Step 2
Preoperative Considerations
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Emphysema is an irreversible and progressive lung disease that results in the enlargement and destruction of terminal air spaces. LVRS is a procedure that removes the most diseased portions of the lung and provides emphysema patients an opportunity for a better quality of life.
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LVRS removes the nonfunctional, hyperinflated lung parenchyma and allows the remaining healthy lung tissue to expand and regain function. LVRS improves lung elasticity and chest-wall mechanics while increasing diaphragm contractility. After volume reduction, ventilation and perfusion in healthy lung tissue increase, allowing for both functional and symptomatic improvements.
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In response to concerns about the safety and effectiveness of LVRS, the National Heart Lung and Blood Institute and the Center for Medicare and Medicaid Services conducted the National Emphysema Treatment Trial (NETT). The study was designed to clarify the short- and long-term risks and benefits of LVRS by comparing medical treatment to LVRS in patients with severe emphysema. The 5-year study concluded that select patient groups experienced improved quality of life and increased exercise capacity after surgery. Patients with primarily upper lobe disease and low exercise capacity are considered preferred candidates for LVRS, and patients with diffuse or non–upper lobe emphysema and high exercise capacity are generally considered poor operative candidates because of their increased operative risk with minimal functional improvement. The only true predictor of operative mortality during LVRS has been shown to be the presence of non–upper lobe emphysema.
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LVRS requires strict patient selection guidelines to minimize morbidity and mortality. Candidates undergo a thorough preoperative evaluation, including chest radiograph, chest computed tomography (CT), echocardiogram, cardiac catheterization, pulmonary function tests, and arterial blood gas measurements.
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Cessation of smoking for a minimum of 6 months and completion of 6 to 10 weeks of preoperative pulmonary rehabilitation are considered absolute requirements before patients are allowed to undergo LVRS.
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Anesthetic considerations for LVRS are based on the goals of rapid emergence from anesthesia and immediate postoperative extubation. Rapid extubation after LVRS minimizes the potential for staple-line air leak secondary to positive-pressure ventilation. Thus, short-acting anesthetic agents along with optimal intraoperative and postoperative pain control are essential to regaining prompt spontaneous ventilation. Furthermore, optimal pain control is achieved through a preoperatively inserted thoracic epidural catheter. LVRS is successfully performed with a double-lumen endotracheal tube and either total intravenous anesthesia or inhalational agents.
Step 3
Operative Steps
1
Incision
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A median sternotomy incision is used to gain adequate exposure to both lung fields for bilateral LVRS. A midline vertical incision begins at the suprasternal notch and extends inferiorly to a position just below the xiphoid process ( Fig. 16-1A ).
Figure 16-1
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Alternatively, sequential muscle-sparing thoracotomies could be done at separate sessions if the disease predominates one hemithorax.
2
Exposure
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While dividing the sternum, ventilation should be discontinued to minimize the incidence of lung tissue injury. Sternal division is accomplished with a sternal saw through the midline of the sternal body and manubrium. This process can occur from either a sternal notch–down or xiphoid-up approach, depending on the surgeon’s preference. Bleeding from the periosteum is controlled using electrocautery. After bleeding is controlled, sternal edges are retracted with a sternal spreader placed low in the incision. Generally, 8 to 10 cm of retraction will provide adequate exposure to complete resection of both the right and left lung (see Fig. 16-1B ).
3
Resection
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Based on preoperative imaging studies (usually CT scan), the worst lung undergoes resection first. Using single-lung ventilation, the anesthesiologist should deflate the lung undergoing resection. On deflation, adhesions should be dissected.
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Bimanual palpation or finger pinch can demonstrate the transition between severely to less severely affected lung tissue. The area of lung that is more severely affected is isolated and held in a gastrointestinal clamp ( Fig. 16-2 ). Using a linear GIA stapler, at least 20% to 30% of lung volume should be excised with a continuous staple line ( Fig. 16-3 ). Almost all of upper lobe can be removed, but diseased tissue may still be present. Multiple techniques are used, but resection generally starts in the front of the upper lobe and progresses straight to the back of the lung. An inverted U -shaped technique has also been popular. Staple lines are buttressed with bovine pericardial strips in an attempt to minimize the severity and incidence of air leak ( Fig. 16-4 ). Using low-volume ventilation, staple lines are examined for leak by filling the pleural cavity with saline ( Fig. 16-5 ) to 10 cm H 2 O for 3 to 5 seconds. The lung is then inflated to 20 cm H 2 O for 3 to 5 seconds. If no bubbles are seen, the chest can then be closed.
