Delirium and Iatrogenic Withdrawal Profiles in the Pediatric Intensive Care Unit (PICU): A Latent Profile Analysis of Nurse-Administered Bedside Scales.

Background/Objectives: Delirium and iatrogenic withdrawal syndrome (IWS) overlap clinically in critically ill children. We used latent profile analysis (LPA) of nurse-administered assessments to identify score patterns, not diagnoses; no independent reference standard was available. Methods: This single-center retrospective cohort included 203 pediatric intensive care unit (PICU) records from 84 patients. Raw scores from the IWS and delirium subscores of the Japanese Sophia Observation withdrawal Symptoms-Paediatric Delirium (SOS-PD) scale, the Richmond Agitation-Sedation Scale (RASS), and the Face, Legs, Activity, Cry, Consolability (FLACC) scale were modeled using tied-diagonal Gaussian mixtures for K = 1-5. Selection used the Bayesian information criterion (BIC), entropy, and posterior probabilities. Results: The selected four-profile solution had BIC = 3245.4, entropy = 0.887, and 91.6% of records had a maximum posterior probability ≥ 0.70. Patient-level analyses provided partial support (adjusted Rand index = 0.833); standardization yielded an adjusted Rand index of 0.977. The profiles were Profile 1 (Delirium-predominant), Profile 2 (High-symptom mixed), Profile 3 (Withdrawal-predominant), and Profile 4 (Low-symptom at-target). Separation was strongest and inverse on the SOS-PD subscores (within-input |d| = 3.05 withdrawal; 2.26 delirium), describing input-scale divergence rather than diagnostic discrimination. Untied, categorical, and count models favored two profiles. Conclusions: Joint bedside scores contained model-specific candidate patterns, and profile number was model-dependent. Before prospective external validation, profiles should be treated only as descriptive score summaries and should not be used in clinical care.