Low-dose normal saline washout may not reverse phrenic nerve blockade after shoulder surgery
Click Here to Manage Email Alerts
Results showed 10 mL of normal saline washout did not yield clinically significant reversal of phrenic nerve blockade in patients undergoing shoulder surgery.
Lynn Ngai Gerber, MD, and colleagues randomly assigned patients undergoing shoulder surgery with ultrasound-guided interscalene nerve block to receive either three doses of 10 mL normal saline washouts or sham washouts through an in situ nerve block catheter after postsurgical local anesthetic bolus. Researchers evaluated baseline indicators of pain using the numeric rating scale, measured diaphragmatic thickness using ultrasonography and performed brachial plexus motor and sensory exams in all patients.
Results showed no significant differences in the reversal of diaphragmatic paralysis in the normal saline and sham washout groups. However, a subanalysis that stratified the results by the degree of paralysis showed a significant difference in the number of patients who displayed partial vs. full paralysis of the diaphragm between the two groups. Researchers found no differences in pain scores between the groups both at baseline and at the conclusion of the intervention collection, with no significant change in the numeric rating scale pain score for each patient. Regardless of the assigned group, patients had no differences in brachial plexus motor and sensory exams at baseline, at the conclusion and when comparing individual change in exam scores, according to results.
“Although 10-mL normal saline washouts did not reverse diaphragmatic paralysis from interscalene nerve blocks, it also did not diminish the block’s analgesic effect,” Gerber, who received a resident/fellow travel award for the abstract, told Healio Orthopedics. “Furthermore, more patients in the washout group showed an improvement from full to partial paralysis, suggesting that a larger bolus dose of normal saline may be needed to completely reverse diaphragmatic paralysis. In clinical practice, use of saline washouts may reduce the overall degree of phrenic nerve blockade and thus diaphragmatic paralysis while preserving the block’s analgesic effect, but further dose-finding studies are needed.” – by Casey Tingle
Reference:
Gerber LN, et al. Abstract 770. Presented at: Regional Anesthesia and Acute Pain Medicine Annual Meeting; April 23-25, 2020 (meeting cancelled).
Disclosure: Gerber reports no relevant financial disclosures.
Collapse
Gerber LN, et al. Abstract 770. Presented at: Regional Anesthesia and Acute Pain Medicine Annual Meeting; April 23-25, 2020 (meeting cancelled).
Read more about
Click Here to Manage Email Alerts