ABG Flashcards
What is type 1 respiratory failure?
Hypoxaemia (Pa02 <8kPA) with normocapnia (PaCO2 <6kPa)
What is type 2 respiratory failure?
Hypoxaemia (Pa02 <8kPA) with hypercapnia (PaCO2 >6kPa)
What is type 1 respiratory failure due to
VQ mismatch - the volume of air flowing in and out of the lungs is not matched with the flow of blood to the lung tissue
What are some conditions with decreased ventilation and normal perfusion?
pulmonary oedema, bronchoconstriction
What are some conditions with normal ventilation and decreased perfusion?
pulmonary embolism
What is type 2 respiratory failure due to?
Alveolar hypoventilation - unable to adequately oxygenate and eliminate CO2
What is a condition that causes type 2 resp failure due to increased resistance bc of airway obstruction?
COPD
What are conditions which causes type 2 resp failure due to decreased compliance of the lung tissue and chest wall?
pneumonia, rib fractures, obesity
What are conditions which cause type 2 resp failure due to decreased strength of respiratory muscles?
MND, also drugs acting on respiratory centre to reduce overall ventialtion
What is the effect of pH, CO2 and HCO3- in respiratory acidosis?
Decreased pH, increased CO2 and normal HCO3-
What is the effect of pH, CO2 and HCO3- in respiratory alkalosis?
increased pH, decreased CO2, normal HCO3-
What is the effect of pH, CO2 and HCO3- in respiratory acidosis with metabolic compensation?
decreased or normal pH, increased CO2 and increased HCO3-
What is the effect of pH, CO2 and HCO3- in respiratory alkalosis with compensation?
pH increased or normal, CO2 decreased and increased HCO3-
What is respiratory acidosis?
inadequate alveolar ventilation leading to CO2 retention
What is the cause of respiratory acidosis
Respiratory depression eg opiates asthma, COPD, guillain-barre latrogenic
what is respiratory alkalosis?
excessive alveolar ventilation, more CO2 than normal exhaled
What is the cause of respiratory alkalosis?
Panic attacks, pain, hypoxia, PE, pneumothorax, latrogenic
What is the effect of pH, CO2 and HCO3- in metabolic acidosis?
decreased pH, decreased HCO3-, CO2 normal
What is the effect of pH, CO2 and HCO3- in metabolic alkalosis?
increase pH, increased HCO3-, normal CO2
What is the effect of pH, CO2 and HCO3- in metabolic acidosis with respiratory compensation?
decreased pH, decreased CO2, decreased HC03-
What is the effect of pH, CO2 and HCO3- in metabolic alkalosis with respiratory compensation?
increased pH, increased CO2, increased HCO3-
What is metabolic acidosis?
Increased acid production/acid ingestion OR decreased acid excretion/increased rat of GI and renal HCO3- loss
what are the causes of a high anion gap?
due to increased production/ingestion or reduced excretion of H+ by the kidneys: diabetic ketoacidosis. Lactic acidosis, aspirin overdose, renal failure
what are the causes of a low anion gap?
(due to loss of HCO3-, which is replaced by Cl in plasma: GI loss of HCO3-, renal tubular disease, Addison’s disease
what is an anion gap?
artificial measure to determine presence of unmeasured anions e.g. albumin
what is metabolic alkalosis?
decreased H+ conc. leading to increased bicarbonate
what are the causes of metabolic alkalosis?
GI loss of H+ ions e.g. vomiting, diarrhoea, renal loss of H+ ions e.g. loop and thiazide diuretics, heart failure, cirrhosis, latrogenic
What are the ph, Co2 and HCO3- in mixed respiratory and metabolic acidosis?
decreased pH, increase CO2, decreased HCO3-
What are the ph, Co2 and HCO3- in mixed respiratory and metabolic alkalosis?
decreased pH, decreased CO2, increased HCO3-
What are some conditions where you would see mixed respiratory and metabolic acidosis?
cardiac arrest, multi-organ failure
