Question | Answer |
Acid | - donates a proton; releases H+
H+ + Cl- = Hydrochloric acid
Too much H+
Acidemia - blood
Acidosis-overall condition in body fluids
When acid meets base…they neutralize!
When acid meets base…they neutralize! |
Base | accepts or combines with a proton
Na++ OH- = Sodium Hydroxide
Too much base
Alkalemia - blood
Alkalosis- overall condition in body fluids |
Clinical Manifestations of alkalosis | Death
convulsions
arrhythmia
irritability |
Clinical Manifestations of acidosis | drowsiness
lethargy
coma |
Blood Buffers | Acids are carried by Hb and HCO3 (88%)
Bicarb system is open, primary system
Due to loss of CO2 through breathing
HC03 + H+ = H20 + CO2 (exhaled)
Nonbicarb systems are closed
Nothing is “lost”
Hemoglobin, phosphates, proteins |
Henderson-Hasselbach Equation | Allows you to calculate pH, CO2, or HCO3 if you know 2 of the 3 variables in the formula
Use: to check if pH, PCO2, and HCO3 in an ABG report are compatible, and to predict what happens when you change one component in the ABG |
CO2 excretion depends on: | Perfusion
Diffusion
Ventilation
Think heart, lungs or CNS |
Respiratory Acidosis Clinical signs | hypoxemic manifestations, warm flushed skin, bounding pulse, arrhythmias, > ICP, headaches, <Cl- |
Respiratory Acidosis Causes | acute airway obstruction
massive PE
drugs (sedatives, narcotics)
neuromuscular disease
trauma (brain, spinal cord, chest wall)
obesity
kyphoscoliosis
COPD
cardiac arrest |
Respiratory Alkalosis | Terms: excess CO2 elimination, hypocapnia, hyperventilation
Compensation: kidneys excrete HCO3
acute: -PaCO2 by 5 = HCO3 - by 1
(24-48 hrs)
chronic: -PaCO2 by 10 = HCO3 - by 5 |
Respiratory Alkalosis Clinical signs | tachypnea, dizziness, light-headedness, sweating, paresthesia |
Respiratory Alkalosis Causes | hypoxemia
anxiety
fever
stimulant drugs
pain
brain tumor
sepsis
exercise
early onset asthma
pneumonia, pulmonary edema, CHF
iatrogenic (vent, IPPB |
Metabolic Acidosis Clinical signs | hyperpnea, Kussmaul’s resp.in severe diabetic ketoacidosis, dyspnea, headache, N/V, lethargy, coma (severe) |
Anion Gap | Helps indicate the cause of metabolic acidosis
Anion gap = Na+ - (Cl- + HCO3)
Normal: 9 to 14 mEq/L
Increased (>14) = metabolic acidosis is caused by an increase in fixed acids
Normal anion gap = metabolic acidosis is caused by loss of HCO3 |
Anion Gap Metabolic Acidosis | Due to increased fixed acids
Causes:
Diabetic ketoacidosis
Lactic acidosis
Alcoholic ketoacidosis
Advanced renal failure
Ethylene glycol intoxication
Methanol intoxication (formic acid)
Salicylate intoxication (aspirin) |
Metabolic Alkalosis | Usually accompanied by hypokalemia
-Common in ICU; difficult to treat
Compensation: hypoventilation but usually uncompensated
: lower RR, apnea, cyanosis, N/V, confusion, headache, lethargy, tetany in severe cases |
Metabolic Alkalosis Causes | NG suction
Diuretics
Vomiting
Steroids
Hypokalemia
Hypochloremia
Hypovolemia
NaHCO3 infusion
Excessive antacids or alkali for peptic ulcers
Posthypercapnic met. alkalosis
Massive blood transfusion (>8 units) |