21

Lung volume reduction surgery

Claudio Caviezel and Walter Weder

HISTORY

Chronic obstructive pulmonary disease is a major and wellknown health problem. It was first described as large air spaces in human lung specimens by Ruysch in 1691 ¹ and by Floyer in 1698. ² A few decades later, the first comprehensive clinical and pathological report of a case was published by Watson in 1764. ³ Despite optimal medical therapy and pulmonary rehabilitation, many patients remain disabled and even now lung transplantation is still an option only for a few.

By 1924, Reich had already described the use of pneumoperitoneum in the treatment of pulmonary emphysema due to its effect on the diaphragm. ⁴ His work was followed by Piaggio-Blanco et al. and Carter et al. in 1937 ⁵ and 1950, ⁶ respectively. By restoring the normal diaphragmatic arch with the pneumoperitoneum, they made contraction downward of the flattened muscle possible again. They also could describe a decrease in residual volume (RV) and an increase in vital capacity.

Lung volume reduction surgery (LVRS) was then first described by Brantigan and Mueller in 1957 ⁷ and reintroduced by Cooper et al. in 1995. ⁸

With many observational studies during the 1990s and a large randomized study in 2003 (National Emphysema Treatment Trial [NETT] ⁹ ), LVRS has now been shown to improve lung function, exercise capacity, health status, and even survival in patients with emphysema, and therefore has become an internationally established procedure.

PRINCIPLES AND JUSTIFICATION

LVRS downsizes the hyperinflated lung to a more physiologic size. This makes the diaphragmatic dome move upward and increases the area of muscle apposed to the rib cage. ¹⁰ This effect improves maximal ventilator and exercise capacity by optimizing the match between the size of the lungs and the rib cage. ¹¹ LVRS improves global inspiratory muscle strength and the contribution of the diaphragm to inspiratory pressure generation and tidal volume. ¹² , ¹³ The major effects consist of a reduction in static lung volumes (functional residual capacity and RV), with an associated increase in lung elastic recoil. The latter leads to a reduction in the degree of airflow obstruction and hyperinflation. ¹⁴

These effects are independent from emphysema morphology, and therefore patients with heterogeneous emphysema can benefit from LVRS as well as patients with homogeneous morphology. ¹⁵

Although LVRS has been introduced as a minimal-invasive procedure ¹⁶ and its principles have internationally been established, patient selection is still a key issue and should be performed with a multidisciplinary emphysema board at specialized centers.

PREOPERATIVE ASSESSMENT AND PREPARATION

Despite nicotine abstention and completed pulmonary rehabilitation, there are defined indications for LVRS, with evidence-based probability for benefit.

The NETT showed significant benefit for patients with upper-lobe-predominant heterogeneous emphysema with low exercise capacity. ⁹

As already mentioned, homogeneous emphysema morphology is no contraindication to LVRS, as long as the disadvantage of resected parenchyma contributing to gas exchange is compensated by the beneficiary effect of downsizing the hyperinflated lung. ¹⁵ Symptomatic and large bronchiectasis, recurrent infectious exacerbations, and a daily prednisone intake of more than 20 mg are contraindications for LVRS.

Lung function

LVRS is offered to selected patients with severe obstruction, as defined by forced expiratory volume in 1 second (FEV1) between 20% and 45% of the predicted value, hyperinflation greater than 150%, and residual volume to total lung capacity ratio (RV/TLC) of more than 60%.

The achieved 6-minute walking distance should be between 150 and 450 m.

A diffusing capacity lower than 20% is not a contraindication if FEV1% is greater than 20% in heterogeneous emphysema.

Imaging

The most reliable method of obtaining information on the degree and distribution of emphysema is chest computed tomography (CT) scanning. Lung perfusion scintigraphy has a limited role in prediction of outcome, but it may help to identify target areas for resection in LVRS candidates with homogeneous CT morphology. ¹⁷

Cardiac risk

The left ventricle ejection fraction should be greater than 30%, whereas a mean pulmonary arterial pressure above 35 mmHg, significant arrhythmias, exercise-induced syncope, and myocardial infarction within the last 6 months are contraindications to LVRS. ¹⁸ If peak systolic pulmonary artery pressure is above 45 mmHg on echocardiogram, rightsided heart catheterization is required.

ANESTHESIA

LVRS is typically performed under general anesthesia, with one-lung ventilation established with a double-lumen endotracheal tube. Especially when performed bilaterally, additional epidural analgesia is recommended for a smoother, less eventful postoperative course, due to better ventilation performance (ambulation, coughing, and use of incentive spirometer). Inspiratory pressures must be monitored and minimized in the ventilated lung, especially after the first side has been operated, to prevent rupture of the staple lines.

OPERATION

The operation can be performed as an open or thoracoscopic (video-assisted thoracoscopic surgery [VATS]) procedure and may be done unilaterally or bilaterally or staged bilaterally. The authors prefer one-staged bilateral VATS LVRS in bilateral emphysema.

Stay updated, free articles. Join our Telegram channel

Join