Diaphragm Paralysis
Conditions
Keywords
bupivacaine concentration, interscalene nerve block, diaphragm function, diaphragm weakness
Brief summary
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.
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.
Interventions
DRUGinterscalene nerve block with 0.25% bupivacaine
interscalene nerve block performed with 20 ml of 0.25% bupivacaine
DRUGinterscalene block with 0.125% bupivacaine
interscalene block with 20 ml of 0.125% bupivacaine
Sponsors
University of Utah
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Abnormal Lung Function | At discharge from the post-anesthesia care unit, within 5 hours of the completion of surgery | Lung function was evaluated by examining diaphragm movement using ultrasound imaging and change in room air oxygen saturation (SpO2). Diaphragm movement was assessed using ultrasound as Normal (diaphragm moves caudad with inspiration), Abnormal (diaphragm does not move caudad with inspiration), and Paradoxical (diaphragm moves cephalad with inspiration). Both diaphragm function and room air SpO2 were assessed prior to any intervention to establish a baseline, and again on discharge from the PACU, within 5 hours of the completion of surgery. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Pain Relief | At discharge from the post-anesthesia care unit, within 5 hours of the completion of surgery | Pain relief was assessed by recording the amount of opioid administered intraoperatively and in the PACU. The Visual Analogue Score of pain scores (0-10, with 0 being no pain and 10 being the worst pain imaginable) were recorded at the time of discharge from the PACU, within 5 hours of the completion of surgery. |
| Satisfaction With Pain Control | Within 30 days | A follow-up phone call was made to patients within 30 days of surgery to assess the presence of any complications related to the block and overall satisfaction with pain control. Overall satisfaction was assessed on a 7-point Likert scale of 1-not at all satisfied with pain control 2-mostly unsatisfied with pain control 3-slightly unsatisfied with pain control 4-no opinion 5-slightly satisfied with pain control 6-mostly satisfied with pain control 7-completely satisfied with pain control. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| 0.25% Bupivacaine interscalene nerve block with 0.25% bupivacaine | 15 |
| 0.125% Bupivacaine interscalene nerve block with 0.125% bupivacaine | 15 |
| Total | 30 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Protocol Violation | 0 | 1 |
| Overall Study | Withdrawal by Subject | 1 | 0 |
Baseline characteristics
| Characteristic | 0.25% Bupivacaine | 0.125% Bupivacaine | Total |
|---|---|---|---|
| Age, Continuous | 55.6 years STANDARD_DEVIATION 9.3 | 53.6 years STANDARD_DEVIATION 6.3 | 54.7 years STANDARD_DEVIATION 7.9 |
| Region of Enrollment United States | 15 participants | 15 participants | 30 participants |
| Sex: Female, Male Female | 7 Participants | 6 Participants | 13 Participants |
| Sex: Female, Male Male | 8 Participants | 9 Participants | 17 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 14 | 0 / 14 |
| serious Total, serious adverse events | 0 / 14 | 0 / 14 |
Outcome results
Primary
Abnormal Lung Function
Lung function was evaluated by examining diaphragm movement using ultrasound imaging and change in room air oxygen saturation (SpO2). Diaphragm movement was assessed using ultrasound as Normal (diaphragm moves caudad with inspiration), Abnormal (diaphragm does not move caudad with inspiration), and Paradoxical (diaphragm moves cephalad with inspiration). Both diaphragm function and room air SpO2 were assessed prior to any intervention to establish a baseline, and again on discharge from the PACU, within 5 hours of the completion of surgery.
Time frame: At discharge from the post-anesthesia care unit, within 5 hours of the completion of surgery
Population: Power analysis was performed and a drop-out rate of 10% was anticipated.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| 0.25% Bupivacaine | Abnormal Lung Function | 11 participants w/ abnormal diaphragm fxn |
| 0.125% Bupivacaine | Abnormal Lung Function | 3 participants w/ abnormal diaphragm fxn |
Secondary
Pain Relief
Pain relief was assessed by recording the amount of opioid administered intraoperatively and in the PACU. The Visual Analogue Score of pain scores (0-10, with 0 being no pain and 10 being the worst pain imaginable) were recorded at the time of discharge from the PACU, within 5 hours of the completion of surgery.
Time frame: At discharge from the post-anesthesia care unit, within 5 hours of the completion of surgery
Population: Same as other outcome measures.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| 0.25% Bupivacaine | Pain Relief | 0 Visual Analogue Scale for pain | Standard Deviation 0 |
| 0.125% Bupivacaine | Pain Relief | 0.7 Visual Analogue Scale for pain | Standard Deviation 1.1 |
Secondary
Satisfaction With Pain Control
A follow-up phone call was made to patients within 30 days of surgery to assess the presence of any complications related to the block and overall satisfaction with pain control. Overall satisfaction was assessed on a 7-point Likert scale of 1-not at all satisfied with pain control 2-mostly unsatisfied with pain control 3-slightly unsatisfied with pain control 4-no opinion 5-slightly satisfied with pain control 6-mostly satisfied with pain control 7-completely satisfied with pain control.
Time frame: Within 30 days
Population: Same as other outcome measures
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| 0.25% Bupivacaine | Satisfaction With Pain Control | 6.6 Likert Satisfaction Scale | Standard Deviation 0.5 |
| 0.125% Bupivacaine | Satisfaction With Pain Control | 6.6 Likert Satisfaction Scale | Standard Deviation 1.1 |