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NIV Failure — RACP Adult Medicine MCQ

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ModerateRespiratoryNIV FailureRACP Adult Medicine

A 70-year-old man with obesity hypoventilation syndrome presents with acute hypercapnic respiratory failure (PaCO₂ 75 mmHg, pH 7.22). He has been trialled on NIV (BiPAP) for 2 hours but remains obtunded with worsening acidosis (pH 7.18). He is haemodynamically stable. What is the most appropriate next step?

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Correct answer: A — Invasive mechanical ventilation

Failure of NIV (worsening pH, persistent or worsening hypercapnia, deteriorating consciousness after 1–2 hours of optimised NIV) is an indication for intubation and invasive mechanical ventilation. The pH threshold for considering NIV failure is typically <7.25 after 1–2 hours of adequate NIV. A ceiling-of-care discussion should occur before escalation.

Reference: BTS/ICS – 2024 – NIV Guidelines; eTG Respiratory 2024