Cervical Erector Spinae Plane Block for Dyspnea in Acute Respiratory Failure: A Prospective Cohort

Prospective, single-cohort observational study in an adult ICU. Consecutive eligible patients with acute respiratory failure who receive bilateral cervical ESP block will be enrolled. Dyspnea severity will be measured using a 100-mm Dyspnea Visual Analog Scale (D-VAS), the Respiratory Distress Observation Scale (RDOS), and the Intensive Care RDOS (IC-RDOS) before the block (baseline) and at 30 minutes, 8 hours, 16 hours, and 24 hours after the block. Vital signs (respiratory rate, heart rate, peripheral oxygen saturation, blood pressure) will be recorded at the same time points. From arterial blood gases, pH, PaO₂, PaCO₂, SaO₂, and HCO₃- will be abstracted. Bilateral diaphragm excursion amplitude will be measured with bedside ultrasound. Statistical plan includes normality checks; repeated-measures ANOVA for parametric data or Friedman test for nonparametric data; paired t-test or Wilcoxon as needed; chi-square or Fisher's exact for categorical variables. Planned sample size: 30 (power analysis for repeated measures with effect size 0.25, α=0.05, power=0.90).