In this episode, Dr Swapnil Pawar sits down with Professor Ian Seppelt, intensivist at Nepean Hospital, Sydney, and one of the lead investigators of the SuDDICU trial, to unpack the decades-long story of Selective Digestive Decontamination (SDD) in intensive care.

Ian traces SDD from its haematology origins in the 1970s, through its adoption in the Netherlands, to the extraordinary behind-the-scenes journey of SuDDICU: failed international grants, the pivot from a parallel-group to a crossover cluster design, manufacturing a pharmaceutical-grade SDD preparation from scratch, and navigating ethics approval for a trial without individual patient consent.

They discuss:

• What SDD actually is, and why "selective" matters
• Why infectious disease physicians resisted a therapy with one of the largest evidence bases in critical care
• The SuDDICU results: a non-significant mortality benefit, fewer positive blood cultures, fewer resistant organisms, and no signal of emerging resistance
• The Bayesian view, with a high posterior probability of survival benefit
• Where SDD goes next: enriched subgroups (neurological injury, pancreatitis), the PREVENT trial of prophylactic ceftriaxone in acute brain injury, and the unanswered question of high-resistance settings
• Why we adopt some interventions and ignore others: the psychology of evidence in ICU