Thoracoscopy






What procedures are performed under video-assisted thoracoscopy?


Minimally invasive thoracic surgery can be performed with VAT. Typically, three to five small incisions (portals) are created to allow entry of instruments into the thoracic cavity. A camera is connected to a monitor on which the visual field is displayed.


VAT can be used for biopsy of intrathoracic structures, such as lung, pleura, and mediastinal masses. If the biopsy is positive for cancer, open thoracotomy for a more extensive resection, such as lobectomy or pneumonectomy, may be the next step. Other lung surgical procedures that can be performed with VAT include resection of bullae, treatment of pneumothorax or empyema, and diagnosis and treatment of thoracic trauma.


Esophageal surgery can be performed with VAT, including esophagomyotomy for achalasia, which can also be performed via the abdomen with laparoscopy and thoracoscopy. Traditionally, the Ivor Lewis esophagectomy was performed through the use of laparotomy and right thoracotomy incisions.


Pericardial surgery can be performed with VAT, including pericardiectomy as treatment for pericardial effusion. Excision of a pericardial cyst and “takedown” of the internal mammary artery for coronary artery bypass grafting can also be performed with VAT.





What are the advantages of video-assisted thoracoscopy over traditional thoracotomy?


VAT requires only small incisions compared with a much larger thoracotomy incision. Surgery via thoracotomy requires cutting across chest wall muscles. Ribs are usually spread to allow intrathoracic access, and sometimes rib resection is required. There is a high incidence of tachyarrhythmias after thoracotomy, which may be related to postoperative pain. Epidural analgesia and intercostal nerve blocks are very effective for postoperative pain management and may lead to a lower incidence of arrhythmias. VAT is followed by less pain and respiratory impairment than open thoracotomy, allowing for earlier discharge to home.





What anesthetic techniques can be used for video-assisted thoracoscopy?


VAT is usually performed under general anesthesia. It is essential to provide excellent lung deflation and maintain oxygenation using one-lung ventilation (OLV). With a thoracotomy incision, surgeons can manually retract the lung if necessary, providing greater access and exposure. Under VAT, however, inadequate lung deflation hampers exposure and surgical access. Less than full lung collapse may necessitate thoracotomy, which is associated with greater morbidity and mortality.


OLV can be achieved with a double-lumen tube (DLT), which allows for lung deflation by egress of gas through the tracheal tube lumen. As soon as the patient is turned to the lateral decubitus position, and the position of the tube is rechecked, the lung to be operated on is deflated, and OLV is instituted.


An alternative to a DLT is a bronchial blocker. The most commonly used blockers are the Arndt (Cook, Bloomington, IN), Cohen (Cook), and Uniblocker (Fuji Systems, Tokyo, Japan). The first bronchial blocker available commercially was the Univent tube. This is a single-lumen silicone tube that has a small separate lumen along the anterior concave wall. The separate lumen contains a small hollow bronchial blocker that can be advanced 10 cm beyond the tip of the Univent tube. Once the blocker has been advanced into the bronchus to be blocked, a brief apneic period allows for partial lung collapse before inflating the blocker’s balloon. If the lung is not allowed to deflate before inflating the blocker balloon, lung deflation is delayed. The blocker’s very narrow tube creates substantial resistance to gas flow, increasing the time for lung collapse. Once the lung is deflated, the blocker balloon is inflated, and ventilation (now of only the unblocked lung) is resumed. If necessary, the blocked lung can be collapsed by aspirating residual gas through the lumen of the blocker shaft.


Historically, the Arndt blocker was developed next. It has a lumen through which a wire loop extends beyond the distal tip. A fiberscope is passed through the loop and guides the blocker into the bronchus to be blocked. Once the blocker is positioned, the wire must be removed. Removal of the wire facilitates deflation of the lung via the blocker lumen and prevents unintentional stapling of the wire by surgeons.


The Cohen blocker is a bronchial blocker with a wheel at the proximal end that, when turned, bends the tip of the blocker. This blocker also has a lumen to allow lung deflation. The blocker of the Univent tube was made available more recently as an independent blocker, known as the Uniblocker. It contains a permanent bend near the tip and can be angled into either bronchus. A fiberscope should be available throughout cases using blockers because there is a greater tendency for blockers to become dislocated compared with DLTs.


VAT may be performed to evaluate or treat pleural disease, such as pneumothorax or pleural effusion. Pleural biopsy and pleurodesis may be planned. In these cases, epidural anesthesia or intercostal blocks are alternatives to general anesthesia. Surgery performed under regional block with spontaneous respiration allows for a pneumothorax when the chest (pleural cavity) is opened.

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Jul 14, 2019 | Posted by in ANESTHESIA | Comments Off on Thoracoscopy
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