Lung Volume Reduction Surgery for Emphysema PDF

PREFACE

In our lifetimes in medicine, we have witnessed the discovery of treatments for many devastating diseases that allow their sufferers to lead normal, productive lives. For emphysema, however, such effective treatment has remained elusive. In its advanced stages, patients often become imprisoned by their dyspnea. Their seasons are marked by hospitalizations instead of holidays. Their excursions are limited to the radius of an oxygen tube or the capacity of a tank. The simplest exertions induce terrifying symptoms. As clinicians, we have often felt helpless or useless, with little to offer except sympathy.

Little wonder, then, that the rediscovery of lung volume reduction surgery (LVRS) has excited patients and physicians alike. The best of our previous therapy could only slow the progression of emphysema or prolong a life of dyspnea. For the first time, we can offer a treatment with the potential to substantially improve lung function. For patients, this is like an opportunity to turn back time and to be young again. For physicians, it is an opportunity to heal and to feel the satisfaction associated with the treatment of so many other diseases.

Careful perusal of the medical therapy of emphysema reveals some lessons that foreshadowed LVRS. In the 1930s, abdominal compression belts were reported to relieve dyspnea in patients with emphysema. The stimulus for these devices was the observation that emphysema patients often lean forward when they breathe. Today, the common explanation is that this allows more effective use of respiratory accessory muscles. However, it was hypothesized at the time that this was an attempt to increase abdominal pressure and thereby restore curvature to the diaphragm. Measurements of vital capacity after wearing the abdominal compression belt showed increases of nearly 40%, which was highly significant in a group of 25 patients (1).

In the 1950s, there were several reports of relief of dyspnea by pneumoperitoneum in patients with emphysema. Like abdominal belts, this was an attempt to restore diaphragmatic curvature. Case reports described resurrection from near moribund states (2). Physiological measurements in the roughly 50% of patients with symptomatic relief in case series demonstrated decreased total lung capacity, still greater decreases in residual volume, and a corresponding increase in vital capacity (3, 4). These are precisely the changes described after successful LVRS.

Restoration of diaphragmatic curvature at end-expiration would not, however, be expected to cause any of these changes. In contrast, we speculate that these interventions induced atelectasis, reducing lung volume in a reversible and noninvasive way. It is likely that the most normal lung regions were the first to become atelectatic because they emptied first, so effects on gas exchange may have been deleterious. However, these concepts are receiving new attention as several groups explore noninvasive methods to achieve the benefits of surgical lung volume reduction (5, 6).

Lung volume reduction surgery holds great temptation for both the healers of and sufferers from emphysema. Its lure can be as compelling as breath itself. However, temptation must be tempered by commitment to proceed rationally. Medical history is littered with examples in which desperate or ill-conceived treatments have led to harm. For therapy of emphysema, discarded surgical interventions date back almost to the birth of thoracic surgery. Reasoning that the lungs had grown too large for the chest, costochondrectomy or transverse sternotomy was attempted to provide more room. Conversely, hypothesizing that the chest had grown too large led to attempts to shrink it with thoracoplasty. The theory that emphysema resulted from ischemia to alveolar walls inspired pleurodesis to increase pleural blood flow. Phrenectomy was performed, based on the notion that overvigorous inspiration was ripping alveolar walls. This notion sounds ill-conceived today. However, it is completely consistent with the upper-lobe predominance of emphysema, attributed years later to essentially the same mechanism: excessive stress. Hilar denervation was attempted to decrease bronchoconstriction or mucus hypersecretion that was thought to be mediated by the parasympathetic nervous system. Whole-lung radiation was used to increase elastic recoil by inducing fibrosis, and patients often reported relief (7). These treatments were all based on careful observation and reasoned physiological hypotheses. None is performed today. Their history teaches us just how desperate patients, their families, and often their physicians can be, and is a sober reminder to proceed cautiously. The lessons of the past remind us to evaluate objectively and critically this major surgical procedure.

Similar reminders abound in other areas of medicine. Dramatic relief of angina pectoris was reported following internal mammary artery ligation, which is now known to be without physiological benefit. Blinded, controlled trials of this treatment, which included a sham surgical arm, finally demonstrated the astounding power of the placebo effect (8, 9). Even truly effective, physiologically sound treatments such as coronary artery bypass grafting or organ transplantation matured only after long periods over which techniques and indications were refined. A few visionaries lit the way, but hundreds of others took up the torch, carefully reviewed retrospective data, collected prospective series, executed randomized trials, and revised techniques in an iterative process that continues today. This process is just beginning in LVRS. The procedure shows great promise, but its final place in the pantheon of emphysema therapies is unknown. It has been widely promoted, occasionally denounced, and generated as much confusion as enthusiasm.

Lung Volume Reduction Surgery for Emphysema is an attempt to collect the current state of knowledge about this procedure into one reference but it can neither answer all questions nor stem all controversy. The field is hampered by a lack of data that no amount of argument can overcome. We have, however, learned much about this operation in the few years that it has been widely performed, and LVRS has provided new insight into the nature of emphysema itself. To organize and interpret these new findings, we have assembled a group of world leaders in LVRS and emphysema. We have asked them to describe what is known, what is believed, and what is hoped for, and to distinguish clearly among the three. We hope that this book will be both stimulating and useful to the internists, pulmonologists, anesthesiologists, surgeons, nurses, and therapists who care for these patients, and to the inner scientist perched on each of their shoulders. We wish to thank our mentors, patients, and families for the inspiration they provide daily, and for keeping us, with only partial success, humble. We also note with pride and sadness the chapter on the physiology of emphysema written by our late colleague Joseph Rodarte. Dr. Rodarte was a friend and teacher to us as he was to hundreds of others, and his death is a great loss to science and to humankind.