ABGs

Ph                 7.69
PCo2            23
pO2              151
sO2              99%
HCO2          29

This ABGs belongs to a young male, dialysis-dependent for 1 year complained
Difficulty in breathing. He was just been dialyzed with an ultrafiltrate of 3 liters.
On examination, he was tachypenic.   his blood pressure was 150/90.

The chest was clear on auscultation as well as on an x-ray chest
ABGs performed, shown above.
What does this blood gases show?
How will u manage?






Impression:    Acute respiratory alkalosis with metabolic alkalosis
 
When ABGs were being drawn, the patient attended to pain, His rapid respiratory effort subsided.
In a couple of hours, he was alright and went home.




 Hyperventilation (ie increased alveolar ventilation) is the mechanism responsible for the lowered arterial pCO2 in ALL cases of respiratory alkalosis.

 Respiratory Alkalosis:

Respiratory alkalosis results from hyperventilation which is manifested by excess elimination of CO₂ from the blood and a rise in the blood pH. Examples of specific causes are listed below:

Central Causes (direct action via respiratory centre)

Head Injury Stroke Anxiety-hyperventilation syndrome (psychogenic) Other 'supra-tentorial' causes (pain, fear, stress, voluntary) Various drugs (eg analeptics, propanidid, salicylate intoxication) Various endogenous compounds (eg progesterone during pregnancy, cytokines during sepsis, toxins in patients with chronic liver disease)

2. Hypoxaemia (act via peripheral chemoreceptors)

Respiratory stimulation via peripheral chemoreceptors

3. Pulmonary Causes (act via intrapulmonary receptors)

Pulmonary Embolism Pneumonia Asthma Pulmonary oedema (all types)

4. Iatrogenic (act directly on ventilation)

Excessive controlled ventilation

 Signs and Symptoms of Respiratory Alkalosis
Neurological
light-headedness
numbness and tingling
confusion
inability to concentrate
blurred vision
Cardiovascular
dysrhythmias
palpitations
diaphoresis
Miscellaneous
dry mouth
tetanic spasms of the arms and
legs

CLINICAL APPLICATION:
Treatment of respiratory alkalosis centers on resolving the underlying problem.
Patients presenting with respiratory alkalosis have dramatically increased work of
breathing and must be monitored closely for respiratory muscle fatigue. When the
respiratory muscles become exhausted, acute respiratory failure may ensue




Metabolic Alkalosis


 

Metabolic alkalosis results from elevation of serum bicarbonate. Examples of specific causes:

• Volume contraction (vomiting, overdiuresis, ascites)
• Hypokalemia
• Alkali ingestion (bicarbonate)
• Excess gluco- or mineralocorticoids
• Bartter’s syndrome

Some causes of combined respiratory alkalosis with metabolic alkalois

Physiological:   Pregnancy
In CCF when patient is tackypenic and he is being given diuretic.
In CLD:  often seen when patient has vomiting too.
In Sepsis.