For the anesthesiologist, lung volume reduction surgery is a challenging procedure and the tailoring of the anesthetic management requires profound knowledge of the pathophysiology of COPD, ventilatory mechanics in awake and anesthetized COPD patients and pain management in thoracic surgery. A variety of different approaches to LVRS have been proposed; these include median sternotomy, thoracosternotomy, standard thoracotomy and video-assisted thoracosopic surgery (VATS) with both unilateral and bilateral approaches.
Potential candidates for LVRS undergo extensive evaluation in order to mitigate perioperative risks and contain perioperative complications. Important physiologic variables when evaluating a patient are FEV1 and DLCO, the RV/TLC ratio, PCO2 and oxygen use. The ideal operative candidate should have an FEV1 of 20% to 35% predicted without very severe reductions in DLCO (<20% predicted), a RV/TLV more than 0.67, a PCO2 less than 45 mm Hg, and no or low level supplemental oxygen use.
Intraoperative management is centered on minimizing further insult due to induction of general anesthesia and institution of positive pressure ventilation. Ventilatory management during one-lung ventilation (OLV) aims to balance competitive priorities: maintaining adequate oxygenation, minimizing intrinsic PEEP, minimizing barotrauma and maximizing CO2 elimination.
Intraoperative hypotension may be due to sympathetic blockade from local anesthetics administered through the thoracic epidural catheter, vasodilatory effects of the induction agents, hypovolemia, myocardial ischemia, dynamic hyperinflation or infrequent but possible catastrophic causes such as tension pneumothorax.
Tracheal extubation immediately after surgery is an important aim after LVRS in order to minimize the risk of developing or exacerbating an air leak and avoid the deleterious hemodynamic effects of positive pressure ventilation. Adequate pain control achieved with minimal respiratory depression in LVRS patients is vital to the success of the surgical procedure. Inadequate pain control will result in splinting, poor respiratory effort, and inability to cough and clear secretions leading to airway closure, atelectasis, shunting and hypoxemia.
The patient is a 68-year-old male with advanced emphysema who is scheduled for lung volume reduction surgery (LVRS). He is an ex-smoker who has recently undergone preoperative pulmonary rehabilitation. He has concurrent coronary artery disease and hypertension. Medications include aspirin, valsartan and lovastatin.
Vital signs: BP 140/70, HR 72, and room air oxygen saturation 91%.
Laboratory examination is notable for blood urea nitrogen of 30 mg/dL and creatinine of 1.9 mg/dL. Pulmonary function tests reveal a FEV1 of 0.9 L (30% predicted), FVC of 3.6 L (50% predicted), TLC 7.1L (110% predicted) and DLCO 22% predicted.
Chronic obstructive pulmonary disease (COPD) is characterized by progressive and largely irreversible airflow limitation caused primarily by exposure to tobacco smoke, and less commonly by other noxious stimuli or by alpha1-antitrypsin deficiency. COPD is one of the leading causes of death and disability worldwide. It is expected that by the year 2020, COPD will become the third leading cause of death worldwide.1
The main goals of therapy in COPD patients are focused on ...