Effect of Local Anesthetic Dose on Interscalene Block (Low Dose ISB)

• Handgrip Strength [ Time Frame: A one time assessment pre-operatively in the holding area and each hour (every hour up until 180 minutes) post-operatively in the PACU until patient discharge ] [ Designated as safety issue: No ]
  The primary outcome will be handgrip strength as measured by a dynamometer. A reading will be obtained at baseline (before the interscalene block), upon arrival to the PACU, every 60 minutes after entering the PACU and one reading immediately prior to patient discharge. Two measurements will be taken bilaterally at each time point.
  
  

• Patient Readiness to Discharge [ Time Frame: Participants will be followed every 15 minutes from entry into the PACU until discharge from the hospital up to 180 minutes post PACU arrival. ] [ Designated as safety issue: No ]

  Patient readiness to discharge- Evaluated every 15 minutes using the PADDS discharge criteria.

  1. BP and pulse within 20% of preoperative baseline
  2. Steady gait, no dizziness, or meets preoperative level
  3. Minimal nausea and vomiting: successfully treated with PO medication
  4. The patient should have minimal or no pain
  5. Postoperative bleeding should be consistent with expected blood loss for the procedure
  
  
• Success of the Block [ Time Frame: 10 minutes post block induction in the Operating Room ] [ Designated as safety issue: No ]
  Evaluated by the level of sedation necessary and the surgeon rating of the block. The block will be considered a success if the sedation did not exceed fentanyl 100mcg or propofol 80mcg/kg/min, and the surgeon rated the block as successful with no patient movement or acceptable with minimal patient movement. Conversion to general anesthesia will also be considered a block failure.
  
  
• Patient Satisfaction [ Time Frame: POD 2 - 3 (48-72 hours after the surgical procedure) ] [ Designated as safety issue: No ]
  Patient satisfaction will be evaluated using an online survey. If the patient does not complete the survey in 2 days following discharge, the patient will receive a phone call and the survey will be completed over the phone. While the survey is not a validated measurement of patient satisfaction, it has successfully been used at our institution for other research projects (IRB # 11100).
  
  
• Side Effects [ Time Frame: Duration of stay in the PACU ] [ Designated as safety issue: No ]

  Side effects will also be evaluated by the blinded research assistant

  1. Hoarseness- The patient will subjectively state whether they sound hoarse
  2. Horners- Will be evaluated post-operatively in the PACU
  
  

Traditionally, an interscalene block is done either with nerve stimulator or ultrasound guided using 40-60mL of local anesthetic. The study plans to investigate the difference in hand grip strength post-operatively in patients who will receive interscalene blocks with 40mL versus a lower dose (20mL) of local anesthetic. We suspect the lower dose will achieve adequate surgical anesthesia while creating less motor block and thus, increase patient satisfaction, present fewer complications or adverse affects and decrease time in the recovery room.