Dose-Response Relationships for Hemidiaphragmatic Paresis Following Ultrasound-Guided Supraclavicular Block
Condition: Surgery of Right Upper Extremity
MeSH terms: Paresis
Intervention: Ultrasound Imaging; Supraclavicular Block; Bedside Negative Inspiratory Force Meter
Intervention description: M-mode tracings of right diaphragm motion will be made and recorded by a skilled anesthesiologist. Patients will be examined in the supine position and scanned from a low intercostal or subcostal approach using the liver as an acoustic window. Patients will be asked to perform a "voluntary sniff" (VS) test, for which they will be asked to forcefully inhale through the nose in a sniffing position. The above measurement will be performed immediately preceding the brachial plexus blockade, and then at 15 minute and 30 minutes after block.; The patient will be positioned supine with the head turned to the contralateral side. The ultrasound will be placed in the supraclavicular fossa, and the skin and subcutaneous tissues will be infiltrated lateral to the probe with 2% lidocaine. The anesthesiologist can redirect the needle and perform additional injections for complete coverage of the brachial plexus. The local anesthetic will be a 2:1 mix of 1.5% mepivacaine and 0.5% bupivacaine.; 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.
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: A modified "3+3" dose escalation design, modeled after Phase I dose-finding trials, was used to define the dose response curve for local anesthetic volume in the supraclavicular block and resulting hemidiaphragmatic paresis in patients undergoing right upper extremity surgery with supraclavicular block as the primary anesthetic. Possible dosing levels of 5, 10, 15, 20, 25, 30, 35 and 40 mL of local anesthetic were pre-specified with a cohort of three subjects per dose. Diaphragm function was determined by a blinded assessor with M-mode tracings of the right diaphragm before and after supraclavicular block. Secondary objectives included the assessment of respiratory function via negative inspiratory force, oxygen saturation and subjective dyspnea, as well as the extent of sensory and motor blockade.
Masking: Single (Outcomes Assessor)
Masking description: The physician reviewing the ultrasound images and determining the presence/absence of diaphragm paralysis is masked to treatment assignment.
Enrollment: 24.0
Sex: All
Minimum age: 18 Years
Maximum age: 105 Years
Healthy volunteers: No

Summary:

      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.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Undergoing right upper extremity surgery with supraclavicular block as the primary
             anesthetic

          -  Age greater than or equal to 18 years of age

          -  American Society of Anesthesiologists (ASA) physical status 1 to 3

          -  Able to give informed consent

        Exclusion Criteria:

          -  Patient refusal for supraclavicular block

          -  Inability to give informed consent

          -  Allergy to local anesthetics

          -  Hemidiaphragmatic dysfunction, suspected or known pulmonary disease

          -  Neuromuscular disease

          -  Obstructive or restrictive pulmonary disease

          -  Medical or anatomic contraindication to supraclavicular blockade as judged by
             clinician

          -  Pregnancy