarbonate and pCO2

high pCO2

causes acidosis due to hypoventilation

shifts curve to the left

low pCO2

causes alkalosis due to hyperventilation

shifts curve to the right

metabolic problem

related to metabolism, protein breakdown, and kidney excretion

respiratory problem

related to breathing and ventilation

chemical buffers

proteins and organic molecules that resist pH change

bicarbonate buffering system

major extracellular buffering system

H+/K+ transcellular exchange

movement of hydrogen and potassium to maintain electrical balance

insulin, epinephrine —> catecholamines

too much = periodic paralysis

insulin

drives potassium into cells and hydrogen out

epinephrine and catecholamines

affect potassium and acid movement

periodic paralysis

result of excessive potassium shifting into cells

intracellular fluid (ICF)

buffers inside the cell

phosphate buffer system

intracellular buffer system

calcium phosphate (CaPO4)

bone buffering system

protein buffering system

amino acid binds hydrogen ions

plasma proteins

act as buffers

acidosis

blood pH below 7.35

respiratory acidosis

acidosis caused by increased pCO2

low pH, high pCO2

primary disturbance for respiratory acidosis

hypoventilation and increased CO2

compensation for respiratory acidosis

increased H+ excretion and increased HCO3- reabsorption

symptoms of respiratory acidosis

hypoxia = low levels of oxygen

rapid shallow respirations

low blood pressure

pale to cyanotic skin

headache

hyperkalemia

dysrhythmias

drowsiness + dizziness

increased HCO3- reabsorption

causes of respiratory acidosis

respiratory depression

airway obstruction

pneumonia

COPD (chronic obstructive pulmonary disease)

pulmonary embolismme

metabolic acidosis

acidosis caused by decreased bicarbonate

low pH, low bicarbonateprimaru

primary disturbance for metabolic acidosis

decrease in bicarbonate

compensation of metabolic acidosis

hyperventilation to decrease pCO2

increased H+ excretion and increased HCO3- reabsorption

symptoms of metabolic acidosis

headache

low blood pressure

hyperkalemia

muscle twitching

flushed skin

nausea

vomiting

diarrhea

altered consciousness

kussmaul respirations

causes of metabolic acidosis

DKA (diabetic ketoacidosis)

severe diarrhea

renal failure

shock

alkalosis

blood pH above 7.45

respiratory alkalosis

alkalosis caused by decreased pCO2

high pH, low pCO2

primary disturbance of respiratory alkalosis

decreased pCO2

compensation of respiratory alkalosis

decreased H+ excretion and decreased HCO3- reabsorption

symptoms of respiratory alkalosis

confusion

dysrhythmias

hypoventilation

dizziness

irritability

anxiety

seizures

nausea

vomiting

diarrhea

tremors

muscle cramps

tingling

causes of respiratory alkalosis

excess bicarbonate

overuse of antacids

ROME

respiratory opposite metabolic equal

respiratory opposite (RO)

pH and pCO2 move opposite

metabolic equal (ME)

pH and HCO3 move in the same direction

ABG’s (arterial blood gases)

measure pH, pCO2, and bicarbonate

anion gap

difference between measured cations and anions

normal anion gap metabolic acidosis

decreased bicarbonate with increased chloride

causes of normal anion gap acidosis

diarrhea

renal tubular acidosis

carbonic anhydrase inhibition

elevated anion gap metabolic acidosis

accumulation of unmeasured acids

causes of elevated anion gap acidosis

kidney failure

keoacidosis

lactic acidosis

drugs, toxins

Ketoacidosis

excess ketone production from fat metbaolism causing metabolic acidosis

ketons

aldehydes and ketones such as propanone and acetone

DKA (diabetic ketoacidosis)

keotacidosis caused by insulin deficiency

normal blood glucose

90-120 mg/dL

hypoglycemia

blood glucose less than 90 mg/dL

hyperglycemia

blood glucose greater than 120 mg/dL

signs of DKA

blood glucose greated than 240 mg/dL

polyuria = tendency to go pee more

polydipsia = tendency to drink water more

hyperventilation

dry mouth

fruity breath

fatigue

treatment of DKA

insulin

fluids

electrolytes