title: Medial approach of ultrasound-guided costoclavicular plexus block and its effects on regional perfussion.
abstract: BACKGROUND
  Ultrasound-guided infraclavicular block in the costoclavicular space located between the clavicle and the first rib, reaches the secondary trunks when they are clustered together and lateral to the axillary artery. This block is most often performed through a lateral approach, the difficulty being finding the coracoid process an obstacle and guiding the needle towards the vessels and pleura. A medial approach, meaning from inside to outside, will avoid these structures. Traditionally the assessment of a successful block is through motor or sensitive responses but a sympathetic fibre block can also be evaluated measuring the changes in humeral artery blood flow, skin temperature and/or perfusion index.
  
  
  OBJECTIVE
  To describe the medial approach of the ultrasound-guided costoclavicular block evaluating its development by motor and sensitive response and measurement of sympathetic changes.
  
  
  METHODS
  Description of the technique and administration of 20ml of contrast in a fresh cadaver model, evaluating the distribution with CT-scan and sagittal sections of the anatomic piece. Subsequently in a clinical phase, including 11 patients, we evaluated the establishment of motor, sensitive and sympathetic blocks. We evaluated the sympathetic changes reflected by humeral artery blood flow, skin temperature and distal perfusion index.
  
  
  RESULTS
  In the anatomical model the block was conducted without difficulties, showing an adequate periclavicular distribution of the contrast in the CT-scan and in sagittal sections, reaching the interscalenic space as far as the secondary trunks. Successful blocks were observed in 91% of patients after 25minutes. All the parameters reflecting sympathetic block increased significantly. The humeral artery blood flow showed an increase from 108 ± 86 to 188±141ml/min (P=.05), skin temperature from 32.1±2 to 32.8±9°C (P=.03) and perfusion index from 4±3 to 9±5 (P=.003).
  
  
  CONCLUSIONS
  The medial approach of the ultrasound-guided costoclavicular block is anatomically feasible, with high clinical effectiveness using 20ml of 1.5% mepivacaine. The sympathetic block can be evaluated with all three parameters studied.
authors.affiliation: Máster en Competencias Médicas Avanzadas, Facultad de Medicina, Universitat de Barcelona, Barcelona, España.
authors.forename: D
authors.initials: D
authors.lastname: Nieuwveld
authors.affiliation: Máster en Competencias Médicas Avanzadas, Facultad de Medicina, Universitat de Barcelona, Barcelona, España.
authors.forename: V
authors.initials: V
authors.lastname: Mojica
authors.affiliation: Máster en Competencias Médicas Avanzadas, Facultad de Medicina, Universitat de Barcelona, Barcelona, España.
authors.forename: A E
authors.initials: AE
authors.lastname: Herrera
authors.affiliation: Sección de radiología músculo-esquelética, Centro de Diagnóstico por la Imagen (CDI), Hospital Clínic, Universitat de Barcelona, Barcelona, España.
authors.forename: J
authors.initials: J
authors.lastname: Pomés
authors.affiliation: Facultad de Medicina, Universitat de Barcelona, Barcelona, España.
authors.forename: A
authors.initials: A
authors.lastname: Prats
authors.affiliation: Hospital Clínic, Universitat de Barcelona, profesor asociado de Anatomía, Facultad de Medicina, Universitat de Barcelona, Barcelona, España. Electronic address: xsala@clinic.ub.es.
authors.forename: X
authors.initials: X
authors.lastname: Sala-Blanch
mesh_terms: D001340:Autonomic Nerve Block / Q000379:methods*; D001916:Brachial Artery / Q000502:physiology; D002968:Clavicle; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D018084:Ultrasonography, Interventional
keywords: Bloqueo infraclavicular; Bloqueo simpático; Brachial artery flow; Costoclavicular space; Espacio costoclavicular; Flujo arteria humeral; Infraclavicular block; Perfusion index; Skin temperature; Sympathetic block; Temperatura cutánea; Índice de perfusión