B1.vi · Context-Sensitive Half-Time

Official V5 objective

Describe the concept of context sensitive half-time.

1 SAQ topic 2 SAQ appearances 1 VIVA station

Written examination

SAQ history

2 appearances

Fentanyl vs Remifentanil

2 exam appearances

2024A Q09

(a) Describe the pharmacokinetics of intravenous fentanyl and intravenous remifentanil (40% of marks). (b) Explain how these features create contrasts between the two drugs (20% of marks). (c) Discuss the concept of context sensitive half-time using these drugs as examples (40% of marks).

31%

2018A Q05

Compare and contrast the pharmacokinetics and pharmacodynamics of IV fentanyl and IV remifentanil (60% of marks). Discuss the concept of context sensitive half-time using these drugs as examples (40% of marks).

66%

Oral examination

VIVA history

1 station

2026A · VIVA 7
Relevant examiner prompts

A patient has been on a 3-day infusion of propofol and fentanyl. Explain what happens to the plasma concentrations after the infusions are ceased?

What is CSHT and what factors influence fentanyl’s?

How does context-sensitive half time differ from elimination half-life, and which is more clinically useful in ICU?

Explain strategies to mitigate fentanyl’s long CSHT in ICU.

61.5% successful

Sources: objective text from the relevant CICM syllabus; historical SAQ and VIVA wording from CICM examiner reports.