INTRODUCTION — A variety of medical conditions and postsurgical complications cause pleural disease that may require surgical intervention. These include the presence of fluid (pleural effusion), air (pneumothorax), blood (hemothorax), chyle (chylothorax), purulent material (empyema), or tumor in the pleural space, as well as fibrosis of the pleural space (fibrothorax), or formation of an alveolopleural or bronchopleural fistula.

This topic addresses anesthetic considerations for patients requiring anesthetic care during surgical or other major invasive interventions to treat a pleural disease process. Other topics address medical and surgical management of specific pleural diseases, as noted in each section below.

ANESTHETIC MANAGEMENT: GENERAL CONSIDERATIONS

Preoperative assessment — The preanesthetic consultation focuses on assessment of etiology of pleural disease, such as presence of malignant or nonmalignant fluid (pleural effusion), air (pneumothorax), chyle (chylothorax), blood (hemothorax), or purulent material (empyema), as well as fibrosis of the pleural space (fibrothorax) or formation of an alveolopleural or bronchopleural fistula.

Acute problems (eg, persistent bleeding, sepsis) and chronic comorbid conditions (eg, underlying pulmonary disease, anemia, cancer, heart failure, hepatic failure, frailty) should be recognized and managed before the surgical intervention when possible. In particular, pulmonary risk and the patient's ability to tolerate one lung ventilation (OLV) are assessed (see "Evaluation of perioperative pulmonary risk" and "One lung ventilation: General principles", section on 'Contraindications'). Age and overall physical condition are also considered. (See "Anesthesia for the older adult", section on 'Assessment for frailty'.)

●Elective surgical procedures – Treatable preoperative conditions are addressed. Examples include:

•Pulmonary comorbidities are managed to minimize risk of pulmonary complications. (See "Evaluation of perioperative pulmonary risk" and "Strategies to reduce postoperative pulmonary complications in adults".)

•Preoperative anemia is treated when feasible (see "Perioperative blood management: Strategies to minimize transfusions", section on 'Treatment of anemia'). For selected procedures with expected significant blood loss (eg, decortication), crossmatching for 2 to 4 units of red blood cells is performed. (See 'Empyectomy or decortication' below.)

•Prehabilitation may be considered for older frail patients with functional dependence and weight loss [1,2]. (See "Prehabilitation for anesthesia and surgery" and "Anesthesia for the older adult", section on 'Assessment for frailty'.)

•In patients with chylothorax managed by continuous drainage of chylous pleural fluid, hypovolemia and malnutrition may be present. Nutritional therapy should be optimal before elective surgery. Serum electrolytes, lymphocyte counts, albumin, and total protein are checked in the preoperative period. A fatty food such as cream or olive oil may be administered enterally or via an orogastric tube a few hours before surgery to facilitate intraoperative location of the chyle leak [3-5]. (See "Management of chylothorax".)

•For patients with empyema, antibiotic therapy should be optimal before elective surgery and hemodynamic status should be assessed. (See "Management and prognosis of parapneumonic pleural effusion and empyema in adults", section on 'Antibiotic therapy'.)

●Nonelective surgical procedures – Typically, patients with pleural disease do not present to the operating room for emergency procedures, since tension pneumothorax, large hemothorax, or significant pleural effusion would be treated with bedside tube thoracostomy.

However, rarely, a patient may present in respiratory distress requiring immediate endotracheal intubation, typically with a lung isolation device (eg, double-lumen endotracheal tube or bronchial blocker) if the planned procedure will require OLV. (See "Lung isolation techniques".)

Patients with empyema and sepsis or those with pneumothorax or hemothorax may present with impending hemodynamic instability. (See "Intraoperative management of shock in adults", section on 'Septic shock' and "Intraoperative management of shock in adults", section on 'Tension pneumothorax or hemothorax'.)

Patients with persistent bleeding may have worsening anemia requiring transfusion. (See "Intraoperative transfusion of blood products in adults".)

Monitoring and intravascular access — For procedures that will be limited to minimally invasive techniques (eg, catheter drainage of pleural effusions or pleurodesis), one large-bore peripheral intravenous (IV) catheter is typically adequate if conversion to thoracotomy is highly unlikely. Invasive hemodynamic monitoring (eg, intra-arterial catheter or central venous catheter placement) is not typically necessary for these procedures, unless indicated for patient-specific comorbidities.

For procedures that may involve significant blood loss (eg, decortication/empyectomy or repair of bronchopleural fistula), additional IV access for rapid volume resuscitation may be necessary. If hemodynamic instability is anticipated, invasive circulatory system monitoring (eg, an intra-arterial catheter) is established, ideally prior to induction of general anesthesia. (See "Monitoring during anesthesia", section on 'Circulatory system monitoring'.)

Intraoperative management

●General anesthesia – General anesthesia is necessary for most surgical procedures performed to diagnose or treat pleural diseases. Many of these procedures require OLV. After anesthetic induction for general anesthesia, the patient is intubated with a lung isolation device. A double-lumen endotracheal tube is strongly preferred in most cases to prevent soiling of the airway and contralateral lung in the lateral decubitus position (figure 1 and figure 2), although several lung isolation devices are available. Similar to all procedures employing OLV, a lung protective ventilation strategy should be employed. (See "One lung ventilation: General principles" and "Lung isolation techniques".)

Maintenance of anesthesia is typically accomplished with a potent volatile inhalation anesthetic agent (eg, sevoflurane). Short-acting IV opioids, adjuvant anesthetic agents, and a muscle relaxant are typically employed to supplement the inhalation-based anesthetic technique. Nitrous oxide should be avoided in order to prevent excessive expansion of gas-filled spaces. Patients with empyema or chronic pleural disease are at particular risk because septations or loculations can form closed gas-filled spaces that prevent full chest tube drainage of all pleural space compartments. (See "One lung ventilation: General principles", section on 'Anesthetic choice'.)

Certain intraoperative complications during thoracic surgery should be anticipated and managed immediately. Examples include suspected tension pneumothorax with sudden hemodynamic compromise and desaturation occurring after central line placement on the contralateral side of a patient with an open chest, or before chest opening or after chest closure during surgical repair of a bronchopleural fistula. Another example is recognition of significant bleeding during a decortication procedure.

Patients may be extubated at the end of the case while still in the operating room or interventional suite after most procedures requiring general anesthesia for treatment of pleural disease. As with other pulmonary surgical procedures, the decision to extubate depends on patient-specific and procedure-specific factors (eg, severe preoperative respiratory failure, postoperative need for continuous pulmonary toilet). (See "Anesthesia for open pulmonary resection", section on 'Emergence and postoperative airway management'.)

Details regarding anesthetic considerations for video-assisted thoracoscopic surgery (VATS) or open thoracotomy for pulmonary resection are discussed in separate topics:

•(See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection".)

•(See "Anesthesia for open pulmonary resection".)

●Local anesthesia with monitored anesthesia care — Selected VATS procedures for pleural diseases may be performed with a local anesthetic technique and monitored anesthesia care (MAC) with sedation. Anesthetic choice is based on patient- and pathology-specific factors, as well as provider preferences [6]. Intraoperative management details are described separately. (See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection", section on 'Nonintubated thoracoscopic surgery'.)

CATHETER DRAINAGE OF PLEURAL EFFUSIONS

Causes of pleural effusion — Patients presenting for surgical management of a pleural effusion typically have a large volume or reaccumulation of pleural fluid (figure 3). (See "Mechanisms of pleural liquid accumulation in disease".)

●Malignant pleural effusions – Malignant pleural effusions are usually metastatic and may be associated with pleural tumor (usually lymphoma or lung, breast, or ovarian cancer) [7]. (See "Management of malignant pleural effusions".)

Chylothorax, an accumulation of chyle leaking from the lymphatics into the pleural space, may be caused by malignancy (eg, lymphoma, chronic lymphocytic leukemia, bronchogenic carcinoma, metastatic cancer). (See "Etiology, clinical presentation, and diagnosis of chylothorax".)

Malignant pleural mesothelioma (MPM) is the most common primary malignancy of the pleura and has a poor prognosis. Some centers with expertise in management of MPM offer surgery-based therapy including pleurectomy/decortication or extrapleural pneumonectomy. (See "Initial management of malignant pleural mesothelioma", section on 'Surgery-based therapy'.)

●Nonmalignant pleural effusions – Causes of nonmalignant large pleural effusions include (table 1 and table 2):

•Congestive heart failure

•Nephrotic syndrome

•Infectious (ie, empyema) or noninfectious pleural inflammation

•Hepatic hydrothorax in a patient with ascites due to cirrhosis and portal hypertension. Pleurodesis and/or thoracoscopic repair of diaphragmatic defects may be necessary in some cases. (See "Hepatic hydrothorax".)

•Nonmalignant chylothorax (accumulation of chyle in the pleural space) occurring due to disruption or obstruction of the thoracic duct or its tributaries [5]. Causes include complications of surgery (eg, esophagectomy, lung resection with lymph node dissection) [3,8,9].

•Hemothorax is the presence of blood in the pleural space, usually resulting from thoracic trauma or iatrogenic puncture or transection of a blood vessel (eg, during central line placement, thoracentesis, or chest tube placement). Patients with acute or expanding hemothorax may be hemodynamically unstable. Major bleeding from the great vessels, cardiac injury, and hilar injury is discussed in other topics:

-(See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children", section on 'Hemothorax'.)

-(See "Resuscitative thoracotomy: Technique".)

-(See "Surgical management of severe rib fractures".)

-(See "Overview of blunt and penetrating thoracic vascular injury in adults".)

•Thoracic endometriosis is a rare condition in which endometrial tissue is found in the pleura and/or lung parenchyma, bronchi, or diaphragm. Wedge resections of visible endometrial implants, repair of diaphragmatic defects, and treatment of associated catamenial pneumothorax and/or hemothorax may be necessary. (See "Clinical features, diagnostic approach, and treatment of adults with thoracic endometriosis".)

Procedural considerations — Catheter drainage is performed to manage pleural effusion. Patients with small amounts of fluid, blood, pus, or air in the pleural space may initially be managed by tube thoracostomy alone. Goals of treatment include elimination of liquid or air in the pleural space, complete lung re-expansion, and prevention of recurrence. Often, catheter drainage procedures are performed with local anesthesia at the bedside and do not require anesthetic care. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children" and "Overview of minimally invasive thoracic surgery".)

More invasive surgical treatments for pleural effusions include insertion of an indwelling pleural catheter or pleuroperitoneal shunt placement. (See "Management of malignant pleural effusions" and "Management of nonmalignant pleural effusions in adults".)

In some cases, pleurodesis is performed to obliterate the pleural space [7,10]. (See 'Pleurodesis' below.)

Large volume chylothorax or persistent chyle accumulation (more than 1 L accumulates during a 24-hour period) may require surgical management with thoracic duct ligation. The surgeon may select either a minimally invasive thoracoscopic technique or open thoracotomy for the procedure. (See "Management of chylothorax", section on 'Thoracic duct ligation' and "Management of chylothorax".)

Anesthetic considerations — Anesthetic management for video-assisted thoracoscopic surgery (VATS) to manage pleural effusions is similar to that for other VATS procedures. (See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection".)

Intraoperative transesophageal or thoracic ultrasound may be used to guide drainage of a pleural effusion [7,10]. (See "Imaging of pleural effusions in adults", section on 'Ultrasonography' and "Ultrasound-guided thoracentesis".)

PLEURODESIS — Pleurodesis is the fusion of the visceral and parietal pleura with obliteration of the pleural space. Pleurodesis may be performed in patients who have pneumothorax with a persistent air leak, recurrent pneumothorax, or persistent pleural effusion due to malignant or nonmalignant causes:

●(See "Pneumothorax: Definitive management and prevention of recurrence", section on 'Pleurodesis'.)

●(See "Management of malignant pleural effusions", section on 'Pleurodesis (alternative to IPC or failed IPC)'.)

●(See "Management of nonmalignant pleural effusions in adults", section on 'Pleurodesis'.)

Procedural considerations — Pleurodesis may be accomplished by:

●A sclerosing agent such as talc or doxycycline instilled via a chest tube. (See "Chemical pleurodesis" and "Talc pleurodesis".)

●Mechanical abrasion of the parietal pleura via video-assisted thoracoscopic surgery (VATS) performed using dry gauze, a Bovie scratch pad, cellulose mesh with fibrin glue, or laser abrasion. Thoracoscopy with direct visualization also allows for inspection of the underlying lung to aid decision-making regarding possible additional surgical interventions (eg, pulmonary wedge resection to treat subpleural blebs). (See "Treatment of primary spontaneous pneumothorax in adults" and "Treatment of primary spontaneous pneumothorax in adults", section on 'Indications for definitive procedure after first event'.)

●Insertion of a tunneled indwelling pleural catheter to drain pleural fluid in selected patients (eg, those with recurrent effusions), which may induce pleurodesis without instillation of a sclerosing agent. (See "Management of malignant pleural effusions", section on 'Indwelling pleural catheter (IPC)'.)

Other procedures that may be performed for diagnosis and treatment of persistent or recurrent pneumothorax or pleural effusion include minimally invasive thoracic surgery and/or lung biopsy.

Anesthetic considerations — If VATS is necessary for pleurodesis and/or lung biopsy, anesthetic considerations are similar to those for other VATS procedures. (See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection".)

Notably, chemical pleurodesis is a painful procedure. Pain may be somewhat ameliorated by administration of local anesthetics in the pleural space [11]. Intravenous (IV) and oral opioids are usually needed as well in the postoperative period. Nonsteroidal anti-inflammatory drugs (NSAIDs) are generally avoided due to concerns regarding attenuation of the inflammatory response necessary for successful pleurodesis. However, one clinical trial has noted non-inferiority of NSAIDs compared with opioids for treatment of postoperative pain in this setting [12]. Use of thoracic epidural analgesia (TEA) is another option, although rarely used for isolated pleurodesis [13]. (See "Chemical pleurodesis".)

DEBRIDEMENT OR OPEN DRAINAGE OF EMPYEMA — Empyema is pus in the pleural space, typically due to local bacterial spread from the lung, postoperative infection due to direct inoculation of bacteria into the pleural space during a thoracic procedure, or penetrating chest wall injury [14]. Acute empyema is typically managed with appropriate antibiotic treatment and tube drainage of the empyema with re-expansion of the lung. Patients with empyema who do not improve with antibiotics and tube thoracostomy may have loculations preventing adequate drainage. (See "Management and prognosis of parapneumonic pleural effusion and empyema in adults".)

In some cases, decortication or empyectomy is necessary. (See 'Empyectomy or decortication' below.)

Procedural considerations — Elimination of uniloculated or multiloculated empyemas is often accomplished via a thoracoscopic procedure [15,16]; however, open thoracotomy may be necessary in some cases. Similarly, retained clot may be removed with these procedures to prevent or treat superinfection and/or lung entrapment. (See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection" and "Management and prognosis of parapneumonic pleural effusion and empyema in adults", section on 'Treatment failure'.)

Anesthetic considerations — If the patient has purulent pulmonary secretions, cross contamination from one lung to the other must be avoided. Thus, we typically select a double-lumen tube (DLT) endotracheal tube rather than a bronchial blocker as a DLT provides better seal to prevent potential leakage and contamination. DLTs are also more quickly placed and have a lower incidence of malpositioning during patient movement compared with bronchial blockers. (See "Lung isolation techniques", section on 'Unilateral pulmonary infection'.)

The anesthesiologist should be prepared for possible conversion from a video-assisted thoracoscopic surgery (VATS) procedure to a thoracotomy (eg, if adequate pleural fluid drainage and lung expansion are not achieved). Analgesic considerations should be based on this possibility (eg, obtaining preoperative patient consent for placement of a thoracic epidural for postoperative pain control in the event of conversion to open procedure). (See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection" and "Anesthesia for open pulmonary resection".)

At the end of the case, whether the patient will meet extubation criteria depends upon adequacy of pulmonary reserve and presence of hemodynamic stability as key factors (eg, in patients with systemic inflammatory response syndrome or large shifts in intravascular volume). (See 'Anesthetic management: General considerations' above.)

EMPYECTOMY OR DECORTICATION — Patients with chronic empyema or other inflammatory or traumatic processes may develop pleural fibrosis, with thick pleural fluid and fibrous peel formation covering the visceral and parietal pleura (ie, fibrothorax) and causing lung trapping and incomplete lung re-expansion. Empyectomy or decortication may be necessary in some cases.

Although prognosis is poor, malignant pleural mesothelioma (MPM) may be treated in selected patients with pleurectomy/decortication (ie, removal of both the parietal and visceral pleura with preservation of the lung parenchyma). Extrapleural pneumonectomy (ie, removal of the lung, pericardium, diaphragm, and parietal pleura) is another option selected for treatment of some patients with MPM. (See "Initial management of malignant pleural mesothelioma", section on 'Pleurectomy/decortication (P/D)' and "Initial management of malignant pleural mesothelioma", section on 'Extrapleural pneumonectomy (EPP)'.)

Procedural considerations — Empyectomy procedures involve complete removal of the empyema in the pleural space to allow lung re-expansion. Additional surgical interventions may be necessary to treat empyema complications of previous surgical sites. Some patients require decortication (ie, surgical removal of a fibrotic peel from the lung with preservation of the visceral pleura). (See "Diagnosis and management of pleural causes of nonexpandable lung", section on 'Management of trapped lung'.)

Anesthetic considerations — Surgical management of empyectomy or decortication requires video-assisted thoracoscopic surgery (VATS) or open thoracotomy; anesthetic considerations are discussed separately. (See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection" and "Anesthesia for open pulmonary resection".)

Lung injury and significant bleeding may occur during decortication or empyectomy procedures. For example, lung tissue may be injured during entry into the chest or dissection of the empyema peel from visceral pleura if it is strongly adherent to the lung. Transfusion of red blood cells may be necessary, and persistent oozing from lung surfaces after decortication may necessitate transfusion of hemostatic blood products, such as plasma products or platelets. Intraoperative standard laboratory or point-of-care testing of hemoglobin levels and hemostatic function enables rational decision-making regarding transfusion of red blood cells and other blood components (see "Intraoperative transfusion of blood products in adults", section on 'Intraoperative diagnostic testing'). Although lung resection procedures are typically managed with restrictive fluid management, volume resuscitation should be provided as appropriate in a patient with persistent bleeding. (See "Anesthesia for open pulmonary resection", section on 'Fluid and hemodynamic management'.)

At the conclusion of the procedure, full re-expansion of the lung to fill the pleural space is important to prevent development of postoperative fibrosis of the pleural space. (See "Management and prognosis of parapneumonic pleural effusion and empyema in adults".)

REPAIR OF BRONCHOPLEURAL OR ALVEOLOPLEURAL FISTULA — A bronchopleural fistula is an abnormal connection between the pleural space and a bronchus, while an alveolopleural fistula is a pathologic communication between the pleural space and the pulmonary parenchyma distal to a segmental bronchus (alveoli). The resultant air leak is considered to be prolonged if it persists beyond five days. This type of pneumothorax occurs most commonly after pulmonary resection. (See "Alveolopleural fistula and prolonged air leak in adults" and "Bronchopleural fistula in adults".)

Procedural considerations — Closure of a bronchopleural fistula is accomplished via video-assisted thoracoscopic surgery (VATS) or open thoracotomy. (See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection" and "Anesthesia for open pulmonary resection".)

Repair of an alveolopleural fistula is achieved in most cases with tube thoracostomy and prolonged drainage. In some cases, a thoracotomy may be necessary to repair an alveolopleural fistula by creating a muscle or omental flap to obliterate the leak. (See "Alveolopleural fistula and prolonged air leak in adults", section on 'Surgical repair'.)

For a bronchopleural fistula, depending on the nature of the bronchial dehiscence and the duration of the presence of the fistula, surgical obliteration involving revision of a bronchial stump with debridement of necrotic tissue and suture reclosure of the stump may be necessary. In some cases, primary closure of a bronchopleural fistula may not be possible, and thoracotomy may be necessary to create a muscle (eg, thoracic skeletal muscle, rectus abdominis muscle) or omental flap for reinforcement at the site of the leak [17,18]. (See "Bronchopleural fistula in adults", section on 'Surgical repair (curative)'.)

Anesthetic considerations — Lung isolation is necessary to decrease pressure and air flow on the side of pathology (see "Bronchopleural fistula in adults" and "Lung isolation techniques"). Precise placement of an endobronchial blocker under direct bronchoscopic guidance can provide temporary occlusion of the fistula to stabilize the patient until a more permanent endobronchial intervention (eg, surgical repair) is performed [19]. Such placement of a bronchial blocker should be viewed as a temporizing measure in a patient who is unstable due to air leakage from a bronchopleural fistula.

After confirming proper placement of the lung isolation device, the bronchial cuff should be inflated to isolate the contralateral lung before repositioning the patient for surgical repair. Typically, a lateral decubitus position is selected, with the operative lung or pleural space up. Notably, contamination of the nonoperative lung is most likely to happen during repositioning. Thus, it is important to ensure lung isolation before repositioning, and to carefully avoid accidental displacement of the lung isolation device during repositioning.

Ensuring lung isolation is particularly important in patients with a bronchopleural or alveolopleural fistula since the nonoperative lung may be flooded as saline is instilled into the chest of a patient in the lateral decubitus position if the contralateral lung has not already been isolated. Furthermore, for a VATS procedure, deflation of the operative lung should be accomplished well before insertion of thoracoscopic instruments. (See "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection".)

Similar to all procedures employing one lung ventilation (OLV), a lung protective ventilation strategy should be employed (see "One lung ventilation: General principles", section on 'Ventilation strategies'). However, the tidal volume actually delivered may be difficult to measure due to volume loss from the fistula site.

If harvesting of the rectus abdominis muscle or omentum for muscle transposition is planned, additional repositioning from left lateral decubitus to a supine position will be necessary later in the case to accomplish this abdominal procedure. (See "Patient positioning for surgery and anesthesia in adults", section on 'Lateral decubitus' and "Patient positioning for surgery and anesthesia in adults", section on 'Supine'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Pleural effusion".)

SUMMARY AND RECOMMENDATIONS

●The preanesthetic consultation focuses on assessment of the etiology of pleural disease (eg, malignant or nonmalignant fluid [pleural effusion], air [pneumothorax], chyle [chylothorax], blood [hemothorax], or purulent material [empyema], as well as fibrosis of the pleural space [fibrothorax] or formation of an alveolopleural or bronchopleural fistula). Furthermore, acute problems (eg, persistent bleeding, sepsis) and chronic comorbid conditions (eg, underlying pulmonary disease, anemia, cancer, heart failure, hepatic failure, frailty) should be recognized and treatable conditions are managed before surgery. (See 'Preoperative assessment' above.)

●General anesthesia is necessary for most surgical procedures performed to diagnose or treat pleural diseases, and one lung ventilation (OLV) is often required. Most patients may be extubated at the end of the procedure to treat pleural disease; exceptions include severe preoperative respiratory failure or postoperative need for continuous pulmonary toilet. Intraoperative complications that must be urgently managed include sudden hemodynamic compromise due to pneumothorax or significant bleeding. (See 'Intraoperative management' above.)

●For procedures limited to minimally invasive techniques (eg, catheter drainage, pleurodesis), one large-bore peripheral intravenous (IV) catheter is typically adequate. For procedures that may involve significant blood loss (eg, empyectomy, decortication, repair of bronchopleural fistula), additional IV access for rapid volume resuscitation may be necessary. If hemodynamic instability is anticipated, invasive circulatory system monitoring (eg, an intra-arterial catheter) is established, ideally prior to induction of general anesthesia.

●Specific surgical and anesthetic management to treat pleural disease are discussed in each section above:

•(See 'Catheter drainage of pleural effusions' above.)

•(See 'Pleurodesis' above.)

•(See 'Debridement or open drainage of empyema' above.)

•(See 'Empyectomy or decortication' above.)

•(See 'Repair of bronchopleural or alveolopleural fistula' above.)