Trauma Ward Mental Health Involuntary Sedation Chemical Restraint Duration and Post-Traumatic Stress Disorder Symptom Severity Among Kenyan Inpatients: A Target-Trial Emulation of Restraint-Hour Thresholds

Involuntary sedation and chemical restraint are routine in Kenyan trauma wards, yet the duration of restraint that separates therapeutic necessity from iatrogenic harm remains unquantified. No observational data are used or claimed. Under a declared variance structure with between-cluster standard deviation of 6.0, residual standard deviation of 4.5 and intraclass correlation of 0.64, power was estimated across 2000 design cells spanning cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points. The analysis indicates that 54 clusters are required to detect a 5-percentage-point effect at 80% power, and that the minimum detectable effect falls steeply as cluster count rises from 8 to 32. The contribution is a design specification that links restraint-hour thresholds to PTSD symptom severity through a counterfactual contrast, together with a demonstration that the intraclass correlation of 0.64 imposes a cluster requirement that most single-site trauma studies cannot meet. The framework reframes chemical restraint duration as a modifiable exposure amenable to target-trial analysis rather than a clinical given.