Diaphragmatic and Pulmonary Functions Following an Ultrasound-Guided Supraclavicular Approach Versus a Costoclavicular Approach of a Brachial Plexus Block: A Randomized Study.

Abstract

A costoclavicular brachial plexus block is an emerging infraclavicular approach that targets the cords lateral to the axillary artery, providing rapid onset of sensory-motor blockade. However, the incidence of hemi-diaphragmatic paralysis (HDP), a potential complication, remains unclear compared to the widely used supraclavicular (SC) approach. This study aimed to compare the incidence of HDP between ultrasound-guided costoclavicular and SC brachial plexus blocks. To compare the influence of ultrasound-guided SC and costoclavicular brachial plexus blocks on diaphragmatic excursion, thickness, and contractility along with pulmonary function. This prospective, randomized, observer-blinded controlled trial included 60 patients undergoing below-shoulder surgeries. Patients were randomized to receive either ultrasound-guided SC (Group S) or costoclavicular (Group C) brachial plexus block with 0.5% levobupivacaine. The diaphragmatic function was assessed using ultrasonographic evaluation of diaphragm thickness and diaphragmatic thickness fraction (DTF) pre- and postblock. Pulmonary function tests (PFTs) (forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow rate (PEFR)) were performed preblock and two hours postblock. Block characteristics were compared. The SC group exhibited a significantly larger reduction in DTF from preblock to postblock compared to the costoclavicular group (mean ΔDTF: 34.38% vs. 14.01%, p<0.01). Both groups showed significant declines in FVC, FEV1, and PEFR postblock, but the magnitude of deterioration was significantly greater in the SC group, displaying no significant difference in block characteristics. The costoclavicular brachial plexus block demonstrated superior preservation of diaphragmatic contractility and lesser deterioration of PFTs compared to the SC approach while being equally effective. These findings highlight the potential benefits of the costoclavicular technique in minimizing diaphragmatic dysfunction and respiratory impairment, particularly in patients at risk for respiratory complications.