The thoracic surgery patient population can present significant challenges to clinical care. Patients often are older, current or former smokers, and sicker than other surgical populations. 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. They have diminished physiologic reserve and more limited ability to recover from perioperative complications. In particular, they are prone to pulmonary complications, which are very poorly tolerated. As a result, they may require the services of an intensive care unit (ICU) and its highly trained, specialized staff more frequently than other patient populations. This chapter reviews critical care issues specific to thoracic surgery patients, general issues of management related to sepsis and acute respiratory distress syndrome (ARDS), and strategies for avoiding the common nosocomial complications of critical care.
COMMON CRITICAL CARE ISSUES AFTER THORACIC SURGERY
Secretion Retention, Atelectasis, Pneumonia
Thoracic surgery patients are at increased risk of secretion retention and atelectasis. General anesthesia, particularly when accompanied by one lung ventilation (OLV), causes a marked decrease in functional residual capacity (FRC), which promotes 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 airway resection with anastomosis (e.g., sleeve resection), would be expected to have greater difficulty clearing secretions. Secretion retention over time results in both hypoxemia and hypercarbia. It also predisposes the patient to pneumonia.
Preventing secretion retention and atelectasis requires a systematic, multidisciplinary approach. Time under general anesthesia should be limited to the minimum required to complete the procedure. Patients should be extubated immediately whenever possible. Fiberoptic bronchoscopy 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 volume 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 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 their 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 subset of patients may require more ...