Discuss potential post-thoracotomy complications

Discuss potential post-thoracotomy complications.

Respiratory failure may occur following thoracic surgery. Atelectasis is the most common cause for a decrease in oxygenation postoperatively, and respiratory failure is the most common serious complication. Patients presenting for thoracic surgery typically have a history of cigarette smoking and preoperative lung disease, which is a risk factor.

Respiratory failure may be due to pulmonary edema, which can be cardiogenic or noncardiogenic in origin. Re-expansion pulmonary edema is usually unilateral, and may occur after removal of large amounts of fluid or air from the pleural space. The etiology may be related to increased capillary permeability occurring with atelectasis in conjunction with rapid re-expansion.

There is a high incidence of dysrhythmias following tho-racic surgery. Sinus tachycardia, atrial fibrillation, and supraventricular tachycardia are the most common dysrhyth-mias. Possible etiologies include cardiac manipulation, right atrial distention from pulmonary hypertension, or hypox-emia, especially in the setting of pre-existing cardiac disease.

Right heart failure may occur following pneumonectomy. This can be due to an increase in right ventricular afterload and/or decrease in right ventricular contractility. If the pul-monary vasculature is normal and distensible, the remaining lung can accommodate all of the pulmonary blood flow, with only a small increase in pulmonary artery pressure. If there is a large increase in pressure, the right ventricle is prone to fail-ure due to its relatively thin wall. Traditional treatment includes vasodilation and inotropic support, including cate-cholamines and phosphodiesterase inhibitors. Nitric oxide is beneficial in treating pulmonary hypertension following pneumonectomy. Nitric oxide does not have a systemic effect.

Cardiac herniation is a rare complication, but may occur following intrapericardial pneumonectomy. The heart may herniate through the pericardial defect into the empty thoracic cavity. Torsion may then impede blood flow and lead to cardiovascular collapse. Torsion usually occurs if there is a right intrapericardial pneumonectomy. The torsion can obstruct the superior vena cava and produce a superior vena cava syndrome. Left-sided cardiac hernia-tion may occur following a left intrapericardial pneu-monectomy. The apex of the heart herniates through the defect, and the portion of the ventricle that herniates becomes edematous. This may result in obstruction to flow and ischemia, which can lead to infarction and cardiac arrest.

Following an intrapericardial pneumonectomy, the patient should not be positioned on the side with the operative side dependent. Gravity may pull the heart down through the pericardial defect into the empty hemithorax. If cardiac herniation does occur, the patient should be positioned in the lateral position, with the operative side nondependent, which may improve cardiac function. Surgical treatment is almost always necessary.

Significant postoperative bleeding may occur and is usually diagnosed by quantifying the collection of blood from drainage tubes. Blood loss continuing at a rate greater than 100 mL/h may warrant surgical re-exploration. If bleeding is significant, the blood from the tubes may have a hematocrit above 20%. It is possible for there to be sig-nificant blood loss in the absence of drainage of blood from the tubes, if the tubes are clotted. In that case, a ten-sion hemothorax or pneumothorax can occur.

Lobar torsion may occur following thoracic surgery. The chest radiograph may reveal a lobe that is collapsed or consolidated and in an abnormal position. Immediate sur-gical correction is necessary. Following rotation of the lobe or lung into the normal position, serosanguinous fluid may then drain into the nonaffected lung portion, which needs to be suctioned. A late diagnosis may result in further lung resection and may lead to death.

There may be an air leak following lung resection. This can be detected by air bubbles in the water seal chamber of the chest tube drainage. A bronchopleural fistula (BPF) is a serious complication which can develop in the first 2 weeks after surgery or, less commonly, may be delayed. A chest tube is necessary to provide adequate drainage, and may also facilitate closure of the BPF. The majority of patients with BPF need surgery during which a double-lumen tube and lung isolation are required.

Neural injuries may occur following thoracic surgery. These can result from positioning, or surgical trauma. There can be brachial plexus or ulnar nerve injury from compression due to positioning. Surgery can lead to trauma to the intercostal, long thoracic, or thoracodorsal nerves. Most nerve injuries due to positioning typically resolve, but may take 3–6 months for complete resolution.