Freezing the Physiological Encoder: Explanation Stability Under Bounded Updates of an ICU Model

תקציר מקורי באנגליתarXiv:2607.19020v4 Announce Type: replace Abstract: Clinical prediction models deployed in intensive care units may require model updating when data distributions shift, yet unconstrained adaptation can alter model behavior in ways that are difficult to audit. We propose a structurally bounded updating framework that separates physiological dynamics from treatment context and restricts post-drift adaptation to the treatment pathway and fusion head, while leaving the physiological encoder unchanged. Rather than assuming that physiological information remains stable, we investigate how this predefined update boundary affects model explanations after distribution shift. Using 84,792 MIMIC-IV ICU stays across four temporal transitions, we compare selective adaptation with full model adaptation