Interscalene nerve block impairs ipsilateral lung function and is relatively contraindicated for patients with lung impairment. We present a case of an 89-year-old female smoker with prior left lung lower lobectomy and mild to moderate lung disease who presented for right shoulder arthroplasty and insisted on regional anesthesia. The patient received a multimodal perioperative regimen that consisted of a continuous interscalene block, acetaminophen, ketorolac, and opioids. Surgery proceeded uneventfully and postoperative analgesia was excellent. Pulmonary physiology and management of these patients will be discussed. A risk/benefit discussion should occur with patients having impaired lung function before performance of interscalene blocks. In this particular patient with mild to moderate disease, analgesia was well managed through a multimodal approach including a continuous interscalene block, and close monitoring of respiratory status took place throughout the perioperative period, leading to a successful outcome.
Impaired lung function has traditionally been considered a relative contraindication to interscalene plexus block (ISB). ISB has been shown to cause ipsilateral hemidiaphragmatic paresis virtually 100% of the time [
The patient was an 89-year-old woman, American Society of Anesthesiologists Physical Status 3, with hypertension, hypothyroidism, and a 58-pack-year history of smoking who five years prior had undergone a left lung lower lobectomy for cancer. She was scheduled to undergo a right total shoulder replacement for worsening degenerative disease and pain. Pulmonary function testing performed 17 months prior to surgery revealed a FEV1/FVC ratio of 0.68, indicating mild obstructive disease, and a diffusion capacity (DLCO) of 9.5 mL/mm Hg/min, indicating a moderate gas transfer defect. Physical examination revealed clear lung fields bilaterally and a short hyomental distance on airway exam. Preoperative pulse oximetry on room air revealed an oxygen saturation of 100%. The patient and her family wished to proceed with surgery only under regional anesthesia after consulting with her primary care physician. After discussion of the risks and benefits of regional anesthesia, including the possibility of impaired lung function, pneumothorax on the operative side postoperatively, and mechanical ventilation postoperatively, the patient agreed to perform surgery under a continuous interscalene nerve block (CISB) with light sedation.
The block was performed using continuous ultrasound guidance (GE Logic E, Wauwatosa, WI) and nerve stimulation (B. Braun, Bethlehem, PA). An in-plane, posterior approach technique was utilized for needle insertion and visualization based on the preference of the anesthesiologist performing the procedure (Figure
Ultrasound image of low interscalene block.
In the postoperative anesthesia care unit (PACU) the patient had excellent analgesia. Intravenous fentanyl and morphine were available but she requested no rescue opioids or other medications. Close postoperative monitoring was continued on a surgical ward with frequent pulse oximetry measurements. Analgesia consisted of a multimodal regimen including CISB with ropivacaine 0.2% running at 8 mL/h without a demand function and ketorolac, aspirin, and pregabalin, with a morphine PCA for breakthrough pain. She consumed the equivalent of morphine 17.5 mg IV for breakthrough pain during the first 24 h postoperatively. She reported no side effects and denied significant dyspnea while the catheter was in place, receiving no more than 2 L/min of oxygen via nasal cannula as a precautionary measure during her admission. She used her incentive spirometer multiple times per day. She was discharged home on postoperative day no. 2 after the continuous interscalene catheter had been removed.
Although ISB has traditionally been relatively contraindicated in those with decreased pulmonary function, we presented a case of an elderly woman with prior partial lung resection who experienced a successful outcome through minimizing opioids and close postoperative monitoring. Urmey and McDonald [
Phrenic nerve function is affected by the presence of a CISB, even after the primary block has been resolved. Pere and colleagues [
Pneumothorax following ISB is another consideration that should be discussed. Although many believe pneumothorax is less likely to follow ISB than supraclavicular block, and a recent prospective registry of more than 1,100 brachial plexus blocks (ISB and supraclavicular blocks) reported no pneumothoraces [
Finally, the long-term consequences of interscalene blocks are rarely discussed, but a recent case series [
The anesthesiologist performing the block used an in-plane, posterior approach in which the entire needle is visualized, theoretically providing increased safety, more precise needle positioning, and avoidance of the surgical field [
Digital pressure above the level of the ISB has been studied as a technique used to decrease the spread of local anesthetic to the phrenic nerve. Despite initial enthusiasm, this has been shown repeatedly to be ineffective [
Several investigators have studied the effects of decreasing the local anesthetic volume on hemidiaphragmatic paresis and other respiratory parameters. The results have been inconclusive, with some reporting an improvement in pulmonary function [
Studies examining the effects of using dilute local anesthetic solutions suggest that doing so may decrease some of the unwanted respiratory side effects [
It has been shown that FVC, FEV1, and total lung capacity are reduced after lung lobectomy [
Opioids remain an option but their unwanted side effects, in particular respiratory depression, limit their effectiveness in patients with compromised lung function. Specifically, opioids impair the diaphragm and thoracic muscles, decreasing functional residual capacity and leading to atelectasis [
In summary, this 89-year-old woman was a motivated patient who understood the risks involved. Despite having mild to moderate lung disease, this patient was fairly well compensated and symptom-free on the day of surgery. Although this was reassuring, the potential for respiratory complications was nevertheless present. We believed that the benefits of regional anesthesia outweighed those of general anesthesia, taking the physiologic changes, patient preferences, and our own preferences into account. Through close observation in the PACU and continuing on the surgical ward, her respiratory status was maintained and clinically significant dyspnea and hypoxia were avoided. We believe this was a result of maximizing nonopioid agents and minimizing the consumption of opioids, encouraging incentive spirometer use, and close monitoring for any change in respiratory status.
The patient and her family gave written permission to be included in this case paper.
The authors declare that there is no conflict of interests regarding the publication of this article.
Eric S. Schwenk took care of the patient, conceived the idea for the case report, and helped write the paper. Kishor Gandhi took care of the patient and helped write the paper. Eugene R. Viscusi helped write the paper.
The authors received departmental funding.