Incidence of hemi- diaphragmatic paralysis following supraclavicular brachial plexus block using corner pocket technique: A prospective observational study.

Title: Ultrasound-guided Evaluation of Ipsilateral Hemi-Diaphragmatic Paralysis Following Supraclavicular Brachial Plexus Block Using the Corner Pocket Technique

Objectives:

• Primary Objective: To calculate the incidence of ipsilateral hemi-diaphragmatic paralysis following the supraclavicular brachial plexus block using the Corner Pocket technique via ultrasound.
• Secondary Objectives:
• Investigate the effect of local anaesthetic volume and type (Ropivacaine vs. Bupivacaine) on HDP.
• Assess operator satisfaction with diaphragm evaluation techniques.

Study Design: Prospective observational cohort study. The study will be conducted at Tertiary care Hospital, with a sample size of 78 patients.

Methods:

• Patient Selection: Adults (18+ years) undergoing upper limb surgery with ultrasound-guided supraclavicular block via the Corner Pocket technique.

• Exclusion Criteria: Conditions like acute/chronic pulmonary dysfunction, coagulopathy, or allergy to local anesthetics, among others.

• Procedure: Diaphragmatic function will be assessed using ultrasound before the block, 20 minutes after the block, and at the end of surgery, focusing on diaphragmatic excursion and thickness via subcostal and intercostal approaches.

• Diaphragmatic Excursion: Measured using M-mode ultrasound to assess movement during breathing. A reduction in diaphragmatic excursion (>75%) indicates complete paralysis, while a partial reduction (25-75%) indicates partial paralysis.

• Diaphragmatic Thickness: Measured through intercostal windows. A reduction in the thickness change during deep breathing (≤5%) suggests complete paralysis, and a 5-20% change suggests partial paralysis.

Sample Size Calculation: Based on previous studies showing a 27.8% incidence of HDP with the CP technique, the sample size was calculated to be 78, allowing for a 10% margin of error and 95% confidence.

Results (Hypothesized):

• The study hypothesizes that the incidence of hemi-diaphragmatic paralysis following the CP technique will be lower than previous reported figures (27.8%).
• Additionally, the study will examine if the volume and type of local anaesthetic influence the likelihood of HDP.

Data Collection:

• Baseline data (patient demographics, vitals) and block characteristics (LA used, success of block) will be noted.
• Diaphragm measurements will be taken at three time points: pre-block, 20 minutes post-block, and at the end of surgery.
• The success of the block will be assessed using sensory and motor testing, while HDP will be graded based on changes in diaphragmatic excursion and thickness.

Expected Contributions:

• This study aims to provide evidence for the Corner Pocket technique’s effectiveness in minimizing diaphragmatic paralysis during supraclavicular BPB, offering a safer approach for patients with underlying respiratory conditions or other risk factors.
• It will also compare two techniques for evaluating diaphragm function (subcostal vs. intercostal) to determine which offers the most reliable assessment.