Dyspnea is common and distressing in patients with acute respiratory failure. In our intensive care unit, some patients receive a cervical erector spinae plane (ESP) block to help relieve dyspnea. This study will observe patients who receive bilateral cervical ESP blocks and measure changes in dyspnea using validated scales at predefined time points over 24 hours. We will also track vital signs, arterial blood gas values, and diaphragm movement on ultrasound.

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).

Inclusion Criteria:

• ICU admission with acute respiratory failure.
• Patient or legally authorized representative provides consent.
• Cervical ESP block performed for dyspnea treatment

Exclusion Criteria:

• Infection at block site.
• Known diaphragm paralysis.
• Known allergy to local anesthetics.
• Refusal of consent (patient or representative).

Consecutive adult patients in the mixed medical-surgical ICU of a tertiary university hospital (Hacettepe University Hospital, Ankara, Türkiye). The ICU manages acute respiratory failure due to pneumonia, COPD/asthma, pulmonary edema, and post-operative causes. Patients who receive a cervical ESP block for dyspnea as are observed for changes over 24 hours.