The thoracic surgery patient population can present significant challenges to care. In general, thoracic surgery patients are older, most are current or former smokers, they are sicker than the general surgical population, and most have a higher rate of comorbidity. It is not uncommon for these patients to present with underlying chronic lung disease, some form of arteriovascular disease, hypertension, diabetes, and baseline renal insufficiency. Thoracic surgery patients also have diminished physiologic reserve and more limited ability to recover from perioperative complications. They are particularly prone to pulmonary complications, which are very poorly tolerated in this patient group. As a result, thoracic surgery patients, more than any other group, require the services of an intensive care unit (ICU) and its highly trained, specialized staff. This chapter reviews critical-care issues specific to thoracic surgery patients, general issues of managing sepsis and acute respiratory distress syndrome (ARDS), and strategies to avoid the common nosocomial complications of critical care.
Secretion Retention, Atelectasis, Pneumonia
Thoracic surgery patients are at risk of secretion retention and atelectasis. General anesthesia, particularly when accompanied by one-lung ventilation, causes a marked decrease in functional residual capacity, promoting atelectasis. Surgical manipulation of the lung can lead to retained blood and secretions with partial or complete airway obstruction. Gas flow is further hindered by bronchospasm and decreased compliance of the operative lung. Splinting from postoperative pain or, conversely, respiratory depression from opiates or benzodiazepines further limits lung expansion. Patients with preexisting chronic obstructive pulmonary disease (COPD), asthma, bronchitis, or pneumonia will be at greatest risk. Similarly, patients with impaired cough reflexes, including those who have had an airway resection with anastomosis (e.g., sleeve resection), would be expected to have greater difficulty clearing secretions. Over time, retained secretions give rise to hypoxemia and hypercarbia once sufficient functional lung volume has been lost. They also predispose patients to pneumonia.
Prevention of secretion retention and atelectasis requires a systematic, multidisciplinary approach. The duration of general anesthesia should be limited to the minimum time required to complete the procedure. Patients should be extubated immediately whenever possible. Fiberoptic bronchoscopy performed immediately before extubation facilitates the removal of blood and secretions from the proximal airways. Excellent analgesia combined with aggressive early ambulation will promote recruitment of lung volumes and clearance of secretions. Chest physiotherapy further aids this process. Any patient with a preoperative pulmonary infection should undergo aggressive, culture-directed antibiotic therapy during the immediate perioperative period.
Treatment of retained secretions and atelectasis includes aggressive chest physiotherapy and mobilization. Humidified oxygen, nebulized saline, and bronchodilators can help to thin secretions and promote gas flow. Patients with copious thick secretions may benefit from nebulized N-acetylcysteine or dornase (DNAse), with bronchodilator pretreatment to mitigate treatment-induced bronchospasm. Any patient having significant trouble clearing secretions should be evaluated for the possibility of vocal cord dysfunction, which is a known complication of certain thoracic surgical procedures and results in a markedly impaired cough. A small ...