title: Hypoxia following interscalene block.
abstract: OBJECTIVE
  Interscalene brachial plexus block is often used for surgeries involving the shoulder and upper arm. Known complications include phrenic nerve paralysis, intravascular injection, and cervical epidural block. We report a patient who developed acute hypoxia immediately following this block, presumably secondary to an acute pulmonary thromboembolus (PTE) coupled with phrenic nerve paralysis.
  
  
  METHODS
  A 43-year-old man with end-stage renal disease secondary to hypertension was scheduled for primary placement of a left upper extremity arteriovenous fistula. A technically unremarkable interscalene brachial plexus block was performed using a 22-gauge regional block needle and 35 mL of 1.5% mepivacaine. Immediately following injection, the patient's oxygen saturation decreased from 99% to 85%, and he complained of chest pain and shortness of breath and developed hemoptysis. Workup revealed an elevated hemidiaphragm, but no pneumothorax or evidence of local trauma. A spiral computed tomogram (CT) suggested acute pulmonary thromboemboli as the etiology of the hypoxia and hemoptysis, although the diagnosis was uncertain.
  
  
  CONCLUSIONS
  This case report suggests that manipulations and vasodilation related to an interscalene block may have facilitated the dislodgement of a pre-existing upper extremity thrombus.
authors.affiliation: Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0007, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Rose
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Ness
mesh_terms: D000208:Acute Disease; D000328:Adult; D001132:Arm / Q000601:surgery; D001166:Arteriovenous Shunt, Surgical; D001917:Brachial Plexus; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D008297:Male; D009407:Nerve Block / Q000009:adverse effects*; D011655:Pulmonary Embolism / Q000209:etiology; D012133:Respiratory Paralysis / Q000209:etiology