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Interscalene brachial plexus anesthesia is commonly used for arthroscopic and open procedures of the shoulder. This regional anesthetic targets the trunks of the brachial plexus and anesthetizes the area about the shoulder and proximal arm. Its use may obviate the need for concomitant general anesthesia, potentially reducing the use of postoperative intravenous and oral pain medication. Furthermore, patients often bypass the acute postoperative anesthesia care unit and proceed directly to the ambulatory unit, permitting earlier hospital discharge. Previous reports in the literature have demonstrated higher rates of neurologic, cardiac, and pulmonary complications from this procedure; in particular, the incidence of pneumothorax was reported as high as 3%.1 Techniques to localize the nerves, such as electrical nerve stimulation and, more recently, ultrasound guidance, have reduced these complication rates.2,3 Successful administration of the block has been shown to result in satisfactory postoperative pain relief.2 However, ultrasound-guided interscalene nerve blocks remain operator-dependent and complications may still occur.
We report a case of tension pneumothorax after arthroscopic rotator cuff repair and subacromial decompression with an ultrasound-guided interscalene block. Immediate recognition and treatment of this complication resulted in a good clinical outcome. The patient provided written informed consent for print and electronic publication of this case report.
Case Report
A 56-year-old woman presented with 3 months of right shoulder pain after a fall. Examination was pertinent for weakness in forward elevation and positive rotator cuff impingement signs. She remained symptomatic despite a course of nonsurgical management that included cortisone injections and physical therapy. Magnetic resonance imaging of the shoulder showed a full-thickness supraspinatus tear with minimal fatty atrophy. After a discussion of her treatment options, she elected to undergo an arthroscopic rotator cuff repair with subacromial decompression. An evaluation by her internist revealed no pertinent medical history apart from obesity (body mass index, 36). Specifically, there was no reported history of chronic obstructive pulmonary disease or asthma. She denied any prior cigarette smoking.
The patient was evaluated by the regional anesthesia team and was classified as a class 2 airway. An interscalene brachial plexus block was performed using a 2-inch, 22-gauge needle inserted into the interscalene groove. Using an out-of-plane technique under direct ultrasound guidance, 30 mL of 0.52% ropivacaine was injected. The block was considered successful, and no complications, such as resistance, paresthesias, pain, or blood on aspiration, were noted during injection. The patient had no complaints of chest pain or shortness of breath immediately afterward, and all vital signs were stable throughout the procedure.
The patient was brought to the operating room and placed in the beach-chair position. Induction for general anesthesia was started 15 minutes after the regional anesthetic, with 2 intubation attempts necessary because of poor airway visualization. After placement of the endotracheal tube, breath sounds were noted to be equal bilaterally. The arthroscopic procedure consisted of double-row rotator cuff repair, subacromial decompression, and débridement of the glenohumeral joint for synovitis, using standard arthroscopic portals. There were no difficulties with trocar placement, and bleeding was minimal throughout the case. The total surgical time was 150 minutes and a pump pressure of 30 mm Hg was maintained during the arthroscopy.
Within the first 60 minutes of the start of the arthroscopic procedure, the patient was noted to be intermittently hypotensive with mean arterial pressure (MAP) ranging from the 30s to 130s mm Hg and pulse in the 70 to 80 beats/min range. FiO2 in the 85% to 95% range was maintained throughout the procedure. During that time, 50 μg phenylephrine was administered on 4 separate occasions to maintain her blood pressure. The labile blood pressure was attributed by the anesthesiologist to the beach-chair position. During an attempted extubation upon conclusion of the surgery, the patient became hypotensive with MAP that ranged from the 40s to 60s mm Hg and tachycardic to 90 beats/min. The oxygen saturation was in the low 90s and tidal volume was poor. Absent lung sounds were noted on the right chest. An urgent portable chest radiograph showed a large right-sided tension pneumothorax with mediastinal shift (Figure 1). After an immediate general surgery consultation, a chest tube was placed in the operating room. The patient’s vital signs improved and a repeat chest radiograph revealed successful re-expansion of the lung (Figure 2). She was transferred to the acute postoperative anesthesia care unit and extubated in the intensive care unit later that day.
The patient’s chest tube was removed 2 days later and she was discharged home on hospital day 5 with a completely resolved pneumothorax. She was seen 1 week later in the office for a postoperative visit and reported feeling well without chest pain or shortness of breath.
Discussion
Interscalene brachial plexus anesthesia was first described by Winnie4 in 1970. This block targets the trunks of the brachial plexus, which are enclosed in a fascial sheath between the anterior and middle scalene muscles. In this region lie several structures at risk: the phrenic nerve superficially and inferiorly; the carotid sheath located superficially and medially; the subclavian artery parallel to the trunks; and the cupula of the lung that lies deep and inferior to the anterior scalene muscle. Recognized complications of the block include vocal hoarseness, Horner syndrome, and hemidiaphragmatic paresis caused by the temporary blockade of the ipsilateral recurrent laryngeal nerve, stellate ganglion, and phrenic nerve, in that order.5 Use of the interscalene block has been associated with minimal risk for pneumothorax, because the needle entry point is superior and directed away from the lung pleura.6 This is in contrast to the more inferiorly placed supraclavicular block, located in closer proximity to the lung cupula.5
Two different approaches are commonly used during ultrasound-guided nerve blocks. The in-plane approach generates a long-axis view of the needle by advancing the needle parallel with the long axis of the ultrasound probe. While this allows direct visualization of the needle tip, it requires deeper needle insertion from lateral to medial, causing puncture of the middle scalene muscle that may increase patient discomfort and risk nerve injury within the muscle.7 The out-of-plane approach used on our patient involves needle insertion parallel to the brachial plexus, but along the short axis of the ultrasound probe. Although this permits the operator to assess the periphery of the nerve, it may lead to poor needle-tip visualization during the procedure. As a result, operators often use a combination of tissue disturbance and “hydrolocation,” in which fluid is injected to indicate the needle-tip location.8,9
Tension pneumothorax represents the accumulation of air in the pleural space that leads to impaired pulmonary and cardiac function. It is often caused by disruption or puncture of the parietal or visceral pleura, creating a connection between the alveoli and pleural cavity. The gradual buildup of air in the pleural cavity results in increased intrapleural pressure, which compresses and ultimately collapses the ipsilateral lung. Venous compression restricts blood return to the heart and reduces cardiac output. Clinical manifestations include dyspnea, hypoxemia, tachycardia, and hypotension.10 Multiple techniques were developed to better localize the brachial plexus while reducing injury to nearby structures, including the lung. These include eliciting needle paresthesias, electrical nerve stimulation, and ultrasound guidance. While nerve stimulation was once the gold standard for brachial plexus localization, ultrasound guidance has gained in popularity because of its noninvasive nature and dynamic capability to identify nerves and surrounding structures.11 Perlas and colleagues12 determined the sensitivity of needle paresthesias and nerve stimulation to be 38% and 75%, respectively, in cases in which plexus localization had been confirmed by ultrasound.
Several studies have reported on the efficacy of interscalene nerve block with either nerve stimulation or ultrasound guidance in the setting of shoulder surgery.2,3 Bishop and colleagues3 reviewed 547 patients who underwent interscalene regional anesthesia with nerve stimulation for both arthroscopic and open-shoulder procedures. They reported a 97% success rate and 12 (2.3%) minor complications, including sensory neuropathy and complex regional pain syndrome. There were no cases of pneumothorax, cardiac events, or other major complications.3 In a prospective study of 1319 patients, Singh and colleagues2 reported a 99.6% success rate using ultrasound-guided interscalene blocks for their shoulder surgeries. A total of 38 adverse events (2.88%) were identified: 14 transient neurologic events, including ear numbness, digital numbness, and brachial plexitis; 1 case of intraoperative bradycardia, and 2 cancellations after the block for chest pain and flank pain, which yielded negative cardiac workups. Other complications included postoperative emergency room visits and hospital admissions for reasons unrelated to the block.2 Interscalene regional anesthesia, therefore, provides effective anesthesia for shoulder surgery with low complication rates.
Pneumothorax after ultrasound-guided interscalene block has rarely been reported.13,14 In a review of 144 ultrasound-guided indwelling interscalene catheter placements, a 98% successful block rate with a single complication of small pneumothorax after total shoulder arthroplasty was reported.13 Mandim and colleagues14 reported a case of pneumothorax in a smoker who underwent an ultrasound-guided brachial plexus block prior to open reduction and internal fixation of an ulnar fracture. While the patient was asymptomatic and vital signs remained stable during the procedure, the patient complained postoperatively of chest pain with hypoxia, tachycardia, and hypotension. A chest radiograph confirmed an ipsilateral pneumothorax, and the patient was treated successfully with chest-tube placement. The authors attributed this complication to a higher pleural dome resulting from a hyperinflated lung caused by chronic smoking. Our patient reported no history of smoking and her preoperative chest radiograph had no evidence of lung disease.
In contrast, several cases of pneumothorax after shoulder surgery have been reported in the absence of nerve block. Oldman and Peng1 reported a 41-year-old nonsmoker who underwent arthroscopic labral repair and subacromial decompression. The preoperative nerve block was cancelled, and the patient received general endotracheal anesthesia alone. Fifty minutes after the case, the patient developed chest pain and hypoxia. A chest radiograph showed a small pneumothorax that was managed conservatively. The pneumothorax was attributed to spontaneous rupture of a preexisting lung bulla, suggesting that blocks are not always the cause of this complication. Furthermore, Dietzel and Ciullo15 reported 4 cases of spontaneous pneumothorax within 24 hours of uncomplicated arthroscopic shoulder procedures under general anesthesia in the lateral decubitus position. The patient ages ranged from 22 to 38 years, and medical histories were all significant for preexisting lung disease, remote history of pneumonia, and heavy smoking. Three of the patients experienced symptoms at home the day after surgery. The authors concluded that these cases were likely caused by rupture of blebs or bullae from underlying lung disease; these ruptured blebs or bullae are difficult to detect and usually located in the upper lung. The pressure gradient from the positive pressure of anesthesia and the ipsilateral upper lung is thought to be highest in the lateral decubitus position, increasing their chance of rupture.15
Finally, Lee and colleagues16 described 3 patients aged 40 to 45 years who underwent uncomplicated subacromial decompression in the beach-chair position under general anesthesia. Significant shoulder, neck, and axillary swelling were noted after surgery, and a chest radiograph showed tension pneumothorax, subcutaneous emphysema, and pneumomediastinum. The authors speculated that pressure in the subacromial space may become negative relative to atmospheric pressure when the shaver and suction are running, drawing in air through other portals. When the suction is discontinued, fluid infusion may push air into the surrounding tissue, leading to subcutaneous emphysema, which may spread to the mediastinum.16
Conclusion
Ultrasound-guided interscalene nerve blocks have successfully provided anesthesia for shoulder surgeries with low complication rates. Although the incidence of pneumothorax has decreased significantly with ultrasound guidance, the success of this procedure is highly operator-dependent. We present the case of an otherwise healthy patient without known pulmonary disease who developed a tension pneumothorax after the administration of ultrasound-guided regional and general anesthesia for arthroscopic shoulder surgery. Orthopedic surgeons and anesthesiologists must remain vigilant for pneumothorax during the perioperative period after shoulder surgery performed under interscalene regional aesthesia, particularly in the setting of hypotension, hypoxia, and/or tachycardia. Risk factors, such as history of smoking and preexisting lung disease, may predispose patients to the development of pneumothorax. Timely recognition and placement of a chest tube result in satisfactory clinical outcomes.
1. Oldman M, Peng Pi P. Pneumothorax after shoulder arthroscopy: don’t blame it on regional anesthesia. Reg Anesth Pain Med. 2004;29(4):382-383.
2. Singh A, Kelly C, O’Brien T, Wilson J, Warner JJ. Ultrasound-guided interscalene block anesthesia for shoulder arthroscopy: a prospective study of 1319 patients. J Bone Joint Surg Am. 2012;94(22):2040-2046.
3. Bishop JY, Sprague M, Gelber J, et al. Interscalene regional anesthesia for shoulder surgery. J Bone Joint Surg Am. 2005;87(5):974-979.
4. Winnie AP. Interscalene brachial plexus block. Anesth Analg. 1970;49(3):455-466.
5. Mian A, Chaudhry I, Huang R, Rizk E, Tubbs RS, Loukas M. Brachial plexus anesthesia: a review of the relevant anatomy, complications, and anatomical variations. Clin Anat. 2014;27(2):210-221.
6. Brown AR, Weiss R, Greenberg C, Flatow EL, Bigliani LU. Interscalene block for shoulder arthroscopy: comparison with general anesthesia. Arthroscopy. 1993;9(3):295-300.
7. Marhofer P, Harrop-Griffiths W, Willschke H, Kirchmair L. Fifteen years of ultrasound guidance in regional anaesthesia: Part 2 - recent developments in block techniques. Br J Anaesth. 2010;104(6):673-683.
8. Sites BD, Spence BC, Gallagher J, et al. Regional anesthesia meets ultrasound: a specialty in transition. Acta Anaesthesiol Scand. 2008;52(4):456-466.
9. Ilfeld BM, Fredrickson MJ, Mariano ER. Ultrasound-guided perineural catheter insertion: three approaches but few illuminating data. Reg Anesth Pain Med. 2010;35(2):123-126.
10. Choi WI. Pneumothorax. Tuberc Respir Dis (Seoul). 2014;76(3):99-104.
11. Klaastad O, Sauter AR, Dodgson MS. Brachial plexus block with or without ultrasound guidance. Curr Opin Anaesthesiol. 2009;22(5):655-660.
12. Perlas A, Niazi A, McCartney C, Chan V, Xu D, Abbas S. The sensitivity of motor response to nerve stimulation and paresthesia for nerve localization as evaluated by ultrasound. Reg Anesth Pain Med. 2006;31(5):445-450.
13. Bryan NA, Swenson JD, Greis PE, Burks RT. Indwelling interscalene catheter use in an outpatient setting for shoulder surgery: technique, efficacy, and complications. J Shoulder Elbow Surg. 2007;16(4):388-395.
14. Mandim BL, Alves RR, Almeida R, Pontes JP, Arantes LJ, Morais FP. Pneumothorax post brachial plexus block guided by ultrasound: a case report. Rev Bras Anestesiol. 2012;62(5):741-747.
15. Dietzel DP, Ciullo JV. Spontaneous pneumothorax after shoulder arthroscopy: a report of four cases. Arthroscopy. 1996;12(1):99-102.
16. Lee HC, Dewan N, Crosby L. Subcutaneous emphysema, pneumomediastinum, and potentially life-threatening tension pneumothorax. Pulmonary complications from arthroscopic shoulder decompression. Chest. 1992;101(5):1265-1267.
Interscalene brachial plexus anesthesia is commonly used for arthroscopic and open procedures of the shoulder. This regional anesthetic targets the trunks of the brachial plexus and anesthetizes the area about the shoulder and proximal arm. Its use may obviate the need for concomitant general anesthesia, potentially reducing the use of postoperative intravenous and oral pain medication. Furthermore, patients often bypass the acute postoperative anesthesia care unit and proceed directly to the ambulatory unit, permitting earlier hospital discharge. Previous reports in the literature have demonstrated higher rates of neurologic, cardiac, and pulmonary complications from this procedure; in particular, the incidence of pneumothorax was reported as high as 3%.1 Techniques to localize the nerves, such as electrical nerve stimulation and, more recently, ultrasound guidance, have reduced these complication rates.2,3 Successful administration of the block has been shown to result in satisfactory postoperative pain relief.2 However, ultrasound-guided interscalene nerve blocks remain operator-dependent and complications may still occur.
We report a case of tension pneumothorax after arthroscopic rotator cuff repair and subacromial decompression with an ultrasound-guided interscalene block. Immediate recognition and treatment of this complication resulted in a good clinical outcome. The patient provided written informed consent for print and electronic publication of this case report.
Case Report
A 56-year-old woman presented with 3 months of right shoulder pain after a fall. Examination was pertinent for weakness in forward elevation and positive rotator cuff impingement signs. She remained symptomatic despite a course of nonsurgical management that included cortisone injections and physical therapy. Magnetic resonance imaging of the shoulder showed a full-thickness supraspinatus tear with minimal fatty atrophy. After a discussion of her treatment options, she elected to undergo an arthroscopic rotator cuff repair with subacromial decompression. An evaluation by her internist revealed no pertinent medical history apart from obesity (body mass index, 36). Specifically, there was no reported history of chronic obstructive pulmonary disease or asthma. She denied any prior cigarette smoking.
The patient was evaluated by the regional anesthesia team and was classified as a class 2 airway. An interscalene brachial plexus block was performed using a 2-inch, 22-gauge needle inserted into the interscalene groove. Using an out-of-plane technique under direct ultrasound guidance, 30 mL of 0.52% ropivacaine was injected. The block was considered successful, and no complications, such as resistance, paresthesias, pain, or blood on aspiration, were noted during injection. The patient had no complaints of chest pain or shortness of breath immediately afterward, and all vital signs were stable throughout the procedure.
The patient was brought to the operating room and placed in the beach-chair position. Induction for general anesthesia was started 15 minutes after the regional anesthetic, with 2 intubation attempts necessary because of poor airway visualization. After placement of the endotracheal tube, breath sounds were noted to be equal bilaterally. The arthroscopic procedure consisted of double-row rotator cuff repair, subacromial decompression, and débridement of the glenohumeral joint for synovitis, using standard arthroscopic portals. There were no difficulties with trocar placement, and bleeding was minimal throughout the case. The total surgical time was 150 minutes and a pump pressure of 30 mm Hg was maintained during the arthroscopy.
Within the first 60 minutes of the start of the arthroscopic procedure, the patient was noted to be intermittently hypotensive with mean arterial pressure (MAP) ranging from the 30s to 130s mm Hg and pulse in the 70 to 80 beats/min range. FiO2 in the 85% to 95% range was maintained throughout the procedure. During that time, 50 μg phenylephrine was administered on 4 separate occasions to maintain her blood pressure. The labile blood pressure was attributed by the anesthesiologist to the beach-chair position. During an attempted extubation upon conclusion of the surgery, the patient became hypotensive with MAP that ranged from the 40s to 60s mm Hg and tachycardic to 90 beats/min. The oxygen saturation was in the low 90s and tidal volume was poor. Absent lung sounds were noted on the right chest. An urgent portable chest radiograph showed a large right-sided tension pneumothorax with mediastinal shift (Figure 1). After an immediate general surgery consultation, a chest tube was placed in the operating room. The patient’s vital signs improved and a repeat chest radiograph revealed successful re-expansion of the lung (Figure 2). She was transferred to the acute postoperative anesthesia care unit and extubated in the intensive care unit later that day.
The patient’s chest tube was removed 2 days later and she was discharged home on hospital day 5 with a completely resolved pneumothorax. She was seen 1 week later in the office for a postoperative visit and reported feeling well without chest pain or shortness of breath.
Discussion
Interscalene brachial plexus anesthesia was first described by Winnie4 in 1970. This block targets the trunks of the brachial plexus, which are enclosed in a fascial sheath between the anterior and middle scalene muscles. In this region lie several structures at risk: the phrenic nerve superficially and inferiorly; the carotid sheath located superficially and medially; the subclavian artery parallel to the trunks; and the cupula of the lung that lies deep and inferior to the anterior scalene muscle. Recognized complications of the block include vocal hoarseness, Horner syndrome, and hemidiaphragmatic paresis caused by the temporary blockade of the ipsilateral recurrent laryngeal nerve, stellate ganglion, and phrenic nerve, in that order.5 Use of the interscalene block has been associated with minimal risk for pneumothorax, because the needle entry point is superior and directed away from the lung pleura.6 This is in contrast to the more inferiorly placed supraclavicular block, located in closer proximity to the lung cupula.5
Two different approaches are commonly used during ultrasound-guided nerve blocks. The in-plane approach generates a long-axis view of the needle by advancing the needle parallel with the long axis of the ultrasound probe. While this allows direct visualization of the needle tip, it requires deeper needle insertion from lateral to medial, causing puncture of the middle scalene muscle that may increase patient discomfort and risk nerve injury within the muscle.7 The out-of-plane approach used on our patient involves needle insertion parallel to the brachial plexus, but along the short axis of the ultrasound probe. Although this permits the operator to assess the periphery of the nerve, it may lead to poor needle-tip visualization during the procedure. As a result, operators often use a combination of tissue disturbance and “hydrolocation,” in which fluid is injected to indicate the needle-tip location.8,9
Tension pneumothorax represents the accumulation of air in the pleural space that leads to impaired pulmonary and cardiac function. It is often caused by disruption or puncture of the parietal or visceral pleura, creating a connection between the alveoli and pleural cavity. The gradual buildup of air in the pleural cavity results in increased intrapleural pressure, which compresses and ultimately collapses the ipsilateral lung. Venous compression restricts blood return to the heart and reduces cardiac output. Clinical manifestations include dyspnea, hypoxemia, tachycardia, and hypotension.10 Multiple techniques were developed to better localize the brachial plexus while reducing injury to nearby structures, including the lung. These include eliciting needle paresthesias, electrical nerve stimulation, and ultrasound guidance. While nerve stimulation was once the gold standard for brachial plexus localization, ultrasound guidance has gained in popularity because of its noninvasive nature and dynamic capability to identify nerves and surrounding structures.11 Perlas and colleagues12 determined the sensitivity of needle paresthesias and nerve stimulation to be 38% and 75%, respectively, in cases in which plexus localization had been confirmed by ultrasound.
Several studies have reported on the efficacy of interscalene nerve block with either nerve stimulation or ultrasound guidance in the setting of shoulder surgery.2,3 Bishop and colleagues3 reviewed 547 patients who underwent interscalene regional anesthesia with nerve stimulation for both arthroscopic and open-shoulder procedures. They reported a 97% success rate and 12 (2.3%) minor complications, including sensory neuropathy and complex regional pain syndrome. There were no cases of pneumothorax, cardiac events, or other major complications.3 In a prospective study of 1319 patients, Singh and colleagues2 reported a 99.6% success rate using ultrasound-guided interscalene blocks for their shoulder surgeries. A total of 38 adverse events (2.88%) were identified: 14 transient neurologic events, including ear numbness, digital numbness, and brachial plexitis; 1 case of intraoperative bradycardia, and 2 cancellations after the block for chest pain and flank pain, which yielded negative cardiac workups. Other complications included postoperative emergency room visits and hospital admissions for reasons unrelated to the block.2 Interscalene regional anesthesia, therefore, provides effective anesthesia for shoulder surgery with low complication rates.
Pneumothorax after ultrasound-guided interscalene block has rarely been reported.13,14 In a review of 144 ultrasound-guided indwelling interscalene catheter placements, a 98% successful block rate with a single complication of small pneumothorax after total shoulder arthroplasty was reported.13 Mandim and colleagues14 reported a case of pneumothorax in a smoker who underwent an ultrasound-guided brachial plexus block prior to open reduction and internal fixation of an ulnar fracture. While the patient was asymptomatic and vital signs remained stable during the procedure, the patient complained postoperatively of chest pain with hypoxia, tachycardia, and hypotension. A chest radiograph confirmed an ipsilateral pneumothorax, and the patient was treated successfully with chest-tube placement. The authors attributed this complication to a higher pleural dome resulting from a hyperinflated lung caused by chronic smoking. Our patient reported no history of smoking and her preoperative chest radiograph had no evidence of lung disease.
In contrast, several cases of pneumothorax after shoulder surgery have been reported in the absence of nerve block. Oldman and Peng1 reported a 41-year-old nonsmoker who underwent arthroscopic labral repair and subacromial decompression. The preoperative nerve block was cancelled, and the patient received general endotracheal anesthesia alone. Fifty minutes after the case, the patient developed chest pain and hypoxia. A chest radiograph showed a small pneumothorax that was managed conservatively. The pneumothorax was attributed to spontaneous rupture of a preexisting lung bulla, suggesting that blocks are not always the cause of this complication. Furthermore, Dietzel and Ciullo15 reported 4 cases of spontaneous pneumothorax within 24 hours of uncomplicated arthroscopic shoulder procedures under general anesthesia in the lateral decubitus position. The patient ages ranged from 22 to 38 years, and medical histories were all significant for preexisting lung disease, remote history of pneumonia, and heavy smoking. Three of the patients experienced symptoms at home the day after surgery. The authors concluded that these cases were likely caused by rupture of blebs or bullae from underlying lung disease; these ruptured blebs or bullae are difficult to detect and usually located in the upper lung. The pressure gradient from the positive pressure of anesthesia and the ipsilateral upper lung is thought to be highest in the lateral decubitus position, increasing their chance of rupture.15
Finally, Lee and colleagues16 described 3 patients aged 40 to 45 years who underwent uncomplicated subacromial decompression in the beach-chair position under general anesthesia. Significant shoulder, neck, and axillary swelling were noted after surgery, and a chest radiograph showed tension pneumothorax, subcutaneous emphysema, and pneumomediastinum. The authors speculated that pressure in the subacromial space may become negative relative to atmospheric pressure when the shaver and suction are running, drawing in air through other portals. When the suction is discontinued, fluid infusion may push air into the surrounding tissue, leading to subcutaneous emphysema, which may spread to the mediastinum.16
Conclusion
Ultrasound-guided interscalene nerve blocks have successfully provided anesthesia for shoulder surgeries with low complication rates. Although the incidence of pneumothorax has decreased significantly with ultrasound guidance, the success of this procedure is highly operator-dependent. We present the case of an otherwise healthy patient without known pulmonary disease who developed a tension pneumothorax after the administration of ultrasound-guided regional and general anesthesia for arthroscopic shoulder surgery. Orthopedic surgeons and anesthesiologists must remain vigilant for pneumothorax during the perioperative period after shoulder surgery performed under interscalene regional aesthesia, particularly in the setting of hypotension, hypoxia, and/or tachycardia. Risk factors, such as history of smoking and preexisting lung disease, may predispose patients to the development of pneumothorax. Timely recognition and placement of a chest tube result in satisfactory clinical outcomes.
Interscalene brachial plexus anesthesia is commonly used for arthroscopic and open procedures of the shoulder. This regional anesthetic targets the trunks of the brachial plexus and anesthetizes the area about the shoulder and proximal arm. Its use may obviate the need for concomitant general anesthesia, potentially reducing the use of postoperative intravenous and oral pain medication. Furthermore, patients often bypass the acute postoperative anesthesia care unit and proceed directly to the ambulatory unit, permitting earlier hospital discharge. Previous reports in the literature have demonstrated higher rates of neurologic, cardiac, and pulmonary complications from this procedure; in particular, the incidence of pneumothorax was reported as high as 3%.1 Techniques to localize the nerves, such as electrical nerve stimulation and, more recently, ultrasound guidance, have reduced these complication rates.2,3 Successful administration of the block has been shown to result in satisfactory postoperative pain relief.2 However, ultrasound-guided interscalene nerve blocks remain operator-dependent and complications may still occur.
We report a case of tension pneumothorax after arthroscopic rotator cuff repair and subacromial decompression with an ultrasound-guided interscalene block. Immediate recognition and treatment of this complication resulted in a good clinical outcome. The patient provided written informed consent for print and electronic publication of this case report.
Case Report
A 56-year-old woman presented with 3 months of right shoulder pain after a fall. Examination was pertinent for weakness in forward elevation and positive rotator cuff impingement signs. She remained symptomatic despite a course of nonsurgical management that included cortisone injections and physical therapy. Magnetic resonance imaging of the shoulder showed a full-thickness supraspinatus tear with minimal fatty atrophy. After a discussion of her treatment options, she elected to undergo an arthroscopic rotator cuff repair with subacromial decompression. An evaluation by her internist revealed no pertinent medical history apart from obesity (body mass index, 36). Specifically, there was no reported history of chronic obstructive pulmonary disease or asthma. She denied any prior cigarette smoking.
The patient was evaluated by the regional anesthesia team and was classified as a class 2 airway. An interscalene brachial plexus block was performed using a 2-inch, 22-gauge needle inserted into the interscalene groove. Using an out-of-plane technique under direct ultrasound guidance, 30 mL of 0.52% ropivacaine was injected. The block was considered successful, and no complications, such as resistance, paresthesias, pain, or blood on aspiration, were noted during injection. The patient had no complaints of chest pain or shortness of breath immediately afterward, and all vital signs were stable throughout the procedure.
The patient was brought to the operating room and placed in the beach-chair position. Induction for general anesthesia was started 15 minutes after the regional anesthetic, with 2 intubation attempts necessary because of poor airway visualization. After placement of the endotracheal tube, breath sounds were noted to be equal bilaterally. The arthroscopic procedure consisted of double-row rotator cuff repair, subacromial decompression, and débridement of the glenohumeral joint for synovitis, using standard arthroscopic portals. There were no difficulties with trocar placement, and bleeding was minimal throughout the case. The total surgical time was 150 minutes and a pump pressure of 30 mm Hg was maintained during the arthroscopy.
Within the first 60 minutes of the start of the arthroscopic procedure, the patient was noted to be intermittently hypotensive with mean arterial pressure (MAP) ranging from the 30s to 130s mm Hg and pulse in the 70 to 80 beats/min range. FiO2 in the 85% to 95% range was maintained throughout the procedure. During that time, 50 μg phenylephrine was administered on 4 separate occasions to maintain her blood pressure. The labile blood pressure was attributed by the anesthesiologist to the beach-chair position. During an attempted extubation upon conclusion of the surgery, the patient became hypotensive with MAP that ranged from the 40s to 60s mm Hg and tachycardic to 90 beats/min. The oxygen saturation was in the low 90s and tidal volume was poor. Absent lung sounds were noted on the right chest. An urgent portable chest radiograph showed a large right-sided tension pneumothorax with mediastinal shift (Figure 1). After an immediate general surgery consultation, a chest tube was placed in the operating room. The patient’s vital signs improved and a repeat chest radiograph revealed successful re-expansion of the lung (Figure 2). She was transferred to the acute postoperative anesthesia care unit and extubated in the intensive care unit later that day.
The patient’s chest tube was removed 2 days later and she was discharged home on hospital day 5 with a completely resolved pneumothorax. She was seen 1 week later in the office for a postoperative visit and reported feeling well without chest pain or shortness of breath.
Discussion
Interscalene brachial plexus anesthesia was first described by Winnie4 in 1970. This block targets the trunks of the brachial plexus, which are enclosed in a fascial sheath between the anterior and middle scalene muscles. In this region lie several structures at risk: the phrenic nerve superficially and inferiorly; the carotid sheath located superficially and medially; the subclavian artery parallel to the trunks; and the cupula of the lung that lies deep and inferior to the anterior scalene muscle. Recognized complications of the block include vocal hoarseness, Horner syndrome, and hemidiaphragmatic paresis caused by the temporary blockade of the ipsilateral recurrent laryngeal nerve, stellate ganglion, and phrenic nerve, in that order.5 Use of the interscalene block has been associated with minimal risk for pneumothorax, because the needle entry point is superior and directed away from the lung pleura.6 This is in contrast to the more inferiorly placed supraclavicular block, located in closer proximity to the lung cupula.5
Two different approaches are commonly used during ultrasound-guided nerve blocks. The in-plane approach generates a long-axis view of the needle by advancing the needle parallel with the long axis of the ultrasound probe. While this allows direct visualization of the needle tip, it requires deeper needle insertion from lateral to medial, causing puncture of the middle scalene muscle that may increase patient discomfort and risk nerve injury within the muscle.7 The out-of-plane approach used on our patient involves needle insertion parallel to the brachial plexus, but along the short axis of the ultrasound probe. Although this permits the operator to assess the periphery of the nerve, it may lead to poor needle-tip visualization during the procedure. As a result, operators often use a combination of tissue disturbance and “hydrolocation,” in which fluid is injected to indicate the needle-tip location.8,9
Tension pneumothorax represents the accumulation of air in the pleural space that leads to impaired pulmonary and cardiac function. It is often caused by disruption or puncture of the parietal or visceral pleura, creating a connection between the alveoli and pleural cavity. The gradual buildup of air in the pleural cavity results in increased intrapleural pressure, which compresses and ultimately collapses the ipsilateral lung. Venous compression restricts blood return to the heart and reduces cardiac output. Clinical manifestations include dyspnea, hypoxemia, tachycardia, and hypotension.10 Multiple techniques were developed to better localize the brachial plexus while reducing injury to nearby structures, including the lung. These include eliciting needle paresthesias, electrical nerve stimulation, and ultrasound guidance. While nerve stimulation was once the gold standard for brachial plexus localization, ultrasound guidance has gained in popularity because of its noninvasive nature and dynamic capability to identify nerves and surrounding structures.11 Perlas and colleagues12 determined the sensitivity of needle paresthesias and nerve stimulation to be 38% and 75%, respectively, in cases in which plexus localization had been confirmed by ultrasound.
Several studies have reported on the efficacy of interscalene nerve block with either nerve stimulation or ultrasound guidance in the setting of shoulder surgery.2,3 Bishop and colleagues3 reviewed 547 patients who underwent interscalene regional anesthesia with nerve stimulation for both arthroscopic and open-shoulder procedures. They reported a 97% success rate and 12 (2.3%) minor complications, including sensory neuropathy and complex regional pain syndrome. There were no cases of pneumothorax, cardiac events, or other major complications.3 In a prospective study of 1319 patients, Singh and colleagues2 reported a 99.6% success rate using ultrasound-guided interscalene blocks for their shoulder surgeries. A total of 38 adverse events (2.88%) were identified: 14 transient neurologic events, including ear numbness, digital numbness, and brachial plexitis; 1 case of intraoperative bradycardia, and 2 cancellations after the block for chest pain and flank pain, which yielded negative cardiac workups. Other complications included postoperative emergency room visits and hospital admissions for reasons unrelated to the block.2 Interscalene regional anesthesia, therefore, provides effective anesthesia for shoulder surgery with low complication rates.
Pneumothorax after ultrasound-guided interscalene block has rarely been reported.13,14 In a review of 144 ultrasound-guided indwelling interscalene catheter placements, a 98% successful block rate with a single complication of small pneumothorax after total shoulder arthroplasty was reported.13 Mandim and colleagues14 reported a case of pneumothorax in a smoker who underwent an ultrasound-guided brachial plexus block prior to open reduction and internal fixation of an ulnar fracture. While the patient was asymptomatic and vital signs remained stable during the procedure, the patient complained postoperatively of chest pain with hypoxia, tachycardia, and hypotension. A chest radiograph confirmed an ipsilateral pneumothorax, and the patient was treated successfully with chest-tube placement. The authors attributed this complication to a higher pleural dome resulting from a hyperinflated lung caused by chronic smoking. Our patient reported no history of smoking and her preoperative chest radiograph had no evidence of lung disease.
In contrast, several cases of pneumothorax after shoulder surgery have been reported in the absence of nerve block. Oldman and Peng1 reported a 41-year-old nonsmoker who underwent arthroscopic labral repair and subacromial decompression. The preoperative nerve block was cancelled, and the patient received general endotracheal anesthesia alone. Fifty minutes after the case, the patient developed chest pain and hypoxia. A chest radiograph showed a small pneumothorax that was managed conservatively. The pneumothorax was attributed to spontaneous rupture of a preexisting lung bulla, suggesting that blocks are not always the cause of this complication. Furthermore, Dietzel and Ciullo15 reported 4 cases of spontaneous pneumothorax within 24 hours of uncomplicated arthroscopic shoulder procedures under general anesthesia in the lateral decubitus position. The patient ages ranged from 22 to 38 years, and medical histories were all significant for preexisting lung disease, remote history of pneumonia, and heavy smoking. Three of the patients experienced symptoms at home the day after surgery. The authors concluded that these cases were likely caused by rupture of blebs or bullae from underlying lung disease; these ruptured blebs or bullae are difficult to detect and usually located in the upper lung. The pressure gradient from the positive pressure of anesthesia and the ipsilateral upper lung is thought to be highest in the lateral decubitus position, increasing their chance of rupture.15
Finally, Lee and colleagues16 described 3 patients aged 40 to 45 years who underwent uncomplicated subacromial decompression in the beach-chair position under general anesthesia. Significant shoulder, neck, and axillary swelling were noted after surgery, and a chest radiograph showed tension pneumothorax, subcutaneous emphysema, and pneumomediastinum. The authors speculated that pressure in the subacromial space may become negative relative to atmospheric pressure when the shaver and suction are running, drawing in air through other portals. When the suction is discontinued, fluid infusion may push air into the surrounding tissue, leading to subcutaneous emphysema, which may spread to the mediastinum.16
Conclusion
Ultrasound-guided interscalene nerve blocks have successfully provided anesthesia for shoulder surgeries with low complication rates. Although the incidence of pneumothorax has decreased significantly with ultrasound guidance, the success of this procedure is highly operator-dependent. We present the case of an otherwise healthy patient without known pulmonary disease who developed a tension pneumothorax after the administration of ultrasound-guided regional and general anesthesia for arthroscopic shoulder surgery. Orthopedic surgeons and anesthesiologists must remain vigilant for pneumothorax during the perioperative period after shoulder surgery performed under interscalene regional aesthesia, particularly in the setting of hypotension, hypoxia, and/or tachycardia. Risk factors, such as history of smoking and preexisting lung disease, may predispose patients to the development of pneumothorax. Timely recognition and placement of a chest tube result in satisfactory clinical outcomes.
1. Oldman M, Peng Pi P. Pneumothorax after shoulder arthroscopy: don’t blame it on regional anesthesia. Reg Anesth Pain Med. 2004;29(4):382-383.
2. Singh A, Kelly C, O’Brien T, Wilson J, Warner JJ. Ultrasound-guided interscalene block anesthesia for shoulder arthroscopy: a prospective study of 1319 patients. J Bone Joint Surg Am. 2012;94(22):2040-2046.
3. Bishop JY, Sprague M, Gelber J, et al. Interscalene regional anesthesia for shoulder surgery. J Bone Joint Surg Am. 2005;87(5):974-979.
4. Winnie AP. Interscalene brachial plexus block. Anesth Analg. 1970;49(3):455-466.
5. Mian A, Chaudhry I, Huang R, Rizk E, Tubbs RS, Loukas M. Brachial plexus anesthesia: a review of the relevant anatomy, complications, and anatomical variations. Clin Anat. 2014;27(2):210-221.
6. Brown AR, Weiss R, Greenberg C, Flatow EL, Bigliani LU. Interscalene block for shoulder arthroscopy: comparison with general anesthesia. Arthroscopy. 1993;9(3):295-300.
7. Marhofer P, Harrop-Griffiths W, Willschke H, Kirchmair L. Fifteen years of ultrasound guidance in regional anaesthesia: Part 2 - recent developments in block techniques. Br J Anaesth. 2010;104(6):673-683.
8. Sites BD, Spence BC, Gallagher J, et al. Regional anesthesia meets ultrasound: a specialty in transition. Acta Anaesthesiol Scand. 2008;52(4):456-466.
9. Ilfeld BM, Fredrickson MJ, Mariano ER. Ultrasound-guided perineural catheter insertion: three approaches but few illuminating data. Reg Anesth Pain Med. 2010;35(2):123-126.
10. Choi WI. Pneumothorax. Tuberc Respir Dis (Seoul). 2014;76(3):99-104.
11. Klaastad O, Sauter AR, Dodgson MS. Brachial plexus block with or without ultrasound guidance. Curr Opin Anaesthesiol. 2009;22(5):655-660.
12. Perlas A, Niazi A, McCartney C, Chan V, Xu D, Abbas S. The sensitivity of motor response to nerve stimulation and paresthesia for nerve localization as evaluated by ultrasound. Reg Anesth Pain Med. 2006;31(5):445-450.
13. Bryan NA, Swenson JD, Greis PE, Burks RT. Indwelling interscalene catheter use in an outpatient setting for shoulder surgery: technique, efficacy, and complications. J Shoulder Elbow Surg. 2007;16(4):388-395.
14. Mandim BL, Alves RR, Almeida R, Pontes JP, Arantes LJ, Morais FP. Pneumothorax post brachial plexus block guided by ultrasound: a case report. Rev Bras Anestesiol. 2012;62(5):741-747.
15. Dietzel DP, Ciullo JV. Spontaneous pneumothorax after shoulder arthroscopy: a report of four cases. Arthroscopy. 1996;12(1):99-102.
16. Lee HC, Dewan N, Crosby L. Subcutaneous emphysema, pneumomediastinum, and potentially life-threatening tension pneumothorax. Pulmonary complications from arthroscopic shoulder decompression. Chest. 1992;101(5):1265-1267.
1. Oldman M, Peng Pi P. Pneumothorax after shoulder arthroscopy: don’t blame it on regional anesthesia. Reg Anesth Pain Med. 2004;29(4):382-383.
2. Singh A, Kelly C, O’Brien T, Wilson J, Warner JJ. Ultrasound-guided interscalene block anesthesia for shoulder arthroscopy: a prospective study of 1319 patients. J Bone Joint Surg Am. 2012;94(22):2040-2046.
3. Bishop JY, Sprague M, Gelber J, et al. Interscalene regional anesthesia for shoulder surgery. J Bone Joint Surg Am. 2005;87(5):974-979.
4. Winnie AP. Interscalene brachial plexus block. Anesth Analg. 1970;49(3):455-466.
5. Mian A, Chaudhry I, Huang R, Rizk E, Tubbs RS, Loukas M. Brachial plexus anesthesia: a review of the relevant anatomy, complications, and anatomical variations. Clin Anat. 2014;27(2):210-221.
6. Brown AR, Weiss R, Greenberg C, Flatow EL, Bigliani LU. Interscalene block for shoulder arthroscopy: comparison with general anesthesia. Arthroscopy. 1993;9(3):295-300.
7. Marhofer P, Harrop-Griffiths W, Willschke H, Kirchmair L. Fifteen years of ultrasound guidance in regional anaesthesia: Part 2 - recent developments in block techniques. Br J Anaesth. 2010;104(6):673-683.
8. Sites BD, Spence BC, Gallagher J, et al. Regional anesthesia meets ultrasound: a specialty in transition. Acta Anaesthesiol Scand. 2008;52(4):456-466.
9. Ilfeld BM, Fredrickson MJ, Mariano ER. Ultrasound-guided perineural catheter insertion: three approaches but few illuminating data. Reg Anesth Pain Med. 2010;35(2):123-126.
10. Choi WI. Pneumothorax. Tuberc Respir Dis (Seoul). 2014;76(3):99-104.
11. Klaastad O, Sauter AR, Dodgson MS. Brachial plexus block with or without ultrasound guidance. Curr Opin Anaesthesiol. 2009;22(5):655-660.
12. Perlas A, Niazi A, McCartney C, Chan V, Xu D, Abbas S. The sensitivity of motor response to nerve stimulation and paresthesia for nerve localization as evaluated by ultrasound. Reg Anesth Pain Med. 2006;31(5):445-450.
13. Bryan NA, Swenson JD, Greis PE, Burks RT. Indwelling interscalene catheter use in an outpatient setting for shoulder surgery: technique, efficacy, and complications. J Shoulder Elbow Surg. 2007;16(4):388-395.
14. Mandim BL, Alves RR, Almeida R, Pontes JP, Arantes LJ, Morais FP. Pneumothorax post brachial plexus block guided by ultrasound: a case report. Rev Bras Anestesiol. 2012;62(5):741-747.
15. Dietzel DP, Ciullo JV. Spontaneous pneumothorax after shoulder arthroscopy: a report of four cases. Arthroscopy. 1996;12(1):99-102.
16. Lee HC, Dewan N, Crosby L. Subcutaneous emphysema, pneumomediastinum, and potentially life-threatening tension pneumothorax. Pulmonary complications from arthroscopic shoulder decompression. Chest. 1992;101(5):1265-1267.
