skip to main content

LAM imaging — SCE Respiratory MCQ

Instant feedback + full explanation. One question, done properly.

HardThoracic ImagingLAM imagingSCE Respiratory

A patient with COPD–OSAHS overlap has symptomatic severe OSAHS and persistent awake PaCO2 of 7.4 kPa after recovery from an exacerbation. Respiratory polygraphy confirms nocturnal hypoventilation. Which first-line positive-pressure mode follows NICE?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Non-invasive ventilation because severe awake hypercapnia exceeds 7.0 kPa

Explanation lettering: E = shown as A · C = shown as B · D = shown as C · B = shown as D · A = shown as E

D is correct. NICE suggests CPAP first line in COPD–OSAHS overlap when severe hypercapnia is absent, defined as awake PaCO2 7.0 kPa or less. When PaCO2 is above 7.0 kPa with nocturnal hypoventilation, non-invasive ventilation should be considered because ventilatory support, not airway splinting alone, is needed. Oxygen can mask desaturation without correcting hypoventilation, auto-CPAP does not address the stated hypercapnic phenotype, and adaptive servo-ventilation is not routine therapy for obstructive overlap syndrome.

Reference: https://www.nice.org.uk/guidance/ng202/chapter/2-Obstructive-sleep-apnoeahypopnoea-syndrome#copd-osahs-overlap-syndrome