Eugene M. Golts
Complications of thoracic surgery fall into two broad categories: those common to any surgical procedure and those unique to pulmonary resection. This chapter focuses on the latter for which the risk of postoperative complications ranges from 38% for major pulmonary resections to 0% in patients undergoing wedge thoracoscopic resection. Thorough knowledge of the topic should serve as the basis for successful avoidance of complications and complete recovery of the patients.
Most complications can be prevented, or at least attenuated, by comprehensive preoperative preparation and meticulous intraoperative technique. Prevention of complications begins preoperatively. Surgeons should rely on (1) the comprehensive assessment of the patient’s pulmonary functional status; (2) correction, or improvement in the disease states associated with impaired healing; and (3) optimization of the patient’s functional status by pulmonary rehabilitation and smoking cessation.
Preoperative evaluation of pulmonary function is one of the most extensively studied topics for assessing and risk-stratifying postoperative risk among patients undergoing pulmonary resections. Although controversy exists about those cutoff values that convey higher risk, some points are broadly accepted. All patients regardless of age, physical status, or extent of the lesion should have preoperative pulmonary-specific evaluation. Patients are at lower risk of complications and should be able to withstand pulmonary resection including pneumonectomy, if the FEV1 and DLCO are greater than or equal to 60% of predicted. Further testing, including the quantitative V/Q scan and VO2 max testing may be helpful to assess resectability if the FEV1 and DLCO are lower than the above-mentioned cutoff point.
Optimizing nutrition and diminishing and discontinuing immunosuppressive medications can maximize a patient’s healing potential. Patients need to stop smoking, since smoking cessation improves outcomes following surgical procedures. The ratio of actual postoperative to predictive postoperative FEV1, has been shown to be better in patients undergoing perioperative rehabilitation. Pulmonary rehabilitation of several weeks’ duration is advisable, in cases when the timing of the operation is elective.
Despite careful preoperative evaluation and training, postoperative pulmonary complications occur frequently after pulmonary resection in 14.5% to 38% of patients. Atelectasis is common early after surgery and may progress to pneumonia and even respiratory failure if left untreated. Patients commonly present within the first 48 hours after surgery with nonspecific symptoms such as low-grade fever, shortness of breath, tachypnea, and tachycardia. Radiographic evaluation is usually diagnostic. Incidence can be lowered by preoperative smoking cessation and training in the use of incentive spirometry. Postoperatively, aggressive pain management, particularly the use of the regional anesthesia, allows for the maintenance of adequate respiratory volumes. Adequate pain management along with the use of bronchodilators and mucolytics can help with effective secretion clearance. When massive atelectasis is present, fiberoptic bronchoscopy provides rapid and effective evacuation of secretions as well as evaluation for possible anatomic abnormalities of the airways.
Postoperative hemorrhage is relatively uncommon after pulmonary resection, with reported incidences between 2.4% and 8%. Pulmonary vessels, systemic sources such as intercostal vessels, bronchial arteries, and large systemic vessels are all potential sources of bleeding in any operative scenario. Intraoperative compromise of these blood vessels can occur during dissection, or due to a stapler malfunction. Thorough knowledge of the intraparenchymal vascular anatomy and meticulous dissection help to decrease the incidence of these complications. In addition, bleeding from adhesions and vessels in the inferior pulmonary ligament as well as from dissected lymph node beds can create problems in the immediate postoperative period.
Bloody chest tube output of 200 mL/hour for 2 hours postoperatively, and/or hemodynamic instability suggests significant hemorrhage and warrants prompt further investigation. However, one should never rely solely on the chest tube drainage for determination of the amount of bleeding. Blood clots or adjacent pulmonary parenchyma can obstruct and diminish drainage thereby misleading the observer about the severity of the problem. Serial chest radiographs are useful in detecting an incompletely drained hemothorax. In cases where there is a suspicion of bleeding, the chest tube insertion sites should be examined for presence of the bloody drainage around the chest tubes.
Prompt reexploration is warranted if there is (1) failure to achieve hemodynamic stability despite seemingly adequate resuscitation with blood products, (2) continued excessive drainage from chest drains, or (3) a significant undrained hemothorax on the chest radiograph. Coagulopathies should be aggressively corrected, but this action should not delay potentially life-saving surgery.
When bleeding is suspected, the thoracic cavity should be inspected systematically to evaluate all the above-mentioned sources of bleeding. Sudden massive hemorrhage after pulmonary resection is almost always due to a problem with the major vascular stump, such as a slipped ligature, and requires emergency re-do thoracotomy.
Although postoperative pleural effusion is relatively common after pulmonary resection, high chest tube output in the immediate postoperative period should raise the suspicion of postoperative hemorrhage. Determining the hematocrit of the chest tube drainage may be helpful in differentiating bleeding from innocuous “blood tinged” drainage.
Large amounts of chest tube drainage that occur later in the postoperative course may signify development of chylothorax. The incidence is reported to be less than 2%. One should suspect chylothorax when a large amount of milky drainage is present in the chest tubes after lobectomy, or smaller pulmonary resections, or when there is a rapid accumulation of fluid in the postpneumonectomy space. Occasionally, tension chylothorax can develop, which is manifested by respiratory and circulatory compromise. Chylothorax is best diagnosed by testing pleural fluid for chylomicrons. Lymphangiography can sometimes pinpoint an area of the injury. Treatment should be conservative with cessation of all oral intake and initiation of parenteral nutrition. Somatostatin analogues can be added to decrease chyle production. Presence of excessive drainage despite institution of conservative measures signifies the need for the reoperation which is usually successful.
In the absence of chylothorax, or bleeding, a conservative approach to even large volumes of chest tube output is warranted. In many institutions, including University of California, San Diego (UCSD), chest tubes are removed when the drainage decreases to less than 200 mL/day. Other surgeons accept significantly higher rates of pleural drainage. Most small pleural effusions that recur after the removal of the chest drains can be observed safely. Large or symptomatic effusions should be drained by thoracentesis as the first step. Tube thoracostomy should be considered, if fluid reaccumulates after thoracentesis.
Postoperative air leaks occur commonly after pulmonary resection and usually are small and arise from lung parenchyma denuded of a pleural cover. The reported incidence after resections other than pneumonectomy ranges from 7.6% to above 50%. Variability is largely due to differences in the definition of an “air leak.” In general, an air leak that persists for longer than 7 days is considered a complication. There is no single variable that predicts a higher incidence but low FEV1, steroid use, lobectomy, upper lobe resections, and the presence of adhesions are touted as risk factors. The incidence can be lowered by adherence to a meticulous operative technique. Dissection should be localized to fissures whenever possible. Lung parenchyma should be handled gently with atraumatic instruments. Areas of exposed parenchyma, such as windows for the passage of the staplers, should be over-sewn with the fine absorbable suture or covered with pleural or pericardial fat flaps. Although not airtight, these flaps along with parenchymal expansion allow for closure of potential air leaks. Test inflation of the remaining lung to 25 to 30 cm H2
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