Chapter 148 Postthoracotomy Management Eric Monnet, DVM, PhD, DACVS, DECVS KEY POINTS • Postoperative management of the patient after thoracotomy requires intensive monitoring of pulmonary and cardiovascular function. • Optimization of oxygen delivery is the primary goal during the postoperative period. • Hypoxemia, hypotension, and arrhythmias are very common after thoracotomy. • Aggressive pain control to improve comfort and ventilation is essential. INTRODUCTION Thoracotomy is a common surgical procedure performed to manage cardiac conditions, lung pathology, pleural effusion of various origins, esophageal disease, and mediastinal disease. Intercostal thoracotomy and median sternotomy are the most common approaches used in veterinary medicine. Penetration of the pleural space induces tremendous changes in pulmonary and cardiovascular physiology that can impact patient recovery. These patients require intensive monitoring with an emphasis on evaluation of pulmonary function and hemodynamics. PHYSIOLOGIC EFFECTS OF THORACOTOMY Opening the thoracic cavity results in disruption of the subatmospheric pleural pressure. Consequently lung collapse occurs (atelectasis) and venous return is impaired, compromising cardiac output.1-3 Atelectasis Loss of subatmospheric pleural pressure causes atelectasis, which can be further aggravated by manipulation and retraction of the lungs during the surgical procedure. Atelectasis results in hypoxemia because there are regions of ventilation-perfusion mismatch and shunt. Hypoxemia due to atelectasis and shunt will not respond well to oxygen supplementation. Use of positive end-expiratory pressure at the end of the surgery and before the thoracic cavity is closed will help correct the atelectasis and may help relieve postoperative hypoxemia.4 Reduction of Venous Return With the loss of subatmospheric intrapleural pressure, the large intrathoracic veins have a tendency to collapse, which can cause a reduction in venous return and cardiac output. Residual pneumothorax and fluid accumulation during the postoperative period can also contribute to hemodynamic compromise. These effects are aggravated by fluid losses during surgery. Volume loading the patient before surgery with crystalloid or colloid fluids to a central venous pressure of 6 to 7 cm H2O will help prevent the reduction in cardiac output. Volume loading has to be performed with caution in the patient with cardiac disease, and monitoring of central venous pressure is advised to guide this therapy. Hypothermia Opening of the thoracic cavity with a median sternotomy or an intercostal approach results in a significant drop in the patient’s body temperature because of the increase in the surface area exposed to room air. The longer the surgery, the more pronounced the reduction in temperature will be. This effect is even more significant in younger and smaller animals. Hypothermia causes severe cardiovascular, respiratory, electrolyte, acid-base, and coagulation abnormalities. Continuous temperature monitoring and active rewarming techniques are required during both the intraoperative and postoperative periods. POSTOPERATIVE CONSEQUENCES OF THORACOTOMY After thoracotomy, hypoxemia, residual pneumothorax, pleural effusion, and pain need to be corrected to help the patient restore normal pulmonary5 and cardiovascular physiology. Hypoxemia Hypoxemia is a common problem after thoracic surgery. Hypoxemia during the recovery period is primarily a consequence of atelectasis that develops during the procedure. It can be aggravated during the postoperative period by lateral recumbency of the patient and pleural space disease. In lateral recumbency, the dependent lung is collapsed under the weight of the heart and any fluid accumulation. Ventilation is distributed mostly to the nondependent lung, and gravity distributes blood flow to the dependent lung that is not well ventilated. Therefore the ventilation-perfusion mismatch is worsened. It is very important to turn these patients regularly to reduce the ventilation-perfusion mismatch.6 Pleural Space Disease Residual pneumothorax and accumulation of pleural effusion contribute to hypoxemia because they interfere with lung reexpansion. Thoracostomy tube placement is paramount, and chest tube management is an important aspect of postoperative care. Pneumothorax may be a result of incomplete evacuation of the pleural space at the end of the surgical procedure, or it can be secondary to a pulmonary lesion as a result of the surgery or the primary disease process. Mild to moderate pleural effusion is not uncommon following thoracotomy. Fluid is frequently hemorrhagic in nature, and the volume of fluid production will vary with the nature of the procedure. Large volumes of frank blood (confirmed by a fluid packed cell volume equal to or greater than the peripheral packed cell volume) is of concern, and a surgical consultation should be sought. Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Deteriorating Mental Status Hyperthermia and Fever Ventilator-Associated Lung Injury Allergic Airway Disease in Dogs and Cats and Feline Bronchopulmonary Disease Stay updated, free articles. 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Chapter 148 Postthoracotomy Management Eric Monnet, DVM, PhD, DACVS, DECVS KEY POINTS • Postoperative management of the patient after thoracotomy requires intensive monitoring of pulmonary and cardiovascular function. • Optimization of oxygen delivery is the primary goal during the postoperative period. • Hypoxemia, hypotension, and arrhythmias are very common after thoracotomy. • Aggressive pain control to improve comfort and ventilation is essential. INTRODUCTION Thoracotomy is a common surgical procedure performed to manage cardiac conditions, lung pathology, pleural effusion of various origins, esophageal disease, and mediastinal disease. Intercostal thoracotomy and median sternotomy are the most common approaches used in veterinary medicine. Penetration of the pleural space induces tremendous changes in pulmonary and cardiovascular physiology that can impact patient recovery. These patients require intensive monitoring with an emphasis on evaluation of pulmonary function and hemodynamics. PHYSIOLOGIC EFFECTS OF THORACOTOMY Opening the thoracic cavity results in disruption of the subatmospheric pleural pressure. Consequently lung collapse occurs (atelectasis) and venous return is impaired, compromising cardiac output.1-3 Atelectasis Loss of subatmospheric pleural pressure causes atelectasis, which can be further aggravated by manipulation and retraction of the lungs during the surgical procedure. Atelectasis results in hypoxemia because there are regions of ventilation-perfusion mismatch and shunt. Hypoxemia due to atelectasis and shunt will not respond well to oxygen supplementation. Use of positive end-expiratory pressure at the end of the surgery and before the thoracic cavity is closed will help correct the atelectasis and may help relieve postoperative hypoxemia.4 Reduction of Venous Return With the loss of subatmospheric intrapleural pressure, the large intrathoracic veins have a tendency to collapse, which can cause a reduction in venous return and cardiac output. Residual pneumothorax and fluid accumulation during the postoperative period can also contribute to hemodynamic compromise. These effects are aggravated by fluid losses during surgery. Volume loading the patient before surgery with crystalloid or colloid fluids to a central venous pressure of 6 to 7 cm H2O will help prevent the reduction in cardiac output. Volume loading has to be performed with caution in the patient with cardiac disease, and monitoring of central venous pressure is advised to guide this therapy. Hypothermia Opening of the thoracic cavity with a median sternotomy or an intercostal approach results in a significant drop in the patient’s body temperature because of the increase in the surface area exposed to room air. The longer the surgery, the more pronounced the reduction in temperature will be. This effect is even more significant in younger and smaller animals. Hypothermia causes severe cardiovascular, respiratory, electrolyte, acid-base, and coagulation abnormalities. Continuous temperature monitoring and active rewarming techniques are required during both the intraoperative and postoperative periods. POSTOPERATIVE CONSEQUENCES OF THORACOTOMY After thoracotomy, hypoxemia, residual pneumothorax, pleural effusion, and pain need to be corrected to help the patient restore normal pulmonary5 and cardiovascular physiology. Hypoxemia Hypoxemia is a common problem after thoracic surgery. Hypoxemia during the recovery period is primarily a consequence of atelectasis that develops during the procedure. It can be aggravated during the postoperative period by lateral recumbency of the patient and pleural space disease. In lateral recumbency, the dependent lung is collapsed under the weight of the heart and any fluid accumulation. Ventilation is distributed mostly to the nondependent lung, and gravity distributes blood flow to the dependent lung that is not well ventilated. Therefore the ventilation-perfusion mismatch is worsened. It is very important to turn these patients regularly to reduce the ventilation-perfusion mismatch.6 Pleural Space Disease Residual pneumothorax and accumulation of pleural effusion contribute to hypoxemia because they interfere with lung reexpansion. Thoracostomy tube placement is paramount, and chest tube management is an important aspect of postoperative care. Pneumothorax may be a result of incomplete evacuation of the pleural space at the end of the surgical procedure, or it can be secondary to a pulmonary lesion as a result of the surgery or the primary disease process. Mild to moderate pleural effusion is not uncommon following thoracotomy. Fluid is frequently hemorrhagic in nature, and the volume of fluid production will vary with the nature of the procedure. Large volumes of frank blood (confirmed by a fluid packed cell volume equal to or greater than the peripheral packed cell volume) is of concern, and a surgical consultation should be sought. Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Deteriorating Mental Status Hyperthermia and Fever Ventilator-Associated Lung Injury Allergic Airway Disease in Dogs and Cats and Feline Bronchopulmonary Disease Stay updated, free articles. 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