Pulmonary Function Changes and Diaphragmatic Paralysis Following Ultrasound Guided Supraclavicular Brachial Plexus Blockade: The Effects of Decreased Local Anesthetic Volume
Pulmonary Function Changes and Diaphragmatic Paralysis Following Ultrasound Guided Supraclavicular Brachial Plexus Blockade: The Effects of Decreased Local Anesthetic Volume
This clinical trial is being conducted to study lung function and movement of the major
 muscle involved in breathing (the diaphragm) after a brachial plexus nerve block (nerve
 "freezing"). The purpose of this study is to find out what effects (good and bad) ultrasound
 guided nerve freezing has on the movement of the patient's diaphragm and their lung function.

 The potential advantage of ultrasound guidance will be a lesser chance of freezing the nerves
 that innervate the diaphragm and thus having less of an effect on lung function.
The supraclavicular approach to brachial plexus blockade was first described by Kulenkampf in
 1911. With classic "blind" techniques, an incidence of pneumothorax has been reported ranging
 from 0.5-6.0%, limiting its widespread use, despite the belief that the supraclavicular
 approach is the most consistent, effective technique for anesthetizing the brachial plexus.
 With the advent of ultrasound guidance and real time visualization this risk has been
 minimized and a resurgence in utilization of this approach has occurred. Increased block
 success, diminished performance times, and lower anesthetic volumes have been observed with
 this technique when compared to nerve stimulator techniques. Despite these advantages,
 brachial plexus anesthesia above the clavicle is associated with diaphragmatic dysfunction
 and caution must be demonstrated in patients with respiratory disease. Interscalene brachial
 plexus blockade has been widely documented to produce a 100% incidence of hemidiaphragmatic
 paresis and an associated 25% mean reduction in forced vital capacity (FVC) with local
 anesthetic volumes ranging from 20 - 45mL 8-10, these parameters for supraclavicular brachial
 plexus blockage are not as well defined. Previous investigations report an incidence of
 hemidiaphragmatic paresis of 1-75% with supraclavicular brachial plexus blockade. This study
 will address whether diaphragmatic function and respiratory mechanics can be preserved with
 lower anesthetic volumes in ultrasound guided supraclavicular brachial plexus blockade.
Inclusion Criteria:

 -  eligible patients undergoing Supraclavicular blockade

 Exclusion Criteria:

 -  < 18 years of age,

 -  mental illness precluding informed consent,

 -  infection at the injection site,

 -  coagulopathy,

 -  allergy to local anesthetics,

 -  inability to comprehend English,

 -  pulmonary disease, and

 -  pregnancy