The Effect of Interscalene Peripheral Nerve Block With 0.25% Bupivacaine vs 0.125% Bupivacaine on Lung Function

Condition(s) targeted: Diaphragm Paralysis

Intervention: interscalene nerve block with 0.25% bupivacaine (Drug); interscalene block with 0.125% bupivacaine (Drug)

Phase: N/A

Status: Completed

Sponsored by: University of Utah

Official(s) and/or principal investigator(s):
Elizabeth Thackeray, MD, MPH, Principal Investigator, Affiliation: University of Utah
Jeffrey Swenson, MD, Study Director, Affiliation: University of Utah

Peripheral nerve blocks are used to provide post-operative pain relief. Nerve blocks in the neck, in the interscalene area, provide pain relief after shoulder surgery but can cause temporary weakness or paralysis of the diaphragm. The investigators hypothesized that a lower concentration of bupivacaine would cause less weakness of the diaphragm but still provide good pain relief. Lung function and pain control was studied after interscalene peripheral nerve block with 20 milliliters of 0. 25% bupivacaine or 0. 125% bupivacaine.

Official title: Investigation Into the Effect of 0.25% Bupivacaine for Interscalene Peripheral Nerve Block vs 0.125% Bupivacaine on Pulmonary Function

Study design: Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Treatment

Primary outcome: Abnormal Lung Function

Secondary outcome:

Pain Relief

Satisfaction With Pain Control

Detailed description: Prior to placement of interscalene brachial plexus peripheral nerve block (ISPNB), diaphragm function was assessed using ultrasound as normal, no movement, or paradoxical. Room air pulse oximetry (SpO2) was recorded. Patients were randomized to receive either 0. 25% bupivacaine or 0. 125% bupivacaine. ISPNB was performed using a coded syringe of the study drug, so that the anesthesiologists performing the nerve block, the patient, and the nurses assessing the patient were blinded as to the concentration. Patients were given a general endotracheal anesthesia for rotator cuff repair, and opioids were administered at the discretion of the attending anesthesiologist. When patients met criteria for PACU discharge, diaphragm function was again assessed using ultrasound and room air SpO2 was recorded.

Minimum age: 18 Years. Maximum age: N/A. Gender(s): Both.

Criteria:

Inclusion Criteria:

- patients presenting for outpatient rotator cuff repair

- adults

- English as the primary language

Exclusion Criteria:

- evidence of peripheral nerve damage on affected side

- refusal of peripheral nerve block

- pregnant women

- lung disease, including obstructive sleep apnea

- chronic opioid use

- mental handicap

University of Utah Orthopaedics Center, Salt Lake City, Utah 84108, United States

Starting date: May 2008
Last updated: December 9, 2013