Respiratory acidosis and alkalosis Flashcards
What are the normal partial pressures of arterial blood gas
HCO3-= 34 PaCO2= 40 pa02= 95
What are the normal partial pressures of alveolar gas
PACO2= 36 PA02= 105
What are the normal partial pressures of venous blood gas
PVCO2= 50 PVO2= 30-40
5 main causes of respiratory acidosis
Hypoventilation Airway diseases Chest diseases Nerve/ muscle diseases Severe obesity
Briefly describe what happens in resp acidosis
Build up of CO2–> more acidic
CO2 produced by bodys metabolism and accumulate rapidly if lungs dont dispel
PH=
6.1+log([HC03-]/0.03pCO2)
9 symptoms of respiratory acidosis
- Lethargy
- Headache
- Drowsiness
- Restlessness
- Memory loss
- Muscle weakness
- Fatigue
- Sleeplessness
- Anxiety
10 signs of respiratory acidosis
- Gait disturbances
- Papilledema
- Blunted tendon reflexes
- Slow breathing
- Tachycardia
- Disorientation
- Tremor
- Myoclonic jerks
- Drop in bp
- Swollen eye vessels
What are the parameters for acute resp acidosis
PaC02 above 6.3kPa
Ph< 7.35
4 causes of acute resp acidosis?
Abrupt failure of ventilation
Depression of resp centre
Guilan Barre syndrome
Airway obstruction
What are the parameters for chronic respiratory acidosis
PaCo2 more than 6.3pka
But ph nearly normal
Why is ph nearly normal in chronic respiratory acidosis
Because of renal compensation- elevated HCO3-
What is the maximum level of HC03- in the body
45mmol/L
Syptoms of respiratory alkalosis
Dizziness, light-headidness, agitation, confusion, cramps
Signs of respiratory alkalosis
Muscle twitching, hypernoea, chest pain, blurred visions, spasms
6 main causes of respiratry alkalosis
- Intracerebral haemorrhage
- Anxiety
- Sepsis
- Liver ciarrhosis
- Elevated body temp
- Hypoxia
Define acute respiratory alkalsosis
Respiratory alkalosis that develops rapily
May result in loss of conciousness
What is the minimum concentration of HCO3- achievable
12mmol/L
How long does it take for metabolic compensation to work with resp alkalosis
7 days
How does respiratory alkalosis lead to impaired oxygen delivery to tissues
Decrease in C02 leads to cerebral vessel constriction
Alkaemia shifts 02 dissocociation curve left
How does chronic resp acidosis change potassium levels
Increased H+ excretion in kidney
K+ retained
Hyperkalaemia
How does chronic resp alkalosis change potassium levels
H+ retained in kidney
K+ excreted
Hypokalaemia
What are oxygen adn CO2 levels like in type 1 respiratory failure
Low O2 with normal or low CO2
How can CO2 be low in type 1 resp failure
Co2 diffuses outs of the lung faster than O2
Equation for anion gap
Na+-(Cl-+HC03-)
What is indicated by a high anion gap
Loss of plasma bicarbondate
Metabolic acidosis
What is the anion gap if HC03- is normal and Cl- is high
Normal (patient still unwell)
