QuestionSBA
QuestionChoice
This would occur if the patient was blowing off carbon dioxide due to a high respiratory rate. However, in obstructive sleep apnoea airway obstruction leads to carbon dioxide retention. Furthermore, it is very difficult for patients to maintain a raised respiratory rate for long enough for renal compensation to occur.
10001258
c
Compensated respiratory alkalosis
QuestionChoice
This would occur if there was a build-up of acid due to a metabolic cause which was then compensated for through hyperventilation and blowing off carbon dioxide. However, the most likely diagnosis in this gentleman is obstructive sleep apnoea which results in hypercapnia, not hypocapnia.
10001259
d
Compensated metabolic acidosis
QuestionChoice
The most likely diagnosis is obstructive sleep apnoea (OSA). The airway obstruction in OSA leads to type 2 respiratory failure as patients retain carbon dioxide, however as OSA is a chronic disease, the kidneys have time to produce bicarbonate and compensate for the hypercapnia.
10001256
a
Compensated respiratory acidosis
QuestionChoice
This would occur if there was a reduction of acid due to a metabolic cause which was then compensated for by the patient hyperventilating and retaining carbon dioxide.
10001260
e
compensated metabolic alkalosis
QuestionChoice
In obstructive sleep apnoea, airway obstruction leads to hypercapnia as well as hypoxemia due to air retention in the lungs.
10001257
b
Type 1 respiratory failure
Concept
Chapter
2693
3718
Obstructive Sleep Apnoea
Topic
132
Respiratory
12798
A 40-year-old lorry driver presents to the GP with a 6-month history of headaches when he wakes up. He explains that he is tired during the day and finds himself occasionally falling asleep whilst driving. His wife, who is with him, also mentions that he seems to stop breathing when sleeping at night.

On observation, the patient is of large body habitus and appears to have large hands and apparent prognathism. On examination, his blood pressure is 130/80 and his heart rate is 115.

Given the most likely diagnosis, which is the following is the most likely ABG finding?
a