2024 FSA Podium and Poster Abstracts
P023: CASE REPORT ON POST-OPERATIVE COMPLICATION OF INTERSCALENE NERVE BLOCK
Rachel Cathey, BS; Niharika Suchak, MD, MBBS, MHS, FACP, AGSF; Florida State University College of Medicine
Background: Interscalene brachial plexus block, the most common regional anesthetic technique used in shoulder surgeries as part of a multimodal analgesia approach, is known to decrease postoperative pain, reduce requirements for opioid pain medication, and promote earlier mobilization. This analgesic approach causes a phrenic nerve palsy, which is usually short-lived with spontaneous resolution - many patients do not report symptoms of concern. Chronic phrenic nerve palsy is rare and can present with prolonged hemi-diaphragmatic paresis and symptomatic dyspnea.
Case: Patient X is an 87-year-old Female who presented for an elective right shoulder reverse arthroplasty due to osteoarthritis. Medical history included hypertension, hyperlipidemia, and chronic back pain, left shoulder arthroplasty, and bilateral knee replacements but no lung disease or tobacco usage.
Pre-operative interscalene brachial plexus block was performed under ultrasound-guidance. As a precautionary measure, the patient was administered less than the usual dose of bupivacaine (12.5mL). Post-operatively, she denied shortness of breath and reported her pain was well-controlled with the nerve block and a non-opioid regimen of naproxen and acetaminophen.
One day post-op, the patient complained of shortness of breath with minimal exertion and was found to have decreased oxygen saturation. Chest X-ray showed right hemi-diaphragmatic elevation and associated atelectasis. Her family reported seeing her O2-sat. dip as low as 86% and 79% after short walks to the bathroom. With supplemental oxygen via nasal cannula at 2L/min and use of an incentive spirometer, her status improved to 97% O2-saturation by post-op day 2. Repeat chest X-ray post-op day 37 showed stale eventration of the right hemi-diaphragm.
Methods/Results: The occurrence range of persistent phrenic nerve palsy after dissolution of the nerve block (indwelling catheter is removed and no more local anesthetic surrounds the plexus) is anywhere from 1/2,000 patients to 1/100 patients.
Action steps methods for this patient included discontinuing the indwelling catheter, supplemental oxygen via nasal cannula, incentive spirometry, avoiding recumbent positioning, and ambulation with assistive devices. Within 24 hours following the implementation of these steps, the patient’s oxygen saturation improved to pre-operative values, and she denied continued dyspnea.
Conclusion: Patient X had a routine procedure with conservative measures, yet she was found to have chronic hemi-diaphragmatic elevation. The impact of comorbidities, particularly pre-operative oxygen saturation, asthma, congestive heart failure, and BMI influence the likelihood of this post-operative complication. This patient’s age of 87 years placed her at increased risk of developing respiratory complication. Patient X, with a history of chronic back pain, had a known pain tolerance and elected for a non-opioid post-operative regimen. This patient could have been a candidate for forgoing interscalene nerve block.
Hemi-diaphragmatic elevation due to phrenic nerve palsy occurs with interscalene nerve blocks utilized for shoulder arthroplasty procedures. The chronic presentation of phrenic nerve palsy and diaphragmatic changes following discontinuation of local anesthetic, however, is unexpected and can necessitate symptomatic management.