Dose-Response Relationships for Hemidiaphragmatic Paresis Following Ultrasound-Guided Supraclavicular Brachial Plexus Blockade
Dose-Response Relationships for Hemidiaphragmatic Paresis Following Ultrasound-Guided Supraclavicular Brachial Plexus Blockade
This clinical trial is for subjects undergoing right upper extremity surgery. The aim of the study is to investigate the dose-response relationship between local anesthetic volume and ipsilateral hemidiaphragmatic paresis (HDP) in patients getting ultrasound-guided supraclavicular brachial plexus blocks in a blinded, prospective trial.
With traditional landmark-based or nerve-stimulator techniques, the incidence of HDP following supraclavicular blocks is approximately 50-67%. Ultrasound-guided techniques are thought to enhance precision while reducing the volume of anesthetic used, but even then HDP incidence is nearly 60%. To date, no trials have studied the dose-response relationship between local anesthetic volume and degree of HDP.
Patient Selection
30 eligible patients undergoing right upper extremity surgery and eligible for supraclavicular blocks will be recruited at NewYork-Presbyterian/Weill Cornell Medical Center.
Evaluation of HDP
Baseline M-mode recordings of diaphragm function will be made by an anesthesiologist. Patients will perform "voluntary sniff" (VS) tests, or forceful nasal inhales, immediately preceding the brachial plexus blockade, and again at 15 minutes and 30 minutes after the block.
Diaphragmatic excursion from baseline will be measured in centimeters; three measurements will be made and averaged. Hemidiaphragmatic paresis will be defined as greater than or equal to 60% reduction in diaphragmatic excursion, no movement, or paradoxical movement in the VS test.
Evaluation of Pulmonary Function
A bedside negative inspiratory force (NIF) meter will be used to measure negative inspiratory force prior to the block and 30 minutes after the block.
Evaluation of Supraclavicular Block
At the 15- and 30-minute marks, the investigators will assess sensory blockade and motor block in the axial, musculocutaneous, radial, median, and ulnar distributions. Both will be judged on 3-point scales. The investigators will also apply a 0-10 point verbal rating scale to assess dyspnea at 30 minutes. Oxygen saturation will be measured off of supplemental oxygen before the block and 30 minutes after the block.
Following the assessments, patients will have surgery using brachial plexus blockade as the primary anesthetic.
Inclusion Criteria:
Exclusion Criteria: